1992 Volume 38 Issue 3 Pages 297-304
Japanese soybean paste miso, which has been reported to prevent gastric and mammary cancer and chronic nephritis, was dem-onstrated by electron spin resonance spectrometry using 5, 5'-dimethyl-1 -pyrroline-N-oxide as a scavenger of free radicals. Fifty mg/ml of miso scavenged 100% of 1, 1-Biphenyl- 2 -picrylhydrazyl radicals (3.9×1015 spins/ml); 45 mg/ml quenched 92% of hydroxyl radicals (7.9×1016 spins/ml); and 50 mg/ml quenched 50% of superoxide anion (6.7×1016 spins/ml). In the system of rat cerebral cortex homogenate supplemented with 2mM each of Fe2+ and ascorbic acid, 90% and 82% of the hydrogen and carbon-centered radicals having 1.7×1013 spins/ml and 3.9×1013 spins/ml, respectively, were quenched by 180mg/ml of miso. The thiobarbituric acid-reactive substances, an index of lipid peroxidation in the brain, was inhibited by 10mg/ml of miso. These results showed that miso acts as an antioxidant by scavenging free radicals.
