Investigation On The Chemical Constituents Of Anaphalis Lactea, Anaphalis Margaritacea And Saussurea Caulopter

The thesis primarily describes the phytochemical investigation on the plants ofAnaphalis lactea Maxim.,Anaphalis margaritacea Benth et Hook f.and Saussureacauloptera Hand.-Mazz.collected in Huzhu County of Qinghai Province.Sixty-twocompounds were isolated by means of silica gel column chromatography (CC),preparative thin layer chromatography (prep-TLC) and recrystallization etc.Thestructures of these compounds were elucidated on the basis of spectral evidences,including EI-MS,HRESIMS,1D NMR (¹HNMR,¹³CNMR,DEPT),2D-NMR(COSY,HMQC,HMBC,NOESY),along with comparison to authentic samples orliteratures.Thirty compounds,including four new ones 2',6'-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-4'-methoxychalcone,4,6-dihydroxy-7-isobutyryl-5-prenyl-2(3H)-benzo furanone,7-O-(β-D-glucopyranosyloxy)-5-hydroxy-1(3H)-isobenzofuranoneand (2R,3S)-3-methyl-2-(5-oxo-2-isopropenylhexyl)-cyclopentanone and one newnatural product 7-methoxyplatypterophthalide,were isolated from the ethanol extractof the dried whole plant A.lactea.Others were flavonoids,phthalides,triterpenoidsand sterols.Twenty-two compounds,including four rare flavonoids with multi O-substitutedA-ring,were isolated from the ethanol extract of the dried whole plant A.margaritacea.Ten compounds,including two new ones,2-(p-hydroxyl benzylidene)-4-butylester-(Z)-succinic acid and (1R^*,2R^*,3S^*,4S^*)-1,3-bis(2-butoxy-2-oxoethyl)-2,4-bis(4-hydroxyphenyl)cyclobutane-1,3-dicarboxylic acid,were isolated from S.cauloptera.The free-radical scavenging activity of flavonoids isolated from A.lactea and A.margaritacea was also studied by DPPH assay.Dimeric sesquiterpenoids isolated between 1983 and 2006 were reviewed.The result of this thesis will provide chemical evidences for exploiting thenatural resources and be helpful to plant chemotaxonomy.