<i>Carduus nigrescens</i> seed oil—A rich source of pentacyclic triterpenoids
Abstract
Abstract Pentacyclic triterpene alcohols (3%), their acetates (18%), and their long chain fatty acid esters (11%), together with triterpene acids (18%), represent ca. 50% of the oil from the seed and pericarp of the thistle Carduus nigrescens Vill. (Compositae). Along with the usual fatty acids, alkaline hydrolysis of this oil gave triterpene alcohols, some of which were identified by gas chromatography‐mass spectrometry. Composition of the triterpenoid fraction, as indicated by gas chromatography of the corresponding acetates, was: α‐amyrin (6%), β‐amyrin (15%), lupeol plus ϕ‐taraxasterol (3%), erythrodiol (6%), and oleanolic acid (3%). Several components, representing 16% of the oil, were not identified. The content of pentacyclic triterpenoids is the largest found in plant seed oils.