Avaliação da toxicidade dérmica do acetilcarvacrol em ratos Wistar por meio de análises hematológicas, bioquímicas e histológicas

Abstract

Ticks are ectoparasites of great medical and veterinary importance, mainly due to the fact that they transmit a variety of pathogenic microorganisms. Currently, the control of these parasites is carried out, for the most part, through the application of synthetic acaricides. However, the prolonged and indiscriminate use of these substances has resulted in the selection of resistant tick strains. For this reason, in recent years, investigations into products of plant origin, such as essential oils and their active ingredients with acaricidal activity, have intensified. Carvacrol, a phenolic monoterpene found in essential oils of plants of the Lamiaceae family, has recognized insecticidal, acaricidal and repellent effects. Its acetylation is performed as an attempt to obtain a derivative compound with a better pharmacological profile and less toxicity to non-target organisms. Thus, the aim of this study was to evaluate the dermal toxicity with repeated doses of acetylcarvacrol in Wistar rats in order to investigate the potential risks of its use in mammals. For this, 2,5 mL of the product were applied daily through the skin, in a previously shaved dorsal area, at different concentrations (26, 52 and 104μL/mL) for 21 days. The control group was treated with vehicle alone (5% DMSO). At the end of the treatment period, the animals were anesthetized and euthanized by cardiac puncture and then dissected to collect samples of the liver and the portion of the skin where the substance was applied. The rats developed cumulative irritant contact dermatitis at the site of product application and significant microscopic changes in this region of the skin. Elevated serum levels of urea and hepatic ALT transaminase were also detected. The histological changes observed in the liver of the animals corroborate the elevation of the serum levels of the ALT enzyme, which indicates mild and reversible liver damage. The results indicate that the dermal application of acetylcarvacrol in the experimental conditions described here provoked signs of local and systemic toxicity.