Superoxide anion scavenging activity of alk(en)yl phenol compounds by using PMS-NADH system

Anacardic acid C(15:3) and cardol C(15:3) sigmoidally suppressed superoxide anion (O(2)-) generation using xanthine oxidase. To study this suppression activity, anacardic acids, cardanols and cardols having different numbers of double bonds in alk(en)yl chains were prepared. The O(2)- scavenging activity and H(2)O(2) formation from O(2)- using PMS-NADH were examined. Anacardic acids and cardols indicated sigmoidal O(2)- scavenging activity but cardanols did not. The O(2)- scavenging activity of anacardic acid C(15:3) was weaker than the suppression activity using xanthine oxidase, but the scavenging activity of cardol C(15:3) was quite similar to the suppression using xanthine oxidase. The H(2)O(2) formation from O(2)- decreased by the addition of anacardic acids, cardanols and cardols but increased by the addition of gallic and caffeic acids. From these results, we deduced that the O(2)- suppression activity of xanthine oxidase reaction with cardols is the O(2)- scavenging activity and that anacardic acids and cardols are O(2)- scavengers having low prooxidant property.