Abstract
Remarkably strong inhibition of mutagenicity of 3-hydroxyamino-1-methyl-5H-pyrido [4, 3-b] indole due to direct action of tannins on the mutagen was found. Strong inhibition of mutagenicity of 7β, 8α-dihydroxy-9α, 10α-epoxy-7, 8, 9, 10-tetrahydrobenzo [α] pyrene was observed for the extract of Geranium thunbergii.