Mechanism for the peroxynitrite scavenging activity by anthocyanins

We show that anthocyanins can function as potent inhibitors of the formation of nitrated tyrosine in vitro, and clarified how pelargonidin (Pel), which has a mono-hydroxyl group on the B-ring, can scavenge peroxynitrite (ONOO(-)) by detection of the reaction products. Pel was reacted with ONOO(-), then the reaction mixture was analyzed using high-performance liquid chromatography (HPLC). The HPLC analyses showed two novel peaks assumed to be the reaction products. Based on the instrumental analyses, the reaction products were identified as p-hydroxybenzoic acid and 4-hydroxy-3-nitrobenzoic acid. Pel can protect tyrosine from undergoing nitration through the formation of p-hydroxybenzoic acid and 4-hydroxy-3-nitrobenzoic acid.