Phytochemical studies on medicinal plants: Euphorbia ebracteolata, Pulsatilla chinensis, and Gymnema sylvestre.

摘要

In the present study, three Chinese medicinal plants were investigated for their organic constituents. The materials were extracted and purified by chromatographic separation using a combination of methods. Each compound isolated was fully characterized by spectroscopic data and physical data, in particular, NMR results (1D and 2D) were carefully analyzed and compared with the literature data.; The present investigation has led to the isolation of eighteen organic compounds from an ethanol extract prepared from the roots of Euphorbia ebracteolata (a common traditional Chinese medicine). These compounds can be classified into four types based on their skeletons: steroid, acetophenone derivative, diterpene and triterpene. Four of the compounds are new structures. They are, namely, 2,2′,4,4′-tetrahydroxy-6,6 ′-dimethoxy-3,3′-dimethyl-7,5′ -bisacetophenone, ent-kaurane 3β,16β,17-triol, 3β,7α-dihydroxy-1(10),15-rosadiene, and ebracteolatin A. Ebracteolatin A is a novel rosen diterpene bearing a γ-lactone ring, which has not been found in nature previously.; Nine triterpenes and triterpene glycosides were isolated from an ethanol extract prepared form the roots of Pulsatilla chinesis. Six of them are new compounds identified as 3-oxo-23-hydroxy-lup 20(29)-en-28-oic acid, 3β, 23-dihydroxy-lup-20(29)-en-28-oic acid 3-O-α- L-arabinopyranoside, 3β,23-dihydroxy-lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl(1 → 6)-β- D-glucopyranoside, 3β,23-dihydroxy lup-20(29)-en-28-oic acid 28-O-α-L-rhamnopyranosyl(1 → 4)-β- D-glucopyranosyl(1 → 6)-β-D-glucopyranoside, 3-O-β-D-glucopyranosyl (1 → 3)-α- L-arabinopyranosyl 23-hydroxylbetulinic acid 28-O-α- L-rhamnopyranosyl(1 → 4)-β-D-glucopyranosyl (1 → 6)-β-D-glucopyranosyl ester and 3-O -[β-D-glucopyranosyl(1 → 4)][β- L-rhamnopyranosyl(1 → 2)]-α-L-arabinopyranosyl 23-hydroxylbetulinic acid 28-O-α-L-rhamnopyranosyl(1 → 4)-β-D-glucopyranosyl (1 →6)-β-D-glucopyranosyl ester. Cytotoxic assay results indicated that the triterpene aglycons 23-hydroxybetulinic acid and 3-oxo-23-hydroxy-lup-20(29) en-28-oic acid, as well as two glycosides displayed moderate cytotoxic activities against K-562 human leukemia and Hela cells.; Seventeen triterpenes and triterpene glucoside were isolated from an ethanol extract of the leaves of Gymnema sylvestre. Of these, the structures of ten triterpene glycosides are newly reported. They are, namely, 3-O-β-D-glucopyranosyl(1 → 6)-β-D glucopyranosyl oleanolic acid 28-O-β- D-glucopyranosyl ester, oleanolic acid 3-O-β-D-xylopyranosyl(1 → 6)-β-D-glucopyranosyl(1 → 6)-β-D-glucopyranoside, 3-O-β-D-Xylopyranosyl(1 → 6)-β- D-glucopyranosyl(1 → 6)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl ester, 3-O-β-D-glucopyranosyl(1 → 6)-β-D-glucopyranosyl oleanolic acid 28-O-β- D-glucopyranosyl(1 → 6)-β-D-glucopyranosyl ester, longispinogenin 3-O