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Rahimi B, Malekifard F, Esmaeilnejad B. In vitro anti-Trichomonas gallinae effects of Ziziphus vulgaris L. and Camellia sinensis (L.) Kuntze extracts. Vet Med Sci 2024; 10:e1432. [PMID: 38527006 PMCID: PMC10962798 DOI: 10.1002/vms3.1432] [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: 10/28/2023] [Revised: 02/17/2024] [Accepted: 03/10/2024] [Indexed: 03/27/2024] Open
Abstract
BACKGROUND Trichomonas gallinae is a parasite that causes canker and severe loss and death, especially in young pigeons. Metronidazole (MTZ) is the recommended drug for treating avian trichomoniasis. Due to drug resistance, non-chemical alternatives, such as medicinal plant extracts, are also considered possible therapies for this disease. OBJECTIVES This study compares the antitrichomonal effects of MTZ with extracts of Camellia sinensis and Ziziphus vulgaris on T. gallinae in vitro. METHODS Samples of T. gallinae were taken from infected pigeons. Multi-well plates with different concentrations (5, 10, 25, 50 and 100 µg/mL) of plant extracts were used for the in vitro study. RESULTS The minimum inhibitory concentration (MIC) of C. sinensis extract was 25 µg/mL over 24 h, compared to 50 µg/mL for MTZ. The MIC value of the Z. vulgaris extracts was 50 µg/mL. CONCLUSIONS The results suggest that the extracts of Z. vulgaris and C. sinensis, as potential natural agents, could have anti-avian trichomoniasis properties. This study also shows that MTZ, C. sinensis and Z. vulgaris are equally effective in preventing the growth of T. gallinae trophozoites in the culture.
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Affiliation(s)
- Behnam Rahimi
- DVM graduateFaculty of Veterinary MedicineUrmia UniversityUrmiaIran
| | - Farnaz Malekifard
- Department of PathobiologyFaculty of Veterinary MedicineUrmia UniversityUrmiaIran
| | - Bijan Esmaeilnejad
- Department of PathobiologyFaculty of Veterinary MedicineUrmia UniversityUrmiaIran
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2
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Gál R, Halmosi R, Gallyas F, Tschida M, Mutirangura P, Tóth K, Alexy T, Czopf L. Resveratrol and beyond: The Effect of Natural Polyphenols on the Cardiovascular System: A Narrative Review. Biomedicines 2023; 11:2888. [PMID: 38001889 PMCID: PMC10669290 DOI: 10.3390/biomedicines11112888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/11/2023] [Accepted: 10/19/2023] [Indexed: 11/26/2023] Open
Abstract
Cardiovascular diseases (CVDs) are among the leading causes of morbidity and mortality worldwide. Unhealthy dietary habits have clearly been shown to contribute to the development of CVDs. Beyond the primary nutrients, a healthy diet is also rich in plant-derived compounds. Natural polyphenols, found in fruits, vegetables, and red wine, have a clear role in improving cardiovascular health. In this review, we strive to summarize the results of the relevant pre-clinical and clinical trials that focused on some of the most important natural polyphenols, such as resveratrol and relevant flavonoids. In addition, we aim to identify their common sources, biosynthesis, and describe their mechanism of action including their regulatory effect on signal transduction pathways. Finally, we provide scientific evidence regarding the cardiovascular benefits of moderate, long-term red wine consumption.
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Affiliation(s)
- Roland Gál
- Division of Cardiology, 1st Department of Medicine, Medical School, University of Pecs, 7624 Pecs, Hungary; (R.G.); (R.H.); (K.T.)
- Szentágothai Research Centre, University of Pecs, 7624 Pecs, Hungary
| | - Róbert Halmosi
- Division of Cardiology, 1st Department of Medicine, Medical School, University of Pecs, 7624 Pecs, Hungary; (R.G.); (R.H.); (K.T.)
- Szentágothai Research Centre, University of Pecs, 7624 Pecs, Hungary
| | - Ferenc Gallyas
- Department of Biochemistry and Medical Chemistry, University of Pecs, 7624 Pecs, Hungary;
| | - Michael Tschida
- Medical School, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Pornthira Mutirangura
- Department of Medicine, University of Minnesota Medical School, Minneapolis, MN 55455, USA;
| | - Kálmán Tóth
- Division of Cardiology, 1st Department of Medicine, Medical School, University of Pecs, 7624 Pecs, Hungary; (R.G.); (R.H.); (K.T.)
- Szentágothai Research Centre, University of Pecs, 7624 Pecs, Hungary
| | - Tamás Alexy
- Department of Medicine, Division of Cardiology, University of Minnesota, Minneapolis, MN 55455, USA;
| | - László Czopf
- Division of Cardiology, 1st Department of Medicine, Medical School, University of Pecs, 7624 Pecs, Hungary; (R.G.); (R.H.); (K.T.)
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3
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Guo J, Li K, Lin Y, Liu Y. Protective effects and molecular mechanisms of tea polyphenols on cardiovascular diseases. Front Nutr 2023; 10:1202378. [PMID: 37448666 PMCID: PMC10336229 DOI: 10.3389/fnut.2023.1202378] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023] Open
Abstract
Aging is the most important factor contributing to cardiovascular diseases (CVDs), and the incidence and severity of cardiovascular events tend to increase with age. Currently, CVD is the leading cause of death in the global population. In-depth analysis of the mechanisms and interventions of cardiovascular aging and related diseases is an important basis for achieving healthy aging. Tea polyphenols (TPs) are the general term for the polyhydroxy compounds contained in tea leaves, whose main components are catechins, flavonoids, flavonols, anthocyanins, phenolic acids, condensed phenolic acids and polymeric phenols. Among them, catechins are the main components of TPs. In this article, we provide a detailed review of the classification and composition of teas, as well as an overview of the causes of aging-related CVDs. Then, we focus on ten aspects of the effects of TPs, including anti-hypertension, lipid-lowering effects, anti-oxidation, anti-inflammation, anti-proliferation, anti-angiogenesis, anti-atherosclerosis, recovery of endothelial function, anti-thrombosis, myocardial protective effect, to improve CVDs and the detailed molecular mechanisms.
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Affiliation(s)
- Jun Guo
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing, China
| | - Kai Li
- General Surgery Department, The First People’s Hospital of Tai’an City, Tai’an, China
| | - Yajun Lin
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing Hospital/National Center of Gerontology of National Health Commission, Beijing, China
| | - Yinghua Liu
- Department of Nutrition, The First Medical Center, Chinese PLA General Hospital, Beijing, China
- National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, China
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4
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Mohsenzadeh MS, Razavi BM, Imenshahidi M, Mohajeri SA, Rameshrad M, Hosseinzadeh H. Evaluation of green tea extract and epigallocatechin gallate effects on bisphenol A-induced vascular toxicity in isolated rat aorta and cytotoxicity in human umbilical vein endothelial cells. Phytother Res 2020; 35:996-1009. [PMID: 32893422 DOI: 10.1002/ptr.6861] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 08/04/2020] [Accepted: 08/06/2020] [Indexed: 12/16/2022]
Abstract
This study was designed to assess bisphenol A (BPA)-induced vascular toxicity, the effectiveness of green tea extract and epigallocatechin gallate (EGCG) against BPA toxicity, and possible underlying mechanisms. In isolated rat aorta, contractile and relaxant responses as well as malondialdehyde levels were evaluated. Cell viability and effects on the protein levels of apoptotic (bax, bcl2, and caspase-3), autophagic (LC3), and cell adhesion molecules were calculated using the MTT method and western blotting in human umbilical vein endothelial cells (HUVECs). BPA increased aorta MDA levels (p < .0001) and decreased vascular responses to KCl [20 and 40 mM (p < .0001), 80 mM (p < .001)], phenylephrine [10-8 , 10-6 , and 10-5 M (p < .001), 10-7 and 10-4 M (p < .0001)], and acetylcholine [10-6 M (p < .01), 10-5 and 10-4 M (p < .0001)]. In HUVECs, BPA enhanced the levels of LC3A/B, bax/bcl2 ratio, cleaved caspase-3, and vascular cell adhesion molecule-1. Green tea extract, EGCG, and vitamin E co-treatment with BPA diminished the toxic effects of BPA. These findings provide evidence that green tea extract and EGCG possess beneficial effects in preventing BPA-induced vascular toxicity through increasing the antioxidant activities and the regulation of signaling pathways.
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Affiliation(s)
- Mahdieh Sadat Mohsenzadeh
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bibi Marjan Razavi
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.,Targeted Drug Delivery Research Center, Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohsen Imenshahidi
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Ahmad Mohajeri
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.,Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Rameshrad
- Natural Products and Medicinal Plants Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Hossein Hosseinzadeh
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.,Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
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5
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Lorenz M, Lehmann S, Djordjevic I, Düsterhöft T, Zimmermann BF, Stangl K, Stangl V. Vasodilation of Tea Polyphenols Ex Vivo Is Mediated by Hydrogen Peroxide Under Rapid Compound Decay. Antioxidants (Basel) 2020; 9:antiox9050390. [PMID: 32392754 PMCID: PMC7278881 DOI: 10.3390/antiox9050390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 12/31/2022] Open
Abstract
Improvement of endothelial function represents a major health effect of tea in humans. Ex vivo, tea and tea polyphenols stimulate nitric oxide (NO)-dependent vasodilation in isolated blood vessels. However, it was reported that polyphenols can generate reactive oxygen species (ROS) in vitro. We therefore aimed to elucidate the role of ROS production in tea polyphenol-induced vasodilation in explanted aortic rings. Vasorelaxation of rat aortic rings was assessed in an organ chamber model with low concentrations of epigallocatechin-3-gallate (EGCG), theaflavin-3,3'-digallate (TF3), and with green and black tea, with or without pretreatment with catalase or superoxide dismutase (SOD). The stability of EGCG and TF3 was measured by HPLC, and the levels of hydrogen peroxide (H2O2) were determined. EGCG and green tea-induced vasorelaxation was completely prevented by catalase and slightly increased by SOD. TF3 and black tea yielded similar results. Both EGCG and TF3 were rapidly degraded. This was associated with increasing H2O2 levels over time. Hydrogen peroxide concentrations produced in a time range compatible with tea polyphenol decay induced NO-dependent vasodilation in aortic rings. In conclusion, tea polyphenol-induced vasodilation in vitro is mediated by low levels of H2O2 generated during compound decay. The results could explain the apparent lack of vasodilatory effects of isolated tea polyphenols in humans.
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Affiliation(s)
- Mario Lorenz
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, 10117 Berlin, Germany; (T.D.); (K.S.); (V.S.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 10115 Berlin, Germany
- Correspondence: ; Tel.: +49-30-450-513-186
| | - Stephanie Lehmann
- Fachbereich Veterinärmedizin, Institut für Veterinär-Biochemie, Freie Universität Berlin, 14163 Berlin, Germany;
| | - Ilija Djordjevic
- Klinik und Poliklinik für Herzchirurgie, Herzchirurgische Intensivmedizin und Thoraxchirurgie, Universitätsklinikum Köln, 50937 Köln, Germany;
| | - Thomas Düsterhöft
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, 10117 Berlin, Germany; (T.D.); (K.S.); (V.S.)
| | - Benno F. Zimmermann
- Institut für Ernährungs- und Lebensmittelwissenschaften, Universität Bonn, 53115 Bonn, Germany;
| | - Karl Stangl
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, 10117 Berlin, Germany; (T.D.); (K.S.); (V.S.)
| | - Verena Stangl
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Medizinische Klinik für Kardiologie und Angiologie, Campus Mitte, 10117 Berlin, Germany; (T.D.); (K.S.); (V.S.)
