Natural dietary polyphenolic compounds cause endothelium-dependent vasorelaxation in rat thoracic aorta

This study investigated the possible active principles which support the en dothelial nitric oxide-dependent relaxation produced by red wine and other plant polyphenolic compounds in thoracic aorta from male Wistar rats (12-14 wk old). Relaxation experiments were recorded isometrically on vessels pre contracted with norepinephrine. Ten different chromatographic fractions (3- 18 mg) isolated from red wine polyphenolic compounds (RWPC) and some availa ble defined polyphenols (10-15 mg) were tested. Fractions enriched into eit her anthocyanins or oligomeric condensed tannins exhibited endothelium-depe ndent vasorelaxant activity (maximal relaxation in the range of 59-77%) com parable to the original RWPC. However, polymeric condensed tannins elicited a weaker vasorelaxant activity than the original RWPC (maximal relaxation ranged between 20-47%, P < 0.01). Moreover, the representative of either ph enolic acid derivatives (benzoic acid, vanillic acid, gallic acid), hydroxy cinnamic acid (p-coumaric acid, caffeic acid) or the flavanol [(+)-epicatec hin] classes failed to induce this type of response. Among the anthocyanins , delphinidin (maximal relaxation being 89%), but not malvidin or cyanidin, showed endothelium-dependent vasorelaxation, These results show that antho cyanins and oligomeric-condensed tannins exhibited a pharmacological profil e comparable to the original RWPC, These compounds may be involved in the r eduction of cardiovascular mortality related to the presence of wine, fruit s and vegetables in the diet.