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Liu XW, Yang YJ, Qin Z, Li SH, Bai LX, Ge WB, Li JY. Isobavachalcone From Cullen corylifolium Presents Significant Antibacterial Activity Against Clostridium difficile Through Disruption of the Cell Membrane. Front Pharmacol 2022; 13:914188. [PMID: 35942219 PMCID: PMC9356235 DOI: 10.3389/fphar.2022.914188] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/01/2022] [Indexed: 12/13/2022] Open
Abstract
Background:Clostridium difficile infection (CDI) has been widely reported in human and animals around the world over the past few decades. The high relapse rate and increasing drug resistance of CDI make the discovery of new agents against C. difficile fairly urgent. This study aims to investigate the antibacterial activity against C. difficile from traditional Chinese herb medicine Cullen corylifolium and confirm its active components. Methods: Phenolic extract from the seeds of C. corylifolium was prepared routinely and the contents of relative flavonoids were determined by High Performance Liquid Chromatography (HPLC). In vitro antibacterial activities of the phenolic extract and its major components were tested. The influence of the major components on cell membrane was investigated with membrane integrity by SEM and propidium iodid uptake assay. Cytotoxicity of the extract and its active compounds on Caco-2 cell line was assessed by CCK-8 kit. The in vivo therapeutic efficacy of IBCL was evaluated on the mice model. Results: Phenolic extract was found to be active against C. difficile with minimum inhibitory concentrations (MIC) of 8 μg/mL. As the major component of the extract, IBCL was the most active compound against C. difficile. The MIC of IBCL and 4MBCL were 4 μg/ml and 4 μg/ml, respectively. Meanwhile, PFPE, IBCL, and 4MBCL showed rapid bactericidal effect against C. difficile in 1 h, which was significant compared to antibiotic vancomycin. Mechanism studies revealed that IBCL can disrupt the integrity of the cell membrane, which may lead to the death of bacteria. PFPE was low cytotoxic against Caco-2 cells, and the cytotoxicity of IBCL and 4MBCL were moderate. Symptoms of CDI were effectively alleviated by IBCL on the mice model and weight loss was reduced. From death rates, IBCL showed better efficacy compared to vancomycin at 50 mg/kg dosage. Conclusion: As the major component of phenolic extract of C. corylifolium seeds, IBCL showed significant antibacterial activity against C. difficile in vitro and rapidly killed the bacteria by disrupting the integrity of the cell membrane. IBCL can significantly prevent weight loss and reduce death caused by CDI on the mice model. Therefore, IBCL may be a promising lead compound or drug candidate for CDI.
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Phang YL, Liu S, Zheng C, Xu H. Recent advances in the synthesis of natural products containing the phloroglucinol motif. Nat Prod Rep 2022; 39:1766-1802. [PMID: 35762867 DOI: 10.1039/d1np00077b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Covering: June 2009 to 2021Natural products containing a phloroglucinol motif include simple and oligomeric phloroglucinols, polycyclic polyprenylated acylphloroglucinols, phloroglucinol-terpenes, xanthones, flavonoids, and coumarins. These compounds represent a major class of secondary metabolites which exhibit a wide range of biological activities such as antimicrobial, anti-inflammatory, antioxidant and hypoglycaemic properties. A number of these compounds have been authorized for therapeutic use or are currently being studied in clinical trials. Their structural diversity and utility in both traditional and conventional medicine have made them popular synthetic targets over the years. In this review, we compile and summarise the recent synthetic approaches to the natural products bearing a phloroglucinol motif. Focus has been given on ingenious strategies to functionalize the phloroglucinol moiety at multiple positions. The isolation and bioactivities of the compounds are also provided.
