Study On Extraction Process And Dynamic Changes Of Toosendanin

As a valuable natural pesticide, toosendanin is more and more popular in phytochemical field all over the word. In this paper, we systenatically study the extraction process of toosendanin in the mature fruits of Chinaberry, and respectively analyze the dynamic change of the toosendain content and its structural isomeride distribution in annual fruits and leaves, hoping that it could provide a theoretical basis for comprehensive development and utilization of Melia azedarach L.. The results are as follows:Uniform design and regression analysis were adopted to optimize the extraction process of toosendanin, a kind of vegetal pesticide. And solvent reflux extraction was studied to extract toosendanin from the fruit of chinaberry with the process of eliminating fats, extracting (95℃) and abstracting. As a result, the optimal extracting conditions were: the ratio of feedstock to liquor 1:24 (g:mL) and the time 20 minutes of petroleum, the ratio of feedstock to liquor 1:34 (g:mL) and the time 390 minutes of ethanol, extracting 100 minutes with 125 mL ethyl acetate and the yield of toosendanin reached 0.72%.From July to December, the content of toosendanin in the fruits is significantly different. The content of isomeride A acts parabolic with the highest point 0.53% in the middle of November, while that of the isomeride B is diauxie curve with the two peak in July(0.58%) and November (0.76%). During the growing period of fruits, the total toosendanin content takes on the same trend of isomeride B with the maximum in November (1.27%). From July to December, the contents of toosendanin isomerides in the fruits are significantly different. The content of isomeride B is always higher than that of isomeride A in the growing period except for July and November.From May to October, the content of toosendanin in the leaves is significantly different and acts parabolic with the highest point 0.22% at the beginning of June. The content of isomeride B takes on the same trend of total toosendanin with the maximum in June, while that of the isomeride A is diauxie curve with the maximum in July. During the growing period of leaves, the contents of toosendanin isomerides are significantly different. The content of isomeride B is always much higher than that of isomeride A in the growing period except for July.During different periods, the content of toosendanin in leaves and fruits is significantly different and uncorrelated. The content of toosendanin in the fruits is five times higher than that in the leaves during the growing period except for July, so are the isomerides.The content of toosendanin in different parts of mature fruits is significantly different. The content of total toosendanin in fruit pulps is 25.1% higher than that in seeds; the content of isomeride A in seeds is 55.4% higher than that in fruit pulps; the content of isomeride B in fruit pulps is 3.3 times higher than that in seeds. Also the content of isomerides in the same part of mature fruits is significantly different. The content of isomerides are flat in fruits; the content of isomeride B is 33.3% higher than isomeride A in fruit pulps; the content of isomeride A is four times higher than isomeride B in seeds.The content of toosendanin in mature fruits in Shannxi and Shandong is significantly different. The content of toosendanin in Shannxi is 1.4 times higher than that in Shandong, which indicated that there were obvious geographic variations among Chinaberry populations. Besides, toosendanin in methanol solution would degrade in 35 days at 4℃, which is in according with the kinetic chemical reaction model.