Antimutagenic activity of flavonoids from Sozuku

<p>Pinocembrin (<b>1</b>) and cardamonin (<b>2</b>) from Sozuku showed a suppressive effect on <i>umu</i> gene expression of SOS response in <i>Salmonella typhimurium</i> TA1535/pSK1002 against the mutagen furylfuramide. Compounds <b>1</b> and <b>2</b> suppressed 52% and 36% of SOS-inducing activity at a concentration of 0.20 μmol/mL. The ID<sub>50</sub> value of <b>1</b> was 0.18 μmol/mL. These compounds showed the suppression of 2-amino-3,4-dimethylimidazo-[4,5-f]quinolone (MeIQ) and UV irradiation-induced SOS response. Pinostrobin (<b>3</b>) and 5,7-dimethoxyflavanone (<b>4</b>), methyl ethers of <b>1</b>, showed similar activity to <b>1</b> against MeIQ-induced SOS response, but that of furylfuramide and UV irradiation were decreased. On the other hand, compounds <b>1</b>–<b>4</b> did not show the suppression of activated MeIQ-induced SOS response. Furthermore, compounds <b>1</b>–<b>4</b> showed potent antimutagenic activity against MeIQ mutagenesis in Ames test using the <i>S. typhimurium</i> TA100 and TA98 strains.</p>