Modulating effect of plant flavonoids on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine.

Tests have been carried out with several plant flavonoids to detect their ability to suppress mutagenesis in Salmonella typhimurium strain TA100 NR induced by the direct-acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine. Among the most effective flavonoids are the isoflavone, biochanin A, the flavanone glycoside, naringin, and its aglycone, naringenin, and several flavonols, e.g. morin, fisetin, kaempferol, gossypetin and quercetin, including a flavonol glycoside, rutin. In particular, naringin possesses exceptional antimutagenic activity, in as much as, less than half the equimolar amount can reduce the mutagenic potency of this carcinogen by 50%. These flavonoids appear to act either by preventing passage of the carcinogen into bacterial cells or by altering some cellular processes.