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Affiliation(s)
- Yee Lin Phang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. .,Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai 201203, China
| | - Song Liu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. .,Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai 201203, China
| | - Changwu Zheng
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. .,Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai 201203, China
| | - Hongxi Xu
- Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
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Wang L, Gao M, Kang G, Huang H. The Potential Role of Phytonutrients Flavonoids Influencing Gut Microbiota in the Prophylaxis and Treatment of Inflammatory Bowel Disease. Front Nutr 2021; 8:798038. [PMID: 34970585 PMCID: PMC8713745 DOI: 10.3389/fnut.2021.798038] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/25/2021] [Indexed: 12/19/2022] Open
Abstract
Inflammatory bowel disease (IBD), characterized by the chronic inflammation of the gastrointestinal tract, is comprised of two idiopathic chronic intestinal inflammatory diseases. As the incidence of IBD increases, so does the need for safe and effective treatments. Trillions of microorganisms are colonized in the mammalian intestine, coevolve with the host in a symbiotic relationship. Gut microbiota has been reported to be involved in the pathophysiology of IBD. In this regard, phytonutrients flavonoids have received increasing attention for their anti-oxidant and anti-inflammatory activities. In this review, we address recent advances in the interactions among flavonoids, gut microbiota, and IBD. Moreover, their possible potential mechanisms of action in IBD have been discussed. We conclude that there is a complex interaction between flavonoids and gut microbiota. It is expected that flavonoids can change or reshape the gut microbiota to provide important considerations for developing treatments for IBD.
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Affiliation(s)
- Lina Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Mengxue Gao
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - Guangbo Kang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
| | - He Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China
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4
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Kudera T, Fiserova B, Korytakova M, Doskocil I, Salmonova H, Tulin EE, Nguon S, Bande MM, Kokoska L. In Vitro Selective Antibacterial and Antiproliferative Effects of Ethanolic Extracts from Cambodian and Philippine Plants Used in Folk Medicine for Diarrhea Treatment. Front Pharmacol 2021; 12:746808. [PMID: 34899301 PMCID: PMC8661004 DOI: 10.3389/fphar.2021.746808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Bacterial diarrhea remains a global health problem, especially in developing tropical countries. Moreover, dysbiosis caused by diarrheagenic bacteria and inappropriate antimicrobial treatment has been associated with intestinal carcinogenesis. Despite the rich tradition of the use of herbs for the treatment of gastrointestinal disorders in Cambodian and Philippine folk medicine, many of them have not yet been systematically studied for their in vitro selective inhibitory effects on intestinal bacteria and cells. In the present study, in vitro inhibitory activities of 35 ethanolic extracts derived from 32 Cambodian and Philippine medicinal plants were determined by broth microdilution method against 12 pathogenic bacteria. Furthermore, cytotoxicity against intestinal cancer cells (Caco-2 and HT-29) using thiazolyl blue tetrazolium bromide cytotoxicity assay and safety to six beneficial intestinal bacteria (bifidobacteria and lactobacilli) and intestinal normal cells (FHs 74 Int) were determined for the antimicrobially active extracts. Selectivity indices (SIs) were calculated among the averages of minimum inhibitory concentrations (MICs), half-maximal inhibitory concentrations (IC50), and 80% inhibitory concentrations of proliferation (IC80) for each type of the tested agents. The extracts of Artocarpus blancoi (Elmer) Merr. (Moraceae), Ancistrocladus tectorius (Lour.) Merr. (Ancistrocladaceae), and Pentacme siamensis (Miq.) Kurz (Dipterocarpaceae) produced significant growth-inhibitory effects (MICs = 32-512 μg/ml) against intestinal pathogenic bacteria at the concentrations nontoxic to normal intestinal cells (IC80 values >512 μg/ml; SIs = 0.11-0.2). Moreover, the extract of P. siamensis (Miq.) Kurz was relatively safe to beneficial bacteria (MICs ≥512 μg/ml; SI = 0.1), and together with A. blancoi (Elmer) Merr., they selectively inhibited intestinal cancer cells (IC50 values ≥51.98 ± 19.79 μg/ml; SIs = 0.3 and 0.6). Finally, a strong selective antiproliferative effect on cancer cells (IC50 values 37.89 ± 2.68 to 130.89 ± 13.99 μg/ml; SIs = 0.5) was exerted by Ehretia microphylla Lam. (Boraginaceae), Lagerstroemia cochinchinensis Pierre ex Gagnep. (Lythraceae), and Melastoma saigonense (Kuntze) Merr. (Melastomataceae) (leaves with flower buds). The results suggest that the above-mentioned species are promising materials for the development of new selective antibacterial and antiproliferative agents for the treatment of infectious diarrhea and associated intestinal cancer diseases. However, further research is needed regarding the isolation and identification of their active constituents.
