| As the enhancement of awareness of health and enviroment of the public, studies of drugs of enviroment protection and pollution-free are becoming the dominant direction. Poisonous plants have ever been the principal resources of the traditional pesticides of China, so screening of new pesticide or bioactive skeleton from poisonous plants is not only the economic and effective gateway, and also the reasonable development and utilization of resources of poisonous plants and phytotoxins. In order to look for new acaricide or lead compound from plants, experiments of screening for bioactivity, pre-test for chemical components, isolation for active compounds, analysis for spectroscopy, elucidation for chemical structure and acaricidal investigation for single compounds were conducted.1. Screening of acaricidally active plants: Acaricidal effect of methanolic extracts from 19 plants in 50% concentration on adult mites of Psoroptes cuniculi was investigated in vitro. Crude extracts of 7 species of plants of Stemona tuberosaffiaibu), Citrus tangerina(3upi), Sophora flavescens(KushQn), Dictamnus dasycarpus(Baixianpi~), Melia azedarach(Ku\iaRpi), Macleaya cordata(Bo\uohui) and Anemone hupehensis (Dapowanhuahua) showed a significant activity against mites, among them Baibu and Boluohui, exhibited the highest activity equal to avemectin solution in concentration of 4mg/L, killed all experimental mites in 1.8 h and 1.7 h, respectively.2. Pre-test for chemical constituents of three species of plants: The possible chemical constitution of 3 species of plants of Boluohui, Dapowanhuahua and Polygonum perfoliatum(Gangban.gui) were checked by means of tube-test method. The main components of Boluohui were suggested to be alkaloids. Dapowanhuahua mainly contained saponins, and Kangbangui contained mainly anthraquinone and flavonoids.3. Extraction and primary separation of active compounds from M. cordata:The whole plant of M. cordata was pounded into pieces and soaked by 0.5% HC1 methanol repeatly. The extract fluid was condensed in vacuum and then resolved in hotwater. Through a series of procedure of filtration, acidification, fractionation with chloroform, basification and fractionation with chloroform, the extract was separated into 4 parts(Ml, M2, M3 and M4). The part of M4 was demonstrated to be the most effective fraction by in vitro activity test.4. Bioactivity-guided isolation of from M. cordata: Sample of M4(19g) was subjected to silica gel column chromatography partitioned with gradually increasing polarity of ammonium hydroxide saturated solvent of petroleum : acetic ether methanol(10 :0-0-l-l). After combining the similar sections, M4 part was separated into 5 fractions (Fl, F2, F3, F4 and F5). Then the fraction of F2 was subjected to a silica gel packed column washed with solvent of petroleum acetic ether triethylamine(4 1 0.05), and then was partitioned into two parts of F21 and F22. F21 gave colorless needle-like crystal(MCS) after column chromatography and recrystal-lization with solvent of methanol acetic ether, and F22 gave light-yellowish amorphous powder(MC6) and white needle-like crystal(MC7) through thin layer chromatography (TLC) preparation deloped in solvent of petroleum acetic ether triethylamine(4 1 0.2) and recrystallization with acetone. Column chromatography of F3 with start solvent of petroleum acetic ether '. triethylamine(4 : 1 : 0.05) gave three fractions of F31, F32 and F33. A yellowish needle-like crystal(MC9) was obtained by column chromatography of fraction F31 washed with solvent of petroleumdichloromethane acetone(2 0.5 0.2), a white amorphous crystal (MCI) was given through F32 recrystallization with CHsCN and a colorless prism-like crystal (MC2) was acquired by column chromatography of fraction F33 with solvent of petroleum dichloromethane triethylamine(3 1 0.1). Fraction F4 was chromatograhically separated into F41 and F42 with petroleum acetic ether : triethylamine(l 1.5 : 0.1) solvent. Fractions F41 was subjected to thin layer chromatography... |
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