title: The Janus face of chlorogenic acid on vascular reactivity: A study on rat isolated vessels.
abstract: BACKGROUND
  Chlorogenic acid (CGA), the main polyphenol contained in coffee, is a major contributor to dietary polyphenol intake. Few studies reported its anti-hypertensive properties but the mechanisms are still indefinite.
  
  
  OBJECTIVE
  The present study assessed the direct effect of CGA in endothelium denuded or intact aortic rings from male Wistar rats and the mechanisms involved.
  
  
  RESULTS
  CGA induced a direct endothelium-dependent relaxation that was significantly reduced by L-NAME (10(-4)M), indomethacin (10(-5)M) and combination of apamin (10(-7)M) and charybdotoxin (10(-7)M). Incubation of rings with CGA induced a dual effect on agonist-induced vasorelaxation. At 10(-6)M, it enhanced the relaxant effects of acetylcholine and reduced the contracting effects of phenylephrine due to increased basal and stimulated NOS activity, respectively. At 10(-4)M, CGA blunted acetylcholine and bradykinin-induced vasorelaxation, reduced phenylephrine-induced vasoconstriction but did not change the response to sodium nitroprusside, a NO-donor.
  
  
  CONCLUSIONS
  In summary, CGA induces a direct endothelium-dependent vasodilation by increasing NOS, COX and EDHF signalling pathways. However, this new pharmacological action that can explain some positive effects of CGA in case of hypertension has to be modulated at the light of its deleterious impact on vascular relaxation at high concentrations and incite to be cautious when using high doses of CGA in clinical studies.
authors.affiliation: Laboratoire de Physiologie Animale, Département des Sciences Biologiques, Ecole Normale Supérieure, Université de Yaoundé I, B.P. 47 Yaoundé, Cameroun ; EA 4267 « Fonctions et Dysfonctions Epithéliales », UFR Sciences Médicales et Pharmaceutiques, Université de Bourgogne Franche-Comté, 19 rue Ambroise Paré, bâtiment S, F-25030 Besancon, France.
authors.forename: Esther Ngo Lemba
authors.initials: EN
authors.lastname: Tom
authors.affiliation: EA 4267 « Fonctions et Dysfonctions Epithéliales », UFR Sciences Médicales et Pharmaceutiques, Université de Bourgogne Franche-Comté, 19 rue Ambroise Paré, bâtiment S, F-25030 Besancon, France.
authors.forename: Corine
authors.initials: C
authors.lastname: Girard-Thernier
authors.affiliation: EA 4267 « Fonctions et Dysfonctions Epithéliales », UFR Sciences Médicales et Pharmaceutiques, Université de Bourgogne Franche-Comté, 19 rue Ambroise Paré, bâtiment S, F-25030 Besancon, France. Electronic address: cdemouge@univ-fcomte.fr.
authors.forename: Céline
authors.initials: C
authors.lastname: Demougeot
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002726:Chlorogenic Acid / Q000494:pharmacology* / Q000627:therapeutic use; D004730:Endothelium, Vascular / Q000187:drug effects*; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D000959:Antihypertensive Agents; D002726:Chlorogenic Acid
keywords: Chlorogenic acid; Endothelial pathways; Toxicity; Vasorelaxation