Antimutagenicity mechanisms of the Rhoeo discolor ethanolic extract.

BACKGROUND

Rhoeo discolor, a medical plant from Mexico, is known to be an antioxidant and chemoprotective antimutagen. Rhoeo discolor ethanolic extract (EERD) is a complex mixture, so in this study its antimutagenic mechanisms were further evaluated.

METHODS

Employing Ames test, with uvrB- and uvrB+ strains, its antimutagenic activity against frameshift mutagens 2-amino-anthracene (AA), and 2 amino-fluorene (AF), alkylating: methyl-N'-nitro-N-nitrosoguanidine (MNNG) and ethyl-N'-nitro-N-nitrosoguanidine (ENNG) and mitomycin C were evaluated. Induction of ogt, alkyl-DNA-glycosylases were studied with Salmonella typhimurium strains deficient in ada and ogt genes (YG7100 ada-/ogt+ YG7104 ada+/ogt-, G7108 ada-/ogt-).

RESULTS

EERD, was not antimutagenic against AA or AF on S. typhimurium TA98 neither in UTH8413 uvrB+ strains. It significantly reduced mutations induced by Mitomycin C on strain TA102. EERD was antimutagenic to mutations induced by alkylating compounds on S. typhimurium TA100 or UTH8414 uvrB+. This antimutagenic effect was not observed on strains lacking ogt gene.

CONCLUSIONS

EERD, did not affect CYP450 in vitro microsomal activation of AF or AA, on the Ames test, neither improved DNA uvrB excision repair system. EERD reduced oxidative damages on strain TA102, caused by Mitomycin C. This plant extract might be used to avoid DNA damage by alkylation, corrected mainly alkylguanine transferase protein encoded by ogt gene.