Isao Morimoto

Mutagenicity screening of crude drugs with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay.

This paper describes the screening studies of 104 commercial crude drugs for mutagenicity by the rec-assay with Bacillus subtilis as well as the reversion assay with Ames strains TA98 and TA100 of Salmonella typhimurium. The rec-assays showed that 13 water extracts and 27 methanol extracts of the crude drugs were positive. The Ames assays with or without metabolic activation showed that 24 water extracts and 16 methanol extracts were mutagenic. In total, mutagenic activities were found in 45 samples among the 104 crude drugs tested.

Mutagenicity of isoquinoline alkaloids, especially of the aporphine type

The mutagenicity of 44 isoquinoline alkaloids was tested in Salmonella typhimurium TA100 and TA98 in the presence or absence of S9 mix. The alkaloids tested included compounds from the isoquinoline, benzylisoquinoline, bisbenzylisoquinoline, monoterpene isoquinoline, berberine, morphinane, hasubanan, benzo[c]phenanthridine and aporphine groups. Among the alkaloids tested, liriodenine was the most potent mutagen for TA100 and roemerine was the most potent for TA98. A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides.

Mutagenic activities of gentisin and isogentisin from Gentianae radix (Gentianaceae)

The mutagenic activities of 2 hydroxyxanthones, gentisin and isogentisin, obtained from the methanol extract of Gentianae radix (Gentianaceae) were investigated. The methanol extract of Gentianae radix, which showed mutagenicity in the Ames test in Salmonella typhimurium strain TA100 with S9 mix, was fractionated by column chromatography on Sephadex LH-20, and the fractions were purified by preparative TLC and column chromatography on polyamide. 2 mutagenic materials thus obtained, S1 and S2, each gave a single band on TLC. Identification of S1 and S2 was accomplished by comparing the analytical (mps, elementary analyses) and spectral (UV, IR, mass, NMR) results for S1 and S2 with literature data for gentisin and isogentisin. At doses below 10 micrograms, S1 (gentisin) and S2 (isogentisin) had similar specific mutagenic activities. At doses of over 10 to 50 micrograms, the mutagenic activities of S2 and S1 were 19.1 and 6.94 revertants per microgram respectively. This much lower activity of S1 than S2 may be a result of its poor solubility owing to the presence of the OMe group at C-3. The combined yield of S1 and S2 was about 76 mg (40 mg as S1 and 36 mg as S2), which accounted for 76% of the content of mutagenic compounds (100 mg) estimated roughly from the total mutagenic activity in the extract of the starting materials (100 g).