Author(s): C Kuppusamy, Murugan Kadarkari
Whole plant ethanolic extract of Andrographis paniculata Nees were evaluated under laboratory conditions for larvicidal, pupicidal, adulticidal and ovicidal properties against the malarial vector, Anopheles stephensi Liston. The ethanolic extract of Andrographis paniculata showed higher larvicidal activity in all the larval instars and higher pupicidal activity. The larvae and pupae were found more susceptible at 48h. The ethanolic extract at 3.0 mg/cm2 exhibited 94.2% adulticidal activity. The ethanolic extract caused only moderate ovicidal activity per se but inflicted delayed effects such as high larval and pupal mortality with lethal concentration values for 50% mortality were 55.7003 , 64.4804 , 63.3496 ppm eggs of 0-6h treated for 18h and eggs of 0-18h treated for 6h and 18h respectively. The age of eggs and the duration of treatment also influenced the ovicidal activity. This mosquitocidal effect may be due to the toxic impact of plant compounds such as andrographolides, 14-deoxy-11,12-didehydroandrographolides, andrographoan, homoandrographolides and related diterpenoids, 19-β-D glucosides, flavanoids and other compounds. These compounds may jointly or independently contribute to cause larvicidal, pupicidal, adulticidal and ovicidal activity. So the present investigation revealed the possible role of ethanolic extract of Andrographis paniculata Nees in eco-friendly mosquito control programmes.