Supercritical CO2 extraction of nimbin from neem seeds - an experimental study

Nimbin is one of the many substances found in neem seeds and is reported to have several medicinal properties and uses. For example, it is an anti-pyr etic, can be used to treat arthritis, hypoglycaemia, peptic ulcers, anti-se cretory activity, and it can also be used as an antibiotic. In this paper, we present the results of a preliminary experimental study to extract nimbi n from neem seeds using CO2 supercritical fluid extraction (SFE). The opera ting pressure in the extraction was varied from 10 to 26 MPa, the temperatu re was varied from 308 to 333 K and the flow rate was varied from 0.24 to 1 .24 ml/min. An optimum extraction rate was observed at a pressure of 23 MPa when operating at 308 K. Best extraction conditions occurred at 23 MPa, 30 8 K and a flow rate of 1.24 ml/min for a 2 g sample of neem. The measured e xtraction rate was found to be about 0.18 mg of nimbin/g neem seed per hour of operation which is equivalent to about 0.35 kg nimbin extracted per kg nimbin present in neem seeds. The future work needs to focus on the interac tion between the various operating parameters such as temperature, pressure and flow rate of supercritical carbon dioxide. In addition physical proper ties i.e., particle size, porosity need to be determined in order that a mo del can be developed and tested. (C) 2000 Elsevier Science Ltd. All rights reserved.