Studies On The Chemical Constituents And Bioactivities Of Chukrasia Tabularis A.Juss

This dissertation is composed of four chapters. The first chapter is theexperimental section, including a list of instruments and materials applied inexperiment, source of plant material and experimental procedures of extraction andisolation. The second chapter lays out the experimental results and discussion on them,covering the structure elucidation process of novel compounds, physical and chemicaldata of compounds and bioassay tests on some compounds. The third chapter probesinto the structural characters of phragmalin limonoids, strategy for isolation andbioassay tests. The forth chapter reviews the research progress of chemicalconstituents and bioactivities of Genus Chukrasia.Totally50compouds were acquired from C. tabularis collected in GuangzhouProvince, P.R. China and the structure of21of them were determined so far, whichinvolves teratriterpenoids, tirucallane triterpenoids, sesquiterpenes and so forth.During our research, isolation methods such as column chromatography, gelchromatography, macroporous resin, high performance liquid chromatography, etcand analytical methods such as nuclear magnetic resonance spectrum, infraredspectrum, ultraviolet spectrum, mass spectrum, X-ray diffraction, etc. were harnessed.Among all the conpounds attained,13compounds were determined to be novelones, which can be catagorized into common phragmalin limonoids, C-19norphragmalin limonoids, phragmalin limonoid with α, β-disubstituted furan ring andmexincanolide limonoid. It is noteworthy that2of them （1,2） feature aunprecedented C-15-C-20linkage and the resuting unique2-oxaspiro[4.4]non-3-enefragment.Cytotoxic, anti-inflammatory bioassay tests have been conducted on compounds 1，3，16，21, results revealed that compound1showed moderate cytotoxicities againstall the five tested human tumour cell lines with IC₅₀values ranging from11.72to39.09μM. But they didn’t show significant inhibitory activity againstlipopolysaccharide （LPS） induced nitric oxide （NO） production in macrophage（RAW264.7） cell line. Mixture of1and2, compound3,8,16were tested forantimicrobial activities against five bacterial strains, but none of them showedobvious activitiy.Moreover, it was advanced that ‘¹³C NMR&HPLC Guided Separation Strategy’can be exploited in researches on chemical constituents of genus chukrasia accordingto an analysis of structural characteristics of phragmalin limonoids reported from thisgenus.Finally, this dissertation reviews phragmalin limonoids of great diversity andnon-phragmalin consitituents reported from genus Chukrasia and the bioactivities ofspecies in this genus.Discovery of all these novel compounds and the results of bioassay testsenhanced our knowledge of constituents and bioactivities of C. tabularis, while thenew strategy for studies of chemical constituents of this species can serve as analternative in our investigations of complicated natural products. They can all provivenew scientific evidences and data for further research and even utilization of thisspecies.