[Antioxidative activity of oren-gedoku-to (TJ-15) and toki- shakuyaku-san (TJ-23) in the liver microsomes of rats].

TJ-15 (Oren-Gedoku-To) inhibited enzymatically (NADPH or CumOOH) and non-enzymatically (Fe-askorbate) induced lipid peroxidation in the rat liver microsomes as assessed by the TBA-reactive product accumulation. TJ-23 (Toki-Shakuyaku-San) had little effect on either system. The protective effect of TJ-15 against lipid peroxidation could not be fully accounted for by its action on microsomal electron transfer, as evaluated by studying the kinetics of reduction of cytochrome C. In a free solution TJ-15 and TJ-23 effectively scavenged OH., radicals, as indicated by the inhibition of ethylene production from KMBA, and O2-. anion radicals, as assessed by the inhibitory effect on the rate of NBT reduction. The present results suggest that TJ-15, yet not TJ-23, is capable to reach hydrophobic intra-membrane sites at concentrations at which it is an effective antioxidant. Thus TJ-15 may be a potentially useful protective agent against free radical-mediated damage.