Investigation On The Chemical Constituents And Bioactivities Of The Plants Of Bidens Pilosa And Siegesbeckia Pubescens

The genus Bidens (Compositae) are perennial herbs including about 230 species, distributed in tropical and subtropical regions, especially in America. There are 9 species growing in china, and most of them are treated as weeds. However, many species of this genus are used in various folk medicines such as antimalarial, antibacterial, blood-pressure lowering, antihyperglycemic agents and preventing cancer.Plants of genus Siegesbeckia are annual herbs widely distributed throughout tropical, subtropical and temperate regions of the world. Three species of Siegesbeckia grow in China and their aerial parts have been used as the traditional Chinese medicine Xi-Xian to treat rheumatic arthritis, hypertension, malaria, neurasthenia, and snake-bite.This thesis describes the phytochemical investigation of the aerial parts of B. pilosa collected in Hainan province and the aerial parts of S. pubescene purchased from the Huanghe Medicinal Material Market in Gansu.106 compounds were isolated by means of column chromatography (CC), preparative thin layer chromatography (PTLC), and recrystallization etc. In combination with the spectroscopic data from literature, the structures of 103 compounds have been elucidated on the basis of comprehensive spectroscopic methods, including IR, UV, EI-MS, ESI-MS, HR-ESI-MS,1D/2D NMR, and X-ray diffraction experiments. Nineteen of them were new compounds and one of them was a new natural product.42 compounds were isolated from the aerial parts of B. pilosa, and 39 compounds (including 5 new compounds) of them were elucidated. Their structures were determined as flavonoids, polyacetylenes, sesquiterpenoids, triterpenoids, etc.64 compounds were isolated and elucidated from the aerial parts of S. pubescene.14 compounds of them were new ones, such as diterpenoids, sesquiterpenoids, triterpenoids, steroids, flavonoids, alkaloids, carboxylic acid, liguanoids, etc.The medicinal importance and diverse activities of members of the genus Siegebeckia prompted us to investigate the anticancer activities of typical diterpenoid compounds. Cytotoxic evaluation of seven of the 25 diterpenoids showed that compounds Xc27 and Xc37 exhibited moderate activity against rat hepatic stellate cells (HSC-T6), human cervical carcinoma (Hela) and mouse melanoma B16 cell lines.More and more research are focus on the chemical constituents and medical investigation of the genus Bidens. Herein, we reviewed their using of these studies.The results of this thesis will be supplement for the research on phytochemistry, the relationship of structure and activity, biological activity, chemotaxonomy and screening new medicines. Moreover, they are meaningful in providing scientific evidence to further development and utilization of traditional Chinese medicine resources, especially in special environments, and realization of modernization of traditional Chinese medicine.