Phytochemical Study and Insecticidal Analysis of Hyptis suaveolens L. (Bush Mint) Against Mosquitoes

Abstract

Mosquito-borne diseases remain a significant public health concern globally, particularly in tropical regions like Nigeria, where malaria poses a persistent threat. The development of resistance to synthetic insecticides and the environmental concerns associated with chemical repellents have increased interest in exploring plant-based alternatives for mosquito control. Hyptis suaveolens (Bush mint), a medicinal plant widely distributed in tropical regions, is traditionally known for its insecticidal and repellent properties. This study aimed to investigate the phytochemical composition and insecticidal activity of H. suaveolens against mosquitoes. Samples were collected from the Biological Garden of Sokoto State University, and dried leaves were subjected to 70% ethanolic extraction. Qualitative and quantitative phytochemical screening were conducted in the Chemistry Department of Sokoto State University, while Gas Chromatography-Mass Spectrometry (GC-MS) analysis was carried out at the Central Advanced Science Laboratory, Usmanu Danfodiyo University, Sokoto. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, phenols, and saponins, while glycosides and steroids were absent. GC-MS analysis identified forty compounds, with the highest concentrations being Naphthalene, 1-methyl (20.84%), 1,3-Dimethyl-5-buty cyclohexane (16.37%), and Cyclohexane carboxamide (14.40%). Insecticidal activity was assessed through a human bite repellency cage test following WHO protocols using F1 adult mosquitoes. The ethanolic extract showed 0% mosquito landings on treated hands compared to 63.3% on untreated controls, with a 24-hour post-exposure mortality rate of 73.3%. These findings indicate that H. suaveolens possesses promising phytochemicals with effective insecticidal and repellent properties, supporting its potential as an eco-friendly alternative for mosquito control.

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