Purification and identification of components of γ-oryzanol in rice bran oil

Abstract

High-purity γ-oryzanol was obtained from crude rice bran oil using a normal-phase preparative scale HPLC. A reverse-phase HPLC method was used for separating the individual components of γ-oryzanol present in rice bran oil. Ten fractions were isolated and collected using the reverse-phase HPLC method, and their structures were identified. Identification was accomplished using GC/MS with an electron impact mass spectrum after components were transformed into trimethylsilyl ether derivatives. The 10 components of γ-oryzanol were identified as Δ7-stigmastenyl ferulate, stigmasteryl ferulate, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, Δ7-campestenyl ferulate, campesteryl ferulate, Δ7-sitostenyl ferulate, sitosteryl ferulate, compestanyl ferulate, and sitostanyl ferulate. Three of these, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, and campesteryl ferulate, were major components of γ-oryzanol.