1
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Kim H, Kang S, Go GW. Exploring the multifaceted role of ginkgolides and bilobalide from Ginkgo biloba in mitigating metabolic disorders. Food Sci Biotechnol 2024; 33:2903-2917. [PMID: 39234277 PMCID: PMC11370650 DOI: 10.1007/s10068-024-01656-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 06/08/2024] [Accepted: 07/01/2024] [Indexed: 09/06/2024] Open
Abstract
The ancient Ginkgo biloba tree grows across various regions, with distinctive leaves emitting a unique fragrance. Its extract contains flavonoids, organic acids, and terpenoids. Ginkgolide and bilobalide, which are G. biloba leaf extracts, offer diverse pharmaceutical benefits, including antioxidant, anti-inflammatory, and neuroprotective properties. The antioxidant and anti-inflammatory properties of these compounds are crucial for mitigating neurodegeneration, particularly in diseases such as Alzheimer's disease. Additionally, their effectiveness in countering oxidative stress and inflammation highlights their potential to prevent cardiovascular ailments. This study also suggests that these compounds have a promising impact on lipid metabolism, suggesting their significance in addressing obesity-related metabolic disorders. In conclusion, ginkgolides and bilobalide exhibit promising effects in sustaining the integrity of the nervous and endocrine systems, along with the modulation of lipid metabolism. The diverse health benefits suggest that these compounds could serve as promising therapeutic interventions for various conditions, including neurological, cardiovascular, and metabolic diseases.
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Affiliation(s)
- Hayoon Kim
- Department of Food and Nutrition, Hanyang University, Seoul, 04763 Republic of Korea
| | - Sumin Kang
- Department of Food and Nutrition, Hanyang University, Seoul, 04763 Republic of Korea
| | - Gwang-woong Go
- Department of Food and Nutrition, Hanyang University, Seoul, 04763 Republic of Korea
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2
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Jiang X, He X, Wong J, Scheeff S, Hau SCK, Wong TH, Qin Y, Fan CH, Ma B, Chung NL, Huang J, Zhao J, Yan Y, Xiao M, Song X, Hui TKC, Zuo Z, Wu WKK, Ko H, Chow KHM, Ng BWL. Lactone-to-Lactam Editing Alters the Pharmacology of Bilobalide. JACS AU 2024; 4:3537-3546. [PMID: 39328759 PMCID: PMC11423332 DOI: 10.1021/jacsau.4c00416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/27/2024] [Accepted: 07/01/2024] [Indexed: 09/28/2024]
Abstract
Precise transformations of natural products (NPs) can fine-tune their physicochemical properties while preserving inherently complex and evolutionarily optimized parent scaffolds. Here, we report an unprecedented lactone-to-lactam transformation on bilobalide, thus improving its stability and paving the way for biological exploration of previously inaccessible chemical space that is highly representative of the parent structure. This late-stage molecular editing of bilobalide enables facile access to a unique library of lactam analogues with altered pharmacology. Through phenotypic screening, we identify BB10 as a hit compound with unexpected inhibition of ferroptotic cell death. We further reveal that BB10 suppresses ferroptosis by restoring the expression of glutathione peroxidase 4 (GPX4) in brain cells. This study highlights that even subtle changes on NP scaffolds can confer new pharmacological properties, inspiring the exploration of simple yet critical transformations on complex NPs.
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Affiliation(s)
- Xiaoding Jiang
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Xu He
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Jonathan Wong
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Stephan Scheeff
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Sam Chun-Kit Hau
- Department
of Chemistry, Faculty of Science, The Chinese
University of Hong Kong, Hong Kong SAR, China
| | - Tak Hin Wong
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Yao Qin
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Chi Hang Fan
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Bowen Ma
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Ngai Lam Chung
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Department
of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Junzhe Huang
- Division
of Neurology, Department of Medicine and Therapeutics, Margaret K.L.
Cheung Research Centre for Management of Parkinsonism, Faculty of
Medicine, The Chinese University of Hong
Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Jiajia Zhao
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Yu Yan
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Min Xiao
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Xueqin Song
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Tony K. C. Hui
- Primemax
Biotech Ltd., Wayson
Commercial House, 68-70 Lockhard Road, Wan Chai, Hong Kong SAR, China
| | - Zhong Zuo
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - William Ka-Kei Wu
- Department
of Anaesthesia and Intensive Care and Peter Hung Pain Research Institute, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Li
Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Ho Ko
- Division
of Neurology, Department of Medicine and Therapeutics, Margaret K.L.
Cheung Research Centre for Management of Parkinsonism, Faculty of
Medicine, The Chinese University of Hong
Kong, Shatin, New Territories, Hong Kong SAR, China
- Li
Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Peter
Hung Pain Research Institute, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Gerald Choa
Neuroscience Institute, The Chinese University
of Hong Kong, Hong Kong SAR, China
| | - Kim Hei-Man Chow
- School
of Life Sciences, Faculty of Science, The
Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Gerald Choa
Neuroscience Institute, The Chinese University
of Hong Kong, Hong Kong SAR, China
| | - Billy Wai-Lung Ng
- School
of Pharmacy, Faculty of Medicine, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Li
Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- Peter
Hung Pain Research Institute, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
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3
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Bundy J, Shaw J, Hammel M, Nguyen J, Robbins C, Mercier I, Suryanarayanan A. Role of β3 subunit of the GABA type A receptor in triple negative breast cancer proliferation, migration, and cell cycle progression. Cell Cycle 2024; 23:448-465. [PMID: 38623967 PMCID: PMC11174043 DOI: 10.1080/15384101.2024.2340912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/29/2024] [Indexed: 04/17/2024] Open
Abstract
Triple negative breast cancer (TNBC) is known for its heterogeneous nature and aggressive onset. The unresponsiveness to hormone therapies and immunotherapy and the toxicity of chemotherapeutics account for the limited treatment options for TNBC. Ion channels have emerged as possible therapeutic candidates for cancer therapy, but little is known about how ligand gated ion channels, specifically, GABA type A ligand-gated ion channel receptors (GABAAR), affect cancer pathogenesis. Our results show that the GABAA β3 subunit is expressed at higher levels in TNBC cell lines than non-tumorigenic cells, therefore contributing to the idea that limiting the GABAAR via knockdown of the GABAA β3 subunit is a potential strategy for decreasing the proliferation and migration of TNBC cells. We employed pharmacological and genetic approaches to investigate the role of the GABAA β3 subunit in TNBC proliferation, migration, and cell cycle progression. The results suggest that pharmacological antagonism or genetic knockdown of GABAA β3 subunit decreases TNBC proliferation and migration. In addition, GABAA β3 subunit knockdown causes cell cycle arrest in TNBC cell lines via decreased cyclin D1 and increased p21 expression. Our findings suggest that membrane bound GABAA receptors containing the β3 subunit can be further developed as a potential novel target for the treatment of TNBC.
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Affiliation(s)
- J Bundy
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - J Shaw
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - M Hammel
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - J Nguyen
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - C Robbins
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - I Mercier
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
| | - A Suryanarayanan
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Pharmacology and Toxicology Center (PTC), Philadelphia, PA, USA
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Tong G, Griffin S, Sader A, Crowell AB, Beavers K, Watson J, Buchan Z, Chen S, Shenvi RA. C5 methylation confers accessibility, stability and selectivity to picrotoxinin. Nat Commun 2023; 14:8308. [PMID: 38097583 PMCID: PMC10721898 DOI: 10.1038/s41467-023-44030-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
Minor changes to complex structures can exert major influences on synthesis strategy and functional properties. Here we explore two parallel series of picrotoxinin (PXN, 1) analogs and identify leads with selectivity between mammalian and insect ion channels. These are the first SAR studies of PXN despite its >100-year history and are made possible by advances in total synthesis. We observe a remarkable stabilizing effect of a C5 methyl, which completely blocks C15 alcoholysis via destabilization of an intermediate twist-boat conformer; suppression of this secondary hydrolysis pathway increases half-life in plasma. C5 methylation also decreases potency against vertebrate ion channels (γ-Aminobutyric acid type A (GABAA) receptors) but maintains or increases antagonism of homologous invertebrate GABA-gated chloride channels (resistance to dieldrin (RDL) receptors). Optimal 5MePXN analogs appear to change the PXN binding pose within GABAARs by disruption of a hydrogen bond network. These discoveries were made possible by the lower synthetic burden of 5MePXN (2) and were illuminated by the parallel analog series, which allowed characterization of the role of the synthetically simplifying C5 methyl in channel selectivity. These are the first SAR studies to identify changes to PXN that increase the GABAA-RDL selectivity index.
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Affiliation(s)
- Guanghu Tong
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Samantha Griffin
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Avery Sader
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Anna B Crowell
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland Street, Oberlin, Ohio, 44074, USA
| | - Ken Beavers
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Jerry Watson
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Zachary Buchan
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Shuming Chen
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland Street, Oberlin, Ohio, 44074, USA.
| | - Ryan A Shenvi
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA.
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Xu B, Bai L, Chen L, Tong R, Feng Y, Shi J. Terpenoid natural products exert neuroprotection via the PI3K/Akt pathway. Front Pharmacol 2022; 13:1036506. [PMCID: PMC9606746 DOI: 10.3389/fphar.2022.1036506] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 09/26/2022] [Indexed: 11/13/2022] Open
Abstract
PI3K/Akt, an essential signaling pathway widely present in cells, has been shown to be relevant to neurological disorders. As an important class of natural products, terpenoids exist in large numbers and have diverse backbones, so they have a great chance to be identified as neuroprotective agents. In this review, we described and summarized recent research for a range of terpenoid natural products associated with the PI3K/Akt pathway by classifying their basic chemical structures of the terpenes, identified by electronic searches on PubMed, Web of Science for research, and Google Scholar websites. Only articles published in English were included. Our discussion here concerned 16 natural terpenoids and their mechanisms of action, the associated diseases, and the methods of experimentation used. We also reviewed the discovery of their chemical structures and their derivatives, and some compounds have been concluded for their structure–activity relationships (SAR). As a result, terpenoids are excellent candidates for research as natural neuroprotective agents, and our content will provide a stepping stone for further research into these natural products. It may be possible for more terpenoids to serve as neuroprotective agents in the future.
