Determination of antioxidant capacity, alpha-amylase and glucosidase inhibitory of the bioactive compounds extracted from colored rices +CD

Abstract

Three kinds of brown rice (white rice, red rice and black rice) grown in Vietnam were used to extract their bioactive compounds by alcoholic method and total phenolic and flavonoid contents of the extract were investigated. DPPH radical scavenging assay was used to measure the antioxidant capacity of phenolic extracts and carbohydrate-hydrolyzing enzyme inhibitory capacity also is determined. The results show that phenolic and flavonoid compounds were mainly located in free form in the brown rice which was easily extracted by methanol solvents. In the present study, red rice extracts possessed the best antioxidant activity (78.79 %) in most cases, and showed the strongest inhibitory potential against alpha-amylase (78.56%) and alpha-glucosidase (36.13%) as well. Our study also showed that there were positive relationship among total phenolic contents, antioxidant capacity and carbohydrate-hydrolyzing enzyme inhibition activity. Brown rice extracts could act like both antioxidant and enzyme inhibitors and have a potential to be used in prevention of type 2 diabetes. It also confirmed that brown rice are not only consumed as functional foods but also used as pharmaceutical medicines. Keyword: alpha-amylase, alpha-glucosidase, antioxidant activity, brown rice, diabetes, flavonoid, phenolic.