Penta-acid triglycerides of Chamaepeuce afra seed oil

Abstract

Earlier work in our laboratory demonstrated that chemical hydrolysis of Chamaepeuce afra (Jacq.) DC. seed oil yields a fatty acid mixture containing 14% (by weight) of (+)-threo-9, 10, 18-trihydroxyoctadec-cis-12-enoic acid and 9% of its saturated analog. The novelty of these acids prompted further work on the glyceride structure of this seed oil.2.2. Two classes of unusual triglycerides (85% of the seed oil) have now been isolated and characterized. Each triglyceride class contains one free hydroxyl group as shown by infrared and thin-layer Chromatographic data.3.3. Castor bean (Ricinus communis) lipase hydrolysis of the glycervl ester linkages of the triglycerides yields, in addition to ordinary C16 and C18 fatty acids, a trihydroxy acid moiety with two of the tliree hydroxyl groups acylated. In one triglyceride class, these acylating groups are C12, C16 and C18 fatty acids; and in the second, C16, C18 and acetic acids. By chromium trioxide oxidation it was shown that the terminal hydroxyl group is acylated.4.4. Pancreatic lipase (EC 3.1.1.3) hydrolysis revealed that these acylated trihydroxy acid residues were attached exclusively to the β-position of glycerol and that ordinary C16 and C18 acids occupied the α-positions.