Anti-Oxidant, Pro-Oxidant and Anti-Inflammatory Effects of Unpolished Rice Relevant to Colorectal Cancer

Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rates. Carcinogenesis in the colon is a multistage and multifactorial process. An imbalance between free radical exposure and anti-oxidant defense systems may leads to oxidative stress and attack of macromolecules which can alter signal transduction pathways and gene expression. Consequently, oxidative damage can lead to cellular dysfunction and contribute to pathophysiological processes in a variety of diseases including CRC. One factor tightly associated with CRC is chronic inflammation, which can be present from the earliest stage of tumor onset. Unpolished rice is an attractive chemoprevention in CRC due to their anti-oxidant and anti-inflammatory activities. The aim of this paper is to review evidence linking oxidative stress and inflammation to CRC and to provide essential background information for understanding future research on oxidative stress and inflammation on CRC. Mechanisms of action of unpolished rice in CRC carcinogenesis are also discussed.

Dietary Ziziphus jujuba Fruit Influence on Aberrant Crypt Formation and Blood Cells in Colitis-Associated Colorectal Cancer in Mice

Ziziphus jujuba (ZJ) fruit is rich in bioactive functional components such as polysaccharides, triterpenoid acid, flavonoids and oleamide. It has been commonly used in the treatment of various diseases including diabetes, digestive disorders, diarrhea, skin infections, liver and urinary complaints. However, dietary effects with regard to chemoprevention of colon cancer have not been studied. The present study was performed to evaluate the protective effects of dietary ZJ against colitis-associated colon carcinogenesis in azoxymethane (AOM)-dextran sodium sulphate (DSS)-treated mice. AOM was injected (10 mg/kg b.wt., i.p.) and three cycles of 2% DSS in drinking water for 7 days with 14 days of normal drinking water in-between were administered to induce colitis-associated colon cancer. ZJ fruit was supplemented into feed at levels of 5 and 10%. Dietary ZJ significantly attenuated aberrant crypt foci (ACF) formation and also decreased the progression of hyperplasia to dysplasia. In addition, it significantly reduced circulating white blood cells, lymphocytes, neutrophils, monocytes, eosinophils, basophils and platelets compared to colon cancer mice. We conclude that ZJ supplementation may delay the progression of colon cancer from hyperplasia to dysplasia and ultimately adenocarcinoma and cancer. In addition, it decreased circulating tumor-related leukocytes, main regulators of cancer inflammation. Dietary consumption of ZJ fruit attenuated the formation of ACF and delayed the progression of colon cancer.

Anti-inflammatory and proapoptotic effects of umbelliferone in colon carcinogenesis

Colorectal cancer (CRC) is a serious health problem throughout the world. 5-Flurouracil, the first-line chemotherapy of colorectal cancer often produces more toxicity to neighboring cells; however, it is still used for CRC treatment. To overcome this, umbelliferone (UMB), a less toxic bioflavonoid has been used to test its anticancer effects on animal model. The objective of the present study is to evaluate the anticancer activity of UMB on 1,2-dimethylhydrazine (DMH)-induced rat colon tumorigenesis to determine the development of aberrant crypt foci (ACF), agyrophylic nucleolar organizer regions (AgNORs), mast cell recruitment, pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β and also study the expressions of inducible nitric oxide synthase, cyclooxygenase (COX)-2, and apoptotic markers. DMH-induced rats showed increased ACF number (incidence), multiplicity and its distribution, counts of AgNORs, mast cells, inflammatory markers and apoptotic proteins. Interestingly, UMB supplementation to DMH-induced rats (group 4) significantly ( p < 0.05) suppressed ACF development, AgNORs, mast cells, and inflammatory markers and increased the apoptotic markers as compared to DMH-induced rats (group 2). We concluded that UMB is a potential anticancer agent that can be used for the prevention and treatment of CRC.