Avaliação da toxicidade do extrato aquoso liofilizado de chapéu-de-couro (Echinodorus grandiflorus) em ratas prenhes

Abstract

In Brazil, there are countless species that are used as phytotherapics, and among them there is E. grandiflorus, an Alismatacea aquatic or semi-aquatic herb, popularly known as chapéu-de-couro, commonly used in folk medicine as diuretic and anti-inflammatory and also in the treatment of kidney diseases, rheumatism, skin conditions and liver disorders. Several studies have confirmed its diuretic, anti-inflammatory and antinociceptive, hypotensive, antihypertensive and vasodilatory, antimicrobial, in vitro trypanocidal, leishmanicidal, antineoplastic, immunosuppressive and hypocholesterolemic pharmacological properties, though its toxicity was not evaluated during pregnancy. Numerous agents can interfere with the female reproductive system functionality and with one or more stages of embryo development, but the drugs, due to the frequency that they are used, are on the list of the most concerning factors. Considering the therapeutic potential of E. grandiflorus and the widespread utilization of its tea with curative purposes by the population and the lack of studies about this herb toxicity during pregnancy, its necessary to evaluate its toxicity and the aim of this study was to evaluate this effect on Wistar rats. During 15 days, vaginal smears were performed to observe the regularity of the estrous cycle. Rats with regular estrous cycle were separated into four experimental groups (n=16): C, control group that received saline solution by gavage, during 15 days, and T-250, T-500 and T-1000 which were treatment groups that received doses of 250, 500 and 1000 mg/kg/day of the extract, respectively, during this same period the vaginal smear was also performed. The rats were mated and the pregnant ones were treated up to the 14th day. On the 15th day they were euthanized by the method of exsanguination under full anesthesia and, then, laparotomyzed for examination, the organs were removed and weighed and the maternal, litter and placenta variables were recorded. Blood tests were made and the plasmatic concentrations of urea, creatinine, cholesterol, triglycerides, alanine transaminase and aspartate transaminase were determined. The liver, kidneys, spleen, ovaries and adrenal glands were removed and weighed. The number of corpora lutea, implants, resorptions, and live and dead fetuses were counted. The liver, the spleen, and the kidneys of pregnant rats were processed for histopathological analysis. There were no detectable signs of maternal toxicity, as measured by piloerection, diarrhea, change in ambulation in the cage and death. A reduction in the proportion of the estrous phases was observed after the treatment in the T-1000 group. In all treatment groups the average number of corpora lutea, implantations and reabsorption per dam was similar, as well as the post-implantation loss rate, the proportion of implantation and reabsorption. There were records of anemia and increased aspartate transaminase in all three treatment groups, in the highest dosage it was registered increase of cholesterol and leukocytosis, and histopathological alterations in the kidneys, liver and spleen of the dams. Taken together, this study data indicate that the administration of lyophilized aqueous extract of E. grandiflorus to pregnant rats at the dosages of 250, 500 and 1000 mg/kg/day, under this experiment conditions, was toxic to the dams, but did not affect the reproductive performance and no external malformation was observed in the fetuses.