Mutagens in Japanese pickle identified as flavonoids

A kind of Japanese pickel was mutagenic to TA100 and TA98 with S9 mix. Its activity was one sixth that of the Chinese pickle from Linhsien County (China), reported previously. Mutagens in this Japanese pickle were isolated; the main component was identified as kaempferol, and a minor component as isorhamnetin. Flavonoids are ubiquitous and the principles identified, kaempferol and isorhamnetin, do not seem to be specific to the pickle vegetable, implying that the mutagenic substances responsible for the high incidence of human cancer in China remain to be identified.