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Affiliation(s)
- Tomas Kudera
- Laboratory of Ethnobotany and Ethnopharmacology, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czechia
| | - Barbora Fiserova
- Laboratory of Ethnobotany and Ethnopharmacology, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czechia
| | - Marie Korytakova
- Laboratory of Ethnobotany and Ethnopharmacology, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czechia
| | - Ivo Doskocil
- Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Czech University of Life Sciences Prague, Prague, Czechia
| | - Hana Salmonova
- Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Czech University of Life Sciences Prague, Prague, Czechia
| | | | - Samnang Nguon
- Graduate School, Royal University of Agriculture, Phnom Penh, Cambodia
| | - Marlito M. Bande
- Institute of Tropical Ecology and Environmental Management, Visayas State University, Baybay, Philippines
| | - Ladislav Kokoska
- Laboratory of Ethnobotany and Ethnopharmacology, Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czechia
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5
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Ebselen Not Only Inhibits Clostridioides difficile Toxins but Displays Redox-Associated Cellular Killing. Microbiol Spectr 2021; 9:e0044821. [PMID: 34468187 PMCID: PMC8557875 DOI: 10.1128/spectrum.00448-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ebselen, a reactive organoselenium compound, was shown to inhibit toxins TcdA and TcdB by covalently binding to their cysteine protease domains. It was suggested that ebselen lacked antimicrobial activity against Clostridioides difficile. However, this perception conflicts with C. difficile having essential cysteine-containing enzymes that could be potential targets and the reported antimicrobial activity of ebselen against other species. Hence, we reevaluated the anti-C. difficile properties of ebselen. Susceptibility testing revealed that its activity was either slightly reduced by pyruvate found in Wilkins-Chalgren agar or obliterated by blood in brucella agar. In brain heart infusion (BHI) agar, ebselen inhibited most C. difficile strains (MICs of 2 to 8 μg/ml), except for ribotype 078 that was intrinsically resistant (MIC = 32 to 128 μg/ml). Against C. difficile R20291, at concentrations below its minimal bactericidal concentration (MBC), 16 μg/ml, ebselen inhibited production of toxins and spores. Transcriptome analysis revealed that ebselen altered redox-associated processes and cysteine metabolism and enhanced expression of Stickland proline metabolism, likely to regenerate NAD+ from NADH. In cellular assays, ebselen induced uptake of cysteine, depleted nonprotein thiols, and disrupted the NAD+/NADH ratio. Taken together, killing of C. difficile cells by ebselen occurs by a multitarget action that includes disrupting intracellular redox, which is consistent with ebselen being a reactive molecule. However, the physiological relevance of these antimicrobial actions in treating acute C. difficile infection (CDI) is likely to be undermined by host factors, such as blood, which protect C. difficile from killing by ebselen. IMPORTANCE We show that ebselen kills pathogenic C. difficile by disrupting its redox homeostasis, changing the normal concentrations of NAD+ and NADH, which are critical for various metabolic functions in cells. However, this antimicrobial action is hampered by host components, namely, blood. Future discovery of ebselen analogues, or mechanistically similar compounds, that remain active in blood could be drug leads for CDI or probes to study C. difficile redox biology in vivo.
