Evaluation of bioactivity of aqueous extracts of Bougainvillea spectabilis, Saraca asoca, and Chenopodium album against immature forms of Aedes aegypti

摘要

Background: Increasing rate of vector transmission of dengue has led to the exponential rise in the mortality and morbidity scales in the past five years. There are various natural and synthetic chemical agents available commercially as potent larvicides, but they are either highly toxic, difficult to obtain, have a high manufacturing cost, or show cross-resistance, hence do not suffice as ideal larvicides. The objective was to screen aqueous extracts of Bougainuillea spectabilis (B. spectabilis), Saraca asoca (S.asoca), and Chenopodium album (C. album) for larvicidal activity against Aedes aegypti (A. aegypti). Methods: The larvae were exposed to increasing concentrations of aqueous extracts of B. spectabilis, S. asoca, and C. album under controlled laboratory environment. The mortality was checked after 24 hours, results were statistically analyzed, and LC50 and LC90 were determined. Results: B. spectabilis and S. asoca were found effective as larvicides against A. aegypti with LC50 values of 0.22% and 0.26%, respectively. Conclusion: The aqueous extracts of B. spectabilis and S. asoca are efficient larvicides against A. aegypti and can be used as effective, accessible, and eco-friendly control options for management of A. aegypti, the vector of dengue/chikungunya.