Leaf and Flower Extracts from the Dwarf Elder (): Toxicity and Repellence against Cosmopolitan Mosquito-Borne Diseases Vectors.

As there has been no scientific evidence of the bioactivity of (Adoxaceae) extracts against insects, we chemically characterized leaves and flowers extracted in methanol and water. The crude extracts, phenolic compounds, and amino acids isolated were tested as larvicides against the fourth-instar larvae of and (Diptera: Culicidae). To understand their mode of action, we evaluated the in vitro acetylcholinesterase (AChE) inhibitor effect of the crude extracts on the two mosquito larvae through a colorimetric method. Furthermore, the deterrent effect of the crude extracts against ovipositing females was assessed in the open field. Twelve phenylpropanoids and fourteen amino acids were detected in the extracts, with a prevalence of hydroxycinnamic acids and nonaromatic amino acids. The most toxic compound to larvae after 24 h was gallic acid, followed by the crude leaf extract; on , it was the crude flower extract. The AChE test showed higher inhibition on both mosquito species exerted by the leaf extract if compared to the flower extract, and it also deterred oviposition by females starting from the third day. The results indicated that vegetal extracts could effectively help in the integrated vector management of mosquitoes.