Chemical constituents and larvicidal efficacy of Naringi crenulata (Rutaceae) plant extracts and bioassay guided fractions against Culex quinquefasciatus mosquito (Diptera: Culicidae)

Mosquitoes transmitted several vector borne diseases like malaria, dengue, lymphatic filariasis and now Zika virus. Synthetic chemicals cause much illness to humans, non-target organisms and natural ecosystem. In the present study, larvicidal efficacy of Naringi crenulata (Rutaceae) different leaf extracts and bioassay guided fractions against Culex quinquefasciatus, phytochemical screening and secondary metabolites were characterized by TLC, HPLC, GC-MS and FT-IR analysis. Our results show highest larval mortality was found in acetone extract. For 24h LC50 and LC90 values were, 1.020, 1.931 mg/l. And 48h LC50 and LC90 values were, 3.728, 4.771 mg/l respectively. Fraction 9th showed remarkable larvicidal activity on larvae of Cx. quinquefasciatus. For 24h LC50 and LC90 values were, 5.312, 9.130 mg/l), for 48h LC50 and LC90 values were, 5.000, 9.538 mg/l. Phytochemical screening of N. crenulata crude extract contains phenols, alkaloids, tannins, saponins in acetone extracts. GC-MS analysis results show, 9,12-Octadecadienoic Acid (Z, Z)- (26.846%) is a major chemical constituent may be involved in larvicidal activity. Thin layer chromatography analysis shows nine molecules were separated using chloroform: methanol in the ratio 9.7: 0.3 solvent system. A sharp single peak was obtained in the 9th fraction with retention time of 1.376min with a purity of 99%. FT-IR analysis results confirmed presence of alkynes, alcohols, phenols, carboxylic acids, stretching, wagging and bending of oxygenated bonding. The present study shows that chemical constituents obtained from N. crenulata extracts and 9th fraction have strong larvicidal properties these botanical derived molecules offered alternative to synthetic chemical insecticides.