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Sapkota M, Marreddy RKR, Wu X, Kumar M, Hurdle JG. The early stage peptidoglycan biosynthesis Mur enzymes are antibacterial and antisporulation drug targets for recurrent Clostridioides difficile infection. Anaerobe 2019; 61:102129. [PMID: 31760080 DOI: 10.1016/j.anaerobe.2019.102129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/02/2019] [Accepted: 11/21/2019] [Indexed: 11/30/2022]
Abstract
Sporulation during Clostridioides difficile infection (CDI) contributes to recurrent disease. Cell division and sporulation both require peptidoglycan biosynthesis. We show C. difficile growth and sporulation is attenuated by antisenses to murA and murC or the MurA inhibitor fosfomycin. Thus, targeting the early steps of peptidoglycan biosynthesis might reduce the onset of recurrent CDI.
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Affiliation(s)
- Madhab Sapkota
- University of Texas at Arlington, Department of Biology, Arlington, TX, 76019, United States
| | - Ravi K R Marreddy
- Texas A & M University Health Science Center, Biosciences and Technology, Houston, TX, 77030, United States
| | - Xiaoqian Wu
- Texas A & M University Health Science Center, Biosciences and Technology, Houston, TX, 77030, United States
| | - Manish Kumar
- University of Texas at Arlington, Department of Biology, Arlington, TX, 76019, United States
| | - Julian G Hurdle
- Texas A & M University Health Science Center, Biosciences and Technology, Houston, TX, 77030, United States.
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7
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Tsutsumi LS, Elmore JM, Dang UT, Wallace MJ, Marreddy R, Lee RB, Tan GT, Hurdle JG, Lee RE, Sun D. Solid-Phase Synthesis and Antibacterial Activity of Cyclohexapeptide Wollamide B Analogs. ACS COMBINATORIAL SCIENCE 2018; 20:172-185. [PMID: 29431987 DOI: 10.1021/acscombsci.7b00189] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Herein we report the antibacterial structure-activity relationships of cyclic hexapeptide wollamide analogs derived from solid-phase library synthesis. Wollamide B, a cyclic hexapeptide natural product, has been previously found to have activity against Mycobacterium bovis. To further evaluate its antimycobacterial/antibacterial potential, 27 peptides including wollamides A/B, and desotamide B, were synthesized and subsequently tested against a panel of clinically significant bacterial pathogens. Biological evaluation revealed that the cyclic scaffold, amide functionality in position I, tryptophan residue in position V, and the original stereochemistry pattern of the core scaffold were key for antituberculosis and/or antibacterial activity. In addition, against M. tuberculosis and Gram-positive bacteria, residues in position II and/or VI greatly impacted antibacterial activity and selectivity. Wollamides A (3) and B (2) along with their corresponding II (l-Leu) analog 10 retained the most promising antituberculosis activity, with the lowest minimum inhibitory concentration (MIC) against virulent M. tuberculosis H37Rv (MIC = 1.56 μg/mL), as well as desirable selectivity indices (>100). Importantly, the antimicrobial activities of wollamides A and B do not result from disruption of the bacterial membrane, warranting further investigation into their mechanism of action.
