Chemical reactions including electron transfer (ET) to scavenge ROS such as superoxide radical anion (O2 •-), hydroperoxyl radical (HO2 • ), and hydroxyl radical (HO • ), must be demonstrated to confirm the medicinal effects of piceatannol. Clarifying the ROS scavenging mechanism of piceatannol is a prerequisite to elucidate its medicinal effects, as ROS generated around lesions and inflammatory organs may directly cause several pathologies Cordova-Gomez et al. investigated the peroxyl radical scavenging activity of piceatannol using density functional theory (DFT), compared it with that of trans-resveratrol-its structural analog, and concluded that piceatannol is a better peroxyl scavenger than trans-resveratrol. Piceatannol belongs to the stilbenoid group of polyphenols and possesses a benzene-1,2-diol (ortho-diphenol, catechol) moiety and another phenolic ring linked to each other by an ethylene bridge with four hydroxyl groups (OH). Effective antioxidant activity is related to the quinone-hydroquinone πconjugation characterized by the presence of ortho-or para-diphenolic OHs. The better ROS scavenging of piceatannol compared with that of trans-resveratrol is potentially due to the functionality of its catechol moiety, which can delocalize -electrons with its resonance structure.