Bioactivity guided isolation of mosquito larvicide from Piper longum

Objective: To isolate the larvicidal component from the fruits of Piper Ion guns (P. Ion guns) against the filariasis vector, Culex quinquefasciatus (C. quinquefasciatus). Methods: Pulverized fruits of P. longum were subjected to soxhlet extraction using series of organic solvents of increasing polarity. All the solvent extracts were verified for their larvicidal efficacy against 4th instar larvae of C. quinquefasciatus employing standard WHO procedure. Bioassay guided fractionation through column chromatography lead to the isolation of a bioactive amide, pipyahyine from the petroleum ether extract. Results: Petroleum ether extract was found to be the most active fraction among all the extracts tested with LC50 and LC90 being 1.03 and 2.04 ppm respectively. Whereas, pipyahyine, an isolated component of the same fraction was found to be even more effective than the parent extract in terms of LC50 being 0.58 and 1.88 ppm respectively. Conclusions: From the results, it is evident that P. longum can be considered as a powerful arsenal for the control of mosquito population.