Structure analysis of an allene-containing estolide tetraester triglyceride in the seed oil of Sebastiana commersoniana (Euphorbiaceae)

The seed oil of Sebastiana commersoniana (Euphorbiaceae) was separated into a triglyceride and an estolide fraction by preparative thin-layer chromatography. The triglyceride band was characterized by spectroscopic methods, and its fatty acids have been analyzed by gas chromatography (CC) and CC-mass spectrometry (MS) as their methyl esters. Linolenic acid was the main fatty acid (65%). The estolide band was examined by a combination of spectroscopic and chromatographic methods (ultraviolet, infrared, nuclear magnetic resonance, fast atom bombardment-MS, CC-MS of the fatty acids before and after silylation) and was identified as a tetraglyceride, where one alpha-carbon of the glyceride backbone was esterfied with 8-hydroxy-5,6-octadienoic acid, which itself was esterfied with trans-2,cis-4-decadienoic acid. The remaining positions of the glyceride backbone were occupied by common fatty acids.