Executive Summary : | The whole plant of Leucas aspera, leaves of Artocarpus lakoocha Roxb, aerial parts of Cleome viscose were collected from Western Ghats. The plant materials were successively extracted with petroleum ether (PE), chloroform (CH) and alcohol by soxhlet method. The preliminary larvicidal screening, toxicity studies and juvenile hormone mimicking activity of all extracts were carried out as per WHO pesticide evaluation scheme 2005 on late 3rd /early 4th instar larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The extracts were isolated by Flash chromatography by gradient elution technique using petroleum ether 100% and different proportions of petroleum ether. Fractions collected were subjected to larvicidal bioassay. F2 and F8 of L. aspera containing larvicidal activity, was further isolated with petroleum ether 100%. Among the 4 fractions collected, LA/FC1-2/C2/F3-5/02 and LA/C1/F08/03 exhibited larvicidal activity at 24 hrs. F6-8 and F16-17 were effective and subjected to isolation, which yielded 4 fractions and F16-17 was containing single compound. CV/C1/F6-8/C2/F4/03 and CV/C1/F16-17/04 exhibited larvicidal activity with LD50 of 7.592 ppm, 7.348 ppm, 13.212 ppm and 27.010 ppm, 59.316 ppm, 37.281 ppm at 24 hrs. HPTLC profile and characterization of isolated compounds were established. |