AbstractRepeated p.o. administration of myristicin and dehydrodiisoeugenol, monomeric and dimeric phenylpropanoids from mace, resulted in suppression of the lipid peroxidation in the liver of mice, which was induced by repeated i.p. injection of FeCl2–ascorbic acid–ADP. In addition, a slight decrease of SOD activity by treatment with FeCl2–ascorbic acid–ADP was recovered by administration of these compounds.Various constituents isolated from mace inhibited the lipid peroxidation in a rat liver homogenate, which was induced by FeCl2–ascorbic acid, CCl4–NADPH or ADP–NADPH. Of these compounds, 2,3‐dihydro‐7‐methoxy‐3‐methyl‐2‐ (3,4‐methylenedioxyphenyl)‐5‐propenylbenzofuran, myristicanol‐B and 7‐hydroxymyristicin strongly inhibited the FeCl2–ascorbic acid‐induced lipid peroxidation by 70%–100% at 0.1–0.2 mM, and most of the constituents also strongly inhibited the ADP–NADPH‐induced lipid peroxidation at the same concentrations. On the other hand, these compounds weakly inhibited the CCl4–NADPH‐induced lipid peroxidation.On the basis of the above findings, myristicin and dehydrodiisoeugenol administered to mice may inhibit the lipid peroxidation in the liver possibly by scavenging free radicals or active oxygen species directly.