Chemical Constituents From Five Medicinal Plants And Their Bioactivities

In the course of millions of years from selection and evolution,medicinal plants gradually synthesize a large number of secondary metabolites which have novel structures,chemical diversity,drug-likeness and diverse biological activities.Biological activity research is one of the most concerned in the new drug development process.This thesis uses five medicinal plants including Dendrobium devonianum,,Tahernaemontana corymbosa,Tdivaricata,T bovina3 and Laggera pterodonta.By chromatography,spectroscopy technique and X-Ray diffraction experiments,55 compounds were isolated and identified from above-mentioned five medicinal plants,including 9 new compounds.Synthesis of dihydrostilbenes with inhibitory activity against human neutrophil elastases was also conducted.The specific details are as follows:1.The dried rhizomes of D.devonianum is usually used as a Chinese folk medicinal herb.31 Compounds including 6 new ones were isolated and identified from the rhizomes of D.devonianum.Dendrobiols A-E(?-1??-5)were the new bibenzyl-phenylpropanoids hybrids,Dendrobiol F(?-6)was the new phenylpropanoid.The immunosuppressive activity of some compounds was tested using the lymphocyte transformation test.Compounds ?-7??-9 exhibited significant immunosuppressive activity.2.Four compounds including three new Tabercorinines A-C(?-1??-3)were isolated from the whole plant of.corymbosa.The four alkaloids were tested for the inhibitory activity of acetylcholinesterase and ?-secretase associated with AD disease,Compounds(?-1??-4)showed no bioactivity in the inhibitory activity of?-secretase.In the acetylcholinesterase inhibitory activity test,compound ?-3 showed some inhibitory activity.This type of novel indole alkaloid may be a potential acetylcholinesterase inhibitor precursor3.Six monoterpenoid indole alkaloids were isolatated and their structures were elucidated as Ervaramine type,Vobasine type,Aspidosperma type.Compounds ?-4??-6 were isolated from T divaricatafor the first time.The results of in vitro anti-tumor cell experiments showed that compounds ?-1??-6 had no obvious cytotoxicity against HL-60,SMMC-7721,A-549,MCF-7,SW480 tumor cells4.The alkaloids were first isolated from.bovina.Compound IV-1 was evaluated for its cytotoxic activities against five human cancer cell lines.It showed IC50 values of 14.43,15.37,16.36,12.68 and 13.86 ?M against five human cancer cell lines,respectively.The cytotoxic activity of the compounds ?-2,?3,?-4 has been reported in the literature.5.Five compounds were isolated for the first time from the glandular trichome exudate on the leaves of L pterodonta.Pterodondiol(?-5)was evaluated for its cytotoxicity against HL-60,SMMC-7721,A-549,MCF-7 and SW480 cell lines,It showed no significant cytotoxic activity.6.Dihydrostilbenes have long been considered as an important class of natural products,which had been isolated from many primitive green plants.Our continued interest in searching for new HNEI prompted us to develop an efficient total synthetic route for the natural dihydrostilbenes,and the activities of these compounds were determined through HNE inhibitory activity bioassay,and some compounds exhibited considerable inhibitory effects on HNE.