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, 10115 Berlin, Germany
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Morais IBDM, Silva DB, Carollo CA, Ferreira-Neto ML, Fidelis-de-Oliveira P, Bispo-da-Silva LB. Hypotensive activity of Campomanesia xanthocarpa leaf extract: beyond angiotensin II type 1 receptor blockage. Nat Prod Res 2020; 35:4798-4802. [PMID: 32081043 DOI: 10.1080/14786419.2020.1727467] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The ability of Campomanesia xanthocarpa leaf extract (CXLE) to alter blood pressure and heart rate was evaluated in anesthetized rats. The CXLE-induced hypotension was evaluated before and after losartan, methylatropine, L-N(ω)-nitro-L-arginine methyl ester (L-NAME), hexamethonium, indomethacin, glibenclamide, or nifedipine administration. The constituents of CXLE were identified by LC-DAD-MS. CXLE decreased blood pressure in a dose-dependent manner; only the highest dose decreased heart rate. The hypotension induced by CXLE was sensitive only to losartan, nifedipine, and glibenclamide. L-NAME decreased the time to recover 50% of the hypotensive effect of CXLE without altering its magnitude. Flavan-3-ols, proanthocyanidins (dimers and trimers), and glycosylated flavonols were identified from CXLE. The chemical constituents of CXLE seem to induce not only angiotensin II type 1 receptor blockage, but also ATP-sensitive potassium channels activation and L-type voltage-dependent Ca2+ channels inactivation. Nitric oxide is involved in the maintenance of the hypotensive effect of CXLE.
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Affiliation(s)
- Ingrid Beatriz de Melo Morais
- Department of Pharmacology, Institute of Biomedical Sciences, Federal University of Uberlândia/UFU, Campus Umuarama, Uberlândia, Brazil
| | - Denise Brentan Silva
- Laboratório de Produtos Naturais e Espectrometria de Massas (LAPNEM), Federal University of Mato Grosso do Sul/UFMS, Campo Grande, Brazil
| | - Carlos Alexandre Carollo
- Laboratório de Produtos Naturais e Espectrometria de Massas (LAPNEM), Federal University of Mato Grosso do Sul/UFMS, Campo Grande, Brazil
| | - Marcos Luiz Ferreira-Neto
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia/UFU, Campus Umuarama, Uberlândia, Brazil
| | | | - Luiz Borges Bispo-da-Silva
- Department of Pharmacology, Institute of Biomedical Sciences, Federal University of Uberlândia/UFU, Campus Umuarama, Uberlândia, Brazil
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7
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Jankovic G, Marinko M, Milojevic P, Stojanovic I, Nenezic D, Kanjuh V, Yang Q, He GW, Novakovic A. Mechanisms of endothelium-dependent vasorelaxation induced by procyanidin B2 in venous bypass graft. J Pharmacol Sci 2019; 142:101-108. [PMID: 31874782 DOI: 10.1016/j.jphs.2019.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/22/2019] [Accepted: 11/13/2019] [Indexed: 10/25/2022] Open
Abstract
Cardioprotective abilities of procyanidins, might, at least in part, attribute to their vasodilator properties. The present study was undertaken to assess the vasorelaxant effect of procyanidin B2 on isolated human saphenous vein (HSV) and its underlying mechanisms. Procyanidin B2 relaxed phenylephrine-induced contraction of HSV rings in concentration-dependent manner. The relaxation was dependent on the presence of endothelium and was strongly affected by l-NAME, hydroxocobalamin or ODQ, the inhibitors of NO/cGMP pathway. Indomethacin significantly affected only the relaxation produced by the highest concentrations of procyanidin B2. Apamin and TRAM-34 combination, in the presence of l-NAME and indomethacin, did not additionally decreased procyanidin B2-induced relaxation. In the presence of K+ channel blockers, relaxation induced by procyanidin B2 was partially attenuated by 4-aminopyridine, significantly inhibited by glibenclamide and almost abolished by iberiotoxin. Procyanidin B2 also relaxed the contractions induced by phenylephrine or caffeine in Ca2+-free solution. Finally, nifedipine slightly, while thapsigargin strongly antagonized HSV relaxation. Our results indicate that procyanidin B2 induces endothelium-dependent relaxation of HSV, which results primarily from stimulation of NO production, as well K+ channels opening, especially BKCa, and partially KATP and KV. Regulation of the intracellular Ca2+ release and inhibition of Ca2+ influx probably contribute to procyanidin B2-induced relaxation.
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Affiliation(s)
- Goran Jankovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Marija Marinko
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Predrag Milojevic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Ivan Stojanovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Dragoslav Nenezic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | | | - Qin Yang
- TEDA International Cardiovascular Hospital, Tianjin, China
| | - Guo-Wei He
- TEDA International Cardiovascular Hospital, Tianjin, China
| | - Aleksandra Novakovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia.
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Peixoto-Neves D, Soni H, Adebiyi A. CGRPergic Nerve TRPA1 Channels Contribute to Epigallocatechin Gallate-Induced Neurogenic Vasodilation. ACS Chem Neurosci 2019; 10:216-220. [PMID: 30513192 DOI: 10.1021/acschemneuro.8b00493] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Green tea polyphenol epigallocatechin gallate (EGCG), promotes vasodilation and reduces blood pressure, mechanisms of which are not fully resolved. Recent reports suggested that EGCG can activate heterologously expressed mouse and zebrafish TRPA1 channels. Activation of TRPA1 in sensory neurons triggers the release of calcitonin gene-related peptide (CGRP), a potent vasodilator. Whether CGRP-containing (CGRPergic) sensory nerves contribute to EGCG-induced reduction in vascular resistance remains unclear. In this study, we demonstrate that intravenous infusion of EGCG elevated the plasma level of CGRP in mice, an effect that was attenuated by TRPA1 channel blocker A-967079. EGCG-induced increase in mesenteric artery blood flow and reduction in mean arterial pressure were reversed by A-967079, CGRP receptor antagonist CGRP8-37, and CGRP depletion in perivascular nerves. Moreover, EGCG stimulated TRPA1-dependent intracellular Ca2+ elevation and CGRP release in a differentiated rat embryonic dorsal root ganglion/mouse neuroblastoma hybrid cell line. Together, these data suggest that EGCG-induced activation of TRPA1 channels in perivascular CGRPergic nerves decreases vascular resistance via Ca2+-dependent exocytosis of CGRP.
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Affiliation(s)
- Dieniffer Peixoto-Neves
- Department of Physiology, College of Medicine University of Tennessee Health Science Center, 956 Court Avenue, Memphis, Tennessee 38163, United States
| | - Hitesh Soni
- Department of Physiology, College of Medicine University of Tennessee Health Science Center, 956 Court Avenue, Memphis, Tennessee 38163, United States
| | - Adebowale Adebiyi
- Department of Physiology, College of Medicine University of Tennessee Health Science Center, 956 Court Avenue, Memphis, Tennessee 38163, United States
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MacRae K, Connolly K, Vella R, Fenning A. Epicatechin's cardiovascular protective effects are mediated via opioid receptors and nitric oxide. Eur J Nutr 2018; 58:515-527. [PMID: 29748816 DOI: 10.1007/s00394-018-1650-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 10/13/2017] [Indexed: 12/14/2022]
Abstract
PURPOSE Cardiovascular disease is the leading cause of mortality globally. Epicatechin has previously been shown to improve vascular responses and possess cardioprotective properties. However, the mechanisms underpinning these cardiotropic outcomes remain unknown. The aim of this study was to further identify epicatechin's mechanism of action in the cardiovasculature. METHODS The effects of epicatechin on isolated rat conduit arteries, resistance vessels and cardiac electrophysiology were investigated on resting tension and precontracted vessels and cardiac action potential parameters, both in the presence and in the absence of various antagonists. RESULTS At resting tension, epicatechin alone did not affect the vasoreactivity of either conduit or resistance vessels. In noradrenaline pre-contracted thoracic aortic arteries and potassium chloride pre-contracted mesenteric vessels, epicatechin (10-9-10-4 M) induced significant vasorelaxation. The addition of naloxone (10-5 M), NG-nitro-L-arginine methyl ester (10-5M), 4-aminopyridine (5 mM) and verapamil (10-5 M) attenuated epicatechin-mediated vasorelaxation. No change in epicatechin-mediated vasorelaxation was observed with the addition of atropine (10-5 M). Epicatechin significantly improved cardiac electrophysiology by reducing the resting membrane potential, action potential amplitude and force of contraction that was mitigated following the addition of naloxone (10-5 M). Epicatechin significantly decreased the action potential duration at 20, 50 and 90% duration and time to 90% relaxation of force that was unchanged following the addition of naloxone (10-5 M). CONCLUSIONS These findings suggest epicatechin's vascular responses and cardioprotective effects are mediated through opioid receptors, nitric oxide, potassium channel and calcium channel activation and highlight the importance of the endothelium/nitric oxide in epicatechin mediated vasorelaxation.
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Affiliation(s)
- Kirsty MacRae
- School of Health, Medical and Applied Sciences, CQUniversity, Building 81, North Rockhampton, QLD, 4702, Australia
| | - Kylie Connolly
- School of Health, Medical and Applied Sciences, CQUniversity, Building 81, North Rockhampton, QLD, 4702, Australia
| | - Rebecca Vella
- School of Health, Medical and Applied Sciences, CQUniversity, Building 81, North Rockhampton, QLD, 4702, Australia
| | - Andrew Fenning
- School of Health, Medical and Applied Sciences, CQUniversity, Building 81, North Rockhampton, QLD, 4702, Australia.
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10
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Marinko M, Jankovic G, Nenezic D, Milojevic P, Stojanovic I, Kanjuh V, Novakovic A. (-)-Epicatechin-induced relaxation of isolated human saphenous vein: Roles of K + and Ca 2+ channels. Phytother Res 2017; 32:267-275. [PMID: 29193528 DOI: 10.1002/ptr.5969] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/02/2017] [Accepted: 10/09/2017] [Indexed: 01/05/2023]
Abstract
In this study, we aimed to investigate relaxant effect of flavanol (-)-epicatechin on the isolated human saphenous vein (HSV), as a part of its cardioprotective action, and to define the mechanisms underlying this vasorelaxation. (-)-Epicatechin induced a concentration-dependent relaxation of HSV pre-contracted by phenylephrine. Among K+ channel blockers, 4-aminopyridine, margatoxin, and iberiotoxin significantly inhibited relaxation of HSV, while glibenclamide considerably reduced effects of the high concentrations of (-)-epicatechin. Additionally, (-)-epicatechin relaxed contraction induced by 80 mM K+ , whereas in the presence of nifedipine produced partial relaxation of HSV rings pre-contracted by phenylephrine. In Ca2+ -free solution, (-)-epicatechin relaxed contraction induced by phenylephrine, but had no effect on contraction induced by caffeine. A sarcoplasmic reticulum Ca2+ -ATPase inhibitor, thapsigargin, significantly reduced relaxation of HSV produced by (-)-epicatechin. These results demonstrate that (-)-epicatechin produces endothelium-independent relaxation of isolated HSV rings. Vasorelaxation to (-)-epicatechin probably involves activation of 4-aminopyridine- and margatoxin-sensitive KV channels, BKCa channels, and at least partly, KATP channels. In addition, not only the inhibition of extracellular Ca2+ influx, but regulation of the intracellular Ca2+ release, via inositol-trisphosphate receptors and reuptake into sarcoplasmic reticulum, via stimulation of Ca2+ -ATPase, as well, most likely participate in (-)-epicatechin-induced relaxation of HSV.
