Free radical scavenging activities of γ-oryzanol constituents

Abstract

γ-Oryzanol extracted from brown rice as a free radical scavenger was separated into four constituents, which were identified as cycloartenyl ferulate, 24-methylenecycroartanyl ferulate, β-sitosteryl ferulate and campesteryl ferulate by NMR and MS. All four constituents displayed scavenging activity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The scavenging activities of the four constituents were almost the same as that of ferulic acid. We confirmed that the ferulic acid 4-hydroxyl group was the active unit in γ-oryzanol constituents for DPPH radical scavenging activity.