Exploration and Identification of Neem Bark (AzadirachtaindicaA.Juss) as Larvicide against AedesaegyptiMosquitoes.

Abstract

Synthetic pesticide causes many negative side-effects. For insects, it causes physiological resistances and can kill non-target insects. Resistant insects will need more insecticide dose than before. To avoid the negative effect, World Health Organization (WHO) recomends to use natural insecticide. Resistant mechanism is combination of many factors which are biochemistry, physiology, andbehaviour. The more specific insecticide is used, the easier it causes the resistant effect.Neem is one of plants that has been extensively used to study its insecticidal and medicinal activity. It has opportunity to become strong natural insectides to many insects. Aims of this research were to analysis of extractivecontens of neem bark, toxicity test of bioactive against Aedesegyptilarvae, and isolate and identify bioactive compounds of neems bark in against Ae.aegypti larvae. Neem bark powder was extracted using methanol as a solvent. Obtained extract of this process was separated by different polar solvent. Separation process obtains three fractions that are ethyl acetatesoluble fraction, buthanolsolublefraction, and unsoluble fraction. Each fraction was evaporated to get condensed extract. Effectiveness of each fraction to Ae.aegypti larvae were tested with several concentrations that are 50, 100, 250, 500, and 1000 ppm. This experiment showed that ethyl acetatesolublefraction was the most effective fraction. Phytochemical analysis also confirmed that it contained many compound such as; alkaloid, flavonoid, saponin, and triterpenoid. Then, ethyl acetatesolublefraction was separated using chromatography column and yield 9 fractions. Second fraction (Ef-2) was the best larvicidal efficacy, and it also had higher efficacy than ethyl acetate fraction before it was isolated. Furthermore, magnetic resonance analysis (1H and 13C NMR) of Ef-2 was performed, and the molecul structure of bioactive compound was identifiedas Glycerol 1,2-di-(9Z-octadecenoate) 3-tetradecanoate.