Sterols in Rice Bran

tion, the occurrence of phytohormonal brassinosteroids (6-deoxocastasterone, 28-homoteasterone, and 28-homotyphasterol) in the bran of rice (Oryza sativa L. cv. Koshihikari)4) has also been reported. However, the other minor sterol components have not been reported so far. Recently, attention has been paid to both campestanol and sitostanol, minor common phytosterols, not only because campestanol is a biosynthetic precursor to brassinolide, the most active brassinosteroid5), but also because sitostanol and its fatty acid ester lower the serum cholesterol level by suppressing cholesterol absorption6). We have now investigated 4, 4-dimethyl-, 4monomethyl-, and 4-desmethylsterols in rice bran, with emphasis on minor components. In this paper, we report the GC-MS-based identification results of these sterols.