Contribution of proanthocyanidins to the peroxy radical scavenging capacity of some Italian red wines

Highly reactive radicals, ROO., were generated from 2,2'-azobis[2-(2-imidaz olin-2-yl)propane] and linoleic acid. The ROO. scavenging capacity of some Italian red wines was evaluated following the changes in oxygen consumption . Under the experimental conditions the time course of oxygen consumption s hows two typical behaviors: trolox-like (class II and gallic acid-like (cla ss II). Usually the time course of wine was similar to that of gallic acid. The rate of oxygen consumption was found to decrease exponentially with th e amount of wine or gallic acid added to the test solution. On this basis t he capacity of red wines to scavenge peroxy radicals was expressed as conte nt of gallic acid (S-GA) The S-GA values were found to be correlated to the amount of total proanthocyanidins and total polyphenols of some Italian re d wines (p < 0.01). The proanthocyanidins extracted from seeds were shown t o make a major contribution to the peroxy radical scavenging capacity of re d wines, whereas, interestingly, the chemical class of the low molecular we ight tannins reactive to vanillin did not correlate with the S-GA values.