Investigation On The Chemical Constituents Of Tridax Procumbens And Oxytropis Falcata And Total Synthesis Of A New Pterocarpan

The genus Tridax L.(Compositae) are perennial herbs include about 26 species, distributed in tropical American and southeast Asian.Many species of the genus often are as weeds.Tridax procumbens is the only species of Tridax L.growing in China, mainly distributed in South East and Southern island.It is used in Indian traditional medicine as icterus,also against bronchial catarrh,dysentery and diarrhea.The genus Oxytropis DC(Leguminosae) are perennial herbs has about 300 species all over the world,distributed in the North Temperate Zone.There are 146 species,12 variants,3 deformations in China,distributed in the southwest,northwest to north-east.The plants of the genus are little use in economic.In addition to individual grass plants can do,some also have a certain degree of toxicity,in some alpine pastures and the Arctic region is an important part of the grassland.Oxytropis falcata Bunge,known as a toxic plant,is commonly regarded as "the king of herbal medicine" in Tibetan medicine.It is mainly used for healing sores,diuretics,disinfection,pain elimination,swelling elimination and prevented spur hyperplasia.In this thesis,we have described the phytochemical investigation of the aerial parts of Tridax procumbens collected in Hainan province and the whole plants(aerial parts and roots) of Oxytropis falcata.The chemical constituents were isolated by means of column chromatography(CC),preparative thin layer chromatography (prep-TLC) and recrystallization etc.In combination with the spectroscopic data from literatures,most of the compounds have been elucidated on the basis of comprehensive spectroscopic methods,including UV,IR,ELMS,FABMS,HR-ESIMS,¹H NMR,¹³C NMR,DEPT,¹H-¹H COSY,gHMBC,gHSQC,¹H-¹H NOESY,CD and X-ray diffraction experiments.They belong to sesquiterpene, diterpene,triterpenes,steroids,flavonoids,long-chain en-acetylene,benzene derivatives and their glycosides.38 compounds have been isolated from the aerial parts of T.procumbens,three of which are new ones.Total 77 compounds were isolated from the two parts(aerial parts and roots) of O.falcata,12 are new compounds and three were isolated as new natural products.Furthermore,some compounds were selected for their biological evaluation by DPPH and anticancer activity test.All the selected compounds showed weak inhibitory activity against cancer cells.The new compounds O130,Of33 showed strong ability to eliminate free radicals,with IC₂₀ values of 3.84μM and 12.21μM,respectively.In addition,we have introduced briefly the current research of the pterocarpans especially,total synthesis.Using the commercially available resorcin and 1,2,3-trihydroxy benzene(pyrogallic acid) as starting mateials,lewis acid promoted formal(3+2) cyclization reaction of benzoquinone with 2H-chromenes as the key step. The new compound(±)-Of30 has been synthesized atom economy.The results would be a supplement for the research on bioactivity of chemical constituents in traditional Chinese medicine,helpful reference for pharmacology, chemotaxonomy and screening new medicines.These results would also provide a scientific basis to the further development and utilization of traditional Chinese medicine resources,and realization of modernization of traditional Chinese medicine.