Biochanin A, an isoflavone compound, is reported to have an inhibitory effect on benzo(a)pyrene [B(a)P] metabolism.

We examined the modifying effect of biochanin A on in vivo carcinogenesis using a mouse lung tumor model.

As carcinogens, a single subcutaneous injection of 0.5mg of B(a)P was given within 24 hours after birth.

The test groups were injected with 0.125mg of biochanin A in 0.1ml DMSO by i.p. 3 times a week for 6 weeks after weaning.

All mice were sacrificed at week 9 and the incidence and multiplicity of lung tumors were examined. Concomitant administration of biochanin A showed a significant inhibitory effect on the incidence of tumor-bearing mice (12.5%, P < 0.01), as well as the mean number of tumors (0.13, P < 0.001), compared with the group treated with B(a)P alone in which the incidence was 57.1% and the mean number was 1.0.

These results suggest that biochanin A has inhibitory potential on the development of mouse lung tumor induced by B(a)P.

Lee, Y.S. et al. J Korean Med Sci 1991 Dec;6(4):325-8.