LARVICIDAL ACTIVITY OF LINOLEIC ACID ISOLATED FROM ACACIA PENNATA (L.) WILLD. SUBSP INSUAVIS AGAINST AEDES AEGYPTI (L.) MOSQUITO

Abstract

The use of bio-insecticides to control mosquitoes is gaining popularity and is the subject of substantial research; nevertheless, some of these chemicals may be hazardous to non-target organisms, including humans. Thus, it is preferable to concentrate on identifying bio-insecticides from edible plants. In this study, the larvicidal efficacy of linoleic acid extracted from Acacia pennata (L.) Willd. Subsp insuavis, a typical vegetable in Thai cuisine, was assessed against 3rd-instar larvae of Aedes aegypti. Linoleic acid was extracted and demonstrated to have mosquito larvicidal activity; this was verified by bioassay-guided fractionation of A. pennata ethanolic extract. According to the WHO guidelines, bioassays revealed that all A. pennata extracts had mild larvicidal effects against Ae. aegypti third-instar larvae, with LC50 value of crude extract, fractionated extract, and purified linoleic acid of 197.78, 79.51 and 108.49 mg/l, respectively. As linoleic acid is an essential fatty acid of the human diet and is commonly found in edible plants, it is of particular interest to explore the development of linoleic acid as a possible environmental-friendly mosquito larvicide.