Sialic acid attenuates the cytotoxicity of the lipid hydroperoxides HpODE and HpETE

Abstract

Reduction of peroxide molecular species is an essential function in living organisms. In previous studies, we proposed a new function for the sialic acid N-acetylneuraminic acid (Neu5Ac)—that of antioxidant/hydrogen peroxide scavenging agent. On the basis of the reaction scheme, Neu5Ac is thought to act as a general antioxidant of all hydroperoxide-type species (R–OOHs). The concentration of tert-butyl hydroperoxide ( t-BuOOH) decreased after co-incubation with N-acetylneuraminic acid. Neu5Ac also decreased the R–OOH concentration in solutions of peroxylinolenic acid (13( S)-hydroperoxy-(9 Z,11 E)-octadecadienoic acid, HpODE) and peroxyarachidonic acid (15( S)-hydroperoxy-(5 Z,8 Z,11 Z,13 E)-eicosatetraenoic acid, HpETE)—two lipid hydroperoxides that participate in many physiological events. Moreover, the cytotoxicity of both these lipid hydroperoxides was attenuated by reaction with Neu5Ac acid. Our results suggest that N-acetylneuraminic acid is a potential antioxidant of most hydroperoxides that accumulate in organisms.