Lipid metabolites with free-radical scavenging activity from Euphorbia helioscopia L.

The methanolic extract of the plant Euphorbia helioscopia L. exhibited an interesting free-radical scavenging activity. From the aerial parts of Euphorbia helioscopia L. (Euphorbiaceae), a complex mixture of seven cerebrosides together with glucoclionasterol, a digalactosyldiacylglycerol and a diacylmonogalactosylglycerol were identified. The structures of the cerebrosides were characterized as 1-O--d-glucosides of phytosphingosines, which comprised (2S, 3S, 4E, 8E)-2-amino-4(E),8(E)-octadecadiene-1,3-diol, (2S, 3S, 4E, 8Z)-2-amino-4(E),8(Z)-octadecadiene-1,3-diol, (2S, 3S, 4R, 8Z)-2-amino-8(Z)-octadecene-1,3,4-triol as long chain bases with seven 2-hydroxy fatty acids of varying chain lengths (C16, C24:1, C26:1, C24, C26, C28:1) linked to the amino group. The glycosylglycerides were characterized as (2S)-2,3-O-di-(9,12,15-octadecatrienoyl)-glyceryl-6-O- (˛-d-galactopyranosyl)--d-galactopyranoside and (2S)-2,3-O-di-(9,12,15-octadecatrienoyl)-glyceryl- 1-O--d-galactopyranoside. The structures were established on the basis of spectroscopic data and chemical reactions.