Constituents of oryzanols in jasmine rice bran

Abstract

The steryl ferulate (y-oryzanol) contents of rice bran of 4 different Thai rice varieties, i.e., Pathumthani 1 and Kao Dok Mali 105 (Jasmine rice), Sunpatong 1 (glutinous rice) and Go Ko Chai Nat 1 (white rice) were extracted individually by appropriate solvents, and crude rice bran oils, the products, were further purified using silica column chromatographic and preparative thin-layer chromatographic methods. Mass spectrometry/ mass spectrometry (MS/MS) was used for identification of individual oryzanol constituents. From those tested crude rice bran oils, 10, 7, 5 and 2 components of oryzanol were extracted, respectively. Both 24-methylenecycloartanyl ferulate and cycloartenyl ferulate were found commonly in all tested varieties. Also, sitosteryl and/or ∆7-sitosteryl ferulate, campesteryl and/or ∆7-campesteryl ferulate and stigmastanyl ferulate, were found เท Sunpatong 1, Kao Dok Mali 105 and Pathumthani 1. It addition, cycloartenyl caffeate, campestanyl ferulate and 24-methylenecholesteryl ferulate were found it Kao Dok Mali 105 and Pathumthani 1. other components, i.e., campesteryl caffeate, 24-cycloart-25-ene-3β,24-diol-3β ferulate and 24-hydroxy-24-methylcyclo- artanyl ferulate found เท Pathumthani 1 only. Compare with a-tocopherol and standard oryzanol, antioxidant activities of those extracted oryzanol were performed individually it 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical system. Oryzanol extracted from Sunpatong 1 rice bran, IC50 25.00 pg/ml, possessed the highest antioxidant activity among the tested oryzanols.