Comparison of Phytochemical Contents and Cytoprotective Effects of Different Rice Bran Extracts from Indica and Japonica Rice Cultivars

The present study was aimed to evaluate the phytochemical contents and hepatocyte protective effects of functional extracts from rice bran of indica and japonica rice cultivars, Dasan 1 and Ilpum, respectively. The highest vitamin E (23.51 mg/g) and phytosterol (390.25 mg/g) content was observed in the unsaponifiable matter (USM) of Dasan 1 cultivar. However, USM of Ilpum showed the highest content of total policosanol and squalene (232.73 mg/g and 99.31 mg/g, respectively). The methanolic extract from the defatted rice bran (MEDR) of Dasan 1 showed the highest total polyphenol content, reducing power, and radical scavenging capacity, while USM of Dasan 1 showed the highest cell viability (81.3%) against oxidative stress in HepG2 cells. USM significantly increased glutathione levels and suppressed the production of reactive oxygen species in hepatocytes compared with methanolic extracts of the rice bran oils and/or MEDR. These results provide useful information on the functional extracts of rice bran from indica and japonica rice cultivars, including their antioxidant properties and cytoprotection in HepG2 cells.