Studies On The Secondary Metabolites And Their Bioactivities Of Vladimiria Muliensis And Dicranopteris Linearis

"Mu Xiang" is a traditional Chinese medicine to alleviate pain in abdominal distension,curing indigestion,dysentery and nausea,and arresting vomiting.In the market,the roots of many kinds of Compositae herbs such as Aucklandia lappa, Vladimiria souliei,V.souliei(Franch.) var.cinerea,V.berardioidea,V.edulis,V. edulis caulescens,V.edulis bracteata,V.forrestii,V.muliensis,V.denticulate,Inula helenium L.,and Inulae racemosae are defined as "Mu Xiang".V.muliensis,one of the species of Vladimiria(Compositae),is used by local inhabitants to treat the above symptoms instead of "Mu Xiang" in Muli country.However,there has been no report about the chemical constituents and bioactivity of V.muliensis.The Dicranopteris is a genus of the family Gleicheniaceae and perennial herbs. More than 10 species are mainly distributed in tropic or subtropics.In China there are 6 species(Dicranopteris ampla,D.splendida,D.pedata,D.gigantean,D. taiwanensis,D.linearis),and they are widely distributed in south of the Changjiang River.They are the referent of the acid soil and traditional Chinese medicinal herbs possessing efficacy of antipyretic,diuretic,removing blood stasis and haemostatic. The chemical constituents and bioactivity of Dicranopteris linearis have never been reported.The chemical constituents and their bioactivities of V.muliensis and D.linearis were studied in this thesis.Firstly,the chemical constituents of 132 compounds were isolated by means of silica gel column chromatography(CC),preparative thin layer chromatography(PTLC),and recrystallization etc.Then various spectroscopic methods including IR,UV,CD,EIMS,FABMS,HRESIMS,¹H NMR,¹³C NMR, DEPT,NOED,¹H-¹H COSY,HSQC,HMBC,and single-crystal X-ray crystallography were used to elucidate the structures of 121 compounds,among which there were 18 new compounds. The biggest achievement of the experiment was that 107 compounds were isolated from V.muliensis and 18 of them were new compounds,while 14 compounds isolated from D.linearis were all known compounds.Furthermore the bioactivities of some compounds were also studied.Firstly, MTT method was used to evaluate the antimicrobial activity of six triterpenoids(Vm1 -Vm6) against Escherichia coli,Candida albicans,Pseudomonas aeruginosa, Enterococcus faecalis,Bacillus cereus,Staphylococcus aureus.The results indicated that all the six compounds showed modest antimicrobial activity against the tested strains and compounds Vm2,Vm4,Vm5 showed good activity,especially,compound Vm2 giving an MIC of 7μg/mL against S.aureus.Secondly,SRB method was used to evaluate the cytotoxicity against selected HL-60,HEP-G2,and HeLa cancer cell lines of three pentacyclic pregnanols(Vm66-Vm68) with mitomycin taken as positive control.The results revealed that the three compounds had modest cytotoxicity with IC₅₀≈40μg/mL.The results would be a supplement for the research on bioactivity of chemical constituents as well as structure-activity relationship in traditional Chinese medicine, helpful reference for pharmacology,chemotaxonomy and screening new medicines, and may benefit utilizing and developing the natural resources of our country.Finally,the discovery of the antineoplastic natural product CombretastainA-4 and progress in studies on Combretastains were reviewed in this thesis.