Both the hexane and ethanol extracts of P. americana showed promising potential as an alternative source of a more sustainable, non-toxic and environmentally friendly solution for the control of dengue vector, Ae. aegypti.

Recent studies regarding the harmful effects of synthetic larvicides initiated the need to investigate for unconventional measures that are environmentally safe and target-specific against Aedes aegypti larvae. Thus, the main objectives of the study are to evaluate the larvicidal toxicity of the solvent fractions of Anacardium occidentale shell wastes against the third and fourth instar larvae of A. aegypti and to compare the results with the commercial larvicide product. The shell wastes were extracted with 95% EtOH followed by polarity-based fractionation. The fractions were tested for larvicidal activity according to the World Health Organization bioassay method. These were then characterized by quantitative thin-layer chromatographic (TLC) fingerprinting. The hexane fraction gave the strongest activity among the fractions with an LC50 of 4.01 mg/L and LC90 of 11.29 mg/L highly comparable to the commercial larvicide, which exhibited an LC50 of 1.71 mg/L and LC90 of 8.41 mg/L. The dichloromethane fraction exhibited 9.70 mg/L LC50 and 18.44 mg/L LC90. The remarkable toxicity effects exhibited by these fractions indicate their potential to provide core structures from which sustainable and environmentally safe plant-based larvicidal agents can be synthesized.

Dengue and zika continue to be the most rapidly emerging febrile diseases and pose a negative impact on social and economic activity of the country. Despite of recent innovation in dengue vaccine, eradication of the vector, Aedes aegypti, is still the best way to inhibit dengue and zika outbreaks. In this study, we evaluated the larvicidal and ovicidal activities and characterized the shell wastes of Anacardium occidentale including its stability for a period of two (2) years. The shell wastes were extracted using 95% EtOH and n-hexane and were bio-assayed for larvicidal and ovicidal activities against A. aegypti following the WHO standard bioassay method. The mortality was observed 24 and 48 hours after treatment and data were subjected to probit analysis to determine lethal concentrations (LC 50 and LC 90 ). The ethanol extract was characterized by thin-layer chromatography (TLC) and phytochemical analysis.