New cerebrosides from Euphorbia peplis L.: antimicrobial activity evaluation.

The less polar fraction of the methanolic extract from the plant Euphorbia peplis L. exhibited interesting antifungal and antitubercular activity. A complex mixture of four glucocerebrosides was responsible for this activity. Two new cerebrosides were isolated for the first time from Euphorbiaceae, 4 was assigned as 1-O-(beta-D-glucopyranosyl)-(2S,3S,4E,8E)-2N-[(2'R)-2'-hydroxy-hexadecanoyl]-4 (E), 8 (E)-octadecadiene-1,3-diol and 3 as the 1-O-(beta-D-glucopyranosyl)-(2S,3S,4R,8Z)-2N-[(2'R)-2'-hydroxytetracosanoyl]-8 (Z)-octadecene-1,3,4-triol. The structures were determined on the basis of chemical and spectroscopic evidences. Mass spectrometry of dimethyl disulfide derivatives was useful for the determination of the double-bond positions in the long-chain bases.