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Affiliation(s)
- Marija Marinko
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Goran Jankovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Dragoslav Nenezic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Predrag Milojevic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Ivan Stojanovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | | | - Aleksandra Novakovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
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11
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Abdulkhaleq LA, Assi MA, Noor MHM, Abdullah R, Saad MZ, Taufiq-Yap YH. Therapeutic uses of epicatechin in diabetes and cancer. Vet World 2017; 10:869-872. [PMID: 28919675 PMCID: PMC5591471 DOI: 10.14202/vetworld.2017.869-872] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/13/2017] [Indexed: 12/20/2022] Open
Abstract
Epicatechin is a natural flavonoid found in green tea. It has been reported to possess an immense antioxidant effect which contributes to its therapeutic effect against a handful of ailments. In this review, we discuss its therapeutic role in the management of two of the most important human diseases; diabetes and cancer. The consumption of epicatechin has been shown to reduce blood glucose levels in diabetic patients, while is anticancer effect was attributed to its antioxidant properties, antiangiogenic and direct cytotoxicity to cancer cells. Although the exact mechanism of action of epicatechin is still being explored, there is no doubt that it is a promising candidate as an alternative. The significance of this review is to highlight the importance of the usage of natural products (in this case, epicatechin) as an alternative for the treatment of two potentially fatal diseases which is diabetes and cancer. The aim of this review is to educate the scientific community on the role of epicatechin in ameliorating the effects of diabetes and cancers on human while understanding the potential mechanisms of these aforementioned effects.
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Affiliation(s)
- Layth Abdulmajeed Abdulkhaleq
- Department of Veterinary Laboratory Diagnostics, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Department of Pathology and Poultry Diseases, Faculty of Veterinary Medicine, Baghdad University, Baghdad, Iraq
| | - Mohammed Abdulrazzaq Assi
- Department of Veterinary Preclinical Sciences, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.,Department of Community Health, College of Health and Medical Techniques, Al-Furat Al-Awsat Technical University, Iraq
| | - Mohd Hezmee Mohd Noor
- Department of Veterinary Preclinical Sciences, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Rasedee Abdullah
- Department of Veterinary Laboratory Diagnostics, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mohd Zamri Saad
- Department of Veterinary Laboratory Diagnostics, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Yun Hin Taufiq-Yap
- Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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Endothelial NO Production Is Mandatory for Epigallocatechin-3-Gallate-induced Vasodilation: Results From eNOS Knockout (eNOS-/-) Mice. J Cardiovasc Pharmacol 2016; 65:607-10. [PMID: 25714597 PMCID: PMC4461381 DOI: 10.1097/fjc.0000000000000232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The underlying mechanisms for the vasodilating effects of the tea catechin epigallocatechin-3-gallate (EGCG) are still not fully understood. Besides nitric oxide (NO)-dependent effects, other modes of action are discussed. To elucidate whether the NO pathway is a prerequisite in mediating vasodilating effects, we investigated EGCG-induced vasorelaxation in isolated aortic rings of endothelial nitric oxide knockout (eNOS−/−) mice. Vasodilation to acetylcholine was fully prevented in aortic rings of eNOS−/− mice, confirming lack of vascular NO production. Vasodilation to the exogenous NO donor sodium nitroprusside was preserved in eNOS−/− mice aortic rings. Low concentrations of EGCG (5–15 µM) resulted in strong vasorelaxation in aortic rings of wild type mice, whereas it was completely absent in eNOS−/− mice. In corroboration, relaxation in response to green tea was significantly inhibited in aortic rings of eNOS−/− mice. These results demonstrate that EGCG-induced vasodilation strongly relies on functional NO synthase in endothelial cells and subsequent stimulation of NO production in vessels.
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Novakovic A, Marinko M, Vranic A, Jankovic G, Milojevic P, Stojanovic I, Nenezic D, Ugresic N, Kanjuh V, Yang Q, He GW. Mechanisms underlying the vasorelaxation of human internal mammary artery induced by (-)-epicatechin. Eur J Pharmacol 2015; 762:306-12. [PMID: 26049011 DOI: 10.1016/j.ejphar.2015.05.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 05/03/2015] [Accepted: 05/21/2015] [Indexed: 02/05/2023]
Abstract
Evidences have suggested that flavanol compound (-)-epicatechin is associated with reduced risk of cardiovascular diseases. One of the mechanisms of its cardioprotective effect is vasodilation. However, the exact mechanisms by which (-)-epicatechin causes vasodilation are not yet clearly defined. The aims of the present study were to investigate relaxant effect of flavanol (-)-epicatechin on the isolated human internal mammary artery (HIMA) and to determine the mechanisms underlying its vasorelaxation. Our results showed that (-)-epicatechin induced a concentration-dependent relaxation of HIMA rings pre-contracted by phenylephrine. Among the K(+) channel blockers, 4-aminopyridine (4-AP) and margatoxin, blockers of voltage-gated K(+) (KV) channels, and glibenclamide, a selective ATP-sensitive K(+) (KATP) channels blocker, partly inhibited the (-)-epicatechin-induced relaxation of HIMA, while iberiotoxin, a most selective blocker of large conductance Ca(2+)-activated K(+) channels (BKCa), almost completely inhibited the relaxation. In rings pre-contracted by 80mM K(+), (-)-epicatechin induced partial relaxation of HIMA, whereas in Ca(2+)-free medium, (-)-epicatechin completely relaxed HIMA rings pre-contracted by phenylephrine and caffeine. Finally, thapsigargin, a sarcoplasmic reticulum Ca(2+)-ATPase inhibitor, slightly antagonized (-)-epicatechin-induced relaxation of HIMA pre-contracted by phenylephrine. These results suggest that (-)-epicatechin induces strong endothelium-independent relaxation of HIMA pre-contracted by phenylephrine whilst 4-AP- and margatoxin-sensitive KV channels, as well as BKCa and KATP channels, located in vascular smooth muscle, mediate this relaxation. In addition, it seems that (-)-epicatechin could inhibit influx of extracellular Ca(2+), interfere with intracellular Ca(2+) release and re-uptake by the sarcoplasmic reticulum.
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Affiliation(s)
- Aleksandra Novakovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia.
| | - Marija Marinko
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Vranic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Goran Jankovic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Predrag Milojevic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Ivan Stojanovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Dragoslav Nenezic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute for Cardiovascular Diseases "Dedinje", Belgrade, Serbia
| | - Nenad Ugresic
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | | | - Qin Yang
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong; TEDA International Cardiovascular Hospital, Tianjin, China
| | - Guo-Wei He
- TEDA International Cardiovascular Hospital, Tianjin, China
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Black tea protects against hypertension-associated endothelial dysfunction through alleviation of endoplasmic reticulum stress. Sci Rep 2015; 5:10340. [PMID: 25976123 PMCID: PMC4432571 DOI: 10.1038/srep10340] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 04/10/2015] [Indexed: 12/24/2022] Open
Abstract
Hypertensive patients have been found to be associated with elevated levels of homocysteine, known as hyperhomocysteinemia. Homocysteine (Hcy) can induce endoplasmic reticulum (ER) stress in endothelial cells. This study aims to investigate whether black tea (BT) protects against hypertension-associated endothelial dysfunction through alleviation of ER stress. Rat aortae and cultured rat aortic endothelial cells were treated with Hcy, BT extract, and theaflavin-3,3'-digallate (TF3). Male Sprague Dawley rats were infused with angiotensin II (Ang II) to induce hypertension and orally administrated with BT extract at 15 mg/kg/day for 2 weeks. Hcy impaired endothelium-dependent relaxations of rat aortae and led to ER stress in endothelial cells, which were ameliorated by co-incubation of BT extract and TF3. The blood pressure of Ang II-infused rats and plasma Hcy level were normalized by BT consumption. Impaired endothelium-dependent relaxations in renal arteries, carotid arteries and aortae, and flow-mediated dilatations in third-order mesenteric resistance arteries were improved. Elevations of ER stress markers and ROS level, plus down-regulation of Hcy metabolic enzymes in aortae from Ang II-infused rats were prevented by BT treatment. Our data reveal the novel cardiovascular benefits of BT in ameliorating vascular dysfunctions, providing insight into developing BT into beneficial dietary supplements in hypertensive patients.
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Abstract
The endothelium, a highly active structure, regulates vascular homeostasis through the release of numerous vasoactive factors that control vascular tone and vascular smooth cell proliferation. A larger number of medicinal plants and their isolated chemical constituents have been shown to beneficially affect the endothelium. For example, flavonoids in black tea, green tea, and concord grape cause a vasodilation possibly through their antioxidant properties. Allicin, a by-product of the enzyme alliinase, has been proposed to be the main active metabolite and responsible for most of the biological activities of garlic, including a dose-dependent dilation on the isolated coronaries. Thymoquinone, the principal phytochemical compound found in the volatile oil of the black seed, and the hawthorn extract have also been shown to improve aging-related impairment of endothelium-dependent relaxations in animal models. In this review, the effect of some of the natural products, including Camellia sinensis (black tea and green tea), Vitis labrusca (concord grape), Allium sativum (garlic), and Nigella sativa (black seed) and Crataegus ssp (hawthorn extract), is explored. The molecular mechanisms behind these potential therapeutic effects are also discussed.
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Effectiveness of green tea in a randomized human cohort: relevance to diabetes and its complications. BIOMED RESEARCH INTERNATIONAL 2013; 2013:412379. [PMID: 24102055 PMCID: PMC3786468 DOI: 10.1155/2013/412379] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/17/2013] [Accepted: 08/07/2013] [Indexed: 12/31/2022]
Abstract
Epidemiological studies have argued that green tea could mitigate diabetes and its complications. This study investigated the phytophenolic profile of Mauritian green tea and its antioxidant propensity. The effect of green tea on the risk factors: waist-hip ratio, glucose level, arterial pressure, antioxidant status, and alanine aminotransferase (ALT) in prediabetics was assessed. The experimental group consumed 3 cups of green tea daily for 14 weeks followed by a 2-week washout period. The control group followed a water regimen. Green tea contained high level of phenolics related to its antioxidant power. Green tea suppressed waist-hip ratio of women from a significant increase and suppressed mean arterial pressure of men and women from a significant decrease after week 14. It reduced ALT level in women by 13.0% (P < 0.1) while increasing the antioxidant potential of men and women sera by 2.7% (P < 0.1) and 5.1% (P < 0.1). The study timescale may have been too short to enable demonstration of effects on fasting plasma glucose and HbA1c outcomes. Green tea regimen could form part of a healthy lifestyle that might ameliorate features of metabolic syndrome and subsequent risks for diabetes and its complications. This trial is registered with ClinicalTrials.gov NCT01248143.
