Abstract
A methanol extract from Belamcanda chinensis 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 B. chinensis was re-extracted with hexane, dichloromethane, ethyl acetate and butanol. A suppressive compound in the dichloromethane extract fraction was further fractionated by SiO2 column chromatography. EI-MS and 1H and 13C NMR spectroscopy were then used to delineate the structure of the compound that confers the observed suppressive effect. Comparison of the obtained spectrum with that found in the literature indicated that iristectorigenin B (1) is the suppressive compound. Iristectorigenin B and its methylated derivative (7, 4’-di-O-methyliristectorigenin B(2)) had the suppressive effects on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against furylfuramide, 4NQO, MNNG, and activated Trp-P-1, which do not require liver metabolic activation by S9. These compounds also showed the suppression of SOS-inducing activity against Trp-P-1 and AfB1, which require liver metabolizing enzymes. In addition to the antimutagenic activities of these compounds against furylfuramide, Trp-P-1 and activated Trp-P-1 were also assayed by an Ames test using S. typhimurium TA100.
