Triterpene alcohol and fatty acid composition of shea nuts from seven African countries

Abstract

The content and composition of triterpene alcohol fractions of the non-saponifiable lipids (NSL) along with the fatty acid composition of the kernel fats (n-hexane extracts) of the shea tree (Vitellaria paradoxa; Sapotaceae) were determined for 36 samples from seven sub-Saharan countries: Cote d' Ivoire, Ghana, Nigeria, Cameroun, Chad, Sudan, and Uganda. The fat content of the kernels, proportion of NSL in the fats, and triterpene alcohols in the NSL are in the range of 30-54, 2-12, and 22-72%, respectively. The triterpene alcohol fractions contained alpha-amyrin (1), beta-amyrin (2), lupeol (3), and butyrospermol (4) as the major constituents along with minor or trace amounts of psi-taraxasterol (5), taraxasterol (6), parkeol (7), 24-methylene-24-dihydroparkeol (8), 24-methylenecycloartanol (9), dammaradienol (10), and 24-methylenedammarenol (11). Fatty acid composition is dominated by stearic (28-56%) and oleic (34-61%) acids. Shea butters from West African provenances contained in general higher levels of triterpene alcohols and stearic acid than those from East African provenances. Both stearic acid and total triterpene alcohol contents were significantly correlated to the latitude and elevation of the source population, indicating that higher levels of these compounds are found at higher ambient temperatures.