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Affiliation(s)
- Lissa S. Tsutsumi
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, Hawaii 96720, United States
| | - John M. Elmore
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, MS#1000, Memphis, Tennessee 38105, United States
| | - Uyen T. Dang
- Center for Infectious and Inflammatory Diseases, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, Texas 77030, United States
| | - Miranda J. Wallace
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, MS#1000, Memphis, Tennessee 38105, United States
| | - Ravikanthreddy Marreddy
- Center for Infectious and Inflammatory Diseases, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, Texas 77030, United States
| | - Robin B. Lee
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, MS#1000, Memphis, Tennessee 38105, United States
| | - Ghee T. Tan
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, Hawaii 96720, United States
| | - Julian G. Hurdle
- Center for Infectious and Inflammatory Diseases, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, Texas 77030, United States
| | - Richard E. Lee
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, MS#1000, Memphis, Tennessee 38105, United States
| | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, Hawaii 96720, United States
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Xu N, Meng H, Liu T, Feng Y, Qi Y, Zhang D, Wang H. Blueberry Phenolics Reduce Gastrointestinal Infection of Patients with Cerebral Venous Thrombosis by Improving Depressant-Induced Autoimmune Disorder via miR-155-Mediated Brain-Derived Neurotrophic Factor. Front Pharmacol 2017; 8:853. [PMID: 29230173 PMCID: PMC5712003 DOI: 10.3389/fphar.2017.00853] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/07/2017] [Indexed: 01/03/2023] Open
Abstract
Cerebral venous thrombosis (CVT) often causes human depression, whereas depression-induced low immunity makes the patients susceptible to gastrointestinal infection. Blueberry possesses antidepressant properties which may improve autoimmunity and reduce gastrointestinal infection. Brain-derived neurotrophic factor (BDNF) performs antidepressant function and can be regulated by miR-155, which may be affected by blueberry. To explore the possible molecular mechanism, blueberry compounds were analyzed by high-performance liquid chromatography. Activity of compounds was tested by using HT22 cells. The present study tested 124 patients with CVT-induced mild-to-moderate depressive symptoms (Center for Epidemiologic Studies—Depression Scale [CES-D] ≥16) and gastrointestinal infection. Patients were randomly assigned to blueberry extract group (BG, received 10 mg blueberry extract daily) and placebo group (PG, received 10 mg placebo daily). After 3 months, depression, gastrointestinal infection and lipid profiles were investigated. Serum miR-155 and BDNF were measured using real-time quantitative polymerase chain reaction and or Western Blot. Blueberry treatment improved depressive symptoms and lipid profiles, and also reduced gastrointestinal infection in the BG group (P < 0.05) but those of the PG group (P = 1). These changes were paralleled by increase in serum levels of BDNF and miR-155 (P < 0.05). HPLC analysis showed that blueberry extracts were the main phenolic acids with 0.18, 0.85, 0.26, 0.72, 0.66, 0.4,1, and 1.92 mg/g of gentisic acid, chlorogenic acid, [2]-epicatechin, p-coumaric acid, benzoic acid, p-anisic acid, and quercetin in blueberry extracts, respectively. Phenolics in blueberry are possible causal agents in improving antidepressant activity and reducing gastrointestinal infection. Administration of blueberry increased BDNF expression and miR-155. Blueberry cannot affect BDNF level when miR-155 is overexpressed or inhibited. Phenolics from blueberry reduced gastrointestinal infection of patients with CVT by improving antidepressant activity via upregulation of miR-155-mediated BDNF.
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Affiliation(s)
- Ning Xu
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Hao Meng
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Tianyi Liu
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Yingli Feng
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Yuan Qi
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Donghuan Zhang
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Honglei Wang
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
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Reid R, Bolton D, Tiuftin AA, Kerry JP, Fanning S, Whyte P. Controlling Blown Pack Spoilage Using Anti-Microbial Packaging. Foods 2017; 6:E67. [PMID: 28805679 PMCID: PMC5575642 DOI: 10.3390/foods6080067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 11/16/2022] Open
Abstract
Active (anti-microbial) packaging was prepared using three different formulations; Auranta FV; Inbac-MDA and sodium octanoate at two concentrations (2.5 and 3.5 times their minimum inhibitory concentration (MIC, the lowest concentration that will inhibit the visible growth of the organisms) against Clostridium estertheticum, DSMZ 8809). Inoculated beef samples were packaged using the active packaging and monitored for 100 days storage at 2 °C for blown pack spoilage. The time to the onset of blown pack spoilage was significantly (p < 0.01) increased using Auranta FV and sodium octanoate (caprylic acid sodium salt) at both concentrations. Moreover, sodium octanoate packs had significantly (p < 0.01) delayed blown pack spoilage as compared to Auranta FV. It was therefore concluded that Auranta FV or sodium octanoate, incorporated into the packaging materials used for vacuum packaged beef, would inhibit blown pack spoilage and in the case of the latter, well beyond the 42 days storage period currently required for beef primals.
