Evaluation of Alpinia galanga (Zingiberaceae) extracts and isolated trans-cinnamic acid on some mosquitoes larvae

Abstract

Mosquitoes are vectors for diseases damaging human health and thus, there is an urgent need for insecticidal compounds to control their population. The objective of this study was to determined the efficiency from trans-cinnamic acid isolated from Alpinia galanga (Zingiberales: Zingiberaceae) for control of Aedes aegypti (Dipetera: Culicidae), Anopheles dirus B (Dipetera: Culicidae) and Culex quinquefasciatus (Dipetera: Culicidae). Alpinia galanga (Zingiberales:Zingiberaceae) was extracted by soaking in a sequence of solvents (hexane, dichloromethane, ethyl acetate and methanol), and the isolated trans-cinnamic was separated by preparative thin layer chromatography. All crude extracts and isolated trans-cinnamic were evaluated for their control and affect on detoxification enzyme activities of the third-instar larvae of each mosquito species in laboratory conditions. Our results showed that the hexane crude extract had the best control efficiency in all species, particularly in Cx. quinquefasciatus. The trans-cinnamic acid, isolated compound from hexane crude extract showed as active ingredient against third-instar larvae of each mosquito species. Mortality in this case may result from the inhibition of carboxylesterase. These results indicated that A. galanga which had trans-cinnamic acid as active ingredient compound could represent a promising naturally occurring control agent for all three mosquito species. However, this research consider as an initial prospective study, the other side effect on nontarget species need to concerned before used as commercial product.