A phenolic acid; scavenges DPPH free radicals in a cell-free assay (EC50 = 20.4 μM); inhibits oxidation of LDL isolated from human plasma by 97.6% compared to vehicle control in vitro at 5 μM; the main phenolic compound in V. vinifera white, pink, and black table grapes as well as various wines; levels in red wine positively correlate with inhibition of protein carbonylation and decreased SOD, Gpx, and catalase activities in mice following dietary administration,