Analysis of methylsterol fractions from twenty vegetable oils

Abstract

The 4-monomethylsterol and 4,4-dimethylsterol fractions were separated from the unsaponifiables of 20 vegetable oils by preparative thin layer chromatography, and their compositions were determined by gas liquid chromatography. Tentative identification of the individual components of these fractions was carried out by gas liquid chromatography and combined gas liquid chromatography-mass spectrometry. Among 4-monomethylsterols, obtusifoliol, gramisterol, and citrostadienol occur abundantly in most of the oils. Cycloeucalenol also occurs in some of the oils as a major component of 4-monomethylsterols. Other 4-monomethylsterols tentatively identified are: lophenol, 31-norlanosterol, 31-norcycloartenol, and 31-norlanostenol and/or 4alpha-methylzymostenol. Among 4,4-dimethylsterols, cycloartenol and 24-methylenecycloartanol followed by beta-amyrin and cycloartanol are common to most of the oils. Butyrospermol, alpha-amyrin, lupeol, and cyclobranol together with a 4,4-dimethylsterol, presumably lanostenol, occur in some of the oils. Cyclolaudenol is present in poppy seed oil. Besides these compounds, each of the oils contains some unidentified members of 4-monomethylsterols and 4,4-dimethylsterols. The methylsterol fraction of capsicum seed oil as compared with that of the other oils is characterized by its very high content of lophenol and cycloartanol together with three other members, presumably 31-norlanostenol, 4alpha-methylzymostenol, and lanostenol.