Bioefficacy of Methanolic Leaf Extracts from Coleus amboinicus and Mentha spicata against Aedes aegypti Mosquitoes

Abstract

Mosquito-borne diseases (MBDs) pose significant public health challenges globally, with India and Sub-Saharan Africa accounting for the majority of cases. Aedes aegypti, a primary vector of dengue fever, thrives in an environment with inadequate water supply and poor waste management. The increasing resistance of mosquito population to chemical insecticides necessitates the exploration of alternative control strategies, such as botanical extracts. This study evaluates the adulticidal efficacy of methanolic leaf extracts of Coleus amboinicus and Mentha spicata against the adults of Ae. aegypti. Fresh leaves of both plants were collected, dried, and extracted with methanol. Phytochemical screening revealed a moderate presence of alkaloids, flavonoids, saponins, terpenoids, and glycosides in C. amboinicus, while phenols are highly prevalent, indicating significant biological activity. In contrast, M. spicata displayed a high concentration of alkaloids, flavonoids, and terpenoids, though saponins, phenols, and glycosides were less abundant. Adulticidal bioassays demonstrated that C. amboinicus achieved higher mortality rates across all concentrations compared to M. spicata. The LC50 value for C. amboinicus was 202.00 ppm, while M. spicata exhibited an LC50 of 230.00 ppm. Similarly, the LC90 values were 428.51 ppm and 457.40 ppm for C. amboinicus and M. spicata, respectively. These findings suggest that C. amboinicus has a more balanced and diverse phytochemical profile, which likely contributes to its superior adulticidal activity against Ae. aegypti. This study highlights the potential of C. amboinicus as a natural alternative for mosquito control, warranting further exploration and development for effective vector management.