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Alzoubi KH, Abdel-Hafiz L, Khabour OF, El-Elimat T, Alzubi MA, Alali FQ. Evaluation of the Effect of Hypericum triquetrifolium Turra on Memory Impairment Induced by Chronic Psychosocial Stress in Rats: Role of BDNF. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:5299-5314. [PMID: 33299301 PMCID: PMC7720289 DOI: 10.2147/dddt.s278153] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/14/2020] [Indexed: 12/21/2022]
Abstract
Background Chronic psychosocial stress impairs memory function and leads to a depression-like phenotype induced by a persistent status of oxidative stress. Hypericum perforatum L. (St. John's wort) is widely used to relieve symptoms of anxiety and depression; however, its long-term use is associated with adverse effects. Hypericum triquetrifolium Turra is closely related to H. perforatum. Both plants belong to Hypericaceae family and share many biologically active compounds. Previous work by our group showed that methanolic extracts of H. triquetrifolium have potent antioxidant activity as well as high hypericin content, a component that proved to have stress-relieving and antidepressant effects by other studies. Therefore, we hypothesized that H. triquetrifolium would reduce stress-induced cognitive impairment in a rat model of chronic stress. Objective To determine whether chronic treatment with H. triquetrifolium protects against stress-associated memory deficits and to investigate a possible mechanism. Methods The radial arm water maze (RAWM) was used to test learning and memory in rats exposed to daily stress using the resident-intruder paradigm. Stressed and unstressed rats received chronic H. triquetrifolium or vehicle. We also measured levels of brain-derived neurotrophic factor (BDNF) in the hippocampus, cortex and cerebellum. Results Neither chronic stress nor chronic H. triquetrifolium administration affected performance during acquisition. However, memory tests in the RAWM showed that chronic stress impaired different post-encoding memory stages. H. triquetrifolium prevented this impairment. Furthermore, hippocampal BDNF levels were markedly lower in stressed animals than in unstressed animals, and chronic administration of H triquetrifolium chronic administration protected against this reduction. No significant difference was observed in the effects of chronic stress and/or H. triquetrifolium treatment on BDNF levels in the cerebellum and cortex. Conclusion H. triquetrifolium extract can oppose stress-associated hippocampus-dependent memory deficits in a mechanism that may involve BDNF in the hippocampus.
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Affiliation(s)
- Karem H Alzoubi
- Department of Clinical Pharmacy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Laila Abdel-Hafiz
- Institute of Anatomy II, Medical Faculty, Heinrich Heine Universität, Düsseldorf, Germany.,Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Omar F Khabour
- Department of Medical Laboratory Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Tamam El-Elimat
- Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mohammad A Alzubi
- Integrative Life Sciences Doctoral Program, Department of Pathology, Virginia Commonwealth University, Richmond, VA, USA
| | - Feras Q Alali
- College of Pharmacy, QU Health, Qatar University, Doha Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
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Sahoo S, S. B. Pharmacogenomic assessment of herbal drugs in affective disorders. Biomed Pharmacother 2019; 109:1148-1162. [DOI: 10.1016/j.biopha.2018.10.135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/20/2018] [Accepted: 10/21/2018] [Indexed: 12/14/2022] Open
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Rho SS, Woo YS, Bahk WM. Ginkgo biloba induced mood dysregulation: a case report. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 18:14. [PMID: 29334964 PMCID: PMC5769324 DOI: 10.1186/s12906-018-2081-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 01/03/2018] [Indexed: 01/12/2023]
Abstract
Background Impairment of cognitive function as well as negative symptom is the major factor causing the decline of a patient’s functioning in chronic stages of schizophrenia. However, until now, there were no definite treatment options that could effectively reduce the impairment. Case presentation We report a case of mood dysregulation associated with use of Ginkgo biloba in a patient with schizophrenia. After Ginkgo biloba was given, the patient experienced cluster symptoms of mood dysregulation including irritability, difficulty in controlling anger, agitation and restlessness. We estimated the possibility as “probable” according to Naranjo scale considering circumstantial evidence. Conclusions This case suggests that Ginkgo biloba may have caused mood dysregulation in this patient. Although it is generally accepted as safe, more attention should be given to the adverse effect when treating with Ginkgo biloba.
