Role of Dietary Defatted Rice Bran in the Modulation of Gut Microbiota in AOM/DSS-Induced Colitis-Associated Colorectal Cancer Rat Model.

Defatted rice bran (DRB) is a by-product of rice bran derived after the oil extraction. DRB contains several bioactive compounds, including dietary fiber and phytochemicals. The supplementation with DRB manifests chemopreventive effects in terms of anti-chronic inflammation, anti-cell proliferation, and anti-tumorigenesis in the azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colitis-associated colorectal cancer (CRC) model in rats. However, little is known about its effect on gut microbiota. Herein, we investigated the effect of DRB on gut microbiota and short chain fatty acid (SCFA) production, colonic goblet cell loss, and mucus layer thickness in the AOM/DSS-induced colitis-associated CRC rat model. The results suggested that DRB enhanced the production of beneficial bacteria (Alloprevotella, Prevotellaceae UCG-001, Ruminococcus, Roseburia, Butyricicoccus) and lessened the production of harmful bacteria (Turicibacter, Clostridium sensu stricto 1, Escherichia-Shigella, Citrobacter) present in colonic feces, mucosa, and tumors. In addition, DRB also assisted the cecal SCFAs (acetate, propionate, butyrate) production. Furthermore, DRB restored goblet cell loss and improved the thickness of the mucus layer in colonic tissue. These findings suggested that DRB could be used as a prebiotic supplement to modulate gut microbiota dysbiosis, which decreases the risks of CRC, therefore encouraging further research on the utilization of DRB in various nutritional health products to promote the health-beneficial bacteria in the colon.

Inhibitory Effect of Dietary Defatted Rice Bran in an AOM/DSS-Induced Colitis-Associated Colorectal Cancer Experimental Animal Model.

Defatted rice bran (DRB) is gaining immense popularity worldwide because of its nutritional and functional aspects. Emerging evidence suggests that DRB is a potential source of dietary fiber and phenolic compounds with numerous purported health benefits. However, less is known about its chemoprotective efficacy. In the present study, we determined and examined the nutrient composition of DRB and its chemopreventive effect on azoxymethane and dextran sulphate sodium (AOM/DSS)-induced colitis-associated colorectal cancer (CRC) in rats. The results showed the presence of several bioactive compounds, such as dietary fiber, phytic acid, and phenolic acids, in DRB. In addition, DRB supplementation reduced the progression of CRC symptoms, such as colonic shortening, disease activity index (DAI), and histopathological changes. Interestingly, a significant decrease was observed in total numbers of aberrant crypt foci (ACFs) and tumors with DRB supplementation. Furthermore, DRB supplementation suppressed the expression of pro-inflammatory cytokines (IL-6) and inflammatory mediators (NF-κB and COX-2) through the inactivation of the NF-κB signaling pathway. The administration of DRB revealed a negative effect on cancer cell proliferation by repressing the expression of nuclear ß-catenin, cyclin D1, and c-Myc. These findings suggest that DRB supplementation mitigates chronic inflammation and cancer cell proliferation and delays tumorigenesis in rat AOM/DSS-induced colitis-associated CRC. Therefore, the establishment of DRB as a natural dietary food-derived chemopreventive agent has the potential to have a significant impact on cancer prevention in the global population.

Consumption of Lutein and Zeaxanthin and Its Relation to the Level of Macular Pigment Optical Density in Thai Subjects.

The aim of the study is to determine dietary lutein and zeaxanthin (L/Z) consumption and to evaluate its association with macular pigment optical density (MPOD) in Thai subjects. Methods. This study was a cross-sectional study. A total of 120 ophthalmologically healthy subjects aged between 40 and 72 years were recruited from Bangkok and the vicinity area. Demographic data were collected using a questionnaire, while a semiquantitative food frequency questionnaire assessed the L/Z intake. MPOD was determined using the reflectometry method (VISUCAM 500®, Carl Zeiss Meditec AG). Pearson's correlation coefficient analyzed the relationship between L/Z consumption and MPOD. Results. The mean age of the participants was 50.7 ± 7.5 years. The mean consumption of L/Z was 3.03 ± 2.65 mg per day. The mean MPOD was 0.102 ± 0.023 density units. Consumption of foods rich in L/Z, including ivy gourd (r = 0.217, p < 0.05), Chinese flowering cabbage (r = 0.194, p < 0.05), balsam pear (r = 0.193, p < 0.05), lettuce (r = 0.182, p < 0.05), sweet corn (r = 0.181, p < 0.05), and pumpkin (r = 0.181, p < 0.05), was positively associated with the mean optical density (mean MPOD). Consumption of green onion (r = 0.212, p < 0.05) was positively associated with the sum of optical densities (MPOD volume). In contrast, chilli pepper consumption showed a negative association with mean MPOD (r = -0.220, p < 0.05) and amaranth showed a negative association with MPOD volume (r = -0.283, p < 0.05). No association was found between total L/Z consumption and MPOD. Conclusion. L/Z consumption is low among Thais living in Bangkok and the vicinity area, which may not be sufficient to ensure eye health, and total L/Z consumption is not associated with MPOD.

Parboiled Germinated Brown Rice Protects Against CCl4-Induced Oxidative Stress and Liver Injury in Rats.

Parboiled germinated brown rice (PGBR) of Khao Dawk Mali 105 variety was produced by steaming germinated paddy rice, which is well-known for its nutrients and bioactive compounds. In this study we determined the in vivo antioxidant and hepatoprotective effects of PGBR in carbon tetrachloride (CCl(4))-induced oxidative stress in rats. Male Sprague-Dawley rats, (weight 200-250 g) were randomly divided into (1) control, (2) CCl(4), (3) white rice (WR)+CCl(4), (4) brown rice (BR)+CCl(4), and (5) PGBR+CCl(4) groups. PGBR, BR, and WR diets were produced by replacing corn starch in the AIN76A diet with cooked PGBR, BR, and WR powders, respectively. All rats except the control group were gavaged with 50% CCl4 in olive oil (v/v, 1 mL/kg) twice a week for 8 weeks. CCl(4)-treated rats exhibited significant liver injury, lipid peroxidation, protein oxidation, and DNA damage, as well as obvious changes to liver histopathology compared to control. In addition, CCl(4) treatment decreased the activities of CYP2E1 and antioxidant enzymes: glutathione S-transferase, glutathione peroxidase, superoxide dismutase and catalase, and glutathione (GSH) content. However, the PGBR+CCl(4) group exhibited less liver injury, lipid peroxidation, protein oxidation, and DNA damage, as well as better antioxidant enzyme activities and GSH content. Furthermore, PGBR inhibited degradation of CYP2E1 in CCl(4)-induced decrease of CYP2E1 activity. These data suggest that PGBR may prevent CCl(4)-induced liver oxidative stress and injury through enhancement of the antioxidant capacities, which may be due to complex actions of various bioactive compounds, including phenolic acids, γ-oryzanol, tocotrienol, and GABA.