Larvicidal effects of Jatropha curcas L. against Anopheles arabiensis (Diptera: Culicidea)

Abstract

Crude and column chromatographic fractions of methanol leaf extract of Jatropha curcas were tested for their larvicidal activities against laboratory reared late third instar larvae of Anopheles arabiensis. Crude methanol leaf extract of J .curcas had similar larvicidal activity to 0.5 ppm Temephos (positive control) at test concentrations ranging from 125 -1000 ppm while column chromatographic fractions (F1 and F2 ) of the crude methanol leaf extract of J.curcas showed similar larvicidal activities to 0.5 ppm Temephos at 62.5 and 125 ppm test concentrations. Column chromatographic fraction three (F3) showed similar larvicidal activity to 0.5 ppm Temephos at 125 ppm test concentration. The LC50 and LC90 values of crude methanol leaf extract of J.curcas were found to be 92.09 and 241.09 ppm, respectively. Toxic activities of column chromatographic fraction one (F1) (LC50=28.65 ppm; LC90 = 49.20 ppm) were nearly equal to that of column chromatographic fraction two [F2] (LC50= 30.40 ppm; LC90 = 49.80 ppm). Least toxicity on the test larvae was observed by column chromatographic fraction three [F3] (LC50 = 80.70 ppm; LC90 = 123.70 ppm). Thus, the larvicidal activity of crude methanol leaf extract was not due to the synergistic effects of its fractions. Further studies are recommended to identify larvicidal active ingredients from the active column chromatographic fractions of crude methanol leaf extract of J. curcas.