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Dive into the research topics where Philippe Chabert is active.

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Featured researches published by Philippe Chabert.


Biochemical and Biophysical Research Communications | 2010

The EGCg-induced redox-sensitive activation of endothelial nitric oxide synthase and relaxation are critically dependent on hydroxyl moieties.

Cyril Auger; Jong-Hun Kim; Philippe Chabert; Mehdi Chaabi; Eric Anselm; Xavier Lanciaux; Annelise Lobstein; Valérie B. Schini-Kerth

Several rich sources of polyphenols stimulate the endothelial formation of nitric oxide (NO), a potent vasoprotecting factor, via the redox-sensitive activation of the PI3-kinase/Akt pathway leading to the phosphorylation of endothelial NO synthase (eNOS). The present study examined the molecular mechanism underlying the stimulatory effect of epicatechins on eNOS. NO-mediated relaxation was assessed using porcine coronary artery rings in the presence of indomethacin, and charybdotoxin plus apamin, inhibitors of cyclooxygenases and EDHF-mediated responses, respectively. The phosphorylation level of Akt and eNOS was assessed in cultured coronary artery endothelial cells by Western blot, and ROS formation using dihydroethidine. (-)-Epigallocatechin-3-O-gallate (EGCg) caused endothelium-dependent relaxations in coronary artery rings and the phosphorylation of Akt and eNOS in endothelial cells. These responses were inhibited by membrane-permeant analogues of superoxide dismutase and catalase, whereas native superoxide dismutase, catalase and inhibitors of major enzymatic sources of reactive oxygen species including NADPH oxidase, xanthine oxidase, cytochrome P450 and the mitochondrial respiration chain were without effect. The EGCg derivative with all hydroxyl functions methylated induced neither relaxations nor the intracellular formation of ROS, whereas both responses were observed when the hydroxyl functions on the gallate moiety were present. In conclusion, EGCg causes endothelium-dependent NO-mediated relaxations of coronary artery rings through the Akt-dependent activation of eNOS in endothelial cells. This response is initiated by the intracellular formation of superoxide anions and hydrogen peroxide, and is critically dependent on the gallate moiety and on the presence of hydroxyl functions possibly through intracellular auto-oxidation.


Journal of Ethnopharmacology | 2010

Procyanidin-rich fractions from Parkia biglobosa (Mimosaceae) leaves cause redox-sensitive endothelium-dependent relaxation involving NO and EDHF in porcine coronary artery

Jean-Marie Tokoudagba; Cyril Auger; Lise Bréant; Saliou Ngom; Philippe Chabert; Noureddine Idris-Khodja; Fernand Gbaguidi; Joachim Gbenou; Mansourou Moudachirou; Annelise Lobstein; Valérie B. Schini-Kerth

AIM OF THE STUDY Parkia biglobosa leaves are traditionally used as an antihypertensive agent in Benin. The present study assessed the vasorelaxant activity of different Parkia biglobosa leaf extracts using isolated porcine coronary artery rings. MATERIALS AND METHODS A hydroalcoholic leaf extract was submitted to a multi-step liquid-liquid fractionation with solvents of increasing polarity and the polyphenolic content of the different fractions was analyzed. Vascular reactivity of the different extracts was assessed using porcine coronary artery rings, in the presence or absence of specific pharmacological inhibitors. RESULTS The hydroalcoholic, ethyl acetate and butanolic extracts contained mainly procyanidins and monomeric flavonoids. Parkia biglobosa leaf crude extract induced a redox-sensitive endothelium-dependent relaxation mediated by both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). The fractionation of the butanolic extract generated 6 fractions, two of which induced stronger vasorelaxation than the original extract and they had a higher phenolic content. CONCLUSIONS Parkia biglobosa leaf extract is able to induce endothelium-dependent NO- and EDHF-mediated relaxation in porcine coronary artery rings. The vasorelaxant activity is dependent on their phenolic content and appears to involve mainly procyanidins.


Pharmaceutical Biology | 2007

Antiplasmodial Activity of Constituents Isolated from Croton lobatus.

