BETA-CAROTENE EFFECTIVELY SCAVENGES TOXIC NITROGEN-OXIDES - NITROGEN-DIOXIDE AND PEROXYNITROUS ACID

beta-Carotene absorbed 2 equimolar amounts of NO2 accompanying the com plete destruction of beta-carotene. Electron spin resonance study usin g enyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl revealed that no significant amounts of NO mere released by the interaction, Nitrogen a toms derived from NO2 were tightly bound to the beta-carotene molecule s. Destruction of beta-carotene was inhibited little by alpha-tocopher ol and polyunsaturated fatty esters, and slightly by ascorbyl palmitat e, indicating that beta-carotene was a more effective scavenger of NO2 . ONOOH/ONOO- and 3-morpholinosydononimine similarly destroyed beta-ca rotene, The results suggest that beta-carotene contributes to the prev ention of cytotoxicity and genotoxicity of NO2 and ONOOH/ONOO- derived from NO. (C) 1997 Federation of European Biochemical Societies.