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Affiliation(s)
- Rachael Reid
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
| | - Declan Bolton
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
| | - Andrey A Tiuftin
- Food Packaging Group, School of Food & Nutritional Sciences, University College Cork, College Road, Cork, Ireland.
| | - Joe P Kerry
- Food Packaging Group, School of Food & Nutritional Sciences, University College Cork, College Road, Cork, Ireland.
| | - Séamus Fanning
- School of Public Health, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Paul Whyte
- School of Public Health, University College Dublin, Belfield, Dublin 4, Ireland.
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10
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Stompor M. 6-Acetamidoflavone obtained by microbiological and chemical methods and its antioxidant activity. J Biotechnol 2016; 237:25-34. [DOI: 10.1016/j.jbiotec.2016.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/01/2016] [Accepted: 09/12/2016] [Indexed: 02/07/2023]
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Rifamycin Resistance in Clostridium difficile Is Generally Associated with a Low Fitness Burden. Antimicrob Agents Chemother 2016; 60:5604-7. [PMID: 27381389 DOI: 10.1128/aac.01137-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/25/2016] [Indexed: 12/22/2022] Open
Abstract
We characterized clinically occurring and novel mutations in the β subunit of RNA polymerase in Clostridium difficile (CdRpoB), conferring rifamycin (including rifaximin) resistance. The Arg505Lys substitution did not impose an in vitro fitness cost, which may be one reason for its dominance among rifamycin-resistant clinical isolates. These observations were supported through the structural modeling of CdRpoB. In general, most mutations lacked in vitro fitness costs, suggesting that rifamycin resistance may in some cases persist in the clinic.
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12
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Cherian PT, Wu X, Yang L, Scarborough JS, Singh AP, Alam ZA, Lee RE, Hurdle JG. Gastrointestinal localization of metronidazole by a lactobacilli-inspired tetramic acid motif improves treatment outcomes in the hamster model of Clostridium difficile infection. J Antimicrob Chemother 2015; 70:3061-9. [PMID: 26286574 DOI: 10.1093/jac/dkv231] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/07/2015] [Indexed: 01/30/2023] Open
Abstract
OBJECTIVES Metronidazole, a mainstay treatment for Clostridium difficile infection (CDI), is often ineffective for severe CDI. Whilst this is thought to arise from suboptimal levels of metronidazole in the colon due to rapid absorption, empirical validation is lacking. In contrast, reutericyclin, an antibacterial tetramic acid from Lactobacillus reuteri, concentrates in the gastrointestinal tract. In this study, we modified metronidazole with reutericyclin's tetramic acid motif to obtain non-absorbed compounds, enabling assessment of the impact of pharmacokinetics on treatment outcomes. METHODS A series of metronidazole-bearing tetramic acid substituents were synthesized and evaluated in terms of anti-C. difficile activities, gastric permeability, in vivo pharmacokinetics, efficacy in the hamster model of CDI and mode of action. RESULTS Most compounds were absorbed less than metronidazole in cell-based Caco-2 permeability assays. In hamsters, lead compounds compartmentalized in the colon rather than the bloodstream with negligible levels detected in the blood, in direct contrast with metronidazole, which was rapidly absorbed into the blood and was undetectable in caecum. Accordingly, four leads were more efficacious (P < 0.05) than metronidazole in C. difficile-infected animals. Improved efficacy was not due to an alternative mode of action, as the leads retained the mode of action of metronidazole. CONCLUSIONS This study provides the clearest empirical evidence that the high absorption of metronidazole lowers treatment outcomes for CDI and suggests a role for the tetramic acid motif for colon-specific drug delivery. This approach also has the potential to lower systemic toxicity and drug interactions of nitroheterocyclic drugs for treating gastrointestine-specific diseases.