Barthélemy Attioua; Bernard Weniger; Philippe Chabert

Abstract Seven constituents were isolated from the stems and leaves of Croton lobatus. L. (Euphorbiaceae), a medicinal plant used in western Africa in traditional folk medicine to cure malaria, pregnancy troubles, and dysentery. Their structures were elucidated by spectroscopic methods. The compounds identified were 3-[(6Z.,9Z.)dodeca-6,9-dienoyloxy]-2-octanoyloxypropyl(6Z.,9Z.)dodeca-6,9-dienoate (1) for the first time and six known compounds: (Z.,Z.,Z.)-9,12,15-octadecatrienoic acid methyl ester (2), 8,11,17,21-tetramethyl-(E.,E.,E.,E.)-8,10,17,21-tetraentetracosanoic acid (3), geranylgeraniol (4), cholestan-3-one (5), betulinic acid (6), and (E.)-3-(4-methoxy-phenyl)-2-phenyl-acrylic acid (7). From the seven compounds, (4) and (6) showed the best antiplasmodial activity in vitro. on Plasmodium falciparum. K1 chloroquine-resistant strain, with IC50 values (µg/mL) of 1.07 and 1.45 mg/mL, respectively, while compounds (2), (3), and (7) showed IC50 below 5 in the same assay. Cytotoxicity of the most active compounds was evaluated on L6 murine myoblast cells. Geranylgeraniol (4) showed good selectivity with an SI value (SI = ratio of cytotoxicity to biological activity) over 25.


Magnetic Resonance in Chemistry | 2010

Structure elucidation of new acacic acid-type saponins from Albizia coriaria

Philippe Chabert; Dieudonné Emmanuel Pegnyemb; Bernard Weniger; Marie-Aleth Lacaille-Dubois; Annelise Lobstein

Three new acacic acid derivatives, named coriariosides C, D, and E (1–3) were isolated from the roots of Albizia coriaria. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR studies and mass spectrometry as 3‐O‐[β‐D‐xylopyranosyl‐(1 → 2)‐β‐D‐fucopyranosyl‐(1 → 6)‐2‐(acetamido)‐2‐deoxy‐β‐D‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐ 6‐O‐(β‐D‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐α‐L‐rhamnopyranosyl‐(1 → 2)‐β‐D‐glucopyranosyl ester (1), 3‐O‐{β‐D‐fucopyranosyl‐(1 → 6)‐[β‐D‐glucopyranosyl‐(1 → 2)]‐β‐D‐glucopyranosyl}‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐α‐L‐rhamno pyranosyl‐(1 → 2)‐β‐D‐glucopyranosyl ester (2), and 3‐O‐[β‐D‐fucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D‐quinovopyranosyl)octa‐2,7‐dienoyl)‐β‐D‐quinovopyranosyl]octa‐2,7‐dienoyl}acacic acid 28‐O‐β‐D‐glucopyranosyl ester (3). Copyright


Journal of Cardiovascular Pharmacology | 2016

Potential of Food and Natural Products to Promote Endothelial and Vascular Health.

Cyril Auger; Amissi Said; Phuong Nga Nguyen; Philippe Chabert; Noureddine Idris-Khodja; Valérie B. Schini-Kerth

Abstract: Endothelial dysfunction is now well established as a pivotal early event in the development of major cardiovascular diseases including hypertension, atherosclerosis, and diabetes. The alteration of the endothelial function is often triggered by an imbalance between the endothelial formation of vasoprotective factors including nitric oxide (NO) and endothelium-dependent hyperpolarization, and an increased level of oxidative stress involving several prooxidant enzymes such as NADPH oxidase and, often also, the appearance of cyclooxygenase-derived vasoconstrictors. Preclinical studies have indicated that polyphenol-rich food and food-derived products such as grape-derived products, black and red berries, green and black teas and cocoa, and omega-3 fatty acids can trigger activating pathways in endothelial cells promoting an increased formation of nitric oxide and endothelium-dependent hyperpolarization. Moreover, intake of such food-derived products has been associated with the prevention and/or the improvement of an established endothelial dysfunction in several experimental models of cardiovascular diseases and in humans with cardiovascular diseases. This review will discuss both experimental and clinical evidences indicating that different types of food and natural products are able to promote endothelial and vascular health, as well as the underlying mechanisms.


Journal of Ethnopharmacology | 2018

Mechanisms underlying vasorelaxation induced in the porcine coronary arteries by Thymus linearis , Benth

Alamgeer; Cyril Auger; Philippe Chabert; Claire Lugnier; M.N. Mushtaq; Valérie B. Schini-Kerth

