Journal of the American Oil Chemists Society · 1971 · 16 citations · 12 references
Abstract The unsaponifiable fraction of Vernonia anthelmintica seed oil has been studied in detail. Preparative thin layer chromatography (TLC) on argentated plates has revealed that the hydrocarbon fraction contains squalene as well as normal odd chain alkanes among which C 31 predominates. A small fraction containing C 18 –C 28 n ‐alcohols was also found. The sterol fraction made up the bulk of the unsaponifiables (66%). This fraction contained at least six sterols but two of these accounted for over 90% of the total. The sterols occur in the oil in the esterified form; gas liquid chromatography shows that they are preferentially esterified to linoleic acid. These esters have been isolated by column chromatography on silica gel and have been separated by preparative TLC. Purification by preparative TLC followed by high resolution mass spectrometry has shown that empirical formulas of the two most abundant sterols are C 29 H 46 O and C 29 H 48 O. The latter corresponds to the already reported Δ 7 ‐avenasterol. The former is a new sterol having three double bonds and a stigmastane backbone.
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