ISOLATION AND IDENTIFICATION OF BIOLARVICIDE FROM SOURSOP (ANNONA MURICATA LINN.) AQUEOUS LEAF EXTRACT TO MOSQUITO (AEDES AEGYPTI LINN.) LARVAE

Abstract

To assess the biolarvicidal compound and larvicidal potentials of methyl ester of hexadeconic acid isolated from Annona muricata Linn. (A. muricata) against mosquito larvae Aedes aegypti Linn. (A. aegypti). The biolarvicidal compound methyl ester of hexadeconic acid was determined using GC-MS, while the larvicidal bioassay was carried out using different concentration of aqueous leaf extract of A. muricata against the larvae of A. aegypti in accordance with the standard protocol. Isolation and identification of larvicide bioactive compound from soursop (A. muricata) leaves against the larvae of A. aegypti mosquito, the transmitters of dengue fever has been carried out. The aquatic (rain water) extract of soursop leaves was an active larvicide agent with a lethal concentration (LC 50) varies with the concentration percentage and time. LC 50 for 2.5% = 3.0 h, 2.0% = 3.30 h, 1.5% = 3.15 h, 1.0% = 4.0 h and 0.5% = 5.0 h respectively. Total mortality occurred at 6.0 h for 2.5% concentration, 6.30 h for 2.0%, 7.30 h for both 1.5 and 1.0%, 8.0 h for 0.5% concentration. Removal of exoskeleton (dechitinising property) occurred between 1.0 h to 2.0 h for these concentrations tested for this work. Separation by TLC, analysis and identification with GC-MS showed peaks of 14 compounds, where there three dominant compounds with a retention time relatively close and have the abundance percentage that are large enough, which are identified as methyl ester of hexadecanoic acid, methyl ester of 9-octadecenoic acid (z), and 5-methyl-2-hexanone oxime with the most dominant compound which is methyl ester of hexadecamic acid which has a 44.11% abundance. The results justify the larvicidal potentials of bioactive compound from the leaf aqueous extract of A. muricata and the need to incorporate them in vector management and control.