Description : | Azadirachtin has also been found to degrade rapidly due to environmental factors such as UV radiation in sunlight, heat, air, moisture, acidity and enzymes present in foliar surfaces therefore it is clear that there is a need for stabilized formulations of neem seed/kernel/oil extracts containing azadirachtin for crop protection, stored grain protection and in public health. We have observed due to our sustained research in this area, that the major quantity of azadirachtin can be extracted directly from powdered neem seeds/kernals with polar solvent such as methanol or aqueous methanol or ethanol (recified spirit) or aqueous ethanol at ambient temperature wherein the fatty oils are predominently retained with the seed/kernel residue so that initial extaction of powerded neem seeds/kernels with hexane/petroleum ether (b.p. 60°- 80° C.) for the removal of fatty oils is avoided. By carrying out the extraction at ambient temperature, thermal degradation of azadirachtin during extraction is minimised. It is possible to disintegrate dry neem seeds/kernels to a suitable powder smoothly in the range of particle size BSS-Technology Demonstration (0.2 mm)-BSS-Technology Demonstration2 (2.4 mm) for the large scale solvent extraction of powdered neem seeds/kemels. Thus, the present invention utilises directly, methanol or aqueous methanol or ethanol or aqueous ethanol for the extraction of azadirachtin from powdered neem seeds/kernels, in a column by continuous percolation. The present invention employs continuous solvent percolation at ambient temperature to avoid decomposition of azadirachtin at higher temperature and it is convenient for modular operations. The present invention also deals specifically with the preparation of emulsifiable concentrate formulation of dry powder enriched in azadirachtin upto 30% for insect/pest control application. |
