Abai, MR

6th International Congress of DipterologyLarvicidal Activities of traditional medicinal plant,Portulaca oleracea against Aedes albopictus (Culicidae) andParatanytarsus grimmii (Chironomidae)Konishi, T. (1), S. Kondo (2), N. Uchiyama (1), N. Nakamura (1) & K. Murugan (3)(1) Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, DoshishaWomen’s College of Liberal Arts, Kodo, Kyotanabe 610-0953, Japan(2) Department of Parasitology, School of Medicine, Aichi Medical University, Aichi480-1195, Japan(3) Department of Zoology, Bharathiar University, Coimbatore 641 046, Tamil Nadu,IndiaWe are searching for the target-specific insecticidal constituents oftraditional medicinal plants for the purpose of the prevention ofphysiological resistance and of the environmental contaminationprevention by use of synthetic pesticides. We found some traditionalmedicinal plants showing the selective larvicidal activities against Aedesalbopictus (Diptera: Culicidae) and Paratanytarsus grimmii (Diptera:Chironomidae). 1)The larvicidal activities of the extract of Portulaca oleracea(Portulacaceae) against Ae. albopictus and P. grimmii were examined.Methanol extract showed highly mortalities at a concentration of 1000µg/ml against the larvae of Ae. albopictus within 24hrs. But it did notentirely show lethal effects against the larvae of P. grimmii at sameconcentration. Methanol extract partitioned with four organic solvents(hexane, chloroform, ethyl acetate and n-butanol) and water. Chloroform,ethyl acetate and n-butanol-soluble fractions showed lower mortalitiesagainst Ae. albopictus and P. grimmii. However, hexane-soluble fractionshowed high selective toxicity against the larvae of both species at 1000µg/ml. Hexane-soluble fraction was provided seven fractions (Fr.1-7) bychromatography. Fractions 2 and 5 showed significant mortalities (61.9%and 100%) against the larvae of Ae. albopictus within 48hrs at 500 µg/ml.A fraction 5 also exhibited 56.5% mortality at 50µg/ml against Ae.albopictus, but this fraction showed no mortality at 500 µg/ml against P.grimmii. This suggests that fraction 5 contains the constituents which141