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Affiliation(s)
- Bingyao Xu
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Lan Bai
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- The State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Lu Chen
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Rongsheng Tong
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- The State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- *Correspondence: Rongsheng Tong, ; Yibin Feng, ; Jianyou Shi,
| | - Yibin Feng
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- *Correspondence: Rongsheng Tong, ; Yibin Feng, ; Jianyou Shi,
| | - Jianyou Shi
- Personalized Drug Therapy Key Laboratory of Sichuan Province, Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China
- The State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- *Correspondence: Rongsheng Tong, ; Yibin Feng, ; Jianyou Shi,
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6
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Ohtawa M. [Comprehensive Studies on the Synthetic Organic Chemistry of Unique Bioactive Natural Products; Total Synthesis, Drug Discovery, and Development of New Reactions]. YAKUGAKU ZASSHI 2022; 142:1067-1075. [PMID: 36184441 DOI: 10.1248/yakushi.22-00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Research on natural product chemistry via organic chemistry ranges from isolation and structural elucidation to total synthesis, drug discovery, and chemical biology. Discoveries in organic chemistry, such as novel reactions and synthetic strategies, are enabled by the studies of total synthesis. Thus, organic (synthetic) chemistry and natural product chemistry are correlated. We conducted comprehensive studies, including structure-activity relationship, drug discovery, and total synthesis studies, on the synthetic organic chemistry of natural products with unique biological activities and the development of novel reactions discovered through these products. This review describes the total synthesis of simpotentin, a novel potentiator of amphotericin B, and the development of the novel lactonization reactions of homopropargyl alcohols via intramolecular ketene trapping.
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Norris EJ, Chen R, Li Z, Geldenhuys W, Bloomquist JR, Swale DR. Mode of action and toxicological effects of the sesquiterpenoid, nootkatone, in insects. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 183:105085. [PMID: 35430075 DOI: 10.1016/j.pestbp.2022.105085] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Nootkatone, a sesquiterpenoid isolated from Alaskan yellow cedar (Cupressus nootkatensis), is known to possess insect repellent and acaricidal properties and has recently been registered for commercial use by the Environmental Protection Agency. Previous studies failed to elucidate the mechanism of action of nootkatone, but we found a molecular overlay of picrotoxinin and nootkatone indicated a high degree of structural and electrostatic similarity. We therefore tested the hypothesis that nootkatone was a GABA-gated chloride channel antagonist, similar to picrotoxinin. The KD50 and LD50 of nootkatone on the insecticide-susceptible strain of Drosophila melanogaster (CSOR) showed resistance ratios of 8 and 11, respectively, compared to the cyclodiene-resistant strain of RDL1675, indicating significant cross-resistance. Nootkatone reversed GABA-mediated block of the larval CSOR central nervous system; nerve firing of 78 ± 17% of baseline in the CSOR strain was significantly different from 24 ± 11% of baseline firing in the RDL1675 strain (p = 0.035). This finding indicated that the resistance was expressed within the nervous system. Patch clamp recordings on D. melanogaster central neurons mirrored extracellular recordings where nootkatone inhibited GABA-stimulated currents by 44 ± 9% at 100 μM, whereas chloride current was inhibited 4.5-fold less at 100 μM in RDL1675. Taken together, these data suggest nootkatone toxicity in D. melanogaster is mediated through GABA receptor antagonism.
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Affiliation(s)
- Edmund J Norris
- Emerging Pathogens Institute, Entomology and Nematology Department, 2055 Mowry Road, University of Florida, Gainesville, FL 32610-0009, USA; USDA/ARS Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32610-0009, USA
| | - Rui Chen
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA
| | - Zhilin Li
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA
| | - Werner Geldenhuys
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
| | - Jeffrey R Bloomquist
- Emerging Pathogens Institute, Entomology and Nematology Department, 2055 Mowry Road, University of Florida, Gainesville, FL 32610-0009, USA
| | - Daniel R Swale
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA.
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Gedikli Ö, Akca M, Yildirim M. Electroencephalographic investigation of the effects of Ginkgo biloba on spike-wave discharges in rats with genetic absence epilepsy. Epilepsy Behav 2021; 122:108165. [PMID: 34343959 DOI: 10.1016/j.yebeh.2021.108165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/31/2021] [Accepted: 06/08/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE EGb 761, a plant extract obtained from the leaves of the Ginkgo biloba tree, is widely used in modern medicine and traditional medicine applications in the treatment of many diseases. However, in some clinical case reports, it has been suggested that G. biloba causes epileptic seizures. A limited number of experimental animal studies related to the effects of G. biloba on epileptic seizures do not provide sufficient information on the solution of a serious clinical problem with contrasting findings. We aimed to investigate the effects of EGb 761 administered in different doses to adult male Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats which is the genetic animal model of absence epilepsy, on absence seizures using in vivo electrophysiological method. In addition, the effects of EGb 761 doses on locomotor behavior of WAG/Rij rats were evaluated with open-field and rotarod behavioral tests. METHODS 50, 100, 200, and 400 mg/kg doses of EGb 761 were administered to male WAG/Rij rats with implanted EEG electrodes by oral gavage for 28 days. Evaluation of absence seizures was performed on spike-wave discharges (SWDs) in EEG recorded for 4 h each week. The number of SWDs, the total duration of SWDs, and the mean duration of SWD were determined for the analysis. RESULTS In the group treated with 400 mg/kg EGb 761, the number of SWDs and the mean duration of SWD at the 1st and 7th doses and the total duration of SWDs at the 1st, 7th and 14th doses were significantly increased (p < 0.05). In all experimental groups treated with EGb 761 doses, there was no significant change in locomotor activity in the open-field and the rotarod tests. CONCLUSION Ginkgo biloba extract EGb 761 increased the epileptic SWD parameters of WAG/Rij rats at high doses (400 mg/kg), causing a pro-epileptic effect on absence seizures. It should be noted that in patients with epilepsy and in high-dose applications, G. biloba extract EGb 761 may lead to an increase in neuronal excitability.
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Affiliation(s)
- Öznur Gedikli
- Department of Physiology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey.
| | - Metehan Akca
- Electroneurophysiology Program, Hamidiye Vocational School of Health Services, University of Health Sciences, Istanbul, Turkey
| | - Mehmet Yildirim
- Department of Physiology, Hamidiye Faculty of Medicine, University of Health Sciences, Istanbul, Turkey
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9
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Janzen D, Slavik B, Zehe M, Sotriffer C, Loos HM, Buettner A, Villmann C. Sesquiterpenes and sesquiterpenoids harbor modulatory allosteric potential and affect inhibitory GABA A receptor function in vitro. J Neurochem 2021; 159:101-115. [PMID: 34263932 DOI: 10.1111/jnc.15469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/11/2021] [Accepted: 07/07/2021] [Indexed: 11/29/2022]
Abstract
Naturally occurring compounds such as sesquiterpenes and sesquiterpenoids (SQTs) have been shown to modulate GABAA receptors (GABAA Rs). In this study, the modulatory potential of 11 SQTs at GABAA Rs was analyzed to characterize their potential neurotropic activity. Transfected HEK293 cells and primary hippocampal neurons were functionally investigated using electrophysiological whole-cell recordings. Significantly different effects of β-caryophyllene and α-humulene, as well as their respective derivatives β-caryolanol and humulol, were observed in the HEK293 cell system. In neurons, the concomitant presence of phasic and tonic GABAA R configurations accounts for differences in receptor modulation by SQTs. The in vivo presence of the γ2 and δ subunits is important for SQT modulation. While phasic GABAA receptors in hippocampal neurons exhibited significantly altered GABA-evoked current amplitudes in the presence of humulol and guaiol, negative allosteric potential at recombinantly expressed α1 β2 γ2 receptors was only verified for humolol. Modeling and docking studies provided support for the binding of SQTs to the neurosteroid-binding site of the GABAA R localized between transmembrane segments 1 and 3 at the (+ α)-(- α) interface. In sum, differences in the modulation of GABAA R isoforms between SQTs were identified. Another finding is that our results provide an indication that nutritional digestion affects the neurotropic potential of natural compounds.
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Affiliation(s)
- Dieter Janzen
- Institute for Clinical Neurobiology, University Hospital, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Benedikt Slavik
- Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Markus Zehe
- Institute of Pharmacy and Food Chemistry, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Christoph Sotriffer
- Institute of Pharmacy and Food Chemistry, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Helene M Loos
- Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany
| | - Andrea Buettner
- Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany
| | - Carmen Villmann
- Institute for Clinical Neurobiology, University Hospital, Julius-Maximilians-University Würzburg, Würzburg, Germany
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10
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Al-Awthan YS, Rauf A, Rashid U, Bawazeer S, Naz S, Bahattab O, Bawazeer S, Muhammad N, Waggas DS, Batiha GES, Shariati MA, Derkho M, Suleria HAR. Sedative-hypnotic effect and in silico study of dinaphthodiospyrols isolated from Diospyros lotus Linn. Biomed Pharmacother 2021; 140:111745. [PMID: 34020246 DOI: 10.1016/j.biopha.2021.111745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/08/2021] [Accepted: 05/13/2021] [Indexed: 10/21/2022] Open
Abstract
Traditionally, Diospyros lotus Linn is used for insomnia and other associated disorders. Insomnia is a worldwide disorder with different etiology which is treated with different synthetic medicine associated with addiction. Natural products are generally devoid of such addition with good efficacy. Current research was conducted to evaluate the sedative and hypnotic effects of dimeric naphthoquinones such as dinaphthodiospyrol A (1), dinaphthodiospyrol B (2), dinaphthodiospyrol C (3), dinaphthodiospyrol D (4), dinaphthodiospyrol E (5) and dinaphthodiospyrol F (6) isolated from the chloroform fractions of D. lotus. The sedative and hypnotic effects at the dose of 5 and 10 mg/kg (each compound) were assessed through open field and phenobarbital induced sleep test, respectively. In the case of open field test the administration of tested compounds significantly hindered the movement of animals, while in case of hypnotic effect the tested samples significantly improved the onset and duration of sleep as compared to control. The overall effects were in a dose dependent manner. The compounds were also assessed for acute toxicity, but no toxicity was observed. In this regard, our research triumphantly announced the strong chemical base for the folkloric values of the plant with their fringe benefits and implemented a platform for further aspects of mechanistic and clinical studies. A possible mechanism of in vivo inhibition was studied by using docking simulations on GABA receptors. Binding orientations and types of interactions revealed that a possible mechanism behind these pharmacological actions might be interaction with GABA receptors.
