Associate Professor, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Malaysia.

Speech Title: Brewers' rice: From waste to potential nutritious foods
Abstract: Colorectal cancer has become a significant global health problem affecting men and women worldwide. Dietary factor has been known to plays a crucial role in the management of various non-communicable diseases. Rice by-products have drawn attentions as functional foods due to their phenolic compounds, as well as vitamins, minerals, and fiber contents. Brewers’ rice is a mixture of broken kernels with rice bran and rice germ, which usually removed during rice milling process. Unlike rice bran, the health benefit of brewers’ rice has yet to be fully studied. Therefore, the present study was designed to investigate whether water extract of brewers’ rice (WBR) confers an inhibitory effect via the regulation of upstream components in the Wnt signaling pathway in colorectal cancer (HT-29) cells. To further determine whether the in vitro mechanisms of action observed in HT-29 cells inhibit the downstream signaling target of the Wnt/β-catenin pathway, we evaluated the mechanistic action of brewers’ rice in regulating the expressions and key protein markers during colon tumorigenesis in male Sprague–Dawley rats. Nutrient analyses demonstrated that brewers’ rice was high in carbohydrate, protein, fat, and minerals such as calcium, phosphorus, iron, sodium, and potassium; fatty acids such as linoleic acid, oleic acid, and palmitic acid. It is also contained a variety of phytochemicals with chemopreventive properties including phytic acid, phenolic antioxidants, and dietary fiber. Brewers’ rice also has a unique ratio of vitamin E isoforms (α-, γ-, δ- tocopherols, and tocotrienols) and γ-oryzanol. In vitro analyses showed that WBR inhibited the proliferation of HT-29 cell line without affecting mouse fibroblast (BALB/c 3T3) cell line. These observed effects are likely attributed to the synergistic/additive effects of the bioactive compounds present in the extract. We also found that the treatment of HT-29 cells with WBR inhibited Wnt signaling activity through upregulation of the casein kinase 1 (CK1) and adenomatous polyposis coli (APC) mRNA levels. In addition, the treatment of HT-29 cells with WBR caused in the induction of apoptosis by the significant activation of caspase-3 and ?8 activities compared with the control (p < 0.05). Overall in vivo analyses revealed that brewers’ rice reduced colon tumor incidence and multiplicity. Dietary administration of brewers’ rice also helped to protect against oxidative stress in azoxymethane (AOM)-induced rat colon carcinogenesis by improved antioxidant capacity like superoxide dismutase (SOD), malondialdehyde (MDA), and nitric oxide (NO). Furthermore, dietary administration of brewers’ rice in AOM-induced rat colon carcinogenesis resulted in the transcriptional upregulation of glycogen synthase kinase 3β (GSK 3β), inducible nitric oxide synthase (iNOS), NF-E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). We discovered that the dietary administration of brewers’ rice downregulated the β-catenin and nuclear factor-kappa B (NF-κB) mRNA levels. The results from western blotting analyses also showed that brewers’ rice diminished the β-catenin, cyclin D1, and c-myc protein levels. Taken together, this data show the potential use of brewers’ rice as a functional food in the prevention and treatment of colorectal cancer.
Keywords: brewers' rice, colorectal cancer, functional foods