Abstract

Mosquitoes transmit numerous diseases such as malaria, chikungunya, dengue fever, and yellow fever. Indiscriminate use of synthetic insecticides to eradicate mosquitoes nowadays steered to diminution in physiological resistance, which has led to investigate a safe and environment friendly alternative. In the current investigation, bakuchi (Psoralea corylifolia Linn.), an ayurvedic drug having krimighna (act against worms) action, was evaluated for larvicidal bioefficacy against Aedes aegypti larvae. Hence, the study was attempted to evaluate the larvicidal bioefficacy of petroleum ether, ethanol, and aqueous extracts of bakuchi beeja against Aedes aegypti larvae. Petroleum ether, ethanol, and aqueous extracts of bakuchi were collected by soxhlet extraction and cold maceration, respectively. The extracts were evaluated for the larvicidal activity. The larvicidal bioassay was performed by following WHO (2005) guidelines with slight modification and the mortality was recorded after 24 h. The obtained mortality data were subjected to log-probit analysis to determine
the median lethal concentrations—LC50 and LC90. Aqueous extract exhibited LC50 at 699.915 ppm, LC90 at 971.635 ppm; ethanolic extract exhibited LC50 at 66.71 ppm, LC90 at 127.80 ppm; and petroleum ether extract exhibited LC50 at 25.8 ppm and LC90 at 61.0 ppm against late third and early fourth instar Aedes aegypti larvae. From the results obtained, it was revealed that among the three extracts of bakuchi, petroleum ether extract exhibited higher mortality at a lower dose when compared to ethanol and aqueous extract. Hence, the study reasonably concludes that bakuchi carry potential as a mosquito larvicide and could be explored for the development of safer larvicide.

Key words: Aedes aegypti, bakuchi (Psoralea corylifolia Linn.), larvicidal activity