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Affiliation(s)
- Philip T Cherian
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xiaoqian Wu
- Department of Biology, University of Texas, Arlington, TX 76019, USA Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Lei Yang
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jerrod S Scarborough
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Aman P Singh
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA Biomedical Sciences Program, Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Zahidul A Alam
- Department of Biology, University of Texas, Arlington, TX 76019, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Julian G Hurdle
- Department of Biology, University of Texas, Arlington, TX 76019, USA Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807, USA
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Jarrad A, Karoli T, Blaskovich MAT, Lyras D, Cooper MA. Clostridium difficile drug pipeline: challenges in discovery and development of new agents. J Med Chem 2015; 58:5164-85. [PMID: 25760275 PMCID: PMC4500462 DOI: 10.1021/jm5016846] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Indexed: 12/17/2022]
Abstract
In the past decade Clostridium difficile has become a bacterial pathogen of global significance. Epidemic strains have spread throughout hospitals, while community acquired infections and other sources ensure a constant inoculation of spores into hospitals. In response to the increasing medical burden, a new C. difficile antibiotic, fidaxomicin, was approved in 2011 for the treatment of C. difficile-associated diarrhea. Rudimentary fecal transplants are also being trialed as effective treatments. Despite these advances, therapies that are more effective against C. difficile spores and less damaging to the resident gastrointestinal microbiome and that reduce recurrent disease are still desperately needed. However, bringing a new treatment for C. difficile infection to market involves particular challenges. This review covers the current drug discovery pipeline, including both small molecule and biologic therapies, and highlights the challenges associated with in vitro and in vivo models of C. difficile infection for drug screening and lead optimization.
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Affiliation(s)
- Angie
M. Jarrad
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Tomislav Karoli
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Mark A. T. Blaskovich
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Dena Lyras
- School
of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Matthew A. Cooper
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
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Mode of action and bactericidal properties of surotomycin against growing and nongrowing Clostridium difficile. Antimicrob Agents Chemother 2015; 59:5165-70. [PMID: 26055381 DOI: 10.1128/aac.01087-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/05/2015] [Indexed: 01/05/2023] Open
Abstract
Surotomycin (CB-183,315), a cyclic lipopeptide, is in phase 3 clinical development for the treatment of Clostridium difficile infection. We report here the further characterization of the in vitro mode of action of surotomycin, including its activity against growing and nongrowing C. difficile. This was assessed through time-kill kinetics, allowing a determination of the effects on the membrane potential and permeability and macromolecular synthesis in C. difficile. Against representative strains of C. difficile, surotomycin displayed concentration-dependent killing of both logarithmic-phase and stationary-phase cultures at a concentration that was ≤16× the MIC. Exposure resulted in the inhibition of macromolecular synthesis (in DNA, RNA, proteins, and cell wall). At bactericidal concentrations, surotomycin dissipated the membrane potential of C. difficile without changes to the permeability of propidium iodide. These observations are consistent with surotomycin acting as a membrane-active antibiotic, exhibiting rapid bactericidal activities against growing and nongrowing C. difficile.
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Feng L, Maddox MM, Alam MZ, Tsutsumi LS, Narula G, Bruhn DF, Wu X, Sandhaus S, Lee RB, Simmons CJ, Tse-Dinh YC, Hurdle JG, Lee RE, Sun D. Synthesis, structure-activity relationship studies, and antibacterial evaluation of 4-chromanones and chalcones, as well as olympicin A and derivatives. J Med Chem 2014; 57:8398-420. [PMID: 25238443 PMCID: PMC4207537 DOI: 10.1021/jm500853v] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
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On
the basis of recently reported abyssinone II and olympicin A, a series
of chemically modified flavonoid phytochemicals were synthesized and
evaluated against Mycobacterium tuberculosis and
a panel of Gram-positive and -negative bacterial pathogens. Some of
the synthesized compounds exhibited good antibacterial activities
against Gram-positive pathogens including methicillin resistant Staphylococcus aureus with minimum inhibitory concentration
as low as 0.39 μg/mL. SAR analysis revealed that the 2-hydrophobic
substituent and the 4-hydrogen bond donor/acceptor of the 4-chromanone
scaffold together with the hydroxy groups at 5- and 7-positions enhanced
antibacterial activities; the 2′,4′-dihydroxylated A
ring and the lipophilic substituted B ring of chalcone derivatives
were pharmacophoric elements for antibacterial activities. Mode of
action studies performed on selected compounds revealed that they
dissipated the bacterial membrane potential, resulting in the inhibition
of macromolecular biosynthesis; further studies showed that selected
compounds inhibited DNA topoisomerase IV, suggesting complex mechanisms
of actions for compounds in this series.
