Study On Chemical Constituents Of Three Medicinal Plants From Liliflorae

Our group has been long focusing on the research on the chemical constituents and genetic relationship of plants from genus Dioscorea and Paris in Liliflorae.Three traditional meidicinal plants from Liliflorae,Dioscorea collettii,Paris thibetica Franch.,and Paris polyphylla Sm.var.yunnanensis,were chose for systemly phytochemistry and cytotoxicity investigations.On the basis of various chromatographic separation technologies and spectroscopic evidences,a total of 50 compounds were isolated and identified from Dioscorea collettii.Compounds 1 and 2a are new compounds.Compound 1,a novel diarylheptanoid skeleton,possesses an unprecedented heterocyclic structure with five chiral centers in which two tetrahydrofuran rings and one tetrahydropyran ring are fused to construct a 6/5/5 tricyclic ring system.The absolute configuration of compound 1was established by ECD calculation and single-crystal X-ray diffraction.We also obtained two pairs of enantiomers?2a,2b,3a,3b?by chiral resolution.Compound 2a is a new dihydroisocoumarin,of which the absolute configuration was determined by comparing the CD spectrum to that reported in the literature and single-crystal X-ray diffraction.We first measured the CD spectrum and the specific optical value of compounds 3a,3b,and then firstly determined the absolute configuration of 3a,3b by ECD calculation.Compound 4 has not been reported in the literature and we reported its NMR data for the first time.The hypothetical biosynthetic routes of diarylheptanoids and monocyclic phenols from Dioscorea collettii were discussed in the thesis.In addition,some selected compounds were tested for theirs cytotoxicity against human lung cancer NCL-H460 cell lines.Some of them showed moderate cytotoxicities.Compound 9 had strong cytotoxicity against NCL-H460 with IC₅₀ value of 0.23?M in these compounds.Fifteen compounds were isolated and identified from Paris thibetica Franch..All of the compounds were firstly reported from Paris thibetica.,and this is the first report of compounds 10,13-15 from the genus Paris.Compounds 1-8 showed cytotoxicities against human hepatoma cell lines BEL-7402.Among the tested compounds,compound 3 exhibited the strongest cytotoxicity with IC₅₀ value of 0.48?M.Six compounds were isolated and identified from Paris polyphylla Sm.var.yunnanensis,including one polyhydroxylated steroidal saponin with a glycosyl group at C-1 of the aglycones.Combined some others compounds in our group,the cytotoxic activities of 11 compounds on mouse B16 cells were evaluated.Saponins with a glycosyl group at C-1 of the aglycones showed no activities while saponins with a glycosyl group at C-3 of the spirostanol aglycones exhibited strong cytotoxic activities.It was demonstrated that the 3-O-glycoside moiety and spirostanol structure were essential for the proapoptotic activity with regard to anticancer structural relationship of steroid saponins.In addition,based on summarizing the chemical composition reported in the literature,we discussed the relationship of plants of genus Dioscorea and genus Paris respectively.