Antiradical efficacy of phytochemical extracts from defatted rice bran

Abstract

The photochemical compounds oryzanols, tocopherols, tocotrienols and ferulic acid were identified in the crude methanolic extacts (CME) of defatted rice bran (DRB) by HPCL. Enrichment of antioxidants in CME was achieved by sequential extration and fractionation resulting in three enriched fraction viz. acetone extract (AE), acetone extract-lipophilic fraction (AE-LP) and acetone extract-polar fraction (AE-PP). The scavenging effects of DRB extracts and their phytochemical constituents aganist DPHP and superoxide radicals were investigated . The EC50 (g antioxidant/kg DPPH) values of CME, AE, AE-LP, AE-PP, oryzanols, ferulic acid, tocols(Tmix), tricin, ß-sitosterol isolated from CME were identified with the help of spectral data. The DRB extracts and their phytochemical constituents when assayed by cytochrome c and NBT methods showed positive superoxide radical scavenging effects. The order of efficacies of the extracts was AE-PP > AE > CME > AE-LP in both assays, but the activities were higher for the former method. The DPPH as well as superoxide scavenging activities of AE, AE-LP and AE- PP could largely be attributed to the levels of total phenols (TPC) and ferulic acid in it.