LARVICIDAL POTENTIAL OF EXTRACTS OF Persea Americana SEED AND Chromolaena odorata LEAF AGAINST Aedes vittatus MOSQUITO
ABSTRACT
The larvicidal activity of different solvent extracts of (ethanol, ethyl acetate, and n-hexane)
The effectiveness of Chromolaena odorata leaves and Persea americana seed against Aedes vittatus mosquitoes was examined. The most effective fractions were isolated and identified using Gas Chromatography Mass Spectrometry and Fourier Transform Infrared techniques from the most potent solvent (n-hexane) extracts of both plants. All of the extracts contained terpenoids, cardiac glycosides, and steroids, according to phytochemical analysis. In contrast to Chromolaena odorata leaf extract, which had LC50 values of 1.835ppm, 3.314ppm, and 5.163ppm for n-hexane, ethanol, and ethyl acetate, respectively, the larvicidal bioassay of Persea americana seed yielded LC50 values of 0.827ppm, 1.799ppm, and 2.732ppm. fractionation by column chromatography of the most potent n-hexane (raw) extracts of both Persea americana (nHPa6) and Chromolaena odorata (nHCo6) fractions that demonstrated higher mortality, with LC50 values of 0.486 ppm and 1.308 ppm, respectively, showed increased activity in some plant species. Oleic acid was found to be the most prevalent component in both nHPa6 and nHCo6 fractions according to a GC/MS analysis. The FTIR analyses of the compounds nHPa6 and nHCo6 revealed bands of absorption for the functional groups present, including alcohol, alkane, alkene, alkyl halide, aldehyde, carboxylic acid, and carbonyl ester, thereby supporting the GCMS result. The larvicidal properties of the n-hexane, ethanol, and ethyl acetate extracts of P. americana seed and C. odorata leaves should therefore be further explored for the prevention of mosquito larvae.
CHAPTER ONE 1.0 INTRODUCTION
Worldwide, diseases spread by insects continue to be a major cause of morbidity and mortality. More than 700 million people are infected with diseases every year thanks to mosquito species from the genera Anopheles, Aedes, and Culex (Redwane et al., 2002). These diseases include malaria, dengue fever, yellow fever, filariasis, schistosomiasis, and Japanese encephalitis (JE) (Oyewole et al., 2010; Govindarajan, 2009). Humans can develop allergic reactions to mosquito bites that include localized skin irritation and systemic reactions like angioedema. Yellow fever and dengue fever, which are endemic to Southeast Asia, the Pacific island region, Africa, Central America, and South America, are generally thought to be transmitted by Aedes spp.
Vector control has been recommended by the World Health Organization (W.H.O. 2012) as a crucial element of the global prevention strategy.
illness brought on by insects. The use of chemical-based insecticides is the most widely used strategy for controlling diseases spread by mosquitoes, but it comes with a number of drawbacks, including human and environmental toxicity, resistance, affordability, and availability (Ghoshet al., 2012).
Since they are a rich source of bioactive compounds that are readily biodegradable into non-toxic products, plant extracts have been effective sources of phytochemicals as mosquito egg and larval control agents. In fact, numerous studies have documented how effective plant extracts or essential oils are at warding off mosquito larvae. They function as oviposition attractants, insect growth regulators, repellents, and larvicides (Pushpanathan, 2008; Samidurai et al., 2009; Mathivanant et al., 2010).
The fruits of the evergreen Persea Americana tree, which is a member of the Lauraceae family, are typically also called the alligator pear or avocado pear. The plant is native to Central America but has easily adapted to other tropical climates, making it a common crop in tropical and subtropical areas. There are many uses for this plant’s various parts, including edible pulp as a source of nutrients and seed preparation as a medicine (Arukwe et al., 2012).