Cancer chemopreventive effects of a Brazilian folk medicine, Juca, on in vivo two-stage skin carcinogenesis.

Gallic acid (1) and methyl gallate (2) were isolated from Juca, a Brazilian folk medicine, fruits of Caesalpinia ferrea MART (Leguminosae), decreased significantly the average number of papillomas per mouse in the experiment of the promoting effects of 12-O-tetra- decanoylphorbol-13-acetate (TPA) on skin tumor formation in mice initiated with 7,12-dimethylbenz[a]anthracene (DMBA).