Studies on the reactions of sylvatesmin and lantbeside with oxidizing free radicals

Sylvatesmin (SYL) and lantbeside (LAN) are two lignans, isolated from a Chinese folk medicinal herb, Lancea tibetica. Their abilities of scavenging oxidizing free radical models, ·OH, SO4·- and N3·, were investigated in aqueous solution by pulse radiolysis techniques. The OH-adduct radicals with small amount of oxidized products were formed by the reaction of SYL or LAN with ·OH radical. SYL undergoes one-electron oxidation either by SO4·- or N3· radicals, LAN can only be detected to react with stronger oxidant SO4·- radical anion. No reaction between LAN and N3· radical was detectable. The relationship of structure with the abilities of scavenging free radicals was discussed. The reaction rate constants were determined by analysis of the build-up trace of the radical products