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Papadopoulos V, Aghazadeh Y, Fan J, Campioli E, Zirkin B, Midzak A. Translocator protein-mediated pharmacology of cholesterol transport and steroidogenesis. Mol Cell Endocrinol 2015; 408:90-8. [PMID: 25818881 PMCID: PMC4417383 DOI: 10.1016/j.mce.2015.03.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/17/2022]
Abstract
Steroidogenesis begins with cholesterol transfer into mitochondria through the transduceosome, a complex composed of cytosolic proteins that include steroidogenesis acute regulatory protein (STAR), 14-3-3 adaptor proteins, and the outer mitochondrial membrane proteins Translocator Protein (TSPO) and Voltage-Dependent Anion Channel (VDAC). TSPO is a drug- and cholesterol-binding protein found at particularly high levels in steroid synthesizing cells. Its aberrant expression has been linked to cancer, neurodegeneration, neuropsychiatric disorders and primary hypogonadism. Brain steroids serve as local regulators of neural development and excitability. Reduced levels of these steroids have been linked to depression, anxiety and neurodegeneration. Reduced serum testosterone is common among subfertile young men and aging men, and is associated with depression, metabolic syndrome and reduced sexual function. Although testosterone-replacement therapy is available, there are undesired side-effects. TSPO drug ligands have been proposed as therapeutic agents to regulate steroid levels in the brain and testis.
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Affiliation(s)
- Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada.
| | - Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Andrew Midzak
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada
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Kudolo GB. Effect of <i>Ginkgo biloba</i> Extract Ingestion on Plasma Total Cortisol Levels during an Oral Glucose Tolerance Test in Normal Glucose Tolerant Individuals. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/fns.2014.516169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Batarseh A, Papadopoulos V. Regulation of translocator protein 18 kDa (TSPO) expression in health and disease states. Mol Cell Endocrinol 2010; 327:1-12. [PMID: 20600583 PMCID: PMC2922062 DOI: 10.1016/j.mce.2010.06.013] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 06/17/2010] [Indexed: 01/12/2023]
Abstract
Translocator protein (TSPO) is an 18 kDa high affinity cholesterol- and drug-binding protein found primarily in the outer mitochondrial membrane. Although TSPO is found in many tissue types, it is expressed at the highest levels under normal conditions in tissues that synthesize steroids. TSPO has been associated with cholesterol import into mitochondria, a key function in steroidogenesis, and directly or indirectly with multiple other cellular functions including apoptosis, cell proliferation, differentiation, anion transport, porphyrin transport, heme synthesis, and regulation of mitochondrial function. Aberrant expression of TSPO has been linked to multiple diseases, including cancer, brain injury, neurodegeneration, and ischemia-reperfusion injury. There has been an effort during the last decade to understand the mechanisms regulating tissue- and disease-specific TSPO expression and to identify pharmacological means to control its expression. This review focuses on the current knowledge regarding the chemicals, hormones, and molecular mechanisms regulating Tspo gene expression under physiological conditions in a tissue- and disease-specific manner. The results described here provide evidence that the PKCepsilon-ERK1/2-AP-1/STAT3 signal transduction pathway is the primary regulator of Tspo gene expression in normal and pathological tissues expressing high levels of TSPO.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
| | - Vassilios Papadopoulos
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
- Department of Pharmacology and Therapeutics, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
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Hamer M, Owen G, Kloek J. The role of functional foods in the psychobiology of health and disease. Nutr Res Rev 2007; 18:77-88. [DOI: 10.1079/nrr2005103] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe effect of psychological stress on health is becoming a serious concern, with figures from the World Health Organization showing that stress-related disorders affect nearly 450 million individuals worldwide. Heightened physiological stress responses and psychosocial factors have been linked to disease pathways such as hypertension and CVD. This has prompted significant interest within the scientific community, public health bodies and industry to employ interventions to control and reduce the impact of stress on health. There is now strong potential for functional foods to offer stress management benefits. Various physiological pathways have been targeted by specific dietary supplements for stress reduction, including the hypothalamic–pituitary–adrenal axis and sympathetic nervous system. Presently there are a number of ingredients, which include vitamin C, milk proteins, a number of herbal extracts (ginkgo biloba, ginseng, kava, valerian and lemon balm), andn-3 fatty acids, that have demonstrated potential stress reactivity-lowering and mood-enhancing effects, although further work is required to substantiate the efficacy in human subjects. Dietary supplements that can alleviate excessive stress responses may play an increasingly important role for the maintenance of health in a stressful environment. However, future research should employ a greater range of measures that will provide stronger evidence to substantiate functional food claims for stress relief.
