Antimutagenic Activity of Flavonoids from Chrysanthemum morifolium

Abstract

  A methanol extract from the flower heads of Chrysanthemum morifolium 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 was re-extracted with hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction showed a suppressive effect. Suppressive compounds in the ethyl acetate fraction were isolated by silica gel column chromatography and identified as the flavonoids acacetin (1), apigenin (2), luteolin (3), and quercetin (4) by EI-MS, IR, and ¹H and ¹³C NMR spectroscopy. Compounds 1-4 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1-4 suppressed 60.2, 75.7, 90.0, and 66.6% of the SOS-inducing activity at a concentration of 0.70 μmol/ml. The ID₅₀ (50% inhibitory dose) values of 1-4 were 0.62, 0.55, 0.44, and 0.59 μmol/ml. These compounds had the suppressive effects on umu gene expression of the SOS response against other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), which do not require liver-metabolizing enzymes. These compounds also showed the suppression of SOS-inducing activity against the other mutagens aflatoxin B₁ (AfB₁) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver-metabolizing enzymes, and UV irradiation. In addition to the antimutagenic activities of these compounds against furylfuramide, Trp-P-1 and activated Trp-P-1 were also assayed by the Ames test using S. typhimurium TA100.