Biological activities of water-soluble polysaccharides from Opuntia humifusa stem in high-fat-diet-fed mice.

Water-soluble polysaccharide (WSP) of Opuntia humifusa stems was extracted and its biological activities in mice fed with a high-fat diet (HFD) were investigated. The mice were treated with oral doses of WSP for 4 weeks. Body weight, fat mass, serum lipid, and hormone profiles, gastrointestinal tract changes were evaluated. WSP treatment resulted in a decrease in fat mass and improvement of lipid and hormone profiles associated with HFD consumption. In addition, WSP improved the gastrointestinal health of the mice by increasing ghrelin-releasing cells and serotonin-positive cells and boosted immune functions by increasing the expression of CD4+ cells and nitric oxide synthase. Also, WSP treatment reduced gastrointestinal transit time and increased fecal moisture content. These findings suggest that a sufficient intake of WSP from O. humifusa can be beneficial in preventing disorders that are associated with the consumption of HFD including the preservation of gastrointestinal health. PRACTICAL APPLICATIONS: Opuntia humifusa is a traditional edible plant widely eaten in Asia for its high concentrations of vitamin C, polyphenols, and flavonoids. The research investigated the biological activity of WSP extracted from O. humifusa stems. The data obtained from this study sheds light on the use of plant-based polysaccharides in nutraceutical industries as potential functional food materials for the prevention of HFD-related disorders and improvement of gastrointestinal health. The results of this research could serve as a base for further research on this polysaccharide as a source of functional polysaccharides and promotes its usage on a large scale in functional food materials.

Antioxidant activities and phenolic compounds of pigmented rice bran extracts.

UNLABELLED: This study was carried out to investigate the antioxidant activities and phenolic compounds of pigmented rice (black, red, and green rice) and brown rice brans. Antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, 2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) radical cation assay, reducing power, and chelating ability. Phenolic compounds were measured by using HPLC. Pigmented rice brans were extracted by using aqueous mixtures of acetone, ethanol, and methanol to determine the most effective extraction solvent. Of all solvents examined, extract from 40:60 acetone-water mixtures (v/v) provided the highest DPPH radical assay as well as the highest total phenolic and flavonoid content. We finally selected 40% acetone as an extraction solvent for antioxidant study of pigmented rice bran. Antioxidant activities of 40% acetone extracts of pigmented rice bran, measured in the range of 0 to 1500 µg/mL. At 500 µg/mL concentration, red rice bran, which had the highest total phenolic (259.5 µg/mg) and total flavonoid (187.4 µg/mg) contents, showed the highest antioxidant activity: 83.6%, 71.5%, 1.2%, and 16.4% for DPPH radical assay, ABTS radical cation assay, reducing power, and chelating ability, respectively. Red rice bran showed a lower EC(50) value (112.6 µg/mL) than that of butylated hydroxytoluene (144.5 µg/mL) from the DPPH radical assay. The major phenolic acids of red rice bran were ferulic, vanillic and p-coumaric acids. The results indicated pigmented rice bran might be used as a natural antioxidant. PRACTICAL APPLICATION: The present study revealed black and red rice bran shows high antioxidant activities and they contain high amount of phenolic compounds. Indeed, black and red rice bran could be better raw materials for manufacturing the food with high antioxidant activity.