| It was main investigated that to find preferable technics for extraction and purification of azadirachtin A, The effect factors on stability of azadirachtin was researched. The pesticide formulations of azadirachtin with applicable and stable properties were designed and activities of those products were studied.It was studied systematically that every kind of technics for extraction azadirachtin using various solvents. The influence of the way comminutes for neem seed, dosage of solvents, temperature and time for extraction, to handle the craft, respectively; on the yield of azadirachtin were studied. It was first time that use technique combined of marinated and comminuted for extraction azadirachtin from neem seed kernels. The comminute neem seed and extraction azadirachtin were combined to make one step in this manufacture. The difficult problem that comminutes the neem seed kernels with high oil was overcome. The extraction manufacture of azadirachtin was simplified by using the technique of the hydrocarbon to totally precipitate azadirachtin. The yield of azadirachtin was obvious enhanced. The optimal extraction conditions were: ratio of material to liquid 1:2 (m / v) and the extraction time 4×4hr, extraction temperature 20oC; It was found that the extraction yield of azadirachtin were different from with different neem seed and different solvent, The yield of azadirachtin by neem seed with oil or deoil neem seed using optimal extraction conditions were: 0.5385%,0.2941% (methanol),0.4578%,0.2783% (ethanol),0.2867%,0.1667% (Ethyl acetate), 0.3260% (ethanol-petroleum ether 3:1), 0.2140% (acetone), 0.1011% (acetonitrile), 0.0920%(methyl tertiary butyl ether). The highest yield of azadirachtin was using methanol as solvent among those solvent. The purity of azadirachtin product was higher and the technics was simple when using ethyl acetate as solvent. Aazdirachtin was qualitatively analyzed by HPLC, The HPLC/MS method was developed to permit the rapid qualitative of azadirachtin and related triterpenoids from seeds extracted with methanol.It was first time investigated that use of the ultrasonic-assisted process (UAP) for the extraction of azadirachtin by solvent from neem seed. The optimal ultrasonic-assisted extraction conditions were: ratio of materia to liquidl1: 2 (m /v) and ultrasonic power 200 W; It was found that the ultrasonic time were different from with different solvent (methanol -15 min ,ethanol - 20 min; ethyl acetate -10min). The yield of azadirachtin by neem seed with oil or deoil neem seed using (UAP) optimal extraction conditions were: 0.5623%,0.3786% (methanol),0.4578%,0.3658% (ethanol),0.3123%,0.2462% (Ethyl acetate). The yield of azadirachtin A by the ultrasonic-assisted process (UAP) was higher than by stirred method.A new supercritical carbon dioxide fluid extraction methodology was applied to extract azadirachtin A from neem seed kernels. The optimal extraction conditions were: the extraction temperature 32 oC, the pressure of carbon dioxide 32 MPa , mass flow rate of carbon dioxide 10 kg/hr, cosolvent / material( v:m) 3:1. The yield of azadirachtin by neem seed with oil or deoil neem seed using this manufacture were: 0.2501%, 0.2084%. Three kinds of purification technics for azadirachtin were investigated systematically, the preferable solvent purification method for azadirachtin was found by optimize experiment. The purity of purified azadirachtin A was increased from 35.89% to 63.45%. Azadirachtin A was purified by column chromatography silica gel with co-solvents gradient elution. The purity of azadirachtin A which purified by once column chromatography with co-solvents gradient elution was 50%-60%.The purity could be reached 68% as the product was further purified by this method. The performance of adsorption and desorption of azadirachtin A in dynamic and static using XAD-1180 was frist studied. The appropriate adsorption and desorption condition for purification azadirachtin A was found. The optimal adsorption condition were: concentration of azad...
|
PDF Full Text Request