Synergistic activity of Andrographis paniculata nees extracts against the larvae of the malarial vector Anopheles stephensi liston (Diptera: Culicidae)

Abstract

An investigation has been made on the Deltamethrin and different solvent extracts of Andrographis paniculata Nees were evaluated under laboratory conditions for larvicidal activity against the malarial vector Anopheles stephensi Liston.Ethanolic extract with lethal concentration LC50 and LC90 of 35.47and 47.43 after 24h and LC5025.22 and LC90 46.32 ppm after 48h, respectively was found to be the most effective, followed by Acetone, Methanol, Chloroform, Hexane, Petroleum ether and Benzene extracts. LC50 and LC90 for Deltamethrin were 0.0036 and 0.0097 ppm after 24h and 0.0055 and 0.0085 ppm respectively after 48h of exposure respectively. Combined formulations were evaluated for synergistic activity and a 1:4 ratio of Deltamethrin and Ethanolic extract was observed to be more effective than 1:2 and 1:1 ratios. Combinations of Andrographis paniculata extracts with Deltamethrin demonstrated higher larvicidal activity, indicating synergistic activity.