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Meng H, Li C, Feng L, Cheng B, Wu F, Wang X, Li Z, Liu S. Effects of Ginkgolide B on 6-OHDA-induced apoptosis and calcium over load in cultured PC12. Int J Dev Neurosci 2007; 25:509-14. [PMID: 17981425 DOI: 10.1016/j.ijdevneu.2007.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 07/17/2007] [Accepted: 09/19/2007] [Indexed: 10/22/2022] Open
Abstract
Ginkgolide B, one of the major components of Ginkgo biloba extracts, is a potent platelet-activating factor (PAF) receptor antagonist, which is also regarded as having neuroprotective effects on the CNS. The aim of this research is to observe the effects of Ginkgolide B on the PC12 apoptosis induced by 6-hydroxydopamine (6-OHDA) and to explore whether these effects are related to the changes of intracellular Ca(2+) and Calbindin D28K mRNA in PC12 cells. In the present work, the damage of PC12 cells was induced by 100 microM 6-OHDA. The cells survival rate was examined by MTT assays. The intracellular free calcium concentration in PC12 cells was measured by using the fluorescent Ca(2+) indicator fluo-3/AM. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine the expression of Calbindin D28K mRNA in PC12. The data show that the Ginkgolide B inhibited PC12 cells apoptosis induced by 6-OHDA in a dose-dependent manner, and decreased the activity of caspase-3. In addition, Ginkgolide B increased the expression of Calbindin D28K mRNA and inhibited 6-OHDA-induced elevation in the intracellular calcium concentration. Our results showed that the Ginkgolide B inhibited the apoptosis of PC12 induced by 6-OHDA, and the protective effects of Ginkgolide B on PC12 cells are mediated, at least in part, by up-regulating the Calbindin D28K mRNA and by decreasing the intracellular calcium concentration.
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Affiliation(s)
- Haiwei Meng
- Department of Anatomy, School of Medicine of Shandong University, Jinan, China
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Fontana L, Souza AS, Del Bel EA, Oliveira RMWD. Ginkgo biloba leaf extract (EGb 761) enhances catalepsy induced by haloperidol and L-nitroarginine in mice. Braz J Med Biol Res 2005; 38:1649-54. [PMID: 16258634 DOI: 10.1590/s0100-879x2005001100012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ginkgo biloba extract EGb 761 has been reported to have therapeutic effects which have been attributed to anti-oxidant and free radical-scavenging activities, including a direct action on nitric oxide production. L G-nitro-arginine (L-NOARG), a nitric oxide synthase inhibitor, and haloperidol, a drug that blocks dopamine receptors, are both known to induce catalepsy in rodents. Nitric oxide has been shown to influence dopaminergic transmission in the striatum. The purpose of the present study was to evaluate the effect of the extract obtained from leaves of Ginkgo biloba tree EGb 761 on catalepsy induced by haloperidol or by L-NOARG. Albino Swiss mice (35-45 g, N = 8-12) received by gavage a single or repeated oral dose (twice a day for 4 days) of EGb 761 followed by ip injection of haloperidol or L-NOARG. After the treatments, the animals were submitted to behavioral evaluation using the catalepsy test. Acute treatment with 80 mg/kg EGb did not modify the catalepsy induced by L-NOARG but, the dose of 40 mg/kg significantly enhanced haloperidol-induced catalepsy measured at the 10th min of the test. After repeated treatment with 80 mg/kg EGb 761, a significant increase in the cataleptic effect produced by both haloperidol and L-NOARG was observed. These data show that repeated EGb 761 administration increases the effects of drugs that modify motor behavior in mice. Since the catalepsy test has predictive value regarding extrapyramidal effects, the possibility of pharmacological interactions between haloperidol and Ginkgo biloba extracts should be further investigated in clinical studies.
