Phytochemical Screening and Insecticidal Activities of Essential oil of Mentha x piperita L. (Lamiales: Lamiaceae) and their Enzymatic Properties against Mosquito Culex pipiens L. (Diptera: Culicidae)

Abstract

Biopesticides from botanicals are nowadays strongly encouraged for use in the program of controlling insect vectors of diseases and other harmful insects. The present study had the objective of determining the chemical composition of the essential oil of Mentha x piperita L. (Lamiaceae). We also evaluated the larvicidal and ovicidal activities of EO against Culex pipiens L. according to the World Health Organization (WHO) protocol. The chemical composition of EO from the aerial parts of peppermint was analyzed by gas chromatography-mass spectrometry GC/MS. The main components were menthol (28.66 %), limonene (19.01 %), and p-cymene (15.82 %). Also, this research found that M. x piperita EO showed larvicidal activity against fourth-instar larvae. Mortalities were recorded after 24, 48, and 72 h of treatment. It has potent larvicidal activity with increasing concentration and exposure time (LC50 values were 448.74; 181.97 and 152.05 ppm). Besides, EO showed excellent ovicidal activity, the results of which indicated that the hatchability of eggs treated with LC50 and LC25 is 18.13 % and 53.67 %, respectively. Furthermore, the study examines the efficacy of this oil on the glutathione S-transferase (GST) and acetylcholinesterase (AChE) activity of Cx. pipiens larvae treated with LC50 and LC90. This experiment has led to neurotoxic activity and stimulation of the detoxification system, as shown by AChE inhibition and GST induction respectively. In conclusion, M. x piperita EO is a natural larvicide and promising ovicide against Cx. pipiens. Therefore, it is recommended for use as a natural biocide in the implementation of effective mosquito control programs.