ETHNOPHARMACOLOGICAL RELEVANCE Thymus linearis, Benth indigenous to Pakistan has been traditionally used for the treatment of various diseases including hypertension. AIM OF THE STUDY Present study aims to investigate vasorelaxant effect of Thymus linearis and its underlying vasorelaxation mechanisms in porcine coronary artery rings. MATERIALS AND METHODS Aqueous-methanolic extract of aerial parts of Thymus linearis was prepared by maceration process and then bio-guided fractionation was carried out using different solvents. The effects of extract and subsequent fractions were assessed on coronary artery rings with intact and denuded endothelium. The mechanisms of vasorelaxant effect were investigated using different pharmacological tools. The in-vitro inhibitory effects of the test fractions were also assessed on purified phophodiestrases using radioenzymatic assay. Phytochemical studies were carried out using GCMS. RESULTS The aqueous-methanolic extract elicited similar relaxations in coronary artery rings with and without endothelium in dose dependent fashion and removal of endothelium did not alter this response. Further, n-butanolic fraction of Thymus liniaris (TLB) was found to be the most potent among other derived fractions. TLB did not alter the relaxation produced by endothelium dependent vasodilators in rings with intact endothelium. However, TLB significantly potentiated the relaxation elicited by cyclic AMP and cyclic GMP elevating drugs but not those to soluble guanylyl cyclase activators (YC-1 and BAY 41-2272) and K+ channel openers (levcromakalim and 1-EBIO). Pretreatment with TLB inhibited in a concentration-dependent manner contractions to KCl, CaCl2 and U46619 in coronary artery rings without endothelium. Further, TLB was found to non-selectively inhibit the PDE activity in concentration manner. CONCLUSION n-Butanolic fraction of Thymus linearis possesses endothelium independent vasorelaxant effects in coronary artery by direct acting on the smooth muscles. These effects involve the elevation of the cyclic AMP and cyclic GMP possibly through the inhibition of various PDEs. GCMS analysis revel presence of thymole and carvacrol as major constituents. Furthermore, these investigations also support the folklore use of Thymus linearis in hypertension.


Archives of Cardiovascular Diseases | 2009

C007 Redox-sensitive activation of endothelial nitric oxide synthase by catechins: role of hydroxyl moieties

Cyril Auger; Jong-Hun Kim; Mehdi Chaabi; Philippe Chabert; Eric Anselm; X. Lanciaux; Annelise Lobstein; Valérie B. Schini-Kerth

Objectives Several rich sources of polyphenols have been shown to strongly increase the endothelial formation of nitric oxide (NO), a potent vasoprotecting factor, via the redox-sensitive activation of the PI3-kinase/Akt pathway leading to the phosphorylation of endothelial NO synthase. The purpose of the present study was to investigate the molecular mechanisms underlying the stimulatory effect of catechins on the endothelial formation of NO using different catechins (flavan-3-ols). Methods Vascular reactivity studies were performed using porcine coronary artery rings, which were suspended in organ chambers for the measurement of changes in isometric tension. All experiments were performed in the presence of indomethacin (an inhibitor of cyclooxygenases), and the combination of apamin and charybdotoxin (two inhibitors of endothelium-derived hyperpolarizing factor-mediated effects) to assess only the NO component of the relaxation. Cultures of porcine coronary artery endothelial cells (P1) were used to determine the phosphorylation level of Akt and endothelial NO synthase by Western blot analysis. Both natural and synthetic catechins were evaluated. Results (-)-Epigallocatechin-3-O-gallate (EGCg) induced potent endothelium-dependent relaxations in porcine coronary artery rings. The EGCg-induced relaxation was inhibited by MnTMPyP (a membrane permeant analogue of superoxide dismutase, SOD) whereas extracellular SOD had no effect, indicating a major role of the intracellular formation of ROS. Relaxations to EGCg were minimally affected by rotenone (an inhibitory of the mitochondrial respiratory chain), sulphenazol (an inhibitor of cytochrome P450), apocynin (an inhibitor of NADPH oxidase) or allopurinol (an inhibitor of xanthine oxidase). The replacement of all hydroxyl groups of EGCg by O-methyl groups resulted in the total loss of the relaxing activity whereas partial replacement decreased the relaxing activity. Conclusions EGCg caused endothelium-dependent relaxations of coronary arteries via the redox-sensitive formation of NO in endothelial cells. The stimulatory effect does not involve major intracellular sources of ROS including the mitochondrial respiratory chain, xanthine oxidase, NADPH oxidase and cytochrome P450 but is critically dependent on the presence of hydroxyl groups possibly leading to auto-oxidation of the polyphenol.


Biofactors | 2006

Anti-mitotic properties of resveratrol analog (Z)-3,5,4′-trimethoxystilbene

Philippe Chabert; André Fougerousse; Raymond Brouillard


Phytochemistry Letters | 2010

Acylated flavonol pentaglycosides from Baphia nitida leaves

Mehdi Chaabi; Philippe Chabert; Catherine Vonthron-Sénécheau; Bernard Weniger; Modibo Ouattara; Hugo Corstjens; Ilse Sente; Lieve Declercq; Annelise Lobstein


Fitoterapia | 2012

Labdane-type diterpenes and flavones from Dodonaea viscosa

Hippolyte K. Wabo; Philippe Chabert; Michel F. Tala; Jean Peluso; Christian D. Muller; Haruhisa Kikuchi; Yoshiteru Oshima; Annelise Lobstein

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Cyril Auger

University of Strasbourg

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Mehdi Chaabi

University of Strasbourg

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Amissi Said

University of Strasbourg

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Claire Lugnier

University of Strasbourg

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