Chemopreventive efficacy of curcumin-free aqueous turmeric extract in 7,12-dimethylbenz[a]anthracene-induced rat mammary tumorigenesis

Abstract

The modulating effects of turmeric (T), ethanolic turmeric extract (ETE) and curcumin-free aqueous turmeric extract (CFATE) on the initiation or post-initiation phases of DMBA-induced mammary tumorigenesis were investigated in female Sprague-Dawley rats. Dietary administration of 1% T/0.05% ETE 2 weeks before, on the day of DMBA treatment (day 55) and 2 weeks after the single dose (15 mg/animal) of DMBA (during the initiation period) resulted in significant suppression of DMBA-induced mammary tumorigenesis as seen by a reduction in tumor multiplicity, tumor burden and tumor incidence. However, simultaneous administration of 1% T-derived CFATE as the sole source of drinking water during the initiation phase did not suppress DMBA-induced mammary tumorigenesis. Dietary administration of 1% T/0.05% ETE or 1% T-derived CFATE as the sole source of drinking water starting 48 h after DMBA treatment and continuing until the end of the experiment (during the post-initiation period) resulted in significant suppression of DMBA-induced mammary tumorigenesis as seen by reduction in the tumor multiplicity and/or tumor burden although tumor incidence was unaffected. The present data clearly indicate that dietary administration of T/ETE showed strong chemopreventive activity during initiation as well as post-initiation phases of DMBA-induced rat mammary tumorigenesis while CFATE was found to be weakly active only when it was administered during the post-initiation phase.