A Study On Isolation,Structure Modification And Bioactivities Of Chemical Constituents From Wedelia Prostrata(Hook.et Arn.) Hemsl.

In this thesis, we studied the chemical constituents and bioactivities of Wedelia prostrata and took parts of compounds after isolation as starting material, synthesized derivatives of those compounds, which had pharmacophore groups with improved antitumor biological activity.Wedelia prostrata is the species of Wedelia.genus belonging to the Asteraceae family. The Wedelia has 60 different species, mainly locate in tropical and subtropical area. There are 5 species of Wedelia in China, one of which is Wedelia prostrate. As mangrove associated plants, Wedelia prostrate is abundant plant resources in Fujian Province.The investigation of pharmacology showed that the genus possess efficacy of protection of liver and gallbladder, antiviral, antiinflammatory, killing trypanosomes, antitussive and so on.So far, many chemical constituents have been found in this genus like flavonoids, triterpenoids, organic acids, steroids, volatile oil and so on.The chemical constituents of this plant have been studied. The compounds were isolated by silica column chromatography and Sephadex LH-20 column chromatography. With the employment of modern spectrum technologys like UV, IR, MS, NMR, we elucidated the structures of the isolated compounds. Moreover, some compounds were tested for antitumor activity. From the petroleum ether and ethyl acetate extracts of Wedelia prostrata, ten compounds(W1~W10) were isolated and identified, eight of which were ent-kaurane type diterpenoid and the last two were oleanane type triterpenoid. Compounds W2, W5, W6, W7, W8 and W10 were obtained from Wedelia prostrata for the first time. The antitumor activity of the ten compounds was determined by MTT assay, and only W1 showed inhibition activity on K562 and SW1116.Compound W1, ent- kaur- 16- en- 19-oic acid, on the basis of the ent kaurene structure. This compound as raw material, synthesis the derivative which has the recognized pharmacophore: ?-methylene ketone structure. Base on the structure of the derivative, synthesis ester and amide compounds by further modificate carboxyl, and get eight derivatives; The results showed that,compared with compound W1, antitumor activity of the nine derivatives were greatly improved.The results in this thesis offer phytochemical proofs to plant chemotaxonomy, provide more chemical evidences for exploiting and utilizing the natural resources in Fujian Province, and further promote the secondary development and utilization of chemical composition from new resources of natural compounds.In the end, the reviews have been made for the research profile of Wedelia.and structure modification of chemical constituents from Wedelia prostrata(Hook.et Arn.) Hemsl.