Crude extract and effective fractions from Andrographis paniculata for immature Aedes aegypti and Culex quinquefasciatus mosquito

Abstract

In the quest for environmentally friendly alternatives to combat the challenges of resistance development and environmental toxicity associated with synthetic insecticides in mosquito control, the aim of this study is to explore the potential of fractions derived from Andrographis paniculata as environmentally friendly alternatives for controlling Aedes aegypti and Culex quinquefasciatus mosquitoes, with a focus on assessing their larvicidal, pupicidal, and ovicidal activities. Initially, crude extracts of hexane, chloroform, and methanol from A. paniculata leaves were evaluated for their efficacy against Ae. aegypti and Cx. quinquefasciatus mosquitoes, with the methanol extract showing promising activity. Subsequently, a comprehensive methanol extraction of A. paniculata leaves was conducted, followed by fractionation via column chromatography using various eluents, including chloroform, ethyl acetate, methanol, and their combinations. This process yielded 80 fractions, which were consolidated into 10 fractions based on thin-layer chromatography (TLC) profiles. Each fraction was assessed for ovicidal, larvicidal, and pupicidal activity across concentrations of 2.5, 5.0, 7.5, and 10 ppm. Among these fractions, ‘F-4’ exhibited exceptional efficacy against the larvae, pupae, and eggs of both mosquito species. At a concentration of 10 ppm, ‘F-4’ achieved 100% larval mortality, with LC50 values of 7.2 ppm for Ae. aegypti and 5.0 ppm for Cx. quinquefasciatus. Additionally, ‘F-4’ demonstrated substantial pupicidal activity, with LC50 values of 7.6 ppm for Ae. aegypti and 5.7 ppm for Cx. quinquefasciatus. Furthermore, ‘F-4’ exhibited ovicidal activity, with efficacy ranging between 77% and 78%. These results highlight ‘F-4’ from A. paniculata shows promise as an eco-friendly biocontrol agent against Ae. aegypti and Cx. quinquefasciatus mosquitoes, warranting further investigation for sustainable mosquito control.