EFFECTS OF CURCUMIN, DEMETHOXYCURCUMIN, BISDEMETHOXYCURCUMIN AND TETRAHYDROCURCUMIN ON 12-O-TETRADECANOYLPHORBOL-13-ACETATE-INDUCED TUMOR PROMOTION

Commercial grade curcumin (similar to 77% curcumin, 17% demethoxycurcu min and 3% bisdemethoxycurcumin) is widely used as a yellow coloring a gent and spice in foods, In the present study topical application of c ommercial grade curcumin, pure curcumin or demethoxycurcumin had an eq ually potent inhibitory effect on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced increases in ornithine decarboxylase activity and TPA-i nduced tumor promotion in 7,12-dimethylbenz[a]anthracene-initiated mou se skin, Bisdemethoxycurcumin and tetrahydrocurcumin mere less active. In additional studies we found that commercial grade curcumin, pure c urcumin, demethoxycurcumin and bisdemethoxycurcumin had about the same potent inhibitory effect on TPA-induced inflammation of mouse ears, a s well as TPA-induced transformation of cultured JB6 (P+) cells. Tetra hydrocurcumin was less active, The results indicate that pure curcumin and demethoxycurcumin (the major constituents of commercial grade cur cumin) have the same potent inhibitory effects as commercial grade cur cumin for inhibition of TPA-induced tumor promotion, but bisdemethoxyc urcumin and tetrahydrocurcumin are less active.