Larvicidal and mosquitocidal extracts, a coumarin, isoflavonoids and pterocarpans from Neorautanenia mitis

The present study aimed to evaluate extracts and compounds from tubers of Neorautanenia mitis against the malaria- and filariasis-transmitting mosquitoes, Anopheles gambiae and Culex quinquefaciatus, respectively. The extracts exhibited activity against larvae of A. Gambiae and C. quinquefaciatus mosquitoes, and were also active against adult A. gambiae mosquitoes. The active extracts yielded the coumarin derivative pachyrrhizine, the isoflavonoids neotenone and neorautanone, and the pterocarpans neoduline, nepseudin and 4-methoxyneoduline as the active constituents. The activity of the crude extracts was at about the same magnitude as that of the constituent natural products, the latter's efficacy being almost at the same level. for all the isolated compounds. The mosquitocidal activities of the pure compounds were comparable to those of the standard mosquitocides deltamethrin and alphacypermethrin. These findings corroborate traditional insecticidal application of N. mitis and the results can be extended for the control of mosquitoes especially at breeding sites. (C) 2004 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.