Phytochemical Characterization and Bioefficacy of Bush Mint Leaf Hyptis suaveolens Extracts as Natural Mosquito Larvicides

Abstract

Aims: The aim of the study was to evaluate the larvicidal potentials of H. suaveolens on Anopheles mosquito larvae. Study Design:  Experimental research work. Place and Duration of Study: Leaves were collected from Ezza North and Ikwo Local Government Areas of Ebonyi State Nigeria. While the research was carried out at Applied Biology Departmental Laboratory of Ebonyi State University Abakaliki, International Centre for Ethnomedicine and Drug Development (InterCEDD) Nsukka, and Central Science laboratory of University of Nigeria Nsukka all in Nigeria, Between October 2023 to November 2024. Methodology: Leaves of the plant were collected, air-dried, grounded at the International Centre for Ethnomedicine and Drug Development (InterCEDD). The dried leaves were extracted using absolute ethanol and distilled water at different grammage of 300g/1500mL, 200g/1000mL, 100g/500mL, 50g / 300mL. Phytochemical screening and Quantitative analysis of the plant leaves were done while Bioassay experiments were conducted with third- and fourth-instar Anopheles larvae at extract doses of 1 g and 2 g, monitored at five-minute intervals over 120 minutes. Results: The results revealed the presence of alkaloids, flavonoids, tannins, phenolics, terpenoids, steroids, and saponins. Quantitative analysis indicated particularly high concentrations of phenolics (8278 mg/100 g) and terpenoids (1324.26 mg/100 g). Results of Bioassay experiment showed dose- and time-dependent larval mortality, with ethanolic extracts achieving 100 % mortality within 45–60 minutes and significantly lower EC₅₀ values compared to aqueous extracts. Conclusion: These findings suggest that ethanol more effectively extracts hydrophobic bioactive compounds such as terpenoids and flavonoids responsible for larvicidal activity. This study underscores H. suaveolens as a potent, natural mosquito control agent, offering an eco-friendly alternative to synthetic insecticides.