Gomisin A, a lignan component of Schizandora fruits, inhibits development of preneoplastic lesions in rat liver by 3'-methyl-4-dimethylamino-azobenzene.

The effects of gomisin A, a lignan component of Schizandra fruits, on development of preneoplastic lesions in the liver after a short-term (3 weeks) feeding of 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) to male Donryu rats were investigated, and compared with the effects of phenobarbital. Gomisin A inhibited both increases of the level of glutathione-S-transferase placental form (GST-P) and the number and size of GST-P positive foci in the liver increased after treatment with 3'-MeDAB. Moreover, although the population of diploid nuclei was increased and that of tetraploid nuclei was decreased by pretreatment with 3'-MeDAB, gomisin A returned this to near the normal ploidy pattern. But phenobarbital increased the level of GST-P and the number and size of GST-P positive foci with little affect on the ploidy population changed by 3'-MeDAB. Thus, the effect of gomisin A on hepatocarcinogenesis was inhibitory in contrast with that of phenobarbital. This study suggests that gomisin A is a candidate for a chemopreventive drug inhibiting the promotion process in hepatocarcinogenesis.