Evaluation of bran extracts of rice (<em>Oryza sativa</em>) and selected bean (<em>Phaseolus vulgaris</em> L.) varieties for their antioxidative and anti-hyperglycemic potentials

Abstract

Search of therapeutic potential of natural and locally available food has become a trend due to increasing health concerns among consumers around the world. In this study, extracts of rice bran (<em>Oryza sativa </em>L.) and selected beans (red bean, red kidney bean, and white bean) (<em>Phaseolus vulgaris </em>L.) were obtained using 80% ethanol-water mixture to compare their anti-hyperglycaemic and anti-oxidative potentials. The total phenolic content (TPC), ferric reducing antioxidant power (FRAP), 2,2’-azino-bis (3-ethylbenzothiazoline-6- sulfonic acid (ABTS) radical scavenging activity, 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) radical scavenging activity, and the carbohydrate hydrolyzing enzyme inhibitory potentials of the extracts were studied in-<em>vitro </em>using relevant assays. The highest phenolic content (0.122 mg of Gallic Acid Equivalent /g of extract) was found with red bean extract. FRAP values of the extracts were found to range from 48.98 to 75.94 μmol FeSO4 /g bran extract. The highest ferric reducing power (75.94 μmol FeSO4/g) was displayed by the bran extract of red kidney bean. The highest inhibitory effect against α-amylase (96.18%) was displayed by rice bran extract and the highest inhibitory effect against α-glucosidase (39.57%) was exhibited by red bean extract. This study concluded that the bran extracts of rice and the selected beans were potent sources of natural antioxidants and good postprandial hyperglycaemia regulators.