Journal of Biology and Nature

The global paradigm for suppressing mosquito populations has relied almost exclusively on the application of synthetic chemical insecticides, including organophosphates, organochlorines, carbamates, and synthetic pyrethroids. This study evaluated the phytochemical composition and larvicidal activity of aqueous, ethanol, and isopropanol leaf extracts of Vitex negundo against fourth-instar larvae of Aedes aegypti under laboratory conditions. Leaf powder was extracted by cold maceration for 72 hours using water, ethanol, and isopropanol at a 1:10 (w/v) ratio. The crude extracts were qualitatively screened for major phytochemical groups, including alkaloids, flavonoids, phenols, saponins, tannins, and terpenoids. Larvicidal activity was assessed by exposing batches of 50 larvae to 1,000 µg/mL of each extract, and mortality was recorded at 12, 24, and 48 hours across three independent replicates. A DMSO vehicle control was maintained in parallel. The ethanol extract showed the broadest phytochemical profile, with detectable alkaloids, flavonoids, phenols, tannins, and terpenoids. The isopropanol extract contained flavonoids, phenols, tannins, terpenoids, and saponins, whereas the aqueous extract showed a more limited profile. Larval mortality increased with exposure time in all treated groups. At 48 hours, the ethanol extract produced the highest mortality (68.00% ± 4.62%), followed by the isopropanol extract (52.00% ± 6.43%) and the aqueous extract (16.67% ± 0.67%). No mortality was observed in the control group. Dose-response testing of the ethanol extract showed increasing mortality from 100 to 750 µg/mL, with an estimated LC50 of 520.0 µg/mL and LC90 of 845.0 µg/mL at 48 hours. These findings indicate that ethanol leaf extract of V. negundo has measurable larvicidal activity against A. aegypti larvae under laboratory conditions.