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Affiliation(s)
- Yahya S Al-Awthan
- Department of Biology, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia; Department of Biology, Faculty of Science, Ibb University, Ibb, Yemen
| | - Abdur Rauf
- Department of Chemistry, University of Swabi, Swabi, Anbar 23430, Khyber Pakhtunkhwa (KP), Pakistan.
| | - Umer Rashid
- Department of Chemistry, COMSATS University Islamabad, Islamabad 22060, Pakistan
| | - Sami Bawazeer
- Pharmacognosy Department, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Saima Naz
- Department of Biotechnology, Woman University Mardan, Khyber Pakhtunkhwa, Pakistan
| | - Omar Bahattab
- Department of Biology, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia
| | - Saud Bawazeer
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Umm Al-Qura University, P.O. Box 42, Makkah, Saudi Arabia
| | - Naveed Muhammad
- Department of Pharmacy, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Pakistan
| | - Dania Saad Waggas
- Department of Pharmacology, Fakeeh College for Medical Sciences, Jeddah, Saudi Arabia
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, El-Beheira, Egypt
| | - Mohammad Ali Shariati
- K.G. Razumovsky Moscow State University of Technologies and Management (the First Cossack University), Moscow, Russian Federation
| | - Marina Derkho
- South-Ural State Agrarian University, Troitsk, Russian Federation
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11
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Arya A, Chahal R, Rao R, Rahman MH, Kaushik D, Akhtar MF, Saleem A, Khalifa SMA, El-Seedi HR, Kamel M, Albadrani GM, Abdel-Daim MM, Mittal V. Acetylcholinesterase Inhibitory Potential of Various Sesquiterpene Analogues for Alzheimer's Disease Therapy. Biomolecules 2021; 11:350. [PMID: 33669097 PMCID: PMC7996600 DOI: 10.3390/biom11030350] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is a gradually growing irreversible illness of the brain that almost affects every fifth person (aged > 80 years) in the world. World Health Organization (WHO) also revealed that the prevalence of this disease will enhance (upto double) significantly upto 2030. The poor cholinergic transmission at the synapse is considered to be one of the main reasons behind the progression and occurrence of this disorder. Natural inhibitors of acetylcholine (ACh) such as galanthamine and rivastigmine are used commercially in the treatmentof AD. The biomolecules such assesquiterpenes, possess a great structural diversity and are responsible for a plethora of pharmacological properties. The potential of various sesquiterpenes as anticholinesterase has been reviewed in this article. For this purpose, the various databases, mainly PubMed, Scopus, and Web of Science were investigatedwith different keywords such as "sesquiterpenes+acetylcholinesterase" and "sesquiterpenes+cholinesterase+inhibitors" in the surveyed time frame (2010-2020). A vast literature was evident in the last decade, which affirms the potential of various sesquiterpenes in the improvement of cholinergic transmission by inhibiting the AChE. After data analysis, it was found that 12 compounds out of a total of 58 sesquiterpenes were reported to possess IC50 < 9μM and can be considered as potential candidates for the improvement of learning and memory. Sesquiterpene is an important category of terpenoids, found to possess a large spectrum of biological activities. The outcome of the review clearly states that sesquiterpenes (such as amberboin, lipidiol,etc) from herbs could offer fresh, functional compounds for possible prevention and treatment of AD.
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Affiliation(s)
- Ashwani Arya
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana-124001, India
| | - Rubal Chahal
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana-124001, India
| | - Rekha Rao
- Department of Pharmaceutical Sciences, Guru Jambeshwar University of Science & Technology, Hisar, Haryana-125001, India
| | - Md Habibur Rahman
- Department of Pharmacy, Southeast University, Banani, Dhaka-1213, Bangladesh
- Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26384, Korea
| | - Deepak Kaushik
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana-124001, India
| | - Muhammad Furqan Akhtar
- Riphah Institute of Pharmaceutical Sciences, Lahore Campus, Riphah International University, Lahore 54000, Pakistan
| | - Ammara Saleem
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Shaden M A Khalifa
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91 Stockholm, Sweden
| | - Hesham R El-Seedi
- Pharmacognosy Group, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, Box 574, 751 23 Uppsala, Sweden
- International Research Center for Food Nutrition and Safety, Jiangsu University, Zhenjiang 212013, China
- Department of Chemistry, Faculty of Science, Menoufia University, Shebin El-Kom 32512, Egypt
| | - Mohamed Kamel
- Department of Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
| | - Ghadeer M Albadrani
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11474, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Vineet Mittal
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana-124001, India
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12
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Martínez-García I, Hernández-Soto R, Villasana-Salazar B, Ordaz B, Peña-Ortega F. Alterations in Piriform and Bulbar Activity/Excitability/Coupling Upon Amyloid-β Administration in vivo Related to Olfactory Dysfunction. J Alzheimers Dis 2021; 82:S19-S35. [PMID: 33459655 DOI: 10.3233/jad-201392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Deficits in odor detection and discrimination are premature symptoms of Alzheimer's disease (AD) that correlate with pathological signs in the olfactory bulb (OB) and piriform cortex (PCx). Similar olfactory dysfunction has been characterized in AD transgenic mice that overproduce amyloid-β peptide (Aβ), which can be prevented by reducing Aβ levels by immunological and pharmacological means, suggesting that olfactory dysfunction depends on Aβ accumulation and Aβ-driven alterations in the OB and/or PCx, as well as on their activation. However, this possibility needs further exploration. OBJECTIVE To characterize the effects of Aβ on OB and PCx excitability/coupling and on olfaction. METHODS Aβ oligomerized solution (containing oligomers, monomers, and protofibrils) or its vehicle were intracerebroventricularlly injected two weeks before OB and PCx excitability and synchrony were evaluated through field recordings in vivo and in brain slices. Synaptic transmission from the OB to the PCx was also evaluated in slices. Olfaction was assessed through the habituation/dishabituation test. RESULTS Aβ did not affect lateral olfactory tract transmission into the PCx but reduced odor habituation and cross-habituation. This olfactory dysfunction was related to a reduction of PCx and OB network activity power in vivo. Moreover, the coherence between PCx-OB activities was also reduced by Aβ. Finally, Aβ treatment exacerbated the 4-aminopyridine-induced excitation in the PCx in slices. CONCLUSION Our results show that Aβ-induced olfactory dysfunction involves a complex set of pathological changes at different levels of the olfactory pathway including alterations in PCx excitability and its coupling with the OB. These pathological changes might contribute to hyposmia in AD.
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Affiliation(s)
- Ignacio Martínez-García
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Rebeca Hernández-Soto
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benjamín Villasana-Salazar
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benito Ordaz
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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13
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Demoret RM, Baker MA, Ohtawa M, Chen S, Lam CC, Khom S, Roberto M, Forli S, Houk KN, Shenvi RA. Synthetic, Mechanistic, and Biological Interrogation of Ginkgo biloba Chemical Space En Route to (-)-Bilobalide. J Am Chem Soc 2020; 142:18599-18618. [PMID: 32991152 PMCID: PMC7727090 DOI: 10.1021/jacs.0c08231] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Here we interrogate the structurally dense (1.64 mcbits/Å3) GABAA receptor antagonist bilobalide, intermediates en route to its synthesis, and related mechanistic questions. 13C isotope labeling identifies an unexpected bromine migration en route to an α-selective, catalytic asymmetric Reformatsky reaction, ruling out an asymmetric allylation pathway. Experiment and computation converge on the driving forces behind two surprising observations. First, an oxetane acetal persists in concentrated mineral acid (1.5 M DCl in THF-d8/D2O); its longevity is correlated to destabilizing steric clash between substituents upon ring-opening. Second, a regioselective oxidation of des-hydroxybilobalide is found to rely on lactone acidification through lone-pair delocalization, which leads to extremely rapid intermolecular enolate equilibration. We also establish equivalent effects of (-)-bilobalide and the nonconvulsive sesquiterpene (-)-jiadifenolide on action potential-independent inhibitory currents at GABAergic synapses, using (+)-bilobalide as a negative control. The high information density of bilobalide distinguishes it from other scaffolds and may characterize natural product (NP) space more generally. Therefore, we also include a Python script to quickly (ca. 132 000 molecules/min) calculate information content (Böttcher scores), which may prove helpful to identify important features of NP space.
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Affiliation(s)
- Robert M. Demoret
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Meghan A. Baker
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Masaki Ohtawa
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Shuming Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Ching Ching Lam
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Sophia Khom
- Departments of Molecular Medicine and Neuroscience, La Jolla, California 92037, United States
| | - Marisa Roberto
- Departments of Molecular Medicine and Neuroscience, La Jolla, California 92037, United States
| | - Stefano Forli
- DISCoBio, Scripps Research, La Jolla, California 92037, United States
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Ryan A. Shenvi
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
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14
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Computer simulation aided preparation of molecularly imprinted polymers for separation of bilobalide. J Mol Model 2020; 26:198. [PMID: 32632503 DOI: 10.1007/s00894-020-04460-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/28/2020] [Indexed: 10/23/2022]
Abstract
In this study, the preparation of molecularly imprinted polymers for bilobalide (BBMIPs) was successfully achieved by bulk polymerization with methacrylamide (MAM), trimethylolpropane triacrylate (TMPTA), and acetonitrile (ACN) as functional monomer, cross-linker, and solvent, respectively. After Gaussian software simulation and single factor experiments, the prepared MIPs with a molar ratio of 1:4:15 for BB-MAM-TMPTA were systematically characterized. The hydrogen bonding interaction between BB and MAM was confirmed by a combination of FTIR and NMR analysis. Thermal gravimetric analysis results displayed that MIPs have excellent thermal stability under high temperature. Additionally, the average pore size and surface area of MIPs were found to be higher than those of NIPs through nitrogen adsorption results. The results of static adsorption and kinetic adsorption suggested that the adsorption equilibrium concentration was 0.6 mg/mL and the equilibrium time was 5 h, and the Langmuir and pseudo-second-order kinetic models were proven to fit with static and kinetic adsorption behaviors, respectively. Meanwhile, the selective adsorption study revealed that MIPs show high adsorption and great selectivity towards BB in comparison with other substances having similarly structure. MIPs also possessed a good performance on reusability, maintaining a high recovery rate after being reused 5 times. The application experiment further indicated that MIPs can effectively separate BB from low purity samples. Therefore, the prepared MIPs had a great potential for BB separation.
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15
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Nishimon S, Yamaguchi M, Muraki H, Sakai N, Nishino S. Intraperitoneal injection of ginkgolide B, a major active compound of Ginkgo biloba, dose-dependently increases the amount of wake and decreases non-rapid eye movement sleep in C57BL/6 mice. Neurosci Lett 2020; 722:134832. [PMID: 32050100 DOI: 10.1016/j.neulet.2020.134832] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 12/22/2022]
Abstract
The terpene lactones of Ginkgo biloba extract, namely ginkgolides (A, B, and C) and bilobalide, possess antioxidant, anti-inflammatory, and neuroprotective effects. They are widely prescribed for the treatment of cerebral dysfunctions and neurological impairments. In addition, they demonstrate antagonistic action at the gamma-aminobutyric acid type A and glycine receptors, which are members of the ligand-gated ion channel superfamily. In the present study, the effects of ginkgolides (A, B, and C) and bilobalide on sleep in C57BL/6 mice were investigated. Ginkgolide B was found to dose-dependently increase the amount of wake and decrease that of non-rapid eye movement sleep without changes in the electroencephalography power density of each sleep/wake stage, core body temperature and locomotor activity for the first 6 h after intraperitoneal injection. Of note, the amount of wake after injection of 5 mg/kg of ginkgolide B showed a significant increase (14.9 %) compared with that of vehicle (P = 0.005). In contrast, there were no significant differences in the amount of sleep, core body temperature, and locomotor activity in the mice injected with ginkgolide A and C. Bilobalide briefly induced a decrease in locomotor activity but did not exert significant effects on the amounts of sleep and wake. The modes of action of the wake-enhancing effects of ginkgolide B are unknown. However, it may act through the antagonism of gamma-aminobutyric acid type A and glycine receptors because it is established that these inhibitory amino acids mediate sleep and sleep-related physiology. It is of interest to further evaluate the stimulant and awaking actions of ginkgolide B on the central nervous system in clinical and basic research studies.