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Lorenz M. The Role of Individual Tea Compounds in Cardiovascular Protective Effects of Green and Black Tea. TEA IN HEALTH AND DISEASE PREVENTION 2013:829-840. [DOI: 10.1016/b978-0-12-384937-3.00070-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Jiménez R, Duarte J, Perez-Vizcaino F. Epicatechin: endothelial function and blood pressure. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:8823-8830. [PMID: 22440087 DOI: 10.1021/jf205370q] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Epidemiological studies indicate an inverse relationship between flavanol intake and the risk of cardiovascular disease. Potential mechanisms include their effects on endothelial function and hypertension. A number of studies have shown that flavanol-rich cocoa reduces blood pressure and endothelial dysfunction, whereas black tea may have opposite effects. These results highlight the importance of the different effects of the multitude of phytochemical constituents in these foods and the need for studying the individual flavanols. Epicatechin seems to be a major bioactive constituent of cocoa and other flavanol-rich foods and beverages. It has been shown to improve endothelial function in animals and humans. In salt-sensitive animal models of hypertension, epicatechin lowers blood pressure and the associated end-organ damage. Nitric oxide (NO) seems to play a key role in the protection of both hypertension and endothelial dysfunction.
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Affiliation(s)
- Rosario Jiménez
- Department of Pharmacology, School of Pharmacy, Universidad de Granada , 18071 Granada, Spain
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Ma X, He D, Ru X, Chen Y, Cai Y, Bruce IC, Xia Q, Yao X, Jin J. Apigenin, a plant-derived flavone, activates transient receptor potential vanilloid 4 cation channel. Br J Pharmacol 2012; 166:349-58. [PMID: 22049911 DOI: 10.1111/j.1476-5381.2011.01767.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Transient receptor potential vanilloid 4 (TRPV4) is a Ca(2+) -permeable channel with multiple modes of activation. Apigenin is a plant-derived flavone, which has potential preventive effects on the development of cardiovascular disease. We set out to explore the effects of apigenin on TRPV4 channel activity and its role in vasodilatation. EXPERIMENTAL APPROACH The effects of apigenin (0.01-30 µM) on TPRV4 channels were investigated in HEK293 cells over-expressing TRPV4, rat primary cultured mesenteric artery endothelial cells (MAECs) and isolated small mesenteric arterial segments using whole-cell patch clamp, fluorescent Ca(2+) imaging, intracellular recording and pressure myography. KEY RESULTS Whole-cell patch clamp and fluorescent Ca(2+) imaging in HEK cells over-expressing TRPV4 showed that apigenin concentration-dependently stimulated the TRPV4-mediated cation current and Ca(2+) influx. In MAECs, apigenin stimulated Ca(2+) influx in a concentration-dependent manner. These increases in cation current and Ca(2+) influx were markedly inhibited by TRPV4-specific blockers and siRNAs. Furthermore, pressure myography and intracellular recording in small third-order mesenteric arteries showed that apigenin dose-dependently evoked smooth muscle cell membrane hyperpolarization and subsequent vascular dilatation, which were significantly inhibited by TRPV4-specific blockers. TRPV4 blocker or charybdotoxin (200 nM) plus apamin (100 nM) diminished the apigenin-induced dilatation. CONCLUSION AND IMPLICATIONS This is the first study to demonstrate the selective stimulation of TRPV4 by apigenin. Apigenin was found to activate TRPV4 channels in a dose-dependent manner in HEK cells over-expressing TRPV4 and in native endothelial cells. In rat small mesenteric arteries, apigenin acts on TRPV4 in endothelial cells to induce EDHF-mediated vascular dilatation.
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Affiliation(s)
- Xin Ma
- Department of Cellular and Molecular Pharmacology, Jiangnan University, Wuxi, China.
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Increases in blood pressure and heart rate induced by caffeine are inhibited by (-)-epigallocatechin-3-O-gallate: involvement of catecholamines. J Cardiovasc Pharmacol 2012; 58:446-9. [PMID: 21975870 DOI: 10.1097/fjc.0b013e31822d93cb] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In a previous experiment, (-)-epigallocatechin-3-O-gallate (EGCG) reduced caffeine-induced locomotor activity and stereotyped behaviors and inhibited caffeine-induced neuronal stimulant activity. This research was performed to give additional evidence that EGCG counteracts caffeine-induced stimulant effects in animals. EGCG inhibited caffeine-induced cardiovascular activation measures, such as arterial pressure and heart rate. In addition, the increases in the levels of adrenaline and noradrenaline in the blood induced by caffeine was reduced by EGCG. We suggest that EGCG may reduce caffeine-induced increases in blood pressure and heart rate and may decrease the levels of catecholamines in the blood. Therefore, EGCG counteracts caffeine-induced cardiovascular activity. The stimulant effects of caffeine should be reduced by the amount of EGCG in green tea.
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Gómez-Guzmán M, Jiménez R, Sánchez M, Zarzuelo MJ, Galindo P, Quintela AM, López-Sepúlveda R, Romero M, Tamargo J, Vargas F, Pérez-Vizcaíno F, Duarte J. Epicatechin lowers blood pressure, restores endothelial function, and decreases oxidative stress and endothelin-1 and NADPH oxidase activity in DOCA-salt hypertension. Free Radic Biol Med 2012; 52:70-9. [PMID: 22001745 DOI: 10.1016/j.freeradbiomed.2011.09.015] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 02/07/2023]
Abstract
Flavanol-rich diets have been reported to exert beneficial effects in preventing cardiovascular diseases, such as hypertension. We studied the effects of chronic treatment with epicatechin on blood pressure, endothelial function, and oxidative status in deoxycorticosterone acetate (DOCA)-salt-induced hypertension. Rats were treated for 5 weeks with (-)-epicatechin at 2 or 10 mg kg(-1)day(-1). The high dose of epicatechin prevented both the increase in systolic blood pressure and the proteinuria induced by DOCA-salt. Plasma endothelin-1 and malondialdehyde levels and urinary iso-prostaglandin F(2α) excretion were increased in animals of the DOCA-salt group and reduced by the epicatechin 10 mg kg(-1) treatment. Aortic superoxide levels were enhanced in the DOCA-salt group and abolished by both doses of epicatechin. However, only epicatechin at 10 mg kg(-1) reduced the rise in aortic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and p47(phox) and p22(phox) gene overexpression found in DOCA-salt animals. Epicatechin increased the transcription of nuclear factor-E2-related factor-2 (Nrf2) and Nrf2 target genes in aortas from control rats. Epicatechin also improved the impaired endothelium-dependent relaxation response to acetylcholine and increased the phosphorylation of both Akt and eNOS in aortic rings. In conclusion, epicatechin prevents hypertension, proteinuria, and vascular dysfunction. Epicatechin also induced a reduction in ET-1 release, systemic and vascular oxidative stress, and inhibition of NADPH oxidase activity.
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Affiliation(s)
- Manuel Gómez-Guzmán
- Department of Pharmacology, School of Pharmacy, School of Medicine, University of Granada, Granada, Spain
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Obara K, Ukai K, Ishikawa T. Mechanism of potentiation by tea epigallocatechin of contraction in porcine coronary artery: The role of protein kinase Cδ-mediated CPI-17 phosphorylation. Eur J Pharmacol 2011; 668:414-8. [DOI: 10.1016/j.ejphar.2011.07.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 06/09/2011] [Accepted: 07/14/2011] [Indexed: 02/01/2023]
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Chronic ( − )-epicatechin improves vascular oxidative and inflammatory status but not hypertension in chronic nitric oxide-deficient rats. Br J Nutr 2011; 106:1337-48. [DOI: 10.1017/s0007114511004314] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The present study analysed the effects of the flavanol ( − )-epicatechin in rats after chronic inhibition of NO synthesis with NG-nitro-l-arginine methyl ester (l-NAME), at doses equivalent to those achieved in the studies involving human subjects. Wistar rats were randomly divided into four groups: (1) control-vehicle, (2) l-NAME, (3) l-NAME-epicatechin 2 (l-NAME-Epi 2) and (4) l-NAME-epicatechin 10 (l-NAME-Epi 10). Rats were daily given by oral administration for 4 weeks: vehicle, ( − )-epicatechin 2 or 10 mg/kg. Animals in the l-NAME groups daily received l-NAME 75 mg/100 ml in drinking-water. The evolution in systolic blood pressure and heart rate, and morphological and plasma variables, proteinuria, vascular superoxide, reactivity and protein expression at the end of the experiment were analysed. Chronic ( − )-epicatechin treatment did not modify the development of hypertension and only weakly affected the endothelial dysfunction induced by l-NAME but prevented the cardiac hypertrophy, the renal parenchyma and vascular lesions and proteinuria, and blunted the prostanoid-mediated enhanced endothelium-dependent vasoconstrictor responses and the cyclo-oxygenase-2 and endothelial NO synthase (eNOS) up-regulation. Furthermore, ( − )-epicatechin also increased Akt and eNOS phosphorylation and prevented the l-NAME-induced increase in systemic (plasma malonyldialdehyde and urinary 8-iso-PGF2α) and vascular (dihydroethidium staining, NADPH oxidase activity and p22phox up-regulation) oxidative stress, proinflammatory status (intercellular adhesion molecule-1, IL-1β and TNFα up-regulation) and extracellular-signal-regulated kinase 1/2 phosphorylation. The present study shows for the first time that chronic oral administration of ( − )-epicatechin does not improve hypertension but reduced pro-atherogenic pathways such as oxidative stress and proinflammatory status of the vascular wall induced by blockade of NO production.
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Li Z, Wang Y, Vanhoutte PM. Epigallocatechin gallate elicits contractions of the isolated aorta of the aged spontaneously hypertensive rat. Basic Clin Pharmacol Toxicol 2011; 109:47-55. [PMID: 21310006 DOI: 10.1111/j.1742-7843.2011.00683.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The present study examined the effect of the green tea catechin epigallocatechin gallate (EGCG) on endothelium-dependent responses in the aorta of 36-week-old spontaneously hypertensive rats (SHR). Isometric tension was measured in isolated aortic rings. The release of prostanoid end products was determined using enzyme immunoassay kits and the intracellular reactive oxygen species (ROS) concentration using confocal microscopy. EGCG did not improve endothelium-dependent relaxations evoked by acetylcholine, except in the presence of indomethacin. EGCG did not inhibit endothelium-dependent contractions induced by acetylcholine or ATP. At 10(-6) M and higher concentrations, EGCG caused increases in tension in the SHR aorta. The EGCG-induced contractions were accompanied by an increased production of ROS. The amount of prostanoid end products was increased significantly by EGCG, indicating that their production followed the activation of cyclooxygenase (COX). These prostanoids in turn stimulated thromboxane-prostanoid (TP) receptors and caused contractions. EGCG induced significantly smaller contractions in aortae of normotensive Wistar-Kyoto rats (WKY), accompanied with a lower production of ROS and a lesser release of prostanoids. These observations suggest that EGCG-induced contractions occur more readily in blood vessels of hypertensive than normotensive animals. The present findings indicate that the increased oxidative stress in the ageing hypertensive animals contributes to the loss of the beneficial effects and the enhancement of the adverse effects of EGCG.
