Study On Extraction Of Toosendanin From The Fruit Of Melia Toosendanin Linn Using Supercritical Carbon Dioxide

Melia azadarach Linn belonging to Meliaceae exists broadly in our country. Toosendanin, the main effective ingredient of the fruit of Melia azadarach Linn, is a kind of tetracyclic triterpene, which can be made into pesticide. Toosendanin could make pieris rapac antifeed and have stomachtoxic activities, and show high feeding inhibitory effects to Toxoptera aurantii. Toosendanin can be put into produce botanical insecticides. This botanical insecticide is a safe and effective and free of toxic residuals and adaptable to controlling pests over cropsWith occurring the upsurge of savageness, nutrition and returning natural all over the world, supercritical fluid extraction technology holds prominent status in the domain of extraction of natural products as a kind of high effective and clean separation technology. This thesis mainly explores the feasibility and the optimal conditions of extracting toosendanin from the fruits of Melia azadarach Linn with supercritical carbon dioxide.The process of extracting toosendanin from the fruits of Melia azadarach Linn using ethanol extraction and crystallization method was firstly studied. And effects of extraction time, erxtraction times and the ratio of liquid to solid on the yield of toosendanin were investigated. Two melting points of the crystal obtained were determined by using differential scanning calorimetric (DSC). Its structure was elucidated by spectroscopic means (ultra violet spectroscopy, electrospray ioniaztion mass spectroscopy and infrared spectroscopy). All the results of qualitative analysis agreed roughly well with the results in the related references.The process of extracting toosendanin was further studied from the fruits of Melia azadarach Linn with supercritical CO₂ using the supercritical fluid extraction apparatus. which was made by ourselves. And effects of extraction temperature and pressure on the extraction yield were investigated. Effects of extraction time, the size of material and the concentration and dosage of modifiers on the extraction yield of toosendanin were studied. The optimal extraction conditions were obtained experimentally. It is found that the yield of toosendanin is up to 98% when using 20 % ethonal modifier at pressure 20 Mpa and temperature 40℃. Moreover, the shrinking model was used to simulate the mass transfer process of toosendaninl in supercritical fluid. A simplex method was used to fit and optimize the model parameters. The numerical solution of yields vs. extraction time was obtained by differential method. The simulating results show that the model fits the experimental data well.