Antioxidant Activity of Different Phenolic Fractions Separated from an Italian Red Wine

TLDR

Liquid/liquid extraction produced three phenolic subfractions—phenolic acids/quercetin‑3‑glucuronide, catechins/quercetin‑3‑glucoside, and anthocyanins—which were assessed for radical scavenging, LDL oxidation inhibition, and platelet aggregation inhibition, and compared to the whole wine before and after dealcoholization. The anthocyanin fraction showed the strongest antioxidant activity, outperforming the other fractions in reactive oxygen species scavenging, LDL oxidation inhibition, and platelet aggregation inhibition, with peroxyl radical scavenging activity three times higher, indicating anthocyanins may be key to red wine’s cardiovascular protection, pending in vivo confirmation.

Abstract

Using liquid/liquid extraction, three fractions were obtained from an Italian red wine containing single polyphenolic subfractions: (1) phenolic acids and quercetin-3-glucuronide, (2) catechins and quercetin-3-glucoside, and (3) anthocyanins. Beside the scavenging capacity of the different fractions against hydroxyl and peroxyl radicals, the in vitro inhibition of low density lipoprotein oxidation and platelet aggregation (two main events in the pathogenesis of atherosclerosis) were tested. The antioxidant activity of the fractions has been compared with that of the original red wine before and after dealcoholization. The anthocyanin fraction was the most effective both in scavenging reactive oxygen species and in inhibiting lipoprotein oxidation and platelet aggregation. This higher activity can be explained by both its high concentration in red wine and its antioxidant efficiency, which, at least for peroxyl radical scavenging, was three times as high as that of the other two fractions. Our results suggest that anthocyanins could be the key component in red wine in light of the protection against cardiovascular diseases, although this hypothesis needs in vivo evidence.