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Affiliation(s)
- Zhuoming Li
- Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong, China
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Scholz EP, Zitron E, Katus HA, Karle CA. Cardiovascular ion channels as a molecular target of flavonoids. Cardiovasc Ther 2010; 28:e46-52. [PMID: 20633021 DOI: 10.1111/j.1755-5922.2010.00212.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Flavonoids are a class of naturally occurring polyphenols abundant in edibles and beverages of plant origin. Epidemiological studies consistently associate high flavonoid intake with a reduced risk for the development of cardiovascular diseases. So far these beneficial effects have been mainly attributed to nonspecific antioxidant and antiinflammatory properties. However, there is an increasing body of evidence that flavonoids specifically target molecular structures including cardiovascular ion channels. Playing a pivotal role in the regulation of vascular tone and cardiac electric activity, ion channels represent a major target for the induction of antihypertensive and cardioprotective effects. Thus, pharmacological properties of flavonoids on cardiovascular ion channels, ion currents and tissue preparations are being increasingly addressed in experimental studies. Whereas it has become clear that cardiovascular ion channels represent an important molecular target of flavonoids, the published data have not yet been systematically reviewed.
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Affiliation(s)
- Eberhard P Scholz
- Department of Internal Medicine III (Cardiology), University Hospital Heidelberg, Heidelberg, Germany.
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Xu Z, Wang X, Dai Y, Kong L, Wang F, Xu H, Lu D, Song J, Hou Z. (+/-)-Praeruptorin A enantiomers exert distinct relaxant effects on isolated rat aorta rings dependent on endothelium and nitric oxide synthesis. Chem Biol Interact 2010; 186:239-46. [PMID: 20433815 DOI: 10.1016/j.cbi.2010.04.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Revised: 04/16/2010] [Accepted: 04/19/2010] [Indexed: 01/04/2023]
Abstract
Praeruptorin A is a coumarin compound naturally occurring in the roots of Peucedanum praeruptorum Dunn., a commonly used traditional Chinese medicine for the treatment of certain respiratory diseases and hypertension. Although previous studies indicated the relaxant effects of (+/-)-praeruptorin A on tracheal and arterial preparations, little is known about the functional characteristics of the enantiomers. In the present study, the two enantiomers were successfully isolated and identified by using a preparative Daicel Chiralpak AD-H column, and their relaxant effects on aorta rings were observed and compared. (+)-Praeruptorin A showed more potent relaxation than (-)-praeruptorin A against KCl- and phenylephrine-induced contraction of rat isolated aortic rings with intact endothelium. Removal of the endothelium remarkably reduced the relaxant effect of (+)-praeruptorin A but not that of (-)-praeruptorin A. Pretreatment of aortic rings with N(omega)-nitro-L-arginine methyl ester (L-NAME, an inhibitor of nitric oxide synthase) or methylene blue (MB, a soluble guanylyl cyclase inhibitor) resulted in similar changes of the relaxant effects of the two enantiomers to endothelium removal. Molecular docking studies also demonstrated that (+)-praeruptorin A was in more agreement to nitric oxide synthase pharmacophores than (-)-praeruptorin A. On the other hand, the two enantiomers of praeruptorin A could slightly attenuate the contraction of rat aortic rings induced by internal Ca(2+) release from sarcoplasmic reticulum (SR). These findings indicated that (+)-praeruptorin A and (-)-praeruptorin A exerted distinct relaxant effects on isolated rat aorta rings, which might be mainly attributed to nitric oxide synthesis catalyzed by endothelial nitric oxide synthase.
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Affiliation(s)
- Zhao Xu
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, Jiangsu, China
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Dugé de Bernonville T, Guyot S, Paulin JP, Gaucher M, Loufrani L, Henrion D, Derbré S, Guilet D, Richomme P, Dat JF, Brisset MN. Dihydrochalcones: Implication in resistance to oxidative stress and bioactivities against advanced glycation end-products and vasoconstriction. PHYTOCHEMISTRY 2010; 71:443-52. [PMID: 20022617 DOI: 10.1016/j.phytochem.2009.11.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 05/14/2023]
Abstract
Flavonoids are a group of polyphenol compounds with known antioxidant activities. Among them, dihydrochalcones are mainly found in apple leaves (Malus domestica). Glycosylated dihydrochalcones were previously found in large amounts in leaves of two genotypes of Malus with contrasting resistance to fire blight, a bacterial disease caused by Erwinia amylovora. In the present study we demonstrate that soluble polyphenol patterns comprised phloridzin alone or in combination with two additional dihydrochalcones, identified as sieboldin and trilobatin. Presence of sieboldin in young leaves correlated well with a high 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Moreover, these leaves displayed enhanced tolerance to paraquat, a photooxidative-stress generating herbicide. Interestingly, phloridzin had a high activity in the oxygen radical absorbance capacity (ORAC) assay, but its presence alone in leaves did not correlate with tolerance to paraquat. In order to further characterise the activity of these compounds, we tested their ability to prevent oxidative-dependent formation of advanced glycation end-products (AGEs) and phenylephrine-induced contraction of isolated rat mesenteric arteries. The antioxidant capacity of sieboldin was clearly demonstrated by showing that this compound (i) prevented vasoconstriction and (ii) inhibited AGEs formation. Both assays provided interesting information concerning a potential use of sieboldin as a therapeutic. Hence, our results strongly argue for a bioactivity of dihydrochalcones as functional antioxidants in the resistance of Malus leaves to oxidative stress. In addition, we demonstrate for the first time that sieboldin is a powerful multipotent antioxidant, effective in preventing physiopathological processes. Further work should aim at demonstrating the potential use of this compound as a therapeutic in treating free radical-involving diseases.
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Roghani M, Baluchnejadmojarad T. Chronic epigallocatechin-gallate improves aortic reactivity of diabetic rats: Underlying mechanisms. Vascul Pharmacol 2009; 51:84-9. [DOI: 10.1016/j.vph.2009.04.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2008] [Revised: 03/22/2009] [Accepted: 04/13/2009] [Indexed: 11/25/2022]
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Lee JH, Seo YS, Lim DY. Provinol inhibits catecholamine secretion from the rat adrenal medulla. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:229-39. [PMID: 19885042 PMCID: PMC2766734 DOI: 10.4196/kjpp.2009.13.3.229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 06/12/2009] [Accepted: 06/18/2009] [Indexed: 11/15/2022]
Abstract
The aim of the present study was to examine the effect of provinol, which is a mixture of polyphenolic compounds from red wine, on the secretion of catecholamines (CA) from isolated perfused rat adrenal medulla, and to elucidate its mechanism of action. Provinol (0.3~3 microg/ml) perfused into an adrenal vein for 90 min dose- and time-dependently inhibited the CA secretory responses evoked by ACh (5.32 mM), high K(+) (a direct membrane-depolarizer, 56 mM), DMPP (a selective neuronal nicotinic N(N) receptor agonist, 100 microM) and McN-A-343 (a selective muscarinic M(1) receptor agonist, 100 microM). Provinol itself did not affect basal CA secretion. Also, in the presence of provinol (1 microg/ml), the secretory responses of CA evoked by Bay-K-8644 (a voltage-dependent L-type dihydropyridine Ca(2+) channel activator, 10 microM), cyclopiazonic acid (a cytoplasmic Ca(2+)-ATPase inhibitor, 10 microM) and veratridine (an activator of voltage-dependent Na(+) channels, 10 microM) were significantly reduced. Interestingly, in the simultaneous presence of provinol (1 microg/ml) plus L-NAME (a selective inhibitor of NO synthase, 30 microM), the CA secretory responses evoked by ACh, high K(+), DMPP, McN-A-343, Bay-K-8644 and cyclpiazonic acid recovered to the considerable extent of the corresponding control secretion in comparison with the inhibition of provinol-treatment alone. Under the same condition, the level of NO released from adrenal medulla after the treatment of provinol (3 microg/ml) was greatly elevated in comparison to its basal release. Taken together, these data demonstrate that provinol inhibits the CA secretory responses evoked by stimulation of cholinergic (both muscarinic and nicotinic) receptors as well as by direct membrane-depolarization from the perfused rat adrenal medulla. This inhibitory effect of provinol seems to be exerted by inhibiting the influx of both calcium and sodium into the rat adrenal medullary cells along with the blockade of Ca(2+) release from the cytoplasmic calcium store at least partly through the increased NO production due to the activation of nitric oxide synthase.
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Affiliation(s)
- Jung-Hee Lee
- DNA Repair Research Center, Chosun University, Gwangju 501-759, Korea
| | - Yu-Seung Seo
- Department of Pharmacology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Dong-Yoon Lim
- Department of Pharmacology, College of Medicine, Chosun University, Gwangju 501-759, Korea
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Romano MR, Lograno MD. Epigallocatechin-3-gallate relaxes the isolated bovine ophthalmic artery: involvement of phosphoinositide 3-kinase-Akt-nitric oxide/cGMP signalling pathway. Eur J Pharmacol 2009; 608:48-53. [PMID: 19249297 DOI: 10.1016/j.ejphar.2009.02.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 01/26/2009] [Accepted: 02/09/2009] [Indexed: 12/13/2022]
Abstract
The present study investigates the direct action and the underlying mechanism(s) of epigallocatechin-3-gallate (EGCG) vasomotor effects on the bovine isolated ophthalmic artery. Adjacent rings were cut from each artery and mounted in a wire miograph system for isometric recording. Concentration-response curves for EGCG were constructed by adding cumulative concentrations of the drug to arterial rings pre-contracted with 5-HT (1 microM). Effects of mechanical endothelial cell removal and of selective blockers of the nitric oxide (NO)/cGMP pathways were investigated on the EGCG relaxant responses. EGCG relaxed ophthalmic arteries and maximum relaxation was 78.4+/-2.64%. Mechanical removal of endothelium, blockade of soluble guanylyl cyclase by 1H-1,2,4-oxadiazolo [4,3-a]quinoxalin-1-one (ODQ, 1 and 5 microM) or inhibition of nitric oxide (NO) synthase by N(G)-nitro-L-arginine (L-NAME, 50 and 100 microM) reduced significantly the relaxant response to catechin; moreover, the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 100 microM) significantly increased the vasorelaxant responses to EGCG. Relaxation to EGCG was inhibited by iberiotoxin (200 nM), a blocker of big-conductance Ca(2+)-activated K(+) (BK(Ca)) channel, whereas the blockade of K(ATP) channel by glibenclamide (5 microM) and of small-conductance Ca(2+)-activated K(+) (SK(Ca)) channel by apamin (100 nM) elicited no effect. Interestingly, also inhibition of phosphoinositide-3-kinase (PI3K) by wortmannin (100 nM) and of Akt by SH6 (1 microM) markedly decreased the EGCG-evoked vasorelaxation. These data suggest that EGCG induced vasorelaxation in ophthalmic arteries with endothelium-intact via the activation of the NO/cGMP signalling pathway and defined an intriguing role for PI3K and Akt as upstream mediators for activation of NO-mediated relaxant responses.
