Avaliação de parâmetros bioquímicos e toxicológicos das cascas de Ceiba speciosa (A. St.-Hill) Ravenna em ratos

Abstract

Ceiba speciosa (MALVACEAE) is a tree species that occurs in the central-west, southeastern and southern regions of Brazil, being used mainly for ornamental purposes. The bark tea of the species is widely consumed in the northwest region of the State of Rio Grande do Sul for reducing blood cholesterol levels and preventing their increase. Although the plant is widely used in the region, there are no reports in the scientific literature about their pharmacological actions or toxicity data, making it impossible to evaluate the risk/benefit in therapeutic employment of C. speciosa. Thus, the objectives of this work were to verify if the treatment with aqueous extract of the barks of Ceiba speciosa for 14 days is able to prevent the increase of blood cholesterol levels in rats with hypercholesterolemia induced by Tyloxapol, evaluate the influence of aqueous extract administration (28 days) on normal rats and carry out preliminary investigation of the toxicity of the species. This work was approved by the Commission of Ethics in Animal Experimentation (CEEA) of Universidade Federal do Pelotas