CONSTITUENTS OF CERAMIDE AND CERAMIDE MONOHEXOSIDE IN RICE BRAN

Previous laboratory studies indicated existence of ceramides and ceramide monochexosides in brown rice grain. More recently evidence was obtained for the presence of these and other sphingolipids (ceramide dihexosides and ceramide trihexosides) in rice bran. The isolation and chemical analysis of constituents of ceramides and ceramide monohexosides in rice bran are described. Ceramide, ceramide monohexoside, ceramide dihexoside and ceramide trihexoside were detected in rice bran. The ceramide and ceramide monohexoside fractions were isolated, and their constituents were analyzed. In the ceramide, fatty acid components consisted of 3 types: normal, 2-hydroxy and 2,3-dihydroxy acids, mainly 2-hydroxylignoceric acid. The major long-chain base components were trihydroxy bases, principally 4-hydroxysphinganine. The principal fatty acid and long-chain base components in the ceramide monohexoside were 2-hydroxyarachidic acid and sphinga-4,8-dienine isomers and 4-hydroxy-8-sphingenine. The component sugar was mostly glucose.