Inhibitory effects of curcumin-free aqueous turmeric extract on benzo[a]pyrene-induced forestomach papillomas in mice

Abstract

The modulating effects of curcumin-free aqueous turmeric extract (CFATE), ethanolic turmeric extract (ETE) and turmeric (T) powder on the benzo(a)pyrene (B(a)P)-induced forestomach tumors were investigated in Swiss female albino mice receiving oral administration of B(a)P at a dose of 1 mg twice weekly for 4 weeks. Administration of 0.2%/1.0%/5.0% turmeric-derived CFATE as sole source of drinking water or 0.01%/0.05%/0.25% ETE in diet or 0.2%/1.0%/5.0% T in diet, 2 weeks before, during and 2 weeks after the last dose of B(a)P (during initiation period) resulted in significant suppression of B(a)P-induced tumorigenesis when compared with the group receiving B(a)P and control diet/drinking water. Among different fractions tested, CFATE appears to be more powerful as not only did it reduce the tumor multiplicity to the lowest levels but it also significantly reduced the tumor incidence. Administration of 5.0% turmeric-derived CFATE as the sole source of drinking water or 0.25% ETE/5.0% T in diet starting from 48 h after the last dose of B(a)P (during the post-initiation period) until the termination of the experiment, also inhibited the formation of multiple gastric tumors by B(a)P, although the suppression of tumor multiplicity was appreciably more in the groups that received 5.0% turmeric-derived CFATE/0.25% ETE treatment during initiation with carcinogen, i.e. 2 weeks before, during and 2 weeks after the last dose of B(a)P. The present data clearly indicate the potential of turmeric-derived CFATE as a powerful chemopreventive fraction and also demonstrate the efficacy of lower, i.e. 1/25th and/or 1/5th of the reported, chemopreventive doses of T/ETE (essentially curcumins) in inhibiting B(a)P-induced forestomach tumors in mice.