Temukut, or brewers’ rice, is a mixture of broken rice, rice bran, and rice germ. Extensive studies have been conducted on rice bran, which possesses various health benefits. Temukut, however has been less well studied. The present study aimed to investigate the antioxidant and growth inhibition properties of temukut extract using colon cancer (HT-29), ovary cancer (Caov-3), and liver cancer (HepG2) cell lines. The antioxidant activity was determined by the β-carotene bleaching assay, analysis of the DPPH radical scavenging capacity, and a FRAP assay. The total phenolic compounds, oryzanol, vitamin E, and phytic acid levels in temukut were also investigated. The antiproliferative activity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. There was a significant difference in the cytotoxicity of two types of temukut extract (water and methanol) for HT-29 and Caov-3 cells (p < 0.05) but not for HepG2 cells. The HepG2 cell line is the least sensitive to temukut, (IC50 = 55.30 μg/mL), whereas the highest sensitivity was observed in Caov-3 cells (IC50 =36.67 μg/mL). No cytotoxic effect of temukut was observed on normal cells (BalBlc3T3). Although the content of the phytochemicals studied (total phenolic compounds, vitamin E, oryzanol, and phytic acid) in temukut was lower than that in rice bran, as has been previously reported, the present study demonstrated temukut’s potential to inhibit the proliferation of HT-29, Caov-3, and HepG2 cells.
This study is carried out to determine the potential of phytic acid extracted from rice bran in the suppression of colon carcinogenesis induced by azoxymethane (AOM) in rats. Seventy-two male Sprague-Dawley rats were divided into 6 groups with 12 rats in each group. The intended rats for cancer treatment received two intraperitoneal injections of AOM in saline (15mg/kg bodyweight) over a 2-week period. The treatments of phytic acid were given in two concentrations: 0.2% (w/v) and 0.5% (w/v) during the post-initiation phase of carcinogenesis phase via drinking water. The colons of the animals were analyzed for detection and quantification of aberrant crypt foci (ACF) after 8 weeks of treatment. The finding showed treatment with 0.2% (w/v) extract phytic acid (EPA) gave the greatest reduction in the formation of ACF. In addition, phytic acid significantly suppressed the number of ACF in the distal, middle and proximal colon as compared to AOM alone (p<0.05). For the histological classification of ACF, treatment with 0.5% (w/v) commercial phytic acid (CPA) had the highest percentage (71%) of non-dysplastic ACF followed by treatment with 0.2% (w/v) EPA (61%). Administration of phytic acid also reduced the incidence and multiplicity of total tumors even though there were no significant differences between groups. In conclusion, this study found the potential value of phytic acid extracted from rice bran in reducing colon cancer risk in rats.
Chemoprevention has become an important area in cancer research due to the failure of current therapeutic modalities. Epidemiological and preclinical studies have demonstrated that nutrition plays a vital role in the etiology of cancer. This study was conducted to determine the chemopreventive effects of germinated brown rice (GBR) in rats induced with colon cancer. GBR is brown rice that has been claimed to be richer in nutrients compared to the common white rice. The male Sprague Dawley rats (6 weeks of age) were randomly divided into 5 groups: (G1) positive control (with colon cancer, unfed with GBR), (G2) fed with 2.5 g/kg of GBR (GBR (g)/weight of rat (kg)), (G3) fed with 5 g/kg of GBR, (G4) fed with 10 g/kg of GBR and (G5) negative control (without colon cancer, unfed with GBR). GBR was administered orally once daily via gavage after injection of 15 mg/kg of body weight of azoxymethane (AOM) once a week for two weeks, intraperitonially. After 8 weeks of treatment, animals were sacrificed and colons were removed. Colonic aberrant crypt foci (ACF) were evaluated histopathologically. Total number of ACF and AC, and multicrypt of ACF, and the expression of beta-catenin and COX-2 reduced significantly (p < 0.05) in all the groups treated with GBR (G2, G3 and G4) compared to the control group (G1). Spearman rank correlation test showed significant positive linear relationship between total beta-catenin and COX-2 score (Spearman's rho = 0.616, p = 0.0001). It is demonstrated that GBR inhibits the development of total number of ACF and AC, and multicrypt of ACF, reduces the expression of beta-catenin and COX-2, and thus can be a promising dietary supplement in prevention of colon cancer.