Larvicidal Activity of Spondias purpurea (Sineguelas) Leaf and Hylocereus costaricensis (Dragon Fruit) Stem Extracts Against Aedes aegypti

The study determined the larvicidal activity of the different concentrations of Spondias purpurea and Hylocereus costaricensis extracts by measuring percent mortality in Aedes aegypti larvae, a primary vector of dengue and other arboviral diseases. The hypothesis proposed that combining both extracts would yield greater larvicidal activity due to potential synergistic interactions. Ethanolic extraction was used to isolate a wide array of phytochemicals. Third- to fourth-instar larvae were exposed to the extracts using WHO standard bioassay methods, and mortality was recorded over a six-hour period. Phytochemical screening revealed active compounds such as alkaloids, saponins, flavonoids, tannins, phenolics, and glycosides. Results showed that the 100% concentrations of both individual extracts had high larvicidal activity, while their 100:100% combination exhibited mortality comparable to 1% Malathion, the positive control. Statistical analysis confirmed significant differences between treatments and control groups (p<0.05), though post hoc tests were not conducted. The novelty of this study lies in the combined use of native Philippine plant extracts as a natural larvicide-an approach not previously reported. The larvicidal effects may be attributed to multiple phytochemical mechanisms, including neurotoxicity, membrane disruption, and enzyme inhibition. The findings highlight the potential of these plant extracts, particularly in combination, as eco-friendly alternatives to synthetic larvicides. Further research is recommended to evaluate their environmental safety, determine LD₅₀ values, assess long-term efficacy, and test performance in real breeding habitats.