Unpolished Thai rice prevents ACF formation and dysplastic progression in AOM-induced rats and induces apoptosis through redox alteration in CaCo-2 cells.

Oxidative stress is associated with colon carcinogenesis including aberrant crypt foci (ACF) formation and it plays an important role in pathophysiological changes in cancer cells. The aims of this study were to investigate the effects of dietary unpolished Thai rice (UTR) on ACF formation and dysplastic progression in azoxymethane (AOM)-treated rats. Anti-cancer efficacy of UTR regarding apoptotic induction and oxidative redox status in human colon cancer (CaCo-2) cells was also investigated. Rats given 20% and 70% of UTR in the diet showed significantly and dose-dependently decreased total number of ACF. UTR treatment also was strongly associated with the low percentage of dysplastic progression and mucin depletion. In addition, we found that UTR significantly induced cancer cell apoptosis, increased cellular oxidants, and decreased the level of GSH/GSSG ratio in CaCo-2 cells. Our study suggests that UTR supplementation may be a useful strategy for CRC prevention with the inhibition of precancerous progression, with induction of cancer cell apoptosis through redox alteration.

Red strain oryza sativa-unpolished thai rice prevents oxidative stress and colorectal aberrant crypt foci formation in rats.

Oxidative stress has been proposed to be involved in colorectal cancer development. Many dark pigments of plants have potent oxidative stress preventive properties. In this study, unpolished Thai rice was assessed for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. Red strain unpolished Thai rice was also administered to rats exposed to azoxymethane (AOM) for induction of aberrant crypt foci (ACF). Serum malondialdehyde (MDA) and ferric reducing antioxidant power (FRAP) were investigated for cellular oxidative stress and serum antioxidants, respectively. Red pigment unpolished Thai rice demonstrated high antioxidant activity and was found to significantly and dose dependently decrease the total density and crypt multiplicity of ACF. Consumption of Thai rice further resulted in high serum antioxidant activity and low MDA cellular oxidative stress. Interestingly, the density of ACF was strongly related to MDA at r=0.964, while it was inversely related with FRAP antioxidants (r=-0.915, p<0.001). The results of this study suggest that the consumption of red strain of unpolished Thai rice may exert potentially beneficial effects on colorectal cancer through decrease in the level of oxidative stress.