Phytochemical Screening, Chemical Composition and Larvicidal Efficacy of Syzygium aromaticum Extracts and Essential Oil against Culex pipiens

Abstract

Culex mosquitoes, as nuisance insects and primary vectors of disease, present an important risk to animal and human health. The aim of the present study was to evaluate the larvicidal potential of various extracts (ethanolic, hydro-ethanolic, and essential oil) of Syzygium aromaticum (clove) against the larvae of Culex pipiens. Ethanolic and hydro-ethanolic extracts from Syzygium aromaticum were prepared by ultrasonication, and their composition was determined by phytochemical screening. Gas chromatography-mass spectroscopy (GC-MS) was performed to characterize the Syzygium aromaticum essential oil, which was produced through hydrodistillation. The extracts were tested for their larvicidal activity against Culex pipiens larvae and the LC50 and LC90 values were determined. The results of the phytochemical screening of the ethanolic and hydroethanolic extracts indicated the presence of flavonoids, sterols, terpenes, coumarins, glycosides, and gall tannins. The chemical composition analysis also revealed that eugenol (78.82%) and caryophyllene (16.51%) were the main compounds present in the essential oil. The LC50 and LC90 values obtained for the hydro-ethanolic extract were 557.90 and 939.71 ppm, respectively, while values of 400.14 and 743.32 ppm, respectively, were recorded for the ethanolic extract. The lethal LC50 and LC90 values of the Syzygium aromaticum essential oil demonstrated effectiveness at 1.220 and 5.260 ppm, respectively. Results of this study showed that extracts of Syzygium aromaticum have larvicidal activity against Culex pipiens and could be explored in the development of novel and sustainable mosquito control strategies.