Evaluation of Larvicidal Activity of Essential Oil from Leaves of Coccinia grandis against Three Mosquito Species

BACKGROUND To study the chemical constituents and larvicidal activity of essential oil extracted from the leaves of Coccinia grandis against three mosquito species. METHODS Essential oil was extracted by hydro distillation using clevenger apparatus and was analyzed for chemical constituents by gas chromatography-mass spectrophotometry (GC-MS). Larvicidal activity was recorded after 12 and 24h of post-exposure against three mosquito species, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. Dead larvae were identified when they failed to move after probing with a needle in the siphon or cervical region. The LC50 and LC90 values for three mosquito larvae were calculated by Probit analysis. RESULTS The GC-MS analysis revealed that essential oil contains 23 different constituents. Out of these 23 constituents, major constituents identified were n-tetracosane (39.18%), n-eicosane (30.04%), tetratriacotane (2.97%), 7-octadecanal (2.81%), and tricosane (2.31%). Essential oil from leaves of Coccinia grandis exhibited significant larvicidal activity against An. stephensi with LC50 and LC90 values 39.41ppm and 123.24ppm, respectively. This was followed by Ae. aegypti and Cx. quinquefasciatus with LC50 and LC90 values of 48.20ppm, 131.84ppm and 52.80ppm, 135.48ppm, respectively after 24h of exposure. CONCLUSION The results could be useful in developing a cost effective, ecofriendly, region specific and practical strategy for the control of mosquito vectors.