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Affiliation(s)
- Maria Rosaria Romano
- Department Pharmacobiology, Section of Pharmacology, University of Bari, Bari, Italy
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Green and black tea are equally potent stimuli of NO production and vasodilation: new insights into tea ingredients involved. Basic Res Cardiol 2009; 104:100-10. [DOI: 10.1007/s00395-008-0759-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 10/14/2008] [Indexed: 10/21/2022]
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Yu BS, Ko WS, Lim DY. Inhibitory Mechanism of Polyphenol Compounds Isolated from Red Wine on Catecholamine Release in the Perfused Rat Adrenal Medulla. Biomol Ther (Seoul) 2008. [DOI: 10.4062/biomolther.2008.16.2.147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Kim KY, Choi SJ, Jang HJ, Zuo DC, Shahi PK, Parajuli SP, Yeum CH, Yoon PJ, Choi S, Jun JY. (-)-epigallocatechin gallate inhibits the pacemaker activity of interstitial cells of cajal of mouse small intestine. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2008; 12:111-5. [PMID: 20157403 DOI: 10.4196/kjpp.2008.12.3.111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of (-)-epigallocatechin gallate (EGCG) on pacemaker activities of cultured interstitial cells of Cajal (ICC) from murine small intestine were investigated using whole-cell patch-clamp technique at 30 and Ca(2+) image analysis. ICC generated spontaneous pacemaker currents at a holding potential of -70 mV. The treatment of ICC with EGCG resulted in a dose-dependent decrease in the frequency and amplitude of pacemaker currents. SQ-22536, an adenylate cyclase inhibitor, and ODQ, a guanylate cyclase inhibitor, did not inhibit the effects of EGCG. EGCG-induced effects on pacemaker currents were not inhibited by glibenclamide, an ATP-sensitive K(+) channel blocker and TEA, a Ca(2+)-activated K(+) channel blocker. Also, we found that EGCG inhibited the spontaneous [Ca(2+)](i) oscillations in cultured ICC. In conclusion, EGCG inhibited the pacemaker activity of ICC and reduced [Ca(2+)](i) oscillations by cAMP-, cGMP-, ATP-sensitive K+ channel-independent manner.
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Affiliation(s)
- Kweon Young Kim
- Department of Rehabilitation, College of Medicine, Chosun University, Gwangju 501-759, Korea
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Rhee SJ, Kim KR, Kim HT, Hong JH. Effects of Catechin on Lipid Composition and Adipose Tissue in Obese Rats Fed High Fat Diet. ACTA ACUST UNITED AC 2007. [DOI: 10.3746/jkfn.2007.36.5.540] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Güida MC, Esteva MI, Camino A, Flawiá MM, Torres HN, Paveto C. Trypanosoma cruzi: in vitro and in vivo antiproliferative effects of epigallocatechin gallate (EGCg). Exp Parasitol 2007; 117:188-94. [PMID: 17673202 DOI: 10.1016/j.exppara.2007.04.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 04/03/2007] [Accepted: 04/23/2007] [Indexed: 12/23/2022]
Abstract
The trypanocidal activity of catechins on Trypanosoma cruzi bloodstream trypomastigotes has been previously reported. Herein, we present the effect of epigallocatechin gallate (EGCg) on parasitemia and survival in a murine model of acute Chagas' disease as well as on the epimastigote form of the parasite. Upon intraperitoneal administration of daily doses of 0.8 mg/kg/day of EGCg for 45 days, mice survival rates increased from 11% to 60%, while parasitemia diminished to 50%. No side effects were observed in EGCg-treated animals. Fifty percent inhibition of epimastigotes growth was achieved with 311 microM EGCg 120 h after drug addition. No lysis, total culture growth inhibition or morphological changes were observed upon addition of 1-3mM EGCg at 24 h. This treatment also produced oligosomal fragmentation of epimastigotes DNA, suggesting a programmed cell death (PCD)-like process. All these findings point out EGCg as a potential new lead compound for chemotherapy of Chagas' disease.
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Affiliation(s)
- María C Güida
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular y Facultad de Ciencias Exactas y Naturales (CONICET-UBA), 1428 Buenos Aires, Argentina.
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Campos-Toimil M, Orallo F. Effects of (-)-epigallocatechin-3-gallate in Ca2+ -permeable non-selective cation channels and voltage-operated Ca2+ channels in vascular smooth muscle cells. Life Sci 2007; 80:2147-2153. [PMID: 17499810 DOI: 10.1016/j.lfs.2007.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 04/02/2007] [Accepted: 04/09/2007] [Indexed: 11/24/2022]
Abstract
The effects of (-)-epigallocatechin-3-gallate (EGCG), the most abundant catechin of tea, on Ca(2+)-permeable non-selective cation currents (NSCC) and voltage-operated Ca(2+) channels (VOCC) have been investigated in cultured rat aortic smooth muscle cells using the whole-cell voltage-clamp technique. Under the Cs(+)/tetraethylammonium (TEA)-containing internal solution, and in the presence of nifedipine (1 microM), EGCG (30 microM) activated a long-lasting inward current, with a reversal potential (E(rev)) of approximately 0 mV. This current was not significantly altered by the replacement of [Cl(-)](i) or [Cl(-)](o), implying that the inward current was not a chloride channel, but a NSCC. SKF 96365 (30 microM) and Cd(2+) (500 microM) almost completely abolished the EGCG-induced NSCC. A higher dose of EGCG (100 microM) additionally activated a nifedipine-sensitive inward current in the absence of depolarization protocol. EGCG (100 microM) also potentiated a nifedipine-sensitive voltage-dependent Ba(2+)-current during the first 5 min of incubation. However, after > 10 min of incubation with EGCG, this current was significantly inhibited. Our results suggest that EGCG caused a Ca(2+) influx into smooth muscle cells via VOCC (probably L-type) and other SKF-96365- and Cd(2+)-sensitive Ca(2+)-permeable channels. The action described here may be responsible for the contraction induced by EGCG in rat aortic rings and for the rise of the intracellular concentration of Ca(2+) in rat aortic smooth muscle cells evoked by this catechin. On the other hand, the inhibition of VOCC after > 10 min of incubation may be, in part, responsible for the relaxation of rat aorta induced by EGCG.
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Affiliation(s)
- Manuel Campos-Toimil
- Departamento de Farmacoloxía, Facultade de Farmacia, Universidade de Santiago de Compostela, Campus Universitario Sur, E-15782 Santiago de Compostela (A Coruña), Spain
| | - Francisco Orallo
- Departamento de Farmacoloxía, Facultade de Farmacia, Universidade de Santiago de Compostela, Campus Universitario Sur, E-15782 Santiago de Compostela (A Coruña), Spain.
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Álvarez E, Campos-Toimil M, Justiniano-Basaran H, Lugnier C, Orallo F. Study of the mechanisms involved in the vasorelaxation induced by (-)-epigallocatechin-3-gallate in rat aorta. Br J Pharmacol 2006; 147:269-80. [PMID: 16299547 PMCID: PMC1751301 DOI: 10.1038/sj.bjp.0706507] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This study investigated several mechanisms involved in the vasorelaxant effects of (-)-epigallocatechin-3-gallate (EGCG). EGCG (1 microM-1 mM) concentration dependently relaxed, after a transient increase in tension, contractions induced by noradrenaline (NA, 1 microM), high extracellular KCl (60 mM), or phorbol 12-myristate 13-acetate (PMA, 1 microM) in intact rat aortic rings. In a Ca2+ -free solution, EGCG (1 microM-1 mM) relaxed 1 microM PMA-induced contractions, without previous transient contraction. However, EGCG (1 microM-1 mM) did not affect the 1 microM okadaic acid-induced contractions. Removal of endothelium and/or pretreatment with glibenclamide (10 microM), tetraethylammonium (2 mM) or charybdotoxin (100 nM) plus apamin (500 nM) did not modify the vasorelaxant effects of EGCG. In addition, EGCG noncompetitively antagonized the contractions induced by NA (in 1.5 mM Ca2+ -containing solution) and Ca2+ (in depolarizing Ca2+ -free high KCl 60 mM solution). In rat aortic smooth muscle cells (RASMC), EGCG (100 microM) reduced increases in cytosolic free Ca2+ concentration ([Ca2+]i) induced by angiotensin II (ANG II, 100 nM) and KCl (60 mM) in 1.5 mM CaCl2 -containing solution and by ANG II (100 nM) in the absence of extracellular Ca2+. In RASMC, EGCG (100 microM) did not modify basal generation of cAMP or cGMP, but significantly reversed the inhibitory effects of NA (1 microM) and high KCl (60 mM) on cAMP and cGMP production. EGCG inhibited the enzymatic activity of all the cyclic nucleotide PDE isoenzymes present in vascular tissue, being more effective on PDE2 (IC50 approximately 17) and on PDE1 (IC50 approximately 25). Our results suggest that the vasorelaxant effects of EGCG in rat aorta are mediated, at least in part, by an inhibition of PDE activity, and the subsequent increase in cyclic nucleotide levels in RASMC, which, in turn, can reduce agonist- or high KCl concentration-induced increases in [Ca2+]i.
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Affiliation(s)
- Ezequiel Álvarez
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Universitario Sur, Santiago de Compostela (A Coruña), E-15782, Spain
| | - Manuel Campos-Toimil
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Universitario Sur, Santiago de Compostela (A Coruña), E-15782, Spain
| | - Hélène Justiniano-Basaran
- CNRS UMR 7034, Pharmacologie et Physicochimie, Université Louis Pasteur de Strasbourg, Illkirch, France
| | - Claire Lugnier
- CNRS UMR 7034, Pharmacologie et Physicochimie, Université Louis Pasteur de Strasbourg, Illkirch, France
| | - Francisco Orallo
- Departamento de Farmacología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Universitario Sur, Santiago de Compostela (A Coruña), E-15782, Spain
- Author for correspondence:
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Hotta Y, Huang L, Muto T, Yajima M, Miyazeki K, Ishikawa N, Fukuzawa Y, Wakida Y, Tushima H, Ando H, Nonogaki T. Positive inotropic effect of purified green tea catechin derivative in guinea pig hearts: the measurements of cellular Ca2+ and nitric oxide release. Eur J Pharmacol 2006; 552:123-30. [PMID: 17059816 DOI: 10.1016/j.ejphar.2006.09.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 08/25/2006] [Accepted: 09/07/2006] [Indexed: 11/15/2022]
Abstract
Each individual and pure catechin isolated from green tea was investigated as to its myocardial or blood pressure effects. The nitric oxide (NO) electrode and fluorometry were used to monitor changes in the NO and Ca(2+) contents of the heart, together with simultaneous recordings of the left ventricular developed pressure. The low dose of (-)-epigallocatechin-3-gallate (EGCg: 10(-6), 10(-5 )M) increased the left ventricular developed pressure with elevation of the transient fura-2 Ca(2+) signal (T(Ca)), but the high dose of EGCg (10(-4 )M) produced a maximum left ventricular developed pressure with decreases in the basal level of T(Ca) in a manner similar to the administration of the Ca-sensitizer pimobendan. However, the level of the transient NO signal (T(NO)) increased dose-dependently without any increases in the width of T(NO). In the isolated right atria, the contractile force of (-)-gallocatechin-3-gallate (GCg) at 10(-8)-10(-4 )M produced the highest pD(2) value, 6.7, in catechins (EGCg: 5.2, pimobendan: 5.1), but did not affect the heart rate. GCg, an artifact due to the epimerization of EGCg during the heating procedure, showed the most prolonged hypotensive effect in rabbits among the catechins. Each catechin (GCg or EGCg), like the NO donor, may have a therapeutic use as an NO-mediated vasorelaxant and may have an additional protective action in myocardial ischemia-reperfusion induced injury.
