Screening And Identification Of Natural Active Compounds From The 25 Kinds Of Medicinal Plants Via The Growth Inhibition Toward Cancer Cells In Vitro

The lung cancer has been the most dangerous cancer in China and worldwide.The chemotherapeutics is currently the major way for treating most cancer patients,especially for the patients with advanced lung cancer.Although with the development of anticancer drugs recently,there are still some big problems which the scientists have to solve such as side effects,drug tolerance.Therefore the research of finding new drugs with low side effects,more effective,is still the great challenge for lung cancer treatment.And the natural drug has many advantages over the synthetic drug,such as the biocompatibility.Natural drugs,especially these from Chinese medicinal herbs,are of abundant resources,not only in their plant species but also their distribution in China.Based on this,building a natural products library and screening the excellent natural drug from the library is a new strategy in the research of anticancer drug.In this thesis,through the establishment of the library of phytochemical extract which resulted in a collection of 36 plant species,of 220 extracts.We screened 150 extracts in vitro via the cell growth inhibitory activity toward A549 using MTT assay.And more than 10 extracts showed repression on A549 cell growth significantly.One research has shown that the extract of petroleum ether from Conyza Canadensis(L.)Cronq.and the chloroform extract of Phytolacca acinosa Roxb showed inhibitory activity on A549 cell growth in a dose dependent manner.And our further studies have shown that these two extracts could arrest the cell cycle at G2/M phase of the A549 cell.Furthermore,I have carried out an isolation of anticancer constituents from Hedera nepalensis K.Koch under the guidance of their cell growth inhibition activities toward human non-small-cell lung cancer cell A549.This is a unreported study.From this research,two major anticancer compounds,hederagenin 3-O-?-L-arabinopyranoside(IC50=13.69±1.29?g/ml)and pulsatilla saponin A(IC50=2.80±0.94?g/ml),responsible for the anticancer activities of Hedera nepalensis K.Koch were characterized collectively through a series of phytochemical chromatography and spectroscopic methods.Further studies have shown that both hederagenin 3-O-?-L-arabinopyranoside and pulsatilla saponin A inhibit A549 cell growth in a dose dependent manner and their growth inhibition on A549 cells are through inducing the cancer cell apoptosis including cell shrinkage,nuclear fragmentation and condensation.The activities of these compounds on cancer cell apoptosis are dose dependent.It is the first time to show that hederagenin 3-O-?-L-arabinopyranoside has apoptotic effect on lung cancer cell and pulsatilla saponin A induced A549 cancer cells apoptosis in a dose dependent manner.