Peroxynitrite scavenging of flavonoids: structure activity relationship

Peroxynitrite can oxidize and nitrosylate biomols. and is assocd. with several diseases. The peroxynitrite scavenging of substituted phenols and several flavonoids was studied. The activity of phenol (poor scavenger) is pos. influenced by electron donating substituents. A good correlation was found between the peroxynitrite scavenging activity of the substituted phenols and the Hammett s or the EHOMO. Flavonols contg. a catechol group (3'- and 4'-OH) in ring B (rutin and monohydroxyethyl rutoside) or an AC-ring with three OH groups (3-, 5- and 7-OH) were potent scavengers. Evidence has been produced that in the AC-ring the 3-OH group was the reactive center and that the reactivity of this group was pos. influenced by electron donating groups at the 5 and/or 7 position (galangin, kaempferol, trihydroxyethyl quercetin). [on SciFinder (R)]