ABSTRACT:
Dengue fever transmitted by Aedes aegypti mosquitoes remains one of a critical public health challenge in the Philippines and other tropical regions. The increasing resistance to synthetic larvicides calls for the development of sustainable and biodegradable alternatives. This study aimed to formulate effervescent granules from the ethanolic leaf extract of Nauclea orientalis (Bangkal) and evaluate its potential larvicidal efficacy against Aedes aegypti larvae. Three effervescent granule formulations were prepared by wet granulation: F1 (2,000 ppm), F2 (4,000 ppm), and F3 (6,000 ppm), incorporating sodium bicarbonate, tartaric acid, and citric acid as effervescent agents. Larvicidal bioassays followed the World Health Organization protocols using 25 third-instar larvae per trial at concentrations of 0.25 g, 0.50 g, and 1.0 g which are observed at 1, 12, and 24 hours. Results showed concentration-dependent and time-dependent larvicidal activity. At 24 hours, the crude extract achieved 28–56% mortality, while effervescent formulations demonstrated superior efficacy. F1 (52–68%), F2 (64–80%), and F3 (72–92%). Temephos achieved 100% mortality by 12 hours; tap water recorded 0% throughout. One-way ANOVA revealed highly significant differences among treatment groups (F = 24.87, p < 0.001), rejecting the null hypothesis. Tukey’s HSD confirmed that F1, F2, and F3 significantly differed from both controls. This research establishes Bangkal effervescent granules as a viable botanical alternative for integrated vector management, contributing to sustainable dengue control strategies in Philippine contexts.