Authors : Korawinwich Boonpisuttinant, Sarinporn Udompong and Rattiya Boonbai
Abstract: Riceberry, deep purple grain (Oryza sativa L.), a cross-breed strain from the Jao Hom Nin rice and Khoa Dawk Mali 105. Rice Bran (RB) and Rice Husk (RH) are considered as wastes from cultivation. In this study, the RB and RH were extracted with the 3 different methods namely boiling with water (H2O), maceration with 95% ethanol (EtOH) and fermentation with Saccharomyces cerevisae var. burgundy (WF). The main phytochemicals found in those extracts were xanthones and flavonoids. For anti-oxidation activity tests, the rice bran extracts from fermentation (RB-WF) extracts gave the highest free radical scavenging activity by DPPH assay (SC50 = 0.25±0.02 mg/mL) and metal chelating activity by Ferrous Ion Chelating (FIC) assay (MC50 = 0.22±0.02 mg/mL) which were comparable to vitamin C and EDTA, respectively (p<0.05). In addition, the rice bran extract from boiling (RB-H2O) and the rice husk extract from fermentation (RH-WF) shown the 2 highest inhibition of lipid peroxidation by Ferric-Thiocyanate (FTC) which was comparable to vitamin E (p<0.05). Moreover, the RB-WF exhibited the highest tyrosinase inhibition activity by the modified dopachrome method (IC50 = 0.11±0.01 mg/mL). This result suggested that the RB-WF extract might be beneficial to be develop as whitening and antioxidant agents for cosmetics.
Korawinwich Boonpisuttinant, Sarinporn Udompong and Rattiya Boonbai, 2019. Tyrosinase Inhibition and Antioxidant Activities of Riceberry (Oryza sativa L.). Journal of Engineering and Applied Sciences, 14: 6127-6130.