ISOLATION AND CHARACTERIZATION OF LARVICIDAL COMPONENTS AGAINST MOSQUITO LARVAE ( AEDES AEGYPTI LINN.) FROM CALODENDRUM CAPENSE THUNB

Abstract

Chromatographic analysis of air-dried root barks and seeds of Calodendrum capense Thunb led to the isolation of calodendrolide ( 1 ), limonin ( 2 ) and limonin diosphenol ( 3 ) whose structures were elucidated using physical and spectroscopic techniques. The compounds and the crude extract were then tested against mosquito 2 nd instar larvae of the species Aedes aegypti Linn senso stricto , a yellow fever vector at concentrations of 25, 50, 75, and 100 ppm. Calodendrolide ( 1 ) was the most toxic as it killed all the larvae even at the lower concentration of 25 ppm. In addition, concentrations of 15, 10, 5 and 1 ppm of this compound retained moderate efficacy. Calodendrolide ( 1 ), C. capense root bark crude, limonin ( 2 ), and limonin diosphenol ( 3 ) had LC 50 values of 13.1, 29.2, 71.6 and 217.1 ppm, respectively. KEY WORDS : Aedes aegypti , Limonoids, Calodendrum capense , 2 nd instar larvae, Limonin, Limonin diosphenol Bull. Chem. Soc. Ethiop. 2005, 19(1), 145-148.