Potential of the vegetable species mandevilla moricandiana (Apocynaceae) to combat larvae of the mosquito Aedes aegypti

Abstract

According to the World Health Organization, 50 to 100 million cases of dengue occur annually worldwide. In parallel, other disease occur through the same Aedes aegypti vector, such as yellow fever, chikungunya and zika. Chemical vector control in Brazil has selected populations of resistant mosquitoes, causing environmental pollution and toxicity to non-target organisms. Vegetables, in turn, have developed strategies to ensure their survival against attack by insects, biosynthesizing insecticidal substances that can therefore be an alternative for the development of environmentally safe and biodegradable larvicides. The objectives of the work are based on the phytochemical study and on the evaluation of the larvicidal activity of the ethanol extract and subfractions of the underground system of the vegetable species Mandevilla moricandiana. The crude extract showed an interesting larvicidal activity, causing mortality of 100% of the larvae at a concentration of 500 ppm (LC50 43.88 ppm). The biofractionation of the M. moricandiana extract generated an increase in biological activity for the low-polarity fractions, such as the dichloromethane (LC50 9.745 ppm) and hexane (LC50 27.42 ppm) fractions, which showed, through GC-MS analysis, terpenoids and steroids as major constituents, and alsothe presence of cardenolides, confirmed by reactions of identification of the lactonic ring.