[Antimutagenic activity and metabolic transformation of ranunculin by rat liver microsomes]

Ranunculin (RAN) was shown to be an antimutagenic agent selectively against mitomycin C (MMC) or methyl methane sulfanate (MMS) treated Salmonella typhimminum TA100/TA102. It decreased the formation of micronucleus of MMC induced polychromatic erythrocytes (PEC) from 46 +/- 9.2% to 20 +/- 6% in mice. The inhibition of RAN on the incorporation of 3H-TdR into DNA disappeared after incubation with rat liver microsomes and cytoplasm since RAN was found to be metabolized by rat liver microsomes in vitro, resulting in a new absorbance peak at 258 nm, determined by RP-HPLC. The data show that RAN may have both antimutagen and antitumor activity, but the latter action may disappear by metabolic transformation.