Isolation and characterization of monoacetyldiglycerides from bovine udder

Abstract

Monoacetyldiglycerides (MADGs) were isolated from an animal tissue, bovine udder, by solvent extraction and silica gel column chromatography. Monoacetyldiglyceride structures were identified using a variety of 1-D and 2-D NMR techniques and collision-induced dissociation (CID) tandem mass spectrometry coupled with fast atom bombardment. CID of sodium-adducted molecular ions ([M+ Na]+) generated numerous types of product ions providing information on the double bond position of fatty acyl groups as well as fatty acid compositions. Structural analysis led to the classification of the MADGs isolated from bovine udder as 1-palmitoyl-2-lauroyl-3-acetyl-rac-glycerol, 1,2-dimyristoyl-3-acetyl-rac-glycerol, 1-palmitoyl-2-myristoyl-3-acetyl-rac- glycerol, 1-oleoyl-2-myristoyl-3-acetyl-rac-glycerol, 1-palmitoyl-2- palmitoleoyl-3-acetyl-rac-glycerol, 1,2-dipalmitoyl-3-acetyl-rac-glycerol, 1- linoleoyl-2-palmitoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-palmitoleoyl-3- acetyl-rac-glycerol, 1-oleoyl-2-palmitoyl-3-acetyl-rac-glycerol, 1-stearoyl- 2-palmitoyl-3-acetyl-rac-glycerol, 1-oleoyl-2-linoleoyl-3-acetyl-rac- glycerol, 1,2-dioleoyl-3-acetyl-rac-glycerol, and 1-stearoyl-2-oleoyl-3- acetyl-rac-glycerol.