Investigation On The Chemical Constituents And Bioactivities Of Euphorbia Humifusa

Euphorbia Linn., the largest genus in the Euphorbiaceae family, comprises about 2000 species in the world. There are about 100 species grown in China, and most of them distribute in Northwestern and Southwestern. Members of the genus have been known to be poisonous to human beings. However, a quite number of Euphorbia species were used as traditional folk medicines. This genus is characterized by the presence of milky latex and the skin-irritant properties. They were mainly used for treatment of warts and tumors.In this thesis, we summarize the chemical constituents, bioactivities and clinic applications from 1991 to 2006 and report the systematic phytochemical studies of the whole plant of Euphorbia humifusa willd., which was collected in Minle County of Gansu Province, China. 35 pure compounds were isolated from the ethanolic extract by means of silica gel column chromatography (CC), preparative thin layer chromatography (prep-TLC), recrystallization, etc. The structures of 28 compounds were elucidated as triterpenoids, steroids, sesquiterpenoid, coumarins, organic acids, glycetides, etc., on the basis of spectral evidences, including EIMS, HRESIMS, 1D and 2D-NMR, IR, UV, along with comparison to authentic samples or the data in the literature. Among them 2 compounds were novel and their structures were elucidated as 3,4-seco-lupa-4(23),20(29)-dien-24-hydroxy-3-oic acid (2) and 23(E)-en-25-ethoxy-3β-cycloartanol (8) respectively. Meanwhile, compounds 2, 4, 5, 6 were tested for their abilities to inhibit human gastric carcinoma cells SGC-7901 using MTT [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] method against 5-Fluorouracil (5-FU), and they exhibited no significant inhibitory effects with IC₅₀ values over 100μM against SGC-7901 cells.The results of this thesis have important values for chemotaxonomy, developing and utilizing the natural resources and studies on the plant pharmacological activity.