Antimutagenic thio compounds from Sisymbrium officinale.

Glucoputranjivin (1) and isopropyl isothiocyanate (2) were isolated from an aqueous dry extract of Sisymbrium officinale and were identified by spectroscopic analysis. The antimutagenic activity of these compounds was evaluated in a bacterial reverse mutation assay using E. coli WP2, WP2uvrA, and WP2uvrA/pKM101 strains, in comparison with the extract. In the absence of the exogenous metabolic activation system S9, the thio compounds exerted antimutagenic activity against the direct-acting mutagen methyl methanesulfonate, in all strains. In the presence of S9, both thio compounds were active against the indirect mutagens 2-aminoanthracene, in WP2uvrA, and 2-aminofluorene, in WP2. The antimutagenicity seems to be due to specific mechanisms, such as the induction of the adaptive response or the excision repair system. Conversely, the inhibition of the CYP450-mediated activation of mutagens was not supported by the present results. An antimutagenic effect was also observed for the S. officinale aqueous extract against the arylamines 2AA and 2AF, but not against MMS. These results suggest that both thio compounds are involved in the antimutagenicity of S. officinale. The antimutagenicity of glucosinolate 1 is reported for the first time.