Relationship among antioxidant activity, vasodilation capacity, and phenolic content of red wines

The relationship among antioxidant activity, based on the electron-spin res onance determination of the reduction of Fremy's radical, vasodilation acti vity, and phenolic content was investigated in 16 red wines. The wines were selected to provide a range of origins, grape varieties, and vinification methods. Sensitive and selective HPLC methods were used for the analysis of the major phenolics in red wine: free and conjugated myricetin, quercetin, kaempferol, and isorhamnetin; (+)-catechin, (-)-epicatechin, gallic acid, p-coumaric acid, caffeic acid, caftaric acid, trans-resveratrol, cis-resver atrol, and trans-resveratrol glucoside. Total anthocyanins were measured us ing a colorimetric assay. The total phenolic content of the wines was deter mined according to the Folin-Ciocalteu colorimetric assay and also by the c umulative measurements obtained by HPLC. The 16 wines exhibited a wide rang e in the values of all parameters investigated. However, the total phenol c ontents, measured both by HPLC and colorimetrically, correlated very strong ly with the antioxidant activity and vasodilation activity. In addition, th e antioxidant activity was associated with gallic acid, total resveratrol, and total catechin. In contrast, only the total anthocyanins were correlate d with vasodilation activity. The results demonstrate that the different ph enolic profiles of wines can produce varying antioxidant and vasodilatant a ctivities, which opens up the possibility that some red wines may provide e nhanced health benefits for the consumer.