Curcumin (
diferuloylmethane), a yellow pigment that is obtained from the rhizomes of Curcuma longa Linn., is a major component of turmeric and is commonly used as a spice and food-
coloring agent. The inhibitory effects of feeding commercial grade
curcumin (77%
curcumin, 17%
demethoxycurcumin, and 3%
bisdemethoxycurcumin) in AIN 76A diet on
carcinogen-induced
tumorigenesis in the forestomach, duodenum, and colon of mice were evaluated. Administration p.o. of commercial grade
curcumin in the diet inhibited
benzo(a)pyrene-induced forestomach
tumorigenesis in A/J mice, N-
ethyl-N'-nitro-N-nitrosoguanidine-induced duodenal
tumorigenesis in C57BL/6 mice, and
azoxymethane (AOM)-induced colon
tumorigenesis in CF-1 mice. Dietary commercial grade
curcumin was given to mice at: (a) 2 weeks before, during, and for 1 week after
carcinogen administration (during the initiation period); (b) 1 week after
carcinogen treatment until the end of the experiment (during the postinitiation period); or (c) during both the initiation and postinitiation periods. Feeding 0.5-2.0% commercial grade
curcumin in the diet decreased the number of
benzo(a)pyrene-induced forestomach
tumors per mouse by 51-53% when administered during the initiation period and 47-67% when administered during the postinitiation period. Feeding 0.5-2.0% commercial grade
curcumin in the diet decreased the number of N-
ethyl-N'-nitro-N-nitrosoguanidine-induced duodenal
tumors per mouse by 47-77% when administered during the postinitiation period. Administration of 0.5-4.0% commercial grade
curcumin in the diet both during the initiation and postinitation periods decreased the number of AOM-induced colon
tumors per mouse by 51-62%. Administration of 2% commercial grade
curcumin in the diet inhibited the number of AOM-induced colon
tumors per mouse by 66% when fed during the initiation period and 25% when fed during the postinitiation period. The ability of commercial grade
curcumin to inhibit AOM-induced colon
tumorigenesis is comparable to that of pure
curcumin (purity greater than 98%). Administration of pure or commercial grade
curcumin in the diet to AOM-treated mice resulted in development of colon
tumors which were generally smaller in number and size as compared to the control group of AOM-treated mice. These results indicate that not only did
curcumin inhibit the number of
tumors per mouse and the percentage of mice with
tumors but it also reduced
tumor size. Histopathological examination of the
tumors showed that dietary
curcumin inhibited the number of
papillomas and
squamous cell carcinomas of the forestomach as well as the number of
adenomas and
adenocarcinomas of the duodenum and colon.