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Affiliation(s)
- Li Feng
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo , 34 Rainbow Drive, Hilo, Hawaii 96720, United States
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Chemical modulation of the biological activity of reutericyclin: a membrane-active antibiotic from Lactobacillus reuteri. Sci Rep 2014; 4:4721. [PMID: 24739957 PMCID: PMC4894453 DOI: 10.1038/srep04721] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/01/2014] [Indexed: 11/08/2022] Open
Abstract
Whilst the development of membrane-active antibiotics is now an attractive therapeutic concept, progress in this area is disadvantaged by poor knowledge of the structure-activity relationship (SAR) required for optimizing molecules to selectively target bacteria. This prompted us to explore the SAR of the Lactobacillus reuteri membrane-active antibiotic reutericyclin, modifying three key positions about its tetramic acid core. The SAR revealed that lipophilic analogs were generally more active against Gram-positive pathogens, but introduction of polar and charged substituents diminished their activity. This was confirmed by cytometric assays showing that inactive compounds failed to dissipate the membrane potential. Radiolabeled substrate assays indicated that dissipation of the membrane potential by active reutericyclins correlated with inhibition of macromolecular synthesis in cells. However, compounds with good antibacterial activities also showed cytotoxicity against Vero cells and hemolytic activity. Although this study highlights the challenge of optimizing membrane-active antibiotics, it shows that by increasing antibacterial potency the selectivity index could be widened, allowing use of lower non-cytotoxic doses.
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Shao Z, Wang L, Xu L, Zhao H, Xiao J. Facile synthesis of azaarene-2-substituted chromanone derivatives via tandem sp3 C–H functionalization/decarboxylation of azaarenes with 4-oxo-4H-chromene-3-carboxylic acid. RSC Adv 2014. [DOI: 10.1039/c4ra09338k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A facile catalyst-free tandem sp3 C–H functionalization/decarboxylation of 4-oxo-4H-chromene-3-carboxylic acid with 2-alkylazaarenes was developed, which can construct the biologically significant azaarene 2-substituted chromanones in a single step.
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Affiliation(s)
- Zhuzhou Shao
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao, China
| | - Liang Wang
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao, China
| | - Lubin Xu
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao, China
| | - Huaili Zhao
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao, China
| | - Jian Xiao
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao, China
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Tsutsumi LS, Owusu YB, Hurdle JG, Sun D. Progress in the discovery of treatments for C. difficile infection: A clinical and medicinal chemistry review. Curr Top Med Chem 2014; 14:152-75. [PMID: 24236721 PMCID: PMC3921470 DOI: 10.2174/1568026613666131113154753] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/06/2013] [Accepted: 09/15/2013] [Indexed: 02/07/2023]
Abstract
Clostridium difficile is an anaerobic, Gram-positive pathogen that causes C. difficile infection, which results in significant morbidity and mortality. The incidence of C. difficile infection in developed countries has become increasingly high due to the emergence of newer epidemic strains, a growing elderly population, extensive use of broad spectrum antibiotics, and limited therapies for this diarrheal disease. Because treatment options currently available for C. difficile infection have some drawbacks, including cost, promotion of resistance, and selectivity problems, new agents are urgently needed to address these challenges. This review article focuses on two parts: the first part summarizes current clinical treatment strategies and agents under clinical development for C. difficile infection; the second part reviews newly reported anti-difficile agents that have been evaluated or reevaluated in the last five years and are in the early stages of drug discovery and development. Antibiotics are divided into natural product inspired and synthetic small molecule compounds that may have the potential to be more efficacious than currently approved treatments. This includes potency, selectivity, reduced cytotoxicity, and novel modes of action to prevent resistance.
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Affiliation(s)
| | | | | | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA.
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