Bioatividade do extrato de piperina (Piper nigrum L.) sobre Atta sexdens Forel, 1908 (Hymenoptera: Formicidae)

Abstract

This study aimed to evaluate the insecticidal potential of a piperine extract (Piper nigrum L.) against workers of Atta sexdens Forel, 1908 (Hymenoptera: Formicidae), a species widely distributed in tropical regions and recognized as a pest with high agricultural and forestry impact. Black pepper of the Bragantina cultivar was used as the raw material for piperine extraction, employing the Soxhlet method with 99.8% ethanol, followed by purification and isolation of the compound. Two topical toxicity bioassays were conducted using different extract concentrations (1, 2.5%, and 5%), with 92% ethanol (first assay) and 70% ethanol (second assay) as controls. In the first assay, total mortality of the workers was observed within 72 hours, suggesting toxicity attributable to 92% ethanol rather than to the piperine extract. In the second assay, using 70% ethanol, mortality after 264 hours of observation was 30% in the control group and 46.6, 56.6, and 40% in the treatments with piperine at 1, 2.5, and 5%, respectively. Despite indications of bioactivity, the results were limited by the low solubility of piperine in the solvent used, which prevented confirmation of its efficacy as a control agent. Thus, it is concluded that further assays employing alternative solubilization methodologies are necessary to validate the use of piperine as a potential bioinsecticide in agroecological management programs.