Glycolipids in Rice Grain

Chemical studies on fats and oils in rice grain have often been carried out by many investigators, but those on the other lipids, e.g. phospholipids, glycolipids, hydrocarbons, steroids and so on, have not so much. The present paper describes the chemical con stitution of the principal glycolipids in rice grain. Brown rice grain of Horyu species, harvested in Hokkaido prefecture in 1969, was smashed and extracted with a mixture of chloroformmethanol (2:1) to collect total lipids. The yield was 2.6%. The lipids were applied to silicic acid column chromatography by sequen tial elution with chloroform, acetone and methanol.1) Crude neutral lipids were eluted with chloroform, crude glycolipids with ace tone and crude phospholipids with methanol. The crude glycolipids were subjected to silicic acid column chromatography with chloro form-acetone2) to be fractionated further. The elution pattern is depicted in Fig. 1, which demonstrates that six fractions of glycolipids were obtained. Each fraction was then puri fied by silicic acid column re-chromatography and by preparative thin-layer silica gel G chromatography. Acyl sterylglycoside, steryl glycoside, cerebroside, monoglycosyl diglyce ride and diglycosyl diglyceride thus prepared gave respectively a single spot on the thinlayer chromatogram and agreed well with the respective reference lipid in the infra-red spectrum. Sulfolipid could not be purified owing to a small amount. In order to investigate the chemical composi tion, each glycolipid was refluxed with hydro chloric acid in methanol.3,4) The hydrolysate formed, i.e. fatty acid, carbohydrate, sterol or fatty base, was analyzed by thin-layer chro matography as well as by gas-liquid chromato