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Affiliation(s)
- L Fontana
- Departamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, Maringá, PR, Brazil
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DeFeudis FV, Drieu K. ?Stress-alleviating? and ?vigilance-enhancing? actions ofGinkgo biloba extract (EGb 761). Drug Dev Res 2004. [DOI: 10.1002/ddr.10351] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kuribara H, Weintraub ST, Yoshihama T, Maruyama Y. An anxiolytic-like effect of Ginkgo biloba extract and its constituent, ginkgolide-A, in mice. JOURNAL OF NATURAL PRODUCTS 2003; 66:1333-1337. [PMID: 14575433 DOI: 10.1021/np030122f] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The anxiolytic-like effects of Ginkgo biloba extract (GBE) and its four terpenoid components (ginkgolide-A, ginkgolide-B, ginkgolide-C, and bilobalide) were assessed using the elevated plus-maze test in mice. Administration of GBE as a single oral dose (0.5 or 1 g/kg, po) caused a state of suppressed motor activity and, thus, shortened the time spent in the open-sided arms. However, when GBE (0.063-1 g/kg, po) was administered daily for 7 days and the plus-maze test was carried out 24 h after the final administration, the time spent in the open-sided arms was prolonged, with the peak anxiolytic-like effect at 0.125 g/kg. A combination of seven-day administration of GBE (0.125 g/kg) and a single dose of diazepam (1 mg/ kg, po, 10 min before testing) enhanced the anxiolytic-like effect. Flumazenil (0.3 mg/kg, ip, 10 min before testing) blocked the effect of diazepam, but not of GBE. Daily administration of ginkgolide-A (1 or 2 mg/kg, po) resulted in an anxiolytic-like effect by the third treatment, with the maximal effect observed after the fifth administration. Neither ginkgolide-B, ginkgolide-C, nor bilobalide produced any anxiolytic-like effects. At doses higher than 0.5 g/kg, GBE not only inhibited motor activity but also suppressed active avoidance behavior, reduced caffeine-induced stimulation, and enhanced pentobarbital-induced sleep, while ginkgolide-A (up to 20 mg/kg) did not exhibit these effects. Diazepam (1 mg/kg) is known to enhance pentobarbital-induced sleep. These results suggest that GBE produces a significant anxiolytic-like effect following repeated administration and that ginkgolide-A is most likely responsible for this effect. There are also indications that although GBE exerts a sedative effect at comparatively higher doses, ginkgolide-A has a relatively weak tendency to produce benzodiazepine-like side effects.
