Efficacy of bioactive compounds from Curcuma aromatica against mosquito larvae

With the development of resistance to conventionally used synthetic insecticides, vector management has become acutely problematic. Hence more attention has been focused on botanicals. Therefore our present study was aimed to evaluate the efficacy of extracts from rhizomes of Curcuma aromatica against the larvae of filariasis vector mosquitoes, Culex quinquefasciatus employing standard WHO procedure at Mysore. The soxhlet extraction was carried out using non-polar organic solvent, petroleum ether. The efficacy of petroleum ether extract seemed to be effective with LC(50) and LC(90) values of 11.42 and 18.00 ppm respectively. Bioassay-guided fractionation through flash chromatography lead to the isolation of two larvicidal compounds namely 9-oxoneoprocurcumenol and neoprocurcumenol. Between the two, 9-oxoneoprocurcumenol exerted significant toxicity (P<0.01) on mosquito larvae with LC(50) value of 5.81 ppm and LC(90) being 9.99 ppm compared to neoprocurcumenol with 13.69 and 23.92 ppm of LC(50) and LC(90) values respectively. From the results, C. aromatica could be considered as one of the powerful candidate to bring about useful botanicals so as to prevent the resurgence of mosquito vectors.