4-demethyl-,4-monomethyl-and 4,4-dimethylsterols in some vegetable oils

Abstract

The content of 4-demethyl-, 4-monomethyl- and 4,4-dimethylsterols in 13 vegetable oils was found to vary between 0.10-1.4%, 0.01-0.08% and 0.02-0.29%, respectively. The largest amount of demethylsterols was found in maize and wheat germ oils, whereas the largest amounts of the dimethylsterols were found in olive and linseed oils. The predominating demethylsterols were sitosterol, campesterol, stigmasterol and Δ5-avenasterol. Among the 4-monomethylsterols, obtusifoliol, gramisterol, cycloeucalenol and citrostadienol predominated, but usually more than 10 components were found in this fraction. The composition of the 4,4-dimethylsterol fraction was also rather complex, with the 9,19-cyclopropanesterols together with α- and β-amyrin predominating. In most of the oils, characteristically high or low percentages of some sterols were found, and a few specific sterols were also noted. A scheme useful for characterization is presented. © 1985 American Oil Chemists' Society.