Antimutagenic activity of (+)-beta-eudesmol and paeonol from Dioscorea japonica

A methanol extract from Dioscorea japonica showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract from D. japonica was reextracted with dichloromethane, n-butanol, and water, respectively. The suppressive compounds in the dichloromethane extract fraction were isolated by SiO2 column chromatography and identified as (+)-beta-eudesmol and 2-hydroxy-4-methoxyacetophenone (paeonol) by EI-MS and H-1 and C-13 NMR spectroscopy. (+)-beta-Eudesmol suppressed the SOS-inducing activity of furylfuramide in the umu test. Gene expression was suppressed 80% at <0.18 mu mol/mL, and the ID50 value was 0.09 mu mol/ mL. Paeonol also suppressed the SOS-inducing activity of furylfuramide in the umu test. Gene expression was suppressed 60% at <1.2 mu umo/mL, and the ID50 value was 0.99 mu mol/mL. (+)-beta-Eudesmol and paeonol were assayed with the mutagen 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]ind (Trp-P-1), which requires liver metabolizing enzymes, and showed suppressive effects on the SOS induction of the mutagen. (+)-beta-Eudesmol suppressed gene expression 48% at <0.18 mu mol/mL. Paeonol suppressed gene expression 76% at <1.2 mu mol/mL, and the ID50 was 0.41 mu mo/mL. The antimutagenic activities of these compounds against furylfuramide and Trp-P-1 were tested by an Ames test using S. typhimurium TA100, which indicated that these compounds showed antimutagenic activity.