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Affiliation(s)
- Yoshihiro Hotta
- Department of Pharmacology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan.
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Tang WJ, Hu CP, Chen MF, Deng PY, Li YJ. Epigallocatechin gallate preserves endothelial function by reducing the endogenous nitric oxide synthase inhibitor level. Can J Physiol Pharmacol 2006; 84:163-71. [PMID: 16900942 DOI: 10.1139/y05-156] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Asymmetric dimethylarginine (ADMA), the endogenous nitric oxide synthase inhibitor, is thought to be a key factor contributing to endothelial dysfunction. Tea catechins can cause an endothelium-dependent vasorelaxation. The present study examined the effect of epigallocatechin gallate (EGCG), the major component of tea catechins, on endothelial dysfunction induced by native low density lipoprotein (LDL) in rats and oxidized LDL (ox-LDL) in cultured endothelial cells, and whether the protective effect of EGCG is related to reduction of ADMA level. A single injection of LDL (4 mg·kg–1, i.v.) markedly reduced endothelium-dependent relaxation and the serum nitrite/nitrate (NO) level, and increased serum concentrations of ADMA, malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α). EGCG (10 or 50 mg·kg–1, i.p.) significantly attenuated the inhibition of vasodilator response to acetylcholine and the decreased serum nitrite/nitrate level, and reduced the elevated levels of ADMA, MDA, and TNF-α. Exposure of endothelial cells to ox-LDL (100 μg·mL–1) for 24 h markedly increased the medium levels of lactate dehydrogenase (LDH), ADMA, TNF-α, and MDA, and decreased the level of nitrite/nitrate in the medium and the activity of dimethylarginine dimethylaminohydrolase (DDAH) in the endothelial cells. EGCG (10 and 100 μg·mL–1) significantly decreased the levels of LDH, ADMA, TNF-α, and MDA, and increased the level of nitrite/nitrate and the activity of DDAH. These results suggest that EGCG protects endothelial dysfunction induced by native LDL in vivo or by ox-LDL in endothelial cells, and the protective effect of EGCG on the endothelium is related to decrease in ADMA level via increasing of DDAH activity.
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Affiliation(s)
- Wei-Jun Tang
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, No.110 Xiang-Ya Road, Changsha 410078, China
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Lim DY. Comparison of green tea extract and epigallocatechin gallate on secretion of catecholamines from the rabbit adrenal medulla. Arch Pharm Res 2005; 28:914-22. [PMID: 16178417 DOI: 10.1007/bf02973877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The present study was designed to examine the effects of green tea extract (CUMC6335) and epigallocatechin gallate (EGCG) on secretion of catecholamines (CA) in the isolated perfused rabbit adrenal gland. In the presence of CUMC6335 (200 microg/mL) into an adrenal vein for 60 min, CA secretory responses evoked by ACh (5.32 mM), high K+ (56 mM), DMPP (100 microM for 2 min), and Bay-K-8644 (10 microM for 4 min) from the isolated perfused rabbit adrenal glands were greatly inhibited in a time-dependent fashion. However, EGCG (10 microg/mL) did not affect CA release evoked by ACh, high K+, and Bay-K-8644. CUMC6335 itself failed to affect basal catecholamine output. Taken together, these results demonstrate that CUMC6335 inhibits CA secretion evoked by stimulation of cholinergic nicotinic receptors, as well as the direct membrane depolarization from the isolated perfused rabbit adrenal gland. It is thought that this inhibitory effect of CUMC6335 may be due at least in part to the blocking action of the L-type dihydropyridine calcium channels in the rabbit adrenomedullary chromaffin cells, which is relevant to the cholinergic nicotinic blockade. It seems that there is a big difference in mode of action between CUMC6335 and EGCG.
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Affiliation(s)
- Dong-Yoon Lim
- Department of Pharmacology, College of Medicine, Chosun University, Gwangju 501-759, Korea.
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Rizvi SI, Zaid MA, Anis R, Mishra N. Protective role of tea catechins against oxidation-induced damage of type 2 diabetic erythrocytes. Clin Exp Pharmacol Physiol 2005; 32:70-5. [PMID: 15730438 DOI: 10.1111/j.1440-1681.2005.04160.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. Oxidative stress is recognized as a major contributing factor for the development of late complications of diabetes. 2. Tea contains polyphenolic compounds (catechins), which have many important biological properties, including strong anti-oxidant activity. 3. The present study was undertaken to evaluate the effect of tea catechins (epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC)) on markers of oxidative stress (malondialdehyde (MDA), reduced glutathione (GSH) and membrane -SH group) in erythrocytes from type 2 diabetics. 4. Oxidative stress was induced in normal and type 2 diabetic erythrocytes by incubating with tert-butyl hydroperoxide (t-BHP). 5. Diabetic erythrocytes have higher MDA and decreased GSH and membrane -SH groups compared with normal erythrocytes. 6. Our results show that tea catechins protect erythrocytes from t-BHP-induced oxidative stress, the effect being more pronounced in diabetic erythrocytes. The relative effectiveness of individual catechins are in the order of EGCG>ECG>EGC>EC. 7. We hypothesise that a higher intake of catechin-rich food by diabetic patients may provide some protection against the development of long-term complications of diabetes.
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Rizvi SI, Zaid MA. Impairment of sodium pump and Na/H exchanger in erythrocytes from non-insulin dependent diabetes mellitus patients: effect of tea catechins. Clin Chim Acta 2004; 354:59-67. [PMID: 15748600 DOI: 10.1016/j.cccn.2004.11.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/08/2004] [Accepted: 11/12/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Tea catechins (EGCG, EGC, ECG and EC) possess many important biological properties. We evaluated the effect of tea catechins on erythrocyte membrane Na(+)/K(+)-ATPase and sodium/hydrogen exchanger (NHE) activity in normal (control) and NIDDM subjects. METHODS Erythrocyte membrane Na(+)/K(+)-ATPase and NHE activity were determined in normal and non-insulin dependent diabetes mellitus (NIDDM) patients. In vitro effect of tea catechins was studied by incubating membrane/intact erythrocytes in assay medium prior to Na(+)/K(+)-ATPase/NHE activity determination. RESULTS A 24.2% decrease in the activity of Na(+)/K(+)-ATPase (p<0.001) and 39.37% increase in activity of NHE (p<0.02) were observed in NIDDM subjects compared to normal. Tea catechins inhibited the activity of Na(+)/K(+)-ATPase and NHE in both normal and NIDDM erythrocytes, the effect was concentration-dependent. The inhibitory effect of EGCG and ECG at micromolar concentrations was greater compared to EGC and EC on Na(+)/K(+)-ATPase. On NHE the inhibition of tea catechins was in the order: EC>EGC>ECG>EGCG at concentrations up to 10 micromol/l. CONCLUSIONS This data may help to explain the anti-carcinogenic and cardioprotective effects of tea catechins. The effect of tea catechins on Na(+)/K(+)-ATPase and NHE may be explained due to a direct effect of these compounds on plasma membrane leading to a change in membrane fluidity.
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Affiliation(s)
- Syed Ibrahim Rizvi
- Department of Biochemistry, University of Allahabad, Allahabad - 211 002, India
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Attaguile G, Perticone G, Mania G, Savoca F, Pennisi G, Salomone S. Cistus incanus and Cistus monspeliensis inhibit the contractile response in isolated rat smooth muscle. JOURNAL OF ETHNOPHARMACOLOGY 2004; 92:245-250. [PMID: 15138007 DOI: 10.1016/j.jep.2004.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 02/12/2004] [Accepted: 02/23/2004] [Indexed: 05/24/2023]
Abstract
The lyophilized aqueous extracts from Cistus incanus L. (CI) and Cistus monspeliensis L. (CM) collected in Sicily were studied in order to evaluate their myorelaxant activity by using isolated smooth muscle of rat ileum and rat aorta. Both CI and CM extracts concentration-dependently inhibited the contractile response to acetylcholine (ACh), phenylephrine (PE) and to 100 mM KCl. The concentration-contraction curves to ACh in ileum and to PE in aorta, were displaced to the right by Cistus extracts in a non-competitive manner, with a depression of the maximum contractile response. The EC50 (microg/ml) of CM and CI were: ileum/KCl, CM 457+/-99, CI 681+/-80; ileum/ACh 100 microM, CM 297+/-66, CI 335+/-41; aorta/KCl, CM 360+/-21, CI 843+/-36; and aorta/PE 10 microM, CM 287+/-33, CI 451+/-58. The two extracts resulted almost equi-active in ileum, whereas CM was more active than CI in aorta. These data indicate that Cistus extracts act as spasmolytic on intestinal and vascular smooth muscle. The antagonism they exert on ACh-, PE- and KCl-evoked contractions seems to be functional, because it is not specifically directed toward any particular receptor; furthermore, a calcium-antagonist activity seems unlikely, since the extracts are capable of completely block the contractile response to agonists.
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Affiliation(s)
- G Attaguile
- Department of Experimental and Clinical Pharmacology, University of Catania, Viale A. Doria 6, 95125 Catania, Italy.
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Paveto C, Güida MC, Esteva MI, Martino V, Coussio J, Flawiá MM, Torres HN. Anti-Trypanosoma cruzi activity of green tea (Camellia sinensis) catechins. Antimicrob Agents Chemother 2004; 48:69-74. [PMID: 14693520 PMCID: PMC310206 DOI: 10.1128/aac.48.1.69-74.2004] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The trypanocidal action of green tea catechins against two different developmental stages of Trypanosoma cruzi is reported for the first time. This activity was assayed with the nonproliferative bloodstream trypomastigote and with the intracellular replicative amastigote parasite forms. An ethyl acetate fraction from Camellia sinensis green tea leaves, which contains most of the polyphenolic compounds and the maximal trypanocidal activity, was obtained by fractionation of the aqueous extract with organic solvents. The active compounds present in this extract were further purified by LH-20 column chromatography and were identified by high-performance liquid chromatography analysis with a photo diode array detector and gas chromatography coupled to mass spectroscopy. The following flavan-3-ols derivatives, known as catechins, were identified: catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate. The purified compounds lysed more than 50% of the parasites present in the blood of infected BALB/c mice at concentrations as low as 0.12 to 85 pM. The most active compounds were gallocatechin gallate and epigallocatechin gallate, with minimal bactericidal concentrations that inhibited 50% of isolates tested of 0.12 and 0.53 pM, respectively. The number of amastigotes in infected Vero cells decreased by 50% in the presence of each of these compounds at 100 nM. The effects of the catechins on the recombinant T. cruzi arginine kinase, a key enzyme in the energy metabolism of the parasite, were assayed. The activity of this enzyme was inhibited by about 50% by nanomolar concentrations of catechin gallate or gallocatechin gallate, whereas the other members of the group were less effective. On the basis of these results, we suggest that these compounds could be used to sterilize blood and, eventually, as therapeutic agents for Chagas' disease.
