HPLC‐DAD System‐Based Phenolic Content Analysis and In Vitro Antioxidant Activities of Rice Bran Obtained from Aush Dhan (Oryza Sativa) of Bangladesh. Issue 4 (28th May 2015) - Reza, Hasan Mahmud
Abstract Food fibers are recently gaining interest in the scientific community for their beneficial role in various diseases such as diabetes, cardiovascular diseases, cancer and neurodegenerative diseases. Rice bran is an important source of food fibers. The objective of this study was to determine the presence of polyphenolic compounds in rice bran of Aush Dhan and determine the in vitro antioxidant activities in different extracts such as ethanol, ethylacetate and toluene extracts. Various antioxidant assays, including DPPH (1, 1‐diphenyl‐2‐picrylhydrazyl) free radical scavenging, nitric oxide scavenging, hydrogen peroxide, reducing power, total phenolic content and total flavonoid content, were studied. Moreover, high‐performance liquid chromatography (HPLC) was used to identify and quantify the phenolic compounds. The extracts showed effective DPPH free radical, hydrogen peroxide radical and nitric oxide scavenging activities. However, reducing power was not significant compared with the standard antioxidant ascorbic acid. Phytochemical analysis shows that rice bran contains reducing sugar, flavonoids and tannins. Furthermore, high‐performance liquid chromatography coupled with photodiode array detector (HPLC‐DAD) analysis showed that rice bran contains high amount of rutin hydrate along with epicatechin, which are strong natural antioxidants. These results suggest that rice bran contains high amount of antioxidants, which may be used as a source of polyphenolic compounds and can be used to treat chronic disease. Practical Applications Rice bran is produced every year in an enormous amount in Bangladesh as it is one of the largest producers of rice in the world. Rice bran is used in poultry and cattle farm as animal feed. Recently, it is also used to produce cooking oil and serves as an important ingredient in traditional medicine system in Bangladesh. The assessment of the antioxidant properties, phenolic content and composition of rice bran obtained from Aus Dhan (Oryza sativa) may give insight into their applications in functional foods and nutraceutical development.