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Affiliation(s)
- Hisashi Kuribara
- Center for Cooperative Research, Medical Division, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
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Amri H, Drieu K, Papadopoulos V. Transcriptional suppression of the adrenal cortical peripheral-type benzodiazepine receptor gene and inhibition of steroid synthesis by ginkgolide B. Biochem Pharmacol 2003; 65:717-29. [PMID: 12628485 DOI: 10.1016/s0006-2952(02)01603-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Treatment of rats and adrenocortical cells with ginkgolide B (GKB), a purified component of Ginkgo biloba leaf extracts, reduces the mRNA, protein, and ligand-binding levels of the adrenal peripheral-type benzodiazepine receptor (PBR), a mitochondrial cholesterol-binding protein, leading to decreased corticosteroid synthesis. In the Y1 adrenocortical cell line, GKB reduced both PBR levels and cyclic AMP-induced steroid formation. In these cells, GKB, but not various steroids and vitamins, reduced the expression of a reporter gene driven by the DNA sequence -624/-513 relative to the transcription start site of the PBR encoding gene. GKB treatment did not affect the SV40 promoter and increased the cytochrome P450 17alpha-hydroxylase gene promoter driven expression of the reporter gene. Electrophoretic mobility shift assays (EMSAs) indicated the presence of a functional transcriptional element bound to the -624/-513 DNA fragment. This GKB-induced inhibition of PBR was mediated by an interaction with a transcription factor that binds to the -636/-616 PBR-promoter region. Deletion or mutation of this sequence eliminated the DNA-protein interaction and the inhibitory effect of GKB on PBR gene transcription. This DNA-binding protein could be detected in nuclear extracts of rat brain, liver, and testis, but not kidney. It is also present in the human adrenal glands. However, the inhibitory effect following GKB treatment could be seen only in the adrenal glands. These results demonstrate that the GKB-activated inhibition of glucocorticoid production is due to a specific transcriptional suppression of the adrenal PBR gene and suggest that GKB might serve as a pharmacological tool to control excess glucocorticoid formation.
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Affiliation(s)
- Hakima Amri
- Division of Hormone Research, Department of Cell Biology, Georgetown University Medical Center, 3900 Reservoir Road, Washington, DC 20057, USA
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DeFeudis FV. Effects ofGinkgo biloba extract (EGb 761) on gene expression: Possible relevance to neurological disorders and age-associated cognitive impairment. Drug Dev Res 2003. [DOI: 10.1002/ddr.10151] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Jefcoate C. High-flux mitochondrial cholesterol trafficking, a specialized function of the adrenal cortex. J Clin Invest 2002; 110:881-90. [PMID: 12370263 PMCID: PMC151162 DOI: 10.1172/jci16771] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Colin Jefcoate
- Department of Pharmacology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
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Yao Z, Drieu K, Papadopoulos V. The Ginkgo biloba extract EGb 761 rescues the PC12 neuronal cells from beta-amyloid-induced cell death by inhibiting the formation of beta-amyloid-derived diffusible neurotoxic ligands. Brain Res 2001; 889:181-90. [PMID: 11166702 DOI: 10.1016/s0006-8993(00)03131-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
beta Amyloid (Abeta) treatment induced free radical production and increased glucose uptake, apoptosis and cell death in PC12 nerve cells. Addition of the standardized extract of Ginkgo biloba leaves, EGb 761 together with the Abeta protein prevented, in a dose-dependent manner, the Abeta-induced free radical production, increased glucose uptake, apoptosis and cell death. However, pretreatment of the cells with EGb 761 did not rescue the cells from the Abeta-induced toxicity although it prevented the Abeta-induced reactive oxygen species generation. Moreover, the terpene and flavonoid-free EGb 761 extract, HE 208, although inhibited the Abeta-induced increased glucose uptake, it failed to protect the cells from apoptosis and cytotoxicity induced by Abeta. In conclusion, these results indicate that the terpenoid and flavonoid constituents of EGb 761, acting probably in combination with components present in HE 208, are responsible for rescuing the neuronal cells from Abeta-induced apoptosis and cell death; their mechanism of action being distinct of their antioxidant properties. Because pre- and post-treatment with EGb 761 did not protect the cells from Abeta-induced neurotoxicity, we examined whether EGb 761 interacts directly with Abeta. Indeed, in vitro reconstitution studies demonstrated that EGb 761 inhibits, in a dose-dependent manner, the formation of beta-amyloid-derived diffusible neurotoxic soluble ligands (ADDLs), suggested to be involved in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Z Yao
