Phytochemical prospecting and larvicidal bioactivity of janaguba latex (Himatanthus drasticus) mart. Plumel (Apocynaceae) on Aedes aegypti L. (Diptera: Culicidae)
Biolarvicide; Arboviruses; Dengue; Phenolic compounds.
Arboviruses are a public health problem. In Brazil, dengue, chikungunya and zika stand out, transmitted to humans by female Aedes aegypti L mosquitoes. such as damage to the environment, to non-target species and the resistance of this mosquito strains to such products. Thus, the aim of this study was to carry out phytochemical prospecting and evaluate the larvicidal activity of Himatanthus drasticus latex extracts against A. aegypti. The extracts were obtained by macerating 5 g of latex powder concentrated separately in 100 mL of methanol, ethyl acetate and hexane solvents. Concentrations of 100, 200, 300, 400 and 500 ppm of each extract were tested in triplicate with a pyriproxyfen solution as a positive control and distilled water and dimethylsulfoxide as a negative control. The phytochemical prospection of the methanolic extract showed the presence of phenolic compounds, such as anthocyanins, anthocyanidins, catechins, chalcones, aurones, leucoanthocyanidins and condensed tannins. The insecticidal bioactivity was more significant for the methanolic extract. The lethal concentrations (LC) of the 50 and 90% methanolic extract were 190.76 and 464.74 ppm, respectively. After 48 hours of exposure, extracts using methanol, ethyl acetate and hexane in their highest concentrations (500 ppm) caused larval mortality of 100, 73.33 and 66.67%, respectively. These extracts also promoted alterations in the external morphology of the larvae, such as damage to the anal papillae, darkening of the body and reduction in the number of bristles. The methanolic extract showed greater expressiveness for morphological alterations. H. drasticus latex has larvicidal activity against third instar larvae of A. aegypti and is more significant when obtained by maceration in methanol. The methanolic extract of H. drasticus latex contains phenolic compounds with insecticidal activity against A. aegypti larvae.