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Affiliation(s)
- Shohei Nishimon
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Mai Yamaguchi
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Hisae Muraki
- Sleep Medical Center, Osaka Kaisei Hospital, Osaka, Japan
| | - Noriaki Sakai
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Seiji Nishino
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA.
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16
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Fu Y, Li L, Wang Y, Chu G, Kong X, Wang J. Role of GABAA receptors in EEG activity and spatial recognition memory in aged APP and PS1 double transgenic mice. Neurochem Int 2019; 131:104542. [DOI: 10.1016/j.neuint.2019.104542] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 09/02/2019] [Accepted: 09/02/2019] [Indexed: 10/26/2022]
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17
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Xiaoyan L, Li C, Liu T, Ke H, Gong X, Wang Q, Zhang J, Fan X. Chemical analysis, pharmacological activity and process optimization of the proportion of bilobalide and ginkgolides in Ginkgo biloba extract. J Pharm Biomed Anal 2018; 160:46-54. [PMID: 30071391 DOI: 10.1016/j.jpba.2018.07.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 01/19/2023]
Abstract
Variations on the efficacy of commercial Ginkgo biloba preparations have been reported, although all the products follow the same standards. Terpene trilactones (TTLs), including bilobalide (BB) and ginkgolides, are one of the main active components in G. biloba extract and have been received the most attention due to their chemical uniqueness and their importance for quality control. A plenty of studies demonstrated that BB and ginkgolides display differential activities on various biological processes. However, the influence of different ratios of BB and ginkgolides on the efficacy of TTLs has not been detected yet. The aims of this study were: (1) to test whether different ratios of BB and ginkgolides existed in commercial G. biloba preparations; (2) to detect the influence of different ratios of BB and ginkgolides on the in vivo efficacy of TTLs; and (3) to optimize the extraction process of G. biloba to approach the better BB and ginkgolides ratio with the maximum in vivo effects. First, the content and proportion of BB and ginkgolides in various G. biloba preparations were quantified by HPLC-MS analysis. As the results, an obvious fluctuation in the proportion of BB and ginkgolides was observed in the preparations from different commercial suppliers. The ratio was ranged from 0.3 to 0.8. Second, a zebrafish thrombosis model was used to evaluate the antithrombotic effects of different ratios of BB and ginkgolides. The result showed that the proportion of BB and ginkgolides at 1:2 produced the maximum antithrombotic effects. Third, the extraction process of G. biloba was optimized using a design space technique aiming to approach the best BB and ginkgolides ratio obtained from zebrafish experiment. The extraction process was modeled based on the results of Box-Behnken designed experiments. Design space was then calculated using a probability-based method. Within this design space, G. biloba extraction process can be guaranteed to achieve the better BB and ginkgolides ratio with high assurance. Normal operation space for G. biloba extraction process was recommended as ethanol concentration of 50% to 70%, liquid-to-solid ratio of 5.6 mL/g to 7.3 mL/g, and extraction time of 2.2 h to 3.0 h. This work not only suggest that the proportion of BB and ginkgolides should be used as a quality control index in ginkgo preparations besides the content of TTLs, but also provide a way to approach it with the extraction process parameters controlled in the normal operation ranges.
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Affiliation(s)
- Lu Xiaoyan
- Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chen Li
- Zhejiang University - WanBangDe Pharmaceutical Group Co.,Ltd. Joint Research Center for Chinese Medicine Modernization, China
| | - Ting Liu
- Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Han Ke
- Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xingchu Gong
- Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qingqing Wang
- Zhejiang University - WanBangDe Pharmaceutical Group Co.,Ltd. Joint Research Center for Chinese Medicine Modernization, China
| | - Jianbing Zhang
- Zhejiang University - WanBangDe Pharmaceutical Group Co.,Ltd. Joint Research Center for Chinese Medicine Modernization, China
| | - Xiaohui Fan
- Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
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18
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Alimoradian A, Ghasemi S, Zahiri M, Saeedi AH, Miladi H, Sadegh M. Investigation of the effect of Ginkgo biloba leaf extract on spatial memory impairment and hippocampal neuronal loss caused by diabetes induced by streptozotocin in rats. SCIENTIFIC JOURNAL OF KURDISTAN UNIVERSITY OF MEDICAL SCIENCES 2018. [DOI: 10.29252/sjku.23.2.114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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19
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Bilobalide alleviates depression-like behavior and cognitive deficit induced by chronic unpredictable mild stress in mice. Behav Pharmacol 2018; 27:596-605. [PMID: 27509313 DOI: 10.1097/fbp.0000000000000252] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Bilobalide (BB), a unique constituent of Ginkgo biloba, has powerful neuroprotection and stress-alleviating properties. However, whether BB exerts a positive effect on depression and cognitive deficit induced by chronic stress is not known. The present study was designed to investigate the influence of BB on depression and cognitive impairments induced by chronic unpredictable mild stress (CUMS) in mice. During daily exposure to stressors for 5 consecutive weeks, mice were administered BB at the doses of 0, 3, or 6 mg/kg/day intraperitoneally. We replicated the finding that CUMS induced depression-like behavior and cognitive deficits as the CUMS+vehicle (VEH) group showed a significant increase in immobility in the tail suspension test, a decrease in the discrimination index of the novel object recognition task, and increased latency to platform and decreased number of platform crossings in the Morris water maze compared with the control+VEH group. Chronic administration of BB effectively reversed these alterations. In addition, the CUMS+VEH group showed significantly higher levels of baseline serum corticosterone than those of the control+VEH group and BB dose-dependently inhibited this effect. Our results suggest that BB may be useful for inhibition of depression-like behavior and cognitive deficits, and this protective effect was possibly exerted partly through an action on the hypothalamic-pituitary-adrenal axis.
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20
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Savage K, Firth J, Stough C, Sarris J. GABA-modulating phytomedicines for anxiety: A systematic review of preclinical and clinical evidence. Phytother Res 2017; 32:3-18. [DOI: 10.1002/ptr.5940] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/07/2017] [Accepted: 09/07/2017] [Indexed: 01/04/2023]
Affiliation(s)
- Karen Savage
- ARCADIA Mental Health Research Group, Professorial Unit, The Melbourne Clinic, Department of Psychiatry; The University of Melbourne; 2 Salisbury Street Richmond Victoria 3121 Australia
- Centre for Human Psychopharmacology; Swinburne University of Technology; John St Hawthorn Victoria 3122 Australia
| | - Joseph Firth
- Division of Psychology and Mental Health; University of Manchester; Oxford Rd Manchester M13 9PL UK
- NICM, School of Science and Health; Western Sydney University; Sydney NSW Australia
| | - Con Stough
- Centre for Human Psychopharmacology; Swinburne University of Technology; John St Hawthorn Victoria 3122 Australia
| | - Jerome Sarris
- ARCADIA Mental Health Research Group, Professorial Unit, The Melbourne Clinic, Department of Psychiatry; The University of Melbourne; 2 Salisbury Street Richmond Victoria 3121 Australia
- NICM, School of Science and Health; Western Sydney University; Sydney NSW Australia
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21
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Ohtawa M, Krambis MJ, Cerne R, Schkeryantz JM, Witkin JM, Shenvi RA. Synthesis of (-)-11-O-Debenzoyltashironin: Neurotrophic Sesquiterpenes Cause Hyperexcitation. J Am Chem Soc 2017. [PMID: 28644021 DOI: 10.1021/jacs.7b04206] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
11-O-Debenzoyltashironin (1) is a member of the neurotrophic sesquiterpenes, trace plant metabolites that enhance neurite outgrowth in cultured neurons. We report its synthesis in six steps from a butenolide heterodimer via its likely biosynthetic precursor, 3,6-dideoxy-10-hydroxypseudoanisatin, here identified as the chain tautomer of 1. Access to the tashironin chemotype fills a gap in a comparison set of convulsive and neurotrophic sesquiterpenes, which we hypothesized to share a common target. Here we show that both classes mutually hyperexcite rat cortical neurons, consistent with antagonism of inhibitory channels and a mechanism of depolarization-induced neurite outgrowth.
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Affiliation(s)
- Masaki Ohtawa
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Michael J Krambis
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Rok Cerne
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Jeffrey M Schkeryantz
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Jeffrey M Witkin
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Ryan A Shenvi
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
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Bakas T, van Nieuwenhuijzen P, Devenish S, McGregor I, Arnold J, Chebib M. The direct actions of cannabidiol and 2-arachidonoyl glycerol at GABA A receptors. Pharmacol Res 2017; 119:358-370. [DOI: 10.1016/j.phrs.2017.02.022] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 10/20/2022]
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23
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Effects of bilobalide, ginkgolide B and picrotoxinin on GABA A receptor modulation by structurally diverse positive modulators. Eur J Pharmacol 2017; 806:83-90. [PMID: 28416372 DOI: 10.1016/j.ejphar.2017.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/11/2017] [Accepted: 04/13/2017] [Indexed: 12/20/2022]
Abstract
Anxiolytics and anticonvulsants generally positively modulate the action of GABA, whereas many convulsants (including the chloride channel blocker picrotoxinin) negatively modulate the action of GABA on GABAA receptors. Like picrotoxinin, bilobalide and ginkgolide B, active constituents of Ginkgo biloba, have been shown to negatively modulate the action of GABA at α1β2γ2L GABAA receptors. However, unlike picrotoxinin, bilobalide and ginkgolide B are not known to cause convulsions. We have assessed the action of bilobalide, ginkgolide B and picrotoxinin on a range of GABAA modulators (etomidate, loreclezole, propofol, thiopentone sodium, diazepam, and allopregnanolone), using two-electrode voltage clamp electrophysiology at recombinant α1β2γ2L GABAA receptors expressed in Xenopus oocytes. The results indicate that bilobalide and ginkgolide B differ from picrotoxinin in their ability to inhibit the actions of a range of these structurally diverse GABAA positive modulators consistent with these modulators acting on a multiplicity of active sites associated with GABAA receptors. In the presence GABA, ginkgolide B was more potent than bilobalide in inhibiting the GABA-potentiating effect of propofol, equipotent against loreclezole and allopregnanolone, and less potent against etomidate, diazepam, and thiopentone sodium. This indicates that in comparison to picrotoxinin, bilobalide and ginkgolide B differ in their effects on the different modulators.
