Larvicidal efficacy of Vangueria spinosa Roxb. (Rubiaceae) leaf extracts against filarial vector Culex quinquefasciatus

Abstract

Culex quinquefasciatus is the transmitter of some dreadful vector-borne diseases. Such diseases can be controlled by managing the vector population. In this study, the mosquito larvicidal activity of the leaf extracts of a deciduous shrub Vangueria spinosa was evaluated for the first time. Larval mortalities were assessed using crude and different solvent extracts of young leaves of V. spinosa with different concentrations following standard methods. Thin-layer chromatography was done to characterize the major bioactive components liable for larval mortality. Cent percent mortality of the third instar larvae of Cx. quinquefasciatus was recorded at 2.5% concentration of crude extract within 48 hrs. Chloroform: Methanol extract was found to be the deadliest and 100% mortality of third instar larvae was reached in 48 hrs at 50 ppm concentration. The active ingredient which seems to be mainly responsible for larval mortality was steroidal in nature. LC50 of the fraction was calculated as 13.34 ppm for third instar larvae in 24 hrs. No significant effect of these extracts was noted on non-target organisms. So, the leaf of V. spinosa can be used as a potential source for the preparation of mosquito larvicide.