Preliminary Larvicidal Potential of Andrographis Echioides against Dengue Vector Aedes aegypti Larvae

Aim/Background: The present study was conducted to assess the larvicidal potential of Andrographis echiodies against the dengue vector Aedes aegypti larvae. Alcoholic leaf extract of Andrographis echiodies was studied at 500, 250, 125, 62.5, 31.25, and 15.625 ppm concentrations against third-instar larvae of Aedes aegypti. Materials and Methods: 100 larvae of Aedes aegypti mosquitoes were exposed to each concentration of both ethanolic and methanolic crude extract of Andrographis echiodies in a volume of 100ml. To minimize the error five replicates were employed with respective diluted alcoholic solutions as control. The percentage mortality of larvae at different concentrations of both alcoholic extracts and control were recorded after 24 hr and 48 hr of constant exposure followed by LC₅₀ and LC₉₀ determined. Results: The effective and highest coefficient of determination (R₂) was calculated using regression analysis. The effective and highest coefficient of determination (R₂) was 0.88 in 24 hr of exposure of larvae in methanolic leaf extract of Andrographis echioides. Similarly, the effective and highest coefficient of determination (R₂) was 0.94 in 24 hr of exposure larvae in ethanolic leaf extract of Andrographis echioides. Conclusion: From the result it was concluded that both methanolic and ethanolic leaf extract of Andrographis echioides exhibited larvicidal activity against the dengue vector Aedes aegypti larvae and it may be due to its secondary metabolite diterpenoid lactone. Further studies may be needed to expose its exact mechanism of action.