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White DJ, Cox KHM, Hughes ME, Pipingas A, Peters R, Scholey AB. Functional Brain Activity Changes after 4 Weeks Supplementation with a Multi-Vitamin/Mineral Combination: A Randomized, Double-Blind, Placebo-Controlled Trial Exploring Functional Magnetic Resonance Imaging and Steady-State Visual Evoked Potentials during Working Memory. Front Aging Neurosci 2016; 8:288. [PMID: 27994548 PMCID: PMC5133263 DOI: 10.3389/fnagi.2016.00288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/14/2016] [Indexed: 12/28/2022] Open
Abstract
This study explored the neurocognitive effects of 4 weeks daily supplementation with a multi-vitamin and -mineral combination (MVM) in healthy adults (aged 18–40 years). Using a randomized, double-blind, placebo-controlled design, participants underwent assessments of brain activity using functional Magnetic Resonance Imaging (fMRI; n = 32, 16 females) and Steady-State Visual Evoked Potential recordings (SSVEP; n = 39, 20 females) during working memory and continuous performance tasks at baseline and following 4 weeks of active MVM treatment or placebo. There were several treatment-related effects suggestive of changes in functional brain activity associated with MVM administration. SSVEP data showed latency reductions across centro-parietal regions during the encoding period of a spatial working memory task following 4 weeks of active MVM treatment. Complementary results were observed with the fMRI data, in which a subset of those completing fMRI assessment after SSVEP assessment (n = 16) demonstrated increased BOLD response during completion of the Rapid Visual Information Processing task (RVIP) within regions of interest including bilateral parietal lobes. No treatment-related changes in fMRI data were observed in those who had not first undergone SSVEP assessment, suggesting these results may be most evident under conditions of fatigue. Performance on the working memory and continuous performance tasks did not significantly differ between treatment groups at follow-up. In addition, within the fatigued fMRI sample, increased RVIP BOLD response was correlated with the change in number of target detections as part of the RVIP task. This study provides preliminary evidence of changes in functional brain activity during working memory associated with 4 weeks of daily treatment with a multi-vitamin and -mineral combination in healthy adults, using two distinct but complementary measures of functional brain activity.
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Affiliation(s)
- David J White
- Centre for Human Psychopharmacology, School of Health Sciences, Swinburne University, Hawthorn, VIC Australia
| | - Katherine H M Cox
- Centre for Human Psychopharmacology, School of Health Sciences, Swinburne University, Hawthorn, VIC Australia
| | - Matthew E Hughes
- Brain and Psychological Sciences Research Centre, School of Health Sciences, Swinburne University Hawthorn, VIC, Australia
| | - Andrew Pipingas
- Centre for Human Psychopharmacology, School of Health Sciences, Swinburne University, Hawthorn, VIC Australia
| | - Riccarda Peters
- Centre for Human Psychopharmacology, School of Health Sciences, Swinburne University, Hawthorn, VIC Australia
| | - Andrew B Scholey
- Centre for Human Psychopharmacology, School of Health Sciences, Swinburne University, Hawthorn, VIC Australia
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Effects of standardized Ginkgo biloba extract on the acquisition, retrieval and extinction of conditioned suppression: Evidence that short-term memory and long-term memory are differentially modulated. Physiol Behav 2016; 165:55-68. [PMID: 27378507 DOI: 10.1016/j.physbeh.2016.06.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 05/28/2016] [Accepted: 06/29/2016] [Indexed: 01/01/2023]
Abstract
Studies in our laboratory have characterized the putative neuromodulatory effects of a standardized extract of the green leaves of Ginkgo biloba (EGb), which comprises a formulation of 24% ginkgo-flavoglycosides and 6% ginkgo-terpenoid lactones, on conditioned suppression. This model comprises a suitable animal model for investigating the behavioral changes and pharmacological mechanisms that underlie fear memory and anxiety. The characterization of the effects on distinct stages of fear memory or fear extinction will help illustrate both the beneficial and harmful effects. Three hundred adult male Wistar rats were randomly assigned to 30 groups according to the treatment as follows: i-ii) control groups (CS-US and CSno-US); iii) vehicle group (12% Tween®80); and iv-vi) EGb groups (250, 500 and 1000mgkg(-1)); or experimental procedures designed to assess the effects of EGb treatment prior to the acquisition (n=20 per group) and retrieval of conditioned fear (n=10 per group) or prior to the extinction training (n=10 per group) and extinction retention test (n=10 per group). Furthermore, to better understand the effects of acute EGb treatment on fear memory, we conducted two additional analyses: the acquisition of within- and between-session extinction of fear memory (short- and long-term memory, respectively). No difference was identified between the control and treatment groups during the retention test (P>0.05), with the exception of the CSno-US group in relation to all groups (P<0.05). A between-session analysis indicated that EGb at 250mgkg(-1) facilitated the acquisition of extinction fear memory, which was verified by the suppression ration in the first trial of extinction training (SR=0.39) and the extinction retention test session (SR=0.53, P<0.05), without impairments in fear memory acquisition, which were evaluated during the retention test (SR=0.79). Moreover, EGb administered at 1000mgkg(-1) prior to conditioning did not enhance the long-term extinction memory, i.e., it did not prevent the return of extinguished fear memory in the extinction retention test, in which the spontaneous recovery of fear was demonstrated (SR=0.63, P<0.05); however, it significantly facilitated short-term memory as verified by data from the within-session extinction (1 to 8-10 trials) during the retention test (SR=0.73 to SR=0.59; P<0.05) and the extinction retention test (SR=0.63 to SR=0.41; P<0.05). Moreover, spontaneous recovery was identified in response to a higher dose of EGb when administered prior to extinction training (SR=0.75, P<0.05) and the extinction retention test (SR=0.70; P<0.05). At dose of 500mgkg(-1) EGb reduced the suppression ratio when administered prior to the retention test (SR=0.57) and extinction training (SR=0.55; P<0.05) without preventing the acquisition of fear memory, which suggests that EGb has anti-anxiety effects. Taken together, the current findings suggest that EGb differentially modulates short- and long-term memory, as well as anxiety-like behavior. The actions of EGb may provide information regarding the beneficial effects in the prevention and treatment of neurocognitive impairments and anxiety disorders. Additional analyses are necessary to facilitate an understanding of these effects; however, previous data from our group suggest that GABAergic, serotoninergic and glutamatergic receptors are potential targets of the effects of EGb on conditioned suppression.
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A Bilobalide-Producing Endophytic Fungus, Pestalotiopsis uvicola from Medicinal Plant Ginkgo biloba. Curr Microbiol 2016; 73:280-6. [DOI: 10.1007/s00284-016-1060-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 04/01/2016] [Indexed: 11/25/2022]
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Manayi A, Nabavi SM, Daglia M, Jafari S. Natural terpenoids as a promising source for modulation of GABAergic system and treatment of neurological diseases. Pharmacol Rep 2016; 68:671-9. [PMID: 27110875 DOI: 10.1016/j.pharep.2016.03.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 02/28/2016] [Accepted: 03/24/2016] [Indexed: 02/06/2023]
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter reducing neural excitability in the mammalian central nervous system (CNS) with three subclasses of receptors. Several conventional drugs and compounds modulate the GABAergic system, demonstrating different pharmacological effects. In this review, interactions of natural terpenoids with the GABAergic system are highlighted with relation to disorders like anxiety, insomnia, convulsion, pain, and cognitive deficits. Terpenoids with various structures affect the function of the GABAergic system via dissimilar mechanisms. Most of the discussed compounds interact with GABA receptors, but especially with the GABAA subtype. This may be due to the fact that researchers tend to assess the interaction of compounds using GABAA receptors. However, bilobalide, a sesquiterpene, showed anticonvulsant properties through the activation of glutamic acid decarboxylase (GAD) enzyme, which is a key enzyme in biosynthesis of GABA. Therefore, further studies evaluating and comparing terpenoids of different classes and their interaction with the GABA system, along with their pharmacokinetic properties, could be worthwhile in future studies.
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Affiliation(s)
- Azadeh Manayi
- Medicinal Plants Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Maria Daglia
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Pavia, Italy
| | - Samineh Jafari
- Department of Pharmacognosy, Faculty of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran.
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Ng CC, Duke RK, Hinton T, Johnston GA. GABAA receptor cysteinyl mutants and the ginkgo terpenoid lactones bilobalide and ginkgolides. Eur J Pharmacol 2016; 777:136-46. [DOI: 10.1016/j.ejphar.2016.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 03/02/2016] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
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Parveen I, Wang M, Zhao J, Chittiboyina AG, Tabanca N, Ali A, Baerson SR, Techen N, Chappell J, Khan IA, Pan Z. Investigating sesquiterpene biosynthesis in Ginkgo biloba: molecular cloning and functional characterization of (E,E)-farnesol and α-bisabolene synthases. PLANT MOLECULAR BIOLOGY 2015; 89:451-62. [PMID: 26442918 DOI: 10.1007/s11103-015-0381-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/15/2015] [Indexed: 05/12/2023]
Abstract
Ginkgo biloba is one of the oldest living tree species and has been extensively investigated as a source of bioactive natural compounds, including bioactive flavonoids, diterpene lactones, terpenoids and polysaccharides which accumulate in foliar tissues. Despite this chemical diversity, relatively few enzymes associated with any biosynthetic pathway from ginkgo have been characterized to date. In the present work, predicted transcripts potentially encoding enzymes associated with the biosynthesis of diterpenoid and terpenoid compounds, including putative terpene synthases, were first identified by mining publicly-available G. biloba RNA-seq data sets. Recombinant enzyme studies with two of the TPS-like sequences led to the identification of GbTPS1 and GbTPS2, encoding farnesol and bisabolene synthases, respectively. Additionally, the phylogenetic analysis revealed the two terpene synthase genes as primitive genes that might have evolved from an ancestral diterpene synthase.
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Affiliation(s)
- Iffat Parveen
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Mei Wang
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Jianping Zhao
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Amar G Chittiboyina
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Nurhayat Tabanca
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Abbas Ali
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Scott R Baerson
- United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit (USDA-ARS-NPURU), P.O. Box 1848, University, MS, 38677-1848, USA
| | - Natascha Techen
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Joe Chappell
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, 405036, USA
| | - Ikhlas A Khan
- National Center for Natural Products Research, Thad Cochran Research Center, School of Pharmacy, University of Mississippi, University, MS, 38677, USA.
| | - Zhiqiang Pan
- United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit (USDA-ARS-NPURU), P.O. Box 1848, University, MS, 38677-1848, USA.