- Division of Hormone Research, Departments of Cell Biology, Pharmacology, and Neuroscience, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20007, USA
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Cheung F, Siow YL, Chen WZ, O K. Inhibitory effect of Ginkgo biloba extract on the expression of inducible nitric oxide synthase in endothelial cells. Biochem Pharmacol 1999; 58:1665-73. [PMID: 10535759 DOI: 10.1016/s0006-2952(99)00255-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Excessive production of nitric oxide (NO) may have cytotoxic effects through the formation of peroxynitrite with superoxide. The extract of Ginkgo biloba leaves (EGb) has been demonstrated to be a potent scavenger of free radicals. Although EGb has been shown recently to inhibit NO production in macrophages, its effect on NO production in endothelial cells is largely unknown. The objective of this study was to elucidate the mechanism by which EGb affects NO production in a human endothelial cell line (ECV304). After cells were incubated with EGb (10-100 microg/mL) for 2 or 4 hr, the amounts of NO metabolites released by the cells were quantitated, and cellular NOS activities were determined following the conversion of [3H]arginine to [3H]citrulline. NOS protein expression was determined by western immunoblotting analysis. mRNA levels were examined by reverse transcription-polymerase chain reaction (RT-PCR) analysis. EGb (50 microg/mL) caused a 30% reduction of NO metabolites released by endothelial cells. Following EGb treatment, cellular inducible NO synthase (iNOS) activity was reduced by 28% with a concomitant reduction in the levels of iNOS protein mass and mRNA. There was no change in the activity or protein mass of constitutive NO synthase in these cells. EGb inhibited NO production by attenuating the level of iNOS mRNA in ECV304 cells. Selective inhibition of iNOS by EGb may be therapeutically relevant in modulating NO production in endothelial cells.
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Affiliation(s)
- F Cheung
- Department of Pharmacology, Faculty of Medicine, University of Hong Kong, China
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Papadopoulos V, Widmaier EP, Amri H, Zilz A, Li H, Culty M, Castello R, Philip GH, Sridaran R, Drieu K. In vivo studies on the role of the peripheral benzodiazepine receptor (PBR) in steroidogenesis. Endocr Res 1998; 24:479-87. [PMID: 9888528 DOI: 10.3109/07435809809032636] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In various steroidogenic cell models, mitochondrial preparations and submitochondrial fractions, the expression of the mitochondrial 18 kDa peripheral-type benzodiazepine receptor (PBR) protein confers the ability to take up and release, upon ligand activation, cholesterol. Thus, cholesterol becomes available to P450scc on the inner mitochondrial membrane. These in vitro studies were validated by in vivo experiments. Treatment of rats with ginkgolide B (GKB), specifically reduced the ligand binding capacity, protein, and mRNA expression of the adrenocortical PBR and circulating glucocorticoid levels. Treatment with GKB also resulted in inhibition of PBR protein synthesis and corticosterone production by isolated adrenocortical cells in response to ACTH. The ontogeny of both PBR binding capacity and protein directly paralleled that of ACTH-inducible steroidogenesis in rat adrenal cells and in rats injected with ACTH. In addition, the previously described suppression of luteal progesterone synthesis in the pregnant rat by continuous in vivo administration of a gonadotropin-releasing hormone agonist may be due to decreased luteal PBR ligand binding and mRNA. These results suggest that (i) PBR is an absolute prerequisite for adrenocortical and luteal steroidogenesis, (ii) regulation of adrenal PBR expression may be used as a tool to control circulating glucocorticoid levels and (iii) the stress hypo-responsive period of neonatal rats may result from decreased adrenal cortical PBR expression.
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Affiliation(s)
- V Papadopoulos
- Department of Cell Biology, Georgetown University Medical Center, Washington, District of Columbia, USA
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