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Affiliation(s)
- Cristina Paveto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular y Facultad de Ciencias Exactas y Naturales (CONICET-UBA), 1428 Buenos Aires, Argentina.
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Lim DY, Lee ES, Park HG, Kim BC, Hong SP, Lee EB. Comparison of green tea extract and epigallocatechin gallate on blood pressure and contractile responses of vascular smooth muscle of rats. Arch Pharm Res 2003; 26:214-23. [PMID: 12723935 DOI: 10.1007/bf02976833] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present study was conducted to investigate the effects of green tea extract (GTE) on arteral blood pressure and contractile responses of isolated aortic strips of the normotensive rats and to establish the mechanism of action. The phenylephrine (10(-8) approximately 10(-5) M)-induced contractile responses were greatly inhibited in the presence of GTE (0.3 approximately 1.2 mg/mL) in a dose-dependent fashion. Also, high potassium (3.5 x 10(-2) approximately 5.6 x 10(-2) M)-induced contractile responses were depressed in the presence of 0.6 approximately 1.2 mg/mL of GTE, but not affected in low concentration of GTE (0.3 mg/mL). However, epigallocatechin gallate (EGCG, 4 approximately 12 microg/mL) did not affect the contractile responses evoked by phenylephrine and high K+. GTE (5 approximately 20 mg/kg) given into a femoral vein of the normotensive rat produced a dose-dependent depressor response, which is transient. Interestingly, the infusion of a moderate dose of GTE (10 mg/kg/30 min) made a significant reduction in pressor responses induced by intravenous norepinephrine. However, EGCG (1 mg/kg/30 min) did not affect them. Collectively, these results obtained from the present study demonstrate that intravenous GTE causes a dose-dependent depressor action in the anesthetized rat at least partly through the blockade of adrenergic alpha1-receptors. GTE also causes the relaxation in the isolated aortic strips of the rat via the blockade of adrenergic alpha1-receptors, in addition to the unknown direct mechanism. It seems that there is a big difference in the vascular effect between GTE and EGCG.
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Affiliation(s)
- Dong-Yoon Lim
- Department of Pharmacology, College of Medicine, Chosun University, Gwangju 501-759, Korea.
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Sanae F, Miyaichi Y, Hayashi H. Endothelium-dependent contraction of rat thoracic aorta induced by gallic acid. Phytother Res 2003; 17:187-9. [PMID: 12601686 DOI: 10.1002/ptr.1255] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The vascular effect of a component of hydrolysable tannins, gallic acid, was examined in isolated rat thoracic aorta. Gallic acid exerted a contractile effect on the phenylephrine- or prostaglandin F(2/alpha)-precontracted endothelium-intact arteries. In endothelium-denuded arteries, the contractile response to-gallic acid was absent. Pretreatment with N(G)-nitro-L-arginine methyl ester (30 microM) abolished the gallic acid-induced contraction. Pretreatment with indomethacin (10 microM) or BQ610 (100 nM) had no observed effect. Pretreatment with gallic acid (1-10 microM) significantly attenuated the relaxation induced by acetylcholine, and that with 10 microM gallic acid also reduced the potency of sodium nitroprusside in the relaxation, without a reduction in efficacy, in endothelium-denuded arteries. These findings indicate that gallic acid induced endothelium-dependent contraction and strongly inhibited the endothelium-dependent relaxation rather than the endothelium-independent relaxation, probably through inhibition of endothelial nitric oxide (NO) production. Since NO plays an important role in vasodilative regulation and inflammatory disorders, these findings may also indicate that gallic acid interferes with the inflammatory responses.
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Affiliation(s)
- Fujiko Sanae
- Department of Medicine, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa 920-1181, Japan.
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Wartenberg M, Budde P, De Mareés M, Grünheck F, Tsang SY, Huang Y, Chen ZY, Hescheler J, Sauer H. Inhibition of tumor-induced angiogenesis and matrix-metalloproteinase expression in confrontation cultures of embryoid bodies and tumor spheroids by plant ingredients used in traditional chinese medicine. J Transl Med 2003; 83:87-98. [PMID: 12533689 DOI: 10.1097/01.lab.0000049348.51663.2f] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Tumor-induced angiogenesis is a prerequisite for excessive tumor growth. Blood vessels invade the tumor tissue after degradation of the extracellular matrix scaffold by matrix metalloproteinases (MMPs). Inhibition of MMPs has been therefore suggested to be a useful tool to abolish neoangiogenesis of solid tumors. In the present study, antioxidative plant ingredients used in traditional Chinese medicine were investigated for their capacity to down-regulate MMP expression and to inhibit angiogenesis in embryonic stem cell-derived embryoid bodies and tumor-induced angiogenesis in confrontation cultures consisting of embryoid bodies and multicellular DU-145 prostate tumor spheroids. Embryoid bodies transiently expressed MMP-1, MMP-2, and MMP-9 during the time of differentiation of capillary-like structures. In confrontation cultures, MMP expression was increased compared with control tumor spheroids and embryoid bodies cultivated separately. The increased expression of MMPs in confrontation cultures was a result of elevated levels of reactive oxygen species (ROS) upon confrontation culture and was totally abolished in the presence of the free radical scavenger vitamin E. Incubation of embryoid bodies with baicalein, epicatechin, berberine, and acteoside, which are herbal ingredients used in traditional Chinese medicine, significantly inhibited angiogenesis in embryoid bodies and decreased intracellular ROS levels. Tumor-induced angiogenesis in confrontation cultures was totally abolished in the presence of the free radical scavenger vitamin E. Because herbal ingredients down-regulated MMP expression, we conclude that ROS generated during confrontation culture induce the expression of MMPs that are necessary for endothelial cell invasion into the tumor tissue.
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Affiliation(s)
- Maria Wartenberg
- Department of Neurophysiology, University of Cologne, Cologne, Germany
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Shen JZ, Zheng XF, Wei EQ, Kwan CY. Green tea catechins evoke a phasic contraction in rat aorta via H2O2-mediated multiple-signalling pathways. Clin Exp Pharmacol Physiol 2003; 30:88-95. [PMID: 12542460 DOI: 10.1046/j.1440-1681.2003.03796.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The contractile effects of tea polyphenols (TP) and its four principle catechins, namely (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG), on rat aorta contractility were investigated using the isometric tension recording technique. 2. At concentrations of 5-100 mg/L, TP evoked phasic contraction of rat aorta in a concentration-dependent but endothelium-independent manner. Of the four catechins tested, EGCG and EGC (3-300 micromol/L), but not EC and ECG, mimicked the contractile response to TP, suggesting that the epigallol moiety in the B ring may be associated with the contractile effect. 3. Contractions in response to EGCG and EGC were not affected by several endogenous vasoconstrictor receptor antagonists, but could be abolished by 10 micro mol/L BAPTA-AM, a membrane-permeable Ca2+ chelator, or attenuated by removal of extracellular Ca2+, suggesting the involvement of both intracellular and extracellular Ca2+ in evoking the contraction. 4. Pretreatment with non-selective Ca2+ channel antagonists mefenamic acid (10 micro mol/L), tetrandrine (30 micro mol/L) and SKF 96365 (30 micromol/L), but not nifedipine (1 micromol/L), the selective inhibitor of voltage-dependent Ca2+ channels, inhibited the contractile responses to EGC and EGCG, indicating the involvement of Ca2+ influx via non-voltage dependent Ca2+ channels. 5. Several intracellular Ca2+ channel modulators, including procaine (5 mmol/L), dantrolene (30 micromol/L) and 2-amino ethoxydiphenyl borate (50 micromol/L; an inositol 1,4,5-trisphosphate receptor inhibitor), also inhibited EGCG- and EGC-induced contractions, thus suggesting a role of intracellular Ca2+ release in these contractions. 6. Both EGCG- and EGC-induced contractions were depressed, to different degrees, by inhibitors of several receptor-coupled enzymes, including phospholipase C, protein kinase C, phospholipase A2 and tyrosine kinase. Furthermore, both EGCG- and EGC-induced contractions were completely abolished by catalase, but not by superoxide dismutase or mannitol/dimethyl sulphoxide. 7. Taken together, these data show, for the first time, that TP and its related catechins that contain an epigallol structure in the B ring, as in EGCG and EGC, exert direct contractile effects on rat aortic smooth muscle via a H2O2-mediated pathway.
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Affiliation(s)
- Jian-Zhong Shen
- Department of Pharmacology, School of Medicine, Zhejiang University, Hubin Campus, Hangzhou, People's Republic of China
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Sanae F, Miyaichi Y, Kizu H, Hayashi H. Effects of catechins on vascular tone in rat thoracic aorta with endothelium. Life Sci 2002; 71:2553-62. [PMID: 12270760 DOI: 10.1016/s0024-3205(02)02080-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of eight catechin derivatives on vascular tone in rat thoracic aorta were examined. Catechin derivatives (10 microM) potentiated the contractile response to phenylephrine in endothelium-intact arteries. The potentiations produced by EGCg and EGC were almost absent in endothelium-denuded arteries and abolished by N(G)-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis. The catechin derivatives also inhibited endothelium-dependent relaxation in response to acetylcholine. The order of catechin derivatives ranked in terms of both increasing vascular reactivity and impairing endothelium-dependent relaxation was similar; (-)-gallocatechin (GC) >or= (-)-epigallocatechin (EGC) >or= (-)-gallocatechin gallate (GCg) >or= (-)-epigallocatechin gallate (EGCg) >or= (-)-catechin (C) >or= (-)-epicatechin (EC) >or= (-)-catechin gallate (Cg) >or= (-)-epicatechin gallate (ECg). In addition, EGC inhibited the endothelium-independent relaxation evoked by both sodium nitroprusside and NOC-7, a spontanous NO releaser, but EGCg inhibited only that by NOC-7. These findings indicate that catechin derivatives produce a potentiation of the contractile response and an inhibition of the vasorelaxant response, probably through inactivation of endothelium-derived nitric oxide (NO), and that the hydroxyl on C-5 of the B ring together with the stereoscopic structure between the C-3 group and the B ring of flavanols was of importance in mediating the above effects and that the substitution of a gallate group of C-3 attenuated the effects, probably due to a decreased response to solube guanylate cyclase in vascular smooth muscle cells.
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Affiliation(s)
- Fujiko Sanae
- Department of Medicine, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Japan.
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Liao S, Kao YH, Hiipakka RA. Green tea: biochemical and biological basis for health benefits. VITAMINS AND HORMONES 2001; 62:1-94. [PMID: 11345896 DOI: 10.1016/s0083-6729(01)62001-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- S Liao
- Tang Center for Herbal Medicine Research, Ben May Institute for Cancer Research, and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA
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