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Johnston GAR. Advantages of an antagonist: bicuculline and other GABA antagonists. Br J Pharmacol 2014; 169:328-36. [PMID: 23425285 DOI: 10.1111/bph.12127] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/21/2013] [Accepted: 01/31/2013] [Indexed: 11/28/2022] Open
Abstract
The convulsant alkaloid bicuculline continues to be investigated more than 40 years after the first publication of its action as an antagonist of receptors for the inhibitory neurotransmitter GABA. This historical perspective highlights key aspects of the discovery of bicuculline as a GABA antagonist and the sustained interest in this and other GABA antagonists. The exciting advances in the molecular biology, pharmacology and physiology of GABA receptors provide a continuing stimulus for the discovery of new antagonists with increasing selectivity for the myriad of GABA receptor subclasses. Interesting GABA antagonists not structurally related to bicuculline include gabazine, salicylidene salicylhydrazide, RU5135 and 4-(3-biphenyl-5-(4-piperidyl)-3-isoxazole. Bicuculline became the benchmark antagonist for what became known as GABAA receptors, but not all ionotropic GABA receptors are susceptible to bicuculline. In addition, not all GABAA receptor antagonists are convulsants. Thus there are still surprises in store as the study of GABA receptors evolves.
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Affiliation(s)
- Graham A R Johnston
- Pharmacology, School of Medical Sciences, The University of Sydney, NSW, Australia
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Jiang M, Li J, Peng Q, Liu Y, Liu W, Luo C, Peng J, Li J, Yung KKL, Mo Z. Neuroprotective effects of bilobalide on cerebral ischemia and reperfusion injury are associated with inhibition of pro-inflammatory mediator production and down-regulation of JNK1/2 and p38 MAPK activation. J Neuroinflammation 2014; 11:167. [PMID: 25256700 PMCID: PMC4189683 DOI: 10.1186/s12974-014-0167-6] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/13/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Mitogen-activated protein kinase (MAPK) signaling pathways are implicated in inflammatory and apoptotic processes of cerebral ischemia and reperfusion (I/R) injury. Hence, MAPK pathways represent a promising therapeutic target. Exploring the full potential of inhibitors of MAPK pathways is a useful therapeutic strategy for ischemic stroke. Bilobalide, a predominant sesquiterpene trilactone constituent of Ginkgo biloba leaves, has been shown to exert powerful neuroprotective properties, which are closely related to both anti-inflammatory and anti-apoptotic pathways. We investigated the neuroprotective roles of bilobalide in the models of middle cerebral artery occlusion and reperfusion (MCAO/R) and oxygen-glucose deprivation and reoxygenation (OGD/R) of cerebral I/R injury. Moreover, we attempted to confirm the hypothesis that its protection effect is via modulation of pro-inflammatory mediators and MAPK pathways. METHODS Male Sprague-Dawley rats were subjected to MCAO for 2 h followed by reperfusion for 24 h. Bilobalide was administered intraperitoneally 60 min before induction of middle cerebral artery occlusion (MCAO). After reperfusion, neurological deficit scores, infarct volume, infarct weight, and brain edema were assessed. Ischemic penumbrae of the cerebral cortex were harvested to determine superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide, TNF-α, interleukin 1β (IL-1β), p-ERK1/2, p-JNK1/2, and p-p38 MAPK concentration. Similarly, the influence of bilobalide on the expression of nitric oxide, TNF-α, IL-1β, p-ERK1/2, p-JNK1/2, and p-p38 MAPK was also observed in an OGD/R in vitro model of I/R injury. RESULTS Pretreatment with bilobalide (5, 10 mg/kg) significantly decreased neurological deficit scores, infarct volume, infarct weight, brain edema, and concentrations of MDA, nitric oxide, TNF-α, IL-1β, and increased SOD activity. Furthermore, bilobalide (5, 10 mg/kg) pretreatment significantly down-regulated both p-JNK1/2 and p-p38 MAPK expression, whereas they had no effect on p-ERK1/2 expression in the ischemic penumbra. Supporting these observations in vivo, pretreatment with bilobalide (50, 100 μM) significantly down-regulated nitric oxide, TNF-α, IL-1β, p-JNK1/2, and p-p38 MAPK expression, but did not change p-ERK1/2 expression in rat cortical neurons after OGD/R injury. CONCLUSIONS These data indicate that the neuroprotective effects of bilobalide on cerebral I/R injury are associated with its inhibition of pro-inflammatory mediator production and down-regulation of JNK1/2 and p38 MAPK activation.
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Sánchez-Borzone M, Delgado-Marín L, García DA. Inhibitory Effects of Carvone Isomers on the GABAA
Receptor in Primary Cultures of Rat Cortical Neurons. Chirality 2014; 26:368-72. [DOI: 10.1002/chir.22328] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 03/12/2014] [Accepted: 03/15/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Mariela Sánchez-Borzone
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT); CONICET-Universidad Nacional de Córdoba; Córdoba Argentina
| | - Leticia Delgado-Marín
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT); CONICET-Universidad Nacional de Córdoba; Córdoba Argentina
| | - Daniel A. García
- Instituto de Investigaciones Biológicas y Tecnológicas (IIBYT); CONICET-Universidad Nacional de Córdoba; Córdoba Argentina
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Hall BJ, Karim N, Chebib M, Johnston GAR, Hanrahan JR. Modulation of ionotropic GABA receptors by 6-methoxyflavanone and 6-methoxyflavone. Neurochem Res 2013; 39:1068-78. [PMID: 24078264 DOI: 10.1007/s11064-013-1157-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/12/2013] [Accepted: 09/17/2013] [Indexed: 11/25/2022]
Abstract
We evaluated the effects of 6-methoxyflavanone and 6-methoxyflavone on wild-type α1/α2β2γ2L GABAA and ρ1 GABAC receptors and on mutant ρ1I307S, ρ1W328 M, ρ1I307S/W328 M GABAC receptors expressed in Xenopus oocytes using two-electrode voltage clamp and radioligand binding. 6-Methoxyflavanone and 6-methoxyflavone act as a flumazenil-insensitive positive allosteric modulator of GABA responses at human recombinant α1β2γ2L and α2β2γ2L GABAA receptors. However, unlike 6-methoxyflavone, 6-methoxyflavanone was relatively inactive at α1β2 GABAA receptors. 6-Methoxyflavanone inhibited [(3)H]-flunitrazepam binding to rat brain membranes. Both flavonoids were found to be inactive as modulators at ρ1, ρ1I307S and ρ1W328 M GABA receptors but acted as positive allosteric modulators of GABA at the benzodiazepine sensitive ρ1I307S/W328 M GABA receptors. This double mutant retains ρ1 properties of being insensitive to bicuculline and antagonised by TPMPA and THIP. Additionally, 6-methoxyflavanone was also a partial agonist at ρ1W328 M GABA receptors. The relative inactivity of 6-methoxyflavanone at α1β2 GABAA receptors and it's partial agonist action at ρ1W328 M GABA receptors suggest that it exhibits a unique profile not matched by other flavonoids.
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Affiliation(s)
- Belinda J Hall
- Department of Pharmacology, The University of Sydney, Sydney, NSW, 2006, Australia
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Zeng Z, Zhu J, Chen L, Wen W, Yu R. Biosynthesis pathways of ginkgolides. Pharmacogn Rev 2013; 7:47-52. [PMID: 23922456 PMCID: PMC3731879 DOI: 10.4103/0973-7847.112848] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 12/28/2012] [Accepted: 06/01/2013] [Indexed: 11/16/2022] Open
Abstract
The ginkgolides, acting as anti-platelet-activating factors, have been studied for many years. The biosynthetic pathway of ginkgolides is still far away from unveiling at the level of molecular genetics and biochemistry. There are at least 11 kinds of enzymes having been cloned from Ginkgo biloba L., which catalyze the formation of ginkgolides via a series of reactions. Some researchers have indicated that the addition of precursors and elicitors can influence the accumulation of ginkgolides in the suspension cell cultures of G. biloba. There are also other factors that can influence the production of ginkgolides. This review focuses on the aforementioned aspects to discuss the biosynthetic pathways of the ginkgolides.
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Affiliation(s)
- Zihan Zeng
- Biotechnological Institute of Chinese Materia Medica, Jinan University, Guangzhou, China
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Bilobalide, a unique constituent of Ginkgo biloba, inhibits inflammatory pain in rats. Behav Pharmacol 2013; 24:298-306. [DOI: 10.1097/fbp.0b013e32836360ab] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ma L, Wang S, Tai F, Yuan G, Wu R, Liu X, Wei B, Yang X. Effects of bilobalide on anxiety, spatial learning, memory and levels of hippocampal glucocorticoid receptors in male Kunming mice. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 20:89-96. [PMID: 23083816 DOI: 10.1016/j.phymed.2012.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 08/03/2012] [Accepted: 09/15/2012] [Indexed: 06/01/2023]
Abstract
With various constituents in ginkgo biloba extract, the detailed internal mechanism underlying a reduction in anxiety and improvements to learning and memory from GBE is not well understood. The present study investigated whether bilobalide, an important constituent in GBE, could affect anxiety, spatial learning and memory in male mice and whether hippocampal glucocorticoid receptor expression is associated with alteration in these behaviors. Mice were treated orally either with sesame seed oil or one of three dosages of bilobalide (2.5, 5.0 and 10.0 mg/kg) daily until testing. A series of behavioral tests showed that repeated bilobalide treatment decreased levels of anxiety-like behavior and increased locomotor activity in open field and elevated plus maze tests. Treatment with bilobalide also shortened the time taken to find the platform in a Morris water-maze test. Mice exposed to bilobalide showed higher and dose-dependent levels of glucocorticoid receptor expression in the hippocampus. These results suggest that bilobalide reduces anxiety levels and enhances spatial learning and memory, possibly through an increase in hippocampal glucocorticoid receptor expression. This finding sheds light on the mechanisms underlying the effect of ginkgo biloba extract on behavior and also provides an important candidate drug in treatment of anxiety, depression, hypomnesia and amnesia.
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Affiliation(s)
- Leige Ma
- Institute of Brain and Behavioral Sciences, College of Life Sciences, Shaanxi Normal University, Xi'an, China
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Huang SH, Lewis TM, Lummis SC, Thompson AJ, Chebib M, Johnston GA, Duke RK. Mixed antagonistic effects of the ginkgolides at recombinant human ρ1 GABAC receptors. Neuropharmacology 2012; 63:1127-39. [PMID: 22828636 PMCID: PMC3465557 DOI: 10.1016/j.neuropharm.2012.06.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 06/18/2012] [Accepted: 06/24/2012] [Indexed: 11/26/2022]
Abstract
The diterpene lactones of Ginkgo biloba, ginkgolides A, B and C are antagonists at a range of Cys-loop receptors. This study examined the effects of the ginkgolides at recombinant human ρ(1) GABA(C) receptors expressed in Xenopus oocytes using two-electrode voltage clamp. The ginkgolides were moderately potent antagonists with IC(50)s in the μM range. At 10 μM, 30 μM and 100 μM, the ginkgolides caused rightward shifts of GABA dose-response curves and reduced maximal GABA responses, characteristic of noncompetitive antagonists, while the potencies showed a clear dependence on GABA concentration, indicating apparent competitive antagonism. This suggests that the ginkgolides exert a mixed-type antagonism at the ρ(1) GABA(C) receptors. The ginkgolides did not exhibit any obvious use-dependent inhibition. Fitting of the data to a number of kinetic schemes suggests an allosteric inhibition as a possible mechanism of action of the ginkgolides which accounts for their inhibition of the responses without channel block or use-dependent inhibition. Kinetic modelling predicts that the ginkgolides exhibit saturation of antagonism at high concentrations of GABA, but this was only partially observed for ginkgolide B. It also suggests that there may be different binding sites in the closed and open states of the receptor, with a higher affinity for the receptor in the closed state.
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Affiliation(s)
- Shelley H. Huang
- Discipline of Pharmacology, School of Medical Sciences, Faculty of Medicine, University of Sydney, Australia
| | - Trevor M. Lewis
- School of Medical Sciences, University of New South Wales, Australia
| | - Sarah C.R. Lummis
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Andrew J. Thompson
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mary Chebib
- Faculty of Pharmacy, University of Sydney, Australia
| | - Graham A.R. Johnston
- Discipline of Pharmacology, School of Medical Sciences, Faculty of Medicine, University of Sydney, Australia
| | - Rujee K. Duke
- Discipline of Pharmacology, School of Medical Sciences, Faculty of Medicine, University of Sydney, Australia
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Thompson AJ, Alqazzaz M, Ulens C, Lummis SCR. The pharmacological profile of ELIC, a prokaryotic GABA-gated receptor. Neuropharmacology 2012; 63:761-7. [PMID: 22677470 PMCID: PMC3430861 DOI: 10.1016/j.neuropharm.2012.05.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 03/08/2012] [Accepted: 05/19/2012] [Indexed: 02/02/2023]
Abstract
The Erwinia ligand-gated ion channel (ELIC) is a bacterial homologue of vertebrate Cys-loop ligand-gated ion channels. It is activated by GABA, and this property, combined with its structural similarity to GABAA and other Cys-loop receptors, makes it potentially an excellent model to probe their structure and function. Here we characterise the pharmacological profile of ELIC, examining the effects of compounds that could activate or inhibit the receptor. We confirm that a range of amino acids and classic GABAA receptor agonists do not elicit responses in ELIC, and we show the receptor can be at least partially activated by 5-aminovaleric acid and γ-hydroxybutyric acid, which are weak agonists. A range of GABAA receptor non-competitive antagonists inhibit GABA-elicited ELIC responses including α-endosulfan (IC50 = 17 μM), dieldrin (IC50 = 66 μM), and picrotoxinin (IC50 = 96 μM) which were the most potent. Docking suggested possible interactions at the 2′ and 6′ pore-lining residues, and mutagenesis of these residues supports this hypothesis for α-endosulfan. A selection of compounds that act at Cys-loop and other receptors also showed some efficacy at blocking ELIC responses, but most were of low potency (IC50 > 100 μM). Overall our data show that a number of compounds can inhibit ELIC, but it has limited pharmacological similarity to GLIC and to Cys-loop receptors.
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Affiliation(s)
- Andrew J Thompson
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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Chen Q, Yim PD, Yuan N, Johnson J, Cook JM, Smith S, Ionescu-Zanetti C, Wang ZJ, Arnold LA, Emala CW. Comparison of cell expression formats for the characterization of GABA(A) channels using a microfluidic patch clamp system. Assay Drug Dev Technol 2012; 10:325-35. [PMID: 22574655 DOI: 10.1089/adt.2011.415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ensemble recording and microfluidic perfusion are recently introduced techniques aimed at removing the laborious nature and low recording success rates of manual patch clamp. Here, we present assay characteristics for these features integrated into one automated electrophysiology platform as applied to the study of GABA(A) channels. A variety of cell types and methods of GABA(A) channel expression were successfully studied (defined as I(GABA)>500 pA), including stably transfected human embryonic kidney (HEK) cells expressing α(1)β(3)γ(2) GABA(A) channels, frozen ready-to-assay (RTA) HEK cells expressing α(1)β(3)γ(2) or α(3)β(3)γ(2) GABA(A) channels, transiently transfected HEK293T cells expressing α(1)β(3)γ(2) GABA(A) channels, and immortalized cultures of human airway smooth muscle cells endogenously expressing GABA(A) channels. Current measurements were successfully studied in multiple cell types with multiple modes of channel expression in response to several classic GABA(A) channel agonists, antagonists, and allosteric modulators. We obtained success rates above 95% for transiently or stably transfected HEK cells and frozen RTA HEK cells expressing GABA(A) channels. Tissue-derived immortalized cultures of airway smooth muscle cells exhibited a slightly lower recording success rate of 75% using automated patch, which was much higher than the 5% success rate using manual patch clamp technique by the same research group. Responses to agonists, antagonists, and allosteric modulators compared well to previously reported manual patch results. The data demonstrate that both the biophysics and pharmacologic characterization of GABA(A) channels in a wide variety of cell formats can be performed using this automated patch clamp system.
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Affiliation(s)
- Qin Chen
- Fluxion Biosciences, South San Francisco, California, USA
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40
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Cys-loop receptor channel blockers also block GLIC. Biophys J 2011; 101:2912-8. [PMID: 22208189 DOI: 10.1016/j.bpj.2011.10.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/21/2011] [Accepted: 10/24/2011] [Indexed: 11/21/2022] Open
Abstract
The Gloeobacter ligand-gated ion channel (GLIC) is a bacterial homolog of vertebrate Cys-loop ligand-gated ion channels. Its pore-lining region in particular has a high sequence homology to these related proteins. Here we use electrophysiology to examine a range of compounds that block the channels of Cys-loop receptors to probe their pharmacological similarity with GLIC. The data reveal that a number of these compounds also block GLIC, although the pharmacological profile is distinct from these other proteins. The most potent compound was lindane, a GABA(A) receptor antagonist, with an IC₅₀ of 0.2 μM. Docking studies indicated two potential binding sites for this ligand in the pore, at the 9' or between the 0' and 2' residues. Similar experiments with picrotoxinin (IC₅₀ = 2.6 μM) and rimantadine (IC₅₀ = 2.6 μM) reveal interactions with 2'Thr residues in the GLIC pore. These locations are strongly supported by mutagenesis data for picrotoxinin and lindane, which are less potent in a T2'S version of GLIC. Overall, our data show that the inhibitory profile of the GLIC pore has considerable overlap with those of Cys-loop receptors, but the GLIC pore has a unique pharmacology.
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Fernandes ECA, Hendriks HS, van Kleef RGDM, van den Berg M, Westerink RHS. Potentiation of the human GABA(A) receptor as a novel mode of action of lower-chlorinated non-dioxin-like PCBs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:2864-9. [PMID: 20014829 DOI: 10.1021/es902321a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
PCBs are still ubiquitous pollutants despite the ban on their industrial and commercial use. To date, risk characterization and assessment of non-dioxin-like PCBs (NDL-PCBs), especially with respect to neurotoxicity, is hampered by a lack of data. Therefore, the effects of six common NDL congeners (PCB28, 52, 101, 138, 153 and 180) on human GABA(A) receptors, expressed in Xenopus oocytes, were investigated using the two-electrode voltage-clamp technique. When coapplied with GABA (at EC(20)), PCB28 and PCB52 concentration-dependently potentiate the GABA(A) receptor-mediated ion current. Though the LOEC for both PCB28 and PCB52 is 0.3 microM, PCB28 is more potent than PCB52 (maximum potentiation at 10 muM amounting to 98.3 +/- 12.5% and 25.5 +/- 1.4%, respectively). Importantly, coapplication of PCB28 (0.3 microM) and PCB52 (10 microM) resulted in an apparently additive potentiation of the GABA(A) response, whereas coapplication of PCB28 (0.3 microM) and PCB153 (10 microM) attenuated the PCB28-induced potentiation. The present results suggest that the potentiation of human GABA(A) receptor function is specific for lower-chlorinated NDL-PCBs and that higher molecular weight PCBs may attenuate this potentiation as a result of competitive binding to human GABA(A) receptors. Nonetheless, this novel mode of action could (partly) underlie the previously recognized NDL-PCB-induced neurobehavioral alterations.
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Affiliation(s)
- Elsa C Antunes Fernandes
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, The Netherlands.
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42
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Hollands EC, Dale TJ, Baxter AW, Meadows HJ, Powell AJ, Clare JJ, Trezise DJ. Population Patch-Clamp Electrophysiology Analysis of Recombinant GABAA α1β3γ2 Channels Expressed in HEK-293 Cells. ACTA ACUST UNITED AC 2009; 14:769-80. [DOI: 10.1177/1087057109335675] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
γ-Amino butyric acid (GABA)—activated Cl— channels are critical mediators of inhibitory postsynaptic potentials in the CNS. To date, rational design efforts to identify potent and selective GABAA subtype ligands have been hampered by the absence of suitable high-throughput screening approaches. The authors describe 384-well population patch-clamp (PPC) planar array electrophysiology methods for the study of GABAA receptor pharmacology. In HEK293 cells stably expressing human α1β3γ2 GABAA channels, GABA evoked outward currents at 0 mV of 1.05 ± 0.08 nA, measured 8 s post GABA addition. The IGABA was linear and reversed close to the theoretical ECl (—56 mV). Concentration-response curve analysis yielded a mean pEC50 value of 5.4 and Hill slope of 1.5, and for a series of agonists, the rank order of potency was muscimol > GABA > isoguvacine. A range of known positive modulators, including diazepam and pentobarbital, produced concentration-dependent augmentation of the GABA EC 20 response (1 µM). The competitive antagonists bicuculline and gabazine produced concentration-dependent, parallel, rightward displacement of GABA curves with pA2 and slope values of 5.7 and 1.0 and 6.7 and 1.0, respectively. In contrast, picrotoxin (0.2-150 µM) depressed the maximal GABA response, implying a non-competitive antagonism. Overall, the pharmacology of human α1β3γ2 GABAA determined by PPC was highly similar to that obtained by conventional patch-clamp methods. In small-scale single-shot screens, Z′ values of >0.5 were obtained in agonist, modulator, and antagonist formats with hit rates of 0% to 3%. The authors conclude that despite the inability of the method to resolve the peak agonist responses, PPC can rapidly and usefully quantify pharmacology for the α1β3γ2 GABAA isoform. These data suggest that PPC may be a valuable approach for a focused set and secondary screening of GABAA receptors and other slow ligand-gated ion channels. ( Journal of Biomolecular Screening 2009:769-780)
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Affiliation(s)
- Emma C. Hollands
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Tim J. Dale
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Andrew W. Baxter
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Helen J. Meadows
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Andrew J. Powell
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Jeff J. Clare
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom
| | - Derek J. Trezise
- Biochemical & Cellular Targets, Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom,
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Flavan-3-ol derivatives are positive modulators of GABAA receptors with higher efficacy for the α2 subtype and anxiolytic action in mice. Neuropharmacology 2008; 55:900-7. [DOI: 10.1016/j.neuropharm.2008.06.069] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 06/30/2008] [Accepted: 06/30/2008] [Indexed: 11/19/2022]
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44
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Role of glycine receptors and glycine release for the neuroprotective activity of bilobalide. Brain Res 2008; 1201:143-50. [DOI: 10.1016/j.brainres.2008.01.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 01/15/2008] [Accepted: 01/15/2008] [Indexed: 11/18/2022]
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45
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Lynch JW, Chen X. Subunit-specific potentiation of recombinant glycine receptors by NV-31, a bilobalide-derived compound. Neurosci Lett 2008; 435:147-51. [PMID: 18329806 DOI: 10.1016/j.neulet.2008.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 02/04/2008] [Accepted: 02/12/2008] [Indexed: 11/20/2022]
Abstract
Bilobalide, a major bioactive component of Ginkgo biloba herbal extracts, exhibits neuroprotective and anti-ischaemic activity. However, its therapeutic potential is limited because of its instability. Attempts to synthesise a more stable analogue culminated in the development of NV-31. This compound recapitulates some aspects of bilobalide pharmacology. However, although bilobalide inhibits recombinant glycine receptor Cl channels (GlyRs), NV-31 potentiates hippocampal neuron GlyRs. Because of the possible therapeutic relevance of this effect, the present study investigated the molecular mechanism and subunit specificity of NV-31 actions at recombinantly expressed alpha1, alpha1beta, alpha2 and alpha3 GlyRs. NV-31 potentiated alpha1 GlyRs by approximately 135% with an EC50 near 170 nM. Its potentiating effect was observed only at low (EC10) glycine concentrations. The magnitude of its potentiating effect was reduced at alpha1beta GlyRs and it had no effect at all at alpha2 and alpha3 GlyRs. NV-31 was unlikely to bind at the bilobalide pore-binding site as its efficacy was not affected by the alpha1 subunit G2'A and T6'S mutations. However, the S15'C mutation to the alcohol-binding site abolished its effects, suggesting that NV-31 modulates the GlyR via a specific (steric or allosteric) interaction with S15'. GlyRs are potential therapeutic targets for chronic anti-inflammatory pain and movement disorders. NV-31, as a positive modulator of these receptors, thus remains viable as a therapeutic candidate for these disorders.
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Affiliation(s)
- Joseph W Lynch
- School of Biomedical Sciences and Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
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46
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Nooshinfar E, Lashgari R, Haghparast A, Sajjadi S. NMDA receptors are involved in Ginkgo extract-induced facilitation on memory retention of passive avoidance learning in rats. Neurosci Lett 2008; 432:206-11. [DOI: 10.1016/j.neulet.2007.12.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Revised: 11/25/2007] [Accepted: 12/05/2007] [Indexed: 11/15/2022]
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47
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Ivetic V, Popovic M, Naumovic N, Radenkovic M, Vasic V. The effect of Ginkgo biloba (EGb 761) on epileptic activity in rabbits. Molecules 2008; 13:2509-20. [PMID: 18927515 PMCID: PMC6245335 DOI: 10.3390/molecules13102509] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 10/08/2008] [Accepted: 10/09/2008] [Indexed: 11/16/2022] Open
Abstract
Different animal models are used to evaluate the process of epileptogenesis. In this investigation the kindling model of epilepsy was used. The epileptic focus was induced in Chinchilla rabbits by stimulation of the hippocampus with electric stimuli. We presumed that the extracts of Ginkgo biloba affect the formation of kindling epilepsy. Bioelectric activity of the brain was registered throughout the development of kindling with and without standardized extracts from dried ginkgo leaves (EGb 761). For each animal the following has been determined: the values of the minimum current strength necessary for the origination of threshold after-discharge (AD) - discharges appearing after the cessation of stimulation; duration of the threshold AD; number of stimulations necessary for the origination of full kindling; time latency for the development of full kindling; number of spontaneous epileptogenic discharges manifested in EEG two days following the formation of full kindling during 60-minute registration. The results show that the process of epileptogenesis was influenced by EGb 761. It has been established that if the animals received EGb 761, significantly weaker minimum current strength was necessary for the development of the epileptogenic focus and the AD were longer, while the number of necessary electrostimulations for the appearance of full kindling was less and the latency was shorter.
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Affiliation(s)
- Vesna Ivetic
- Department of Neurophysiology, Medical Faculty, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia; E-mails: (N. N.); (V. V.)
| | - Mira Popovic
- Department of Chemistry, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 3, 21000 Novi Sad, Serbia, E-mail:
| | - Nada Naumovic
- Department of Neurophysiology, Medical Faculty, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia; E-mails: (N. N.); (V. V.)
| | - Mirjana Radenkovic
- Department of Physiology, Medical Faculty, University of Nis, Serbia; E-mail: (M. R.)
| | - Vesna Vasic
- Department of Neurophysiology, Medical Faculty, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia; E-mails: (N. N.); (V. V.)
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48
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Kiewert C, Kumar V, Hildmann O, Rueda M, Hartmann J, Naik RS, Klein J. Role of GABAergic antagonism in the neuroprotective effects of bilobalide. Brain Res 2006; 1128:70-8. [PMID: 17134681 PMCID: PMC1865101 DOI: 10.1016/j.brainres.2006.10.042] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 10/07/2006] [Accepted: 10/20/2006] [Indexed: 10/23/2022]
Abstract
Bilobalide, a constituent of Ginkgo biloba, has neuroprotective properties. Its mechanism of action is unknown but it was recently found to block GABA(A) receptors. The goal of this study was to test the potential role of a GABAergic mechanism for the neuroprotective activity of bilobalide. In rat hippocampal slices exposed to NMDA, release of choline indicates breakdown of membrane phospholipids. NMDA-induced choline release was almost completely blocked in the presence of bilobalide (10 microM) and under low-chloride conditions. Bicuculline (100 microM), a competitive antagonist at GABA(A) receptors, reduced NMDA-induced choline release to a small extent (-23%). GABA (100 microM) partially antagonized the inhibitory action of bilobalide. Exposure of hippocampal slices to NMDA also caused edema formation as measured by increases of tissue water content. NMDA-induced edema formation was suppressed by bilobalide and by low-chloride conditions. Bicuculline exerted partial protection (by 30%) while GABA reduced bilobalide's effect by about one third. To investigate bilobalide's interaction with GABA(A) receptors directly, we measured binding of [(35)S]-TBPS to rat cortical membranes. TBPS binding was competitively inhibited by bilobalide in the low micromolar range (IC(50)=3.7 microM). As a functional test, we determined (36)chloride flux in rat corticohippocampal synaptoneurosomes. GABA (100 microM) significantly increased (36)chloride flux (+65%), and this increase was blocked by bilobalide, but with low potency (IC(50): 39 microM). We conclude that, while antagonism of GABA(A) receptors may contribute to bilobalide's neuroprotective effects, additional mechanisms must be postulated to fully explain bilobalide's actions.
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Affiliation(s)
- Cornelia Kiewert
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Science Center, 1300 Coulter Dr., Amarillo, TX 79106, USA
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Hawthorne R, Cromer BA, Ng HL, Parker MW, Lynch JW. Molecular determinants of ginkgolide binding in the glycine receptor pore. J Neurochem 2006; 98:395-407. [PMID: 16805834 DOI: 10.1111/j.1471-4159.2006.03875.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ginkgolides are potent blockers of the glycine receptor Cl- channel (GlyR) pore. We sought to identify their binding sites by comparing the effects of ginkgolides A, B and C and bilobalide on alpha1, alpha2, alpha1beta and alpha2beta GlyRs. Bilobalide sensitivity was drastically reduced by incorporation of the beta subunit. In contrast, the sensitivities to ginkgolides B and C were enhanced by beta subunit expression. However, ginkgolide A sensitivity was increased in the alpha2beta GlyR relative to the alpha2 GlyR but not in the alpha1beta GlyR relative to the alpha1 GlyR. We hypothesised that the subunit-specific differences were mediated by residue differences at the second transmembrane domain 2' and 6' pore-lining positions. The increased ginkgolide A sensitivity of the alpha2beta GlyR was transferred to the alpha1beta GlyR by the G2'A (alpha1 to alpha2 subunit) substitution. In addition, the alpha1 subunit T6'F mutation abolished inhibition by all ginkgolides. As the ginkgolides share closely related structures, their molecular interactions with pore-lining residues were amenable to mutant cycle analysis. This identified an interaction between the variable R2 position of the ginkgolides and the 2' residues of both alpha1 and beta subunits. These findings provide strong evidence for ginkgolides binding at the 2' pore-lining position.
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Affiliation(s)
- Rebecca Hawthorne
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
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50
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Kim SM, Kuzuyama T, Chang YJ, Kim SU. Cloning and characterization of 2-C-methyl-D: -erythritol 2,4-cyclodiphosphate synthase (MECS) gene from Ginkgo biloba. PLANT CELL REPORTS 2006; 25:829-35. [PMID: 16528563 DOI: 10.1007/s00299-006-0136-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 12/13/2005] [Accepted: 01/13/2006] [Indexed: 05/07/2023]
Abstract
Ginkgo biloba contains secondary metabolites with interesting pharmacological properties, including highly modified diterpenoid ginkgolide, potent and selective antagonist of platelet-activating factor. 2-C-Methyl-D: -erythritol 2,4-cyclodiphosphate synthase gene (GbMECS) involved in ginkgolide biosynthesis pathway was cloned and characterized from G. biloba embryonic roots, and the full open reading frame was deduced as protein consisting of 238 amino acid residues. Putative mature protein with a 179 residue-long sequence, obtained by deleting N-terminal chloroplast transit peptide region composed of 59 amino acid residues, rescued Esherichia coli NMW26, an E. coli knock-out mutant of ygbB (EcMECS). Transcription levels of GbMECS were two-fold higher in embryo roots compared to leaves. When full-length GbMECS with chloroplast transit peptide sequence was fused to green fluorescent protein gene (GFP), and transiently expressed in Arabidopsis thaliana protoplast, green fluorescence was found in chloroplast, indication of protein transportation into plastid.
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Affiliation(s)
- Sang-Min Kim
- Program in Applied Life Chemistry, School of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, Korea
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