Phytochemical constituents and larvicidal efficacy of Calopogonium mucunoides leaf and Chrysophyllum albidum seed extracts against the Aedes aegypti larvae
The larvicidal efficacy of Calopogonium mucunoides leaf and Chrysophyllum albidum seed extract against 2nd and 3rd larval instars of Aedes aegypti was investigated in an acute bioassay. The larvicidal bioassay was done in triplicate of ten laboratory-reared larvae of Ae. aegypti at four different concentrations (250, 500, 750, and 1000 ppm) with a simultaneous control at 24 h, 48 h, and 72 h of exposure. Phytochemical screening revealed the presence of alkaloids, terpenoids, tannins, and saponins in the extracts. The larvicidal bioassay of C. mucunoides leaf and C. albidum seed extracts varied significantly with concentration and exposure time (p < 0.05). Lethal concentrations (LC50 and LC90) for C. mucunoides were 2.935 and 7.608 ppm, 2.096 and 6.302 ppm, and 1.626 and 5.866 ppm for 24 h, 48 h, and 72 h (2nd instar larvae), and 2.923 and 11.067 ppm, 2.096 and 9.686 ppm, and 2.033 and 6.946 ppm (3rd instar larvae), while C. albidum had values of 3.231 and 7.393 ppm, 2.755 and 6.123 ppm, and 2.278 and 4.584 ppm at 24 h, 48 h, and 72 h (2nd instar larvae), and 3.731 and 7.021 ppm at 24 h, 2.843 and 4.526 ppm at 48 h, and 2.774 and 4.202 ppm at 72 h (3rd instar larvae). The chloroform fraction of C. mucunoides partitioning gave 100% mortality for 3rd instar larvae, with its leaf extract being more potent than C. albidum seed extract. The potential bioactive compound extant in these plants could become a substitute for conventional insecticides and synthetic pesticides and ought to be further explored for control of mosquito larvae.