ENZYMATIC-SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF 1,3-DIVERNOLOYL GLYCEROL FROM VERNONIA-GALAMENSIS SEED OIL

cis-12,13-Epoxy-cis-octadecenoic (vernolic) acid occurs in triglycerides of the seed oil of Vernonia galamensis. The seeds also contain a lipase capable of hydrolyzing the triglycerides. Previous investigators incubated the seed of Vernonia anthelmintica and isolated 5.6% yield of 1,3-divernoloyl glycerol. We used crude lipase extract from V. galamensis seed to synthesize 1,3-divernoloyl glycerol from vernonia oil in pentane at 40% yield. A 94%, conversion of the 1,3-divernoloyl glycerol to pure vernolic acid (5.34% oxirane = 98.9% purity) was achieved by a low-energy saponification process. The carbon-13 nuclear magnetic resonance (NMR) spectrum of the 1,3-divernoloyl glyceride indicates a potential for using carbon-13 NMR spectroscopy in the identification of isomeric diglycerides. Thus the paper describes the synthesis, spectroscopic and chemical characterization of 1,3-divernoloyl glycerol, in addition to providing quantitative carbon-13 NMR studies of V galamensis oil.