Effect of extraction methods on biological activities of Thai rice bran extracts

Abstract

Rice bran is an essential source of natural bioactive compounds with widely applications. This study aimed to determine the effects of extraction methods on the bioactivities of the extracts. Jasmine and Riceberry rice bran were extracted using 50% ethanolic maceration, cold pressed and subcritical dimethyl ether (DME) extraction. The extracts were analyzed for antioxidant, pro-collagen type I synthesis and 5α-reductase inhibition activities. The results showed that Riceberry rice bran extract exhibited superior antioxidant activity than Jasmine rice bran extract. The highest pro-collagen type I synthesis of Jasmine and Riceberry rice resulted from subcritical DME extraction (50.91%) and maceration (46.99%) respectively. It is a newly found that the subcritical DME extract of Jasmine rice bran displayed the strongest 5α-reductase inhibition activity (73.14 %inhibition) resulting from the biological markers linoleic acid (22.39±0.61 %w/w) and oleic acid (39.48±1.07 %w/w). Therefore, subcritical DME extraction is suitable for preparing rice bran extract for 5α-reductase inhibitor application.

Keywords

• 5α-reductase
• antioxidant
• oryza sativa
• pro-collagen
• rice bran
• subcritical fluid extraction