Glycolipids of soft wheat flour. I. Isolation and characterization of 1-O-(6-O-acyl-β-D-galactopyranosyl)-2,3-di-O-acyl-D-glyceritols and phytosteryl 6-O-acyl-β-D-glucopyranosides

Abstract

Two groups of glycolipids were isolated from soft wheat flour. The first group, 1-O-(6-O-acyl-β-D-galactopyranosyl)-2,3-di-O-acyl-D-glyceritols (1), was saponified to yield fatty acids and 1-O-β-D-galactopyranosyl-D-glyceritol in the molar ratio 3:1. Methylation of 1 followed by saponification of the methylated product gave 1-O-(2,3,4-tri-O-methyl-β-D-galactosyl)-D-glyceritol which provided 2,3,4-tri-O-methyl-D-galactose and glyceritol upon hydrolysis. In periodate oxidation studies 1 consumed two moles of oxidant and yielded tri-O-acyl dialdehydes (6) without liberating fatty acids. Sodium borohydride reduction of 6 followed by saponification, acid hydrolysis, and another borohydride reduction gave glyceritol and ethylene glycol in the expected manner.The second group of glycolipids, phytosteryl 6-O-acyl-β-D-glucopyranosides, was methylated and the products were saponified to give phytosteryl 2,3,4-tri-O-methyl-β-D-glucopyranosides (12) and fatty acids. Methanolysis of 12 gave principally β-sitosterol, campesterol, and methyl 2,3,4-tri-O-methyl-α- and β-D-glucosides.