Nor-cucurbitacins from the leaves of Mareya micrantha (Benth.) Müll. Arg. (Euphorbiaceae)
Résumé
Mareya micrantha, an Ivoirian medicinal plant, was investigated for its chemical constituents and antioxidant properties. This study carried out on the hydroethanolic extract of the leaves led to three new nor-cucurbitacins named: 29-nor-1,2,3,4,5,10-dehydro-3,15 alpha,20 beta-trihydroxy-16 alpha-acetyl-11,22-dioxo-cucurbita-23-ene 2-O-beta-D-glucopyranoside (1), 29-nor-2 beta,20 beta,25-trihydroxy-16 alpha-acetyl-3,11,22-trioxo-cucurbita-4,23-diene (2) and 29-nor-2 beta,15 alpha,20 beta-trihydroxy-16 alpha-acetyl-3,11,22-trioxo-cucurbita-4,23-diene 2-O-beta-D-glucopyranoside (3). The structures were established on the basis of spectral data (NMR, UV, MS and IR). The antioxidant properties evaluated by DPPH and CUPRAC methods gave the best activity with compound 1. The chemotaxonomic significance of the isolation of these compounds in Mareya micrantha, a species belonging to the Euphorbiaceae family, is discussed.