Precipitation of rotenoids resin extracted from Derris elliptica roots by means of clarifying agents

Abstract

Rotenone and its congeners have come into an increasingly widespread usage as the active constituents of a large number of insecticides. The roots of Derris elliptica or 'tuba' plant are used as a source of insecticidal compounds which primarily contain rotenone. The main objective of this work is to obtain the best combination of the main precipitator agent (aluminium sulfate: Al2(SO4)3) with 4 different types of co-precipitator to completely solidify rotenone from liquid crude extract. Rotenone was extracted from Derris elliptica root using two solvent systems: (1) methanol 95% (v/v), and (2) a mixture of methanol and H2O (8:2). After the extraction, the precipitation process was carried out using Al2(SO4)3 (1.5M) with the addition of co-precipitator (clarifying agents) such as calcium hydroxide, sodium carbonate, sodium caseinate and kieselguhr (diatomaceous earth) with a concentration of 1M to 3M. The result has shown that natrium caseinate was the best co-precipitator with the highest yield of 38.65% (w/w) at the highest concentration of 3M. None of the rotenone was detected in the supernatant to indicate that all rotenone content have been precipitated adequately. Finally, the presence of rotenone was confirmed by using qualitative analysis of thin layer chromatography (TLC) method.