| Eurycorymbus cavaleriei(Levl.) Rehd.et Hand.-Mazz.is a dioecious,rare and endemic tree species in China and there is only one species in this genus.The tissue culture,genetic diversity and properties of E.cavaleriei have been previously studied, but few investigations on its chemical components and pharmacological activities have been reported up to now.Pulsatilla chinensis(Bunge) Regel is one of the most important crude drugs in traditional Chinese medicine and have been used for the treatment of intestinal amebiasis,malaria,vaginal trichomoniasis,and bacterial infections.Chemical and pharmacological investigations have indicated that triterpenoid saponins are important bioactive components existing in this plant,which also have been reported to have antiproliferative activity.PhaseⅡenzymes play an important role in the metabolism of chemical carcinogen and other harmful oxidants.The chemical components which can induct the quinone reductase(QR) are regarded having the chemopreventive effects in the initiation of many tumors.The increase of phaseⅡenzymes are considered as the major mechanism of prevention of cancer.According to the above study background,the main target of this thesis is concentrated on characterization of the preventive agents through the reaction with GSH in the extract of E.cavaleriei and P.chinensis and the cleavage pathways of triterpenes by silver complexation using HPLC/ESI-MS~n method.And further,the Structure-activity relationship was discussed and validated through the assay of bioactivities,which provided scientific information for the discovery of new chemopreventive agents from the natural products.The main innovation and academic contributions of this thesis are presented as follows:1.Column chromatography wass used to separate constituents from the petroleum ether and dichloromethane partitions in 95%ethanol extract of the twigs of E.cavaleriei and the structures of 27 compounds were elucidated by IR,UV,MS,NMR and physicochemical properties.All of them were isolated from this plant for the first time, eleven new triterpenes was identified as 3β,6β,7β,11α-tetrahydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T1),11α-acetyloxy-7β-benzoyloxy-3β,6β-dihydroxy -21αH-24-norhopa-4(23),22(29)-diene(EU-T2),11α-acetyloxy-7β-caproyloxy-3β,6β-dihydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T3),7β-benzoyloxy-3β,6β,11α-trihydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T4),6β-acetyloxy-3β,12β-di hydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T5),7β-benzoyloxy-3β,6β,11β-trihydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T6),6β-acetyloxy-7β-benzoy loxy-3β,11β-dihydroxy-21αH-24-norhopa-4(23),22(29)-diene(EU-T7),6β-acetyloxy -12β-benzoyloxy-3β-hydroxyl-21αH-24-norhopa-4(23),22(29)-diene(EU-T8),3β, 12β-dihydroxy-21αH-hop-22(29)-ene-24-oic acid methyl ester(EU-T9),6β-acetyloxy -3β,11β-dihydroxy-21αH-hop-22(29)-ene-24-oic acid methyl ester(EU-T10),7β-benzoyloxy-3β,24ξ,25-trihydroxy-dammar-20(21)-ene(EU-T11),and named as cavalerol A-K(1-11).One novel meroterpene was identified as 5,5'-dihydroxy -4,4'-bis[(2S,4Z)-6-hydroxy-5-methyl-2-(1-methylethenyl)hex-4-en-l-yl]-6,6'-bis(3-me thylbut-2-en-l-yl)-1,1'-biphenyl-2,2'-dicarboxaldehyde(EU-3) and named as cavalerol.2.Column chromatography was used to separate constituents from the petroleum ether and dichloromethane partitions in 95%ethanol extract of P.chinensis and the structures of eleven triterpenoid saponins,one quinone compound and one thiophene compound were elucidated by IR,UV,MS,NMR and physicochemical properties.3.A HPLC/ESI-MS~n method was established to discover the chemical components which were able to induct QR in dichloromethane partitions of 95%ethanol extract of the twigs of E.cavaleriei.Firstly,MS~n experiments were carried out on the nine reference compounds to obtain the fragmentation patterns of the coumarin compounds and differentiate isomers according to the fragment ions.Based on the fragmentation patterns of the reference compounds,this method was applied to studies on the components change after reacting with GSH in dichloromethane partition of the 95% ethanol extracts of E.cavaleriei,two coumarin compounds which had QR induction effects were identified.4.The above HPLC/ESI-MS~n method was employed to study the chemical components which were able to induct QR in petroleum ether partitions of 95%ethanol extract of P.chinensis based on components change after reacting with GSH and one quinone and one thiophene which had QR induction effects were identified.5.The silver complexation of triterpenoid was employed to MS analysis and obvious differences were found in the fragmentation behavior of two types of triterpenoid saponins which had the same molecular basic aglycons separated from the dichloromethane partition of the 95%ethanol extracts of P.chinensis through HPLC-ESI-MS~n in positive ion mode.silver / triterpenoid saponin complexes of the type(Ag + triterpenoid saponin)~+ were analyzed and there were two main pathways of fragmentation in triterpenoid saponins which had aglycons of oleanane skeleton.These studies can assist the effective analysis of two kinds of saponins,and benefit the structural identification of similar constituents in crude plant extracts.6.The silver complexation of triterpene was employed to MS analysis and the fragmentation behavior of triterpene compounds including isomers which had norhopene skeletons separated from dichloromethane partition of the 95%ethanol extracts of E.cavaleriei were studied through ESI-MS~n in positive ion mode.silver / triterpene complexes of the type(Ag + triterpene)~+ were analyzed to differentiate two pairs of isomers and three main pathways of fragmentation were also inferred.This method was quite helpful for characterization of these rare triterpene compounds.7.Hepa 1c1c7 murine hepatoma cells were employed to assay the QR activity of the partitions and components from the 95%ethanol extract of E.cavaleriei and P. chinensis.
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