Isolation of Four Major Compounds of γ-Oryzanol from Rice Bran Oil by Ionic Liquids Modified High-Speed Countercurrent Chromatography and Antimicrobial Activity and Neuroprotective Effect of Cycloartenyl Ferulate In Vitro

Abstract

This study presents an effective high-speed countercurrent chromatography method of two-phase solvent system combined with ionic liquids for the isolation and purification of four major compounds of γ-oryzanol from rice bran oil. The conditions of high-speed countercurrent chromatography, including solvent systems and the content of ionic liquids, were optimized to improve separation efficiency. The optimal solvent system was n-hexane–dichloromethane–acetonitrile–[C4mim][PF6] at a volume ratio of (10:1:10:0.15, v/v). Adding a small amount of ionic liquids significantly improved the separation efficiency. Four compounds of γ-oryzanol, cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate, and sitosteryl ferulate were successfully purified in one run from rice bran oil with the purities of 95.25%, 92.48%, 92.47%, and 93.43%, respectively. The result of bioassay showed that rice bran oil and separated individual cycloartenyl ferulate could significantly inhibit mycelium growth of crop diseases Rhizoctonia solani and Fusarium graminerum, the bioactivity of cycloartenyl was higher than that of the rice bran oil. The cellular antioxidant activity experimental result indicted that cycloartenyl ferulate could alleviate H2O2-induced oxidative stress.