LARVICIDAL ACTIVITY OF THE β-CARBOLINE ALKALOID HARMINE ISOLATED FROM BANISTERIOPSIS CAAPI AGAINST AEDES AEGYPTI

Abstract

The mosquito Aedes aegypti is the main vector of dengue, Zika, and Chikungunya, diseases that affect millions of people annually in the Americas. Control of this vector relies mainly on the use of synthetic insecticides, which present limitations related to resistance development and environmental impacts. In this context, β-carboline alkaloids present in Banisteriopsis caapi have attracted interest due to their neurotoxic activity in insects, suggesting potential larvicidal applications. This study aimed to isolate harmine from B. caapi leaves and evaluate its larvicidal activity against A. aegypti. Dried leaves were subjected to sequential maceration with hexane, ethyl acetate, and ethanol. Harmine purification was carried out using column chromatography and preparative chromatography. Structural identification was confirmed by high-resolution mass spectrometry (LC-HRMS/MS) and proton and carbon-13 nuclear magnetic resonance spectroscopy (¹H and ¹³C NMR). Larvicidal bioassays were conducted using third-instar A. aegypti larvae following a protocol adapted from the World Health Organization (WHO). The crude extracts showed mortality rates of 3% for the hexane extract, 7% for the ethyl acetate extract, and 67% for the ethanolic extract. Isolated harmine showed a mortality rate of 40%. These results demonstrate the moderate potential of harmine as a natural larvicide against A. aegypti, providing a basis for further investigations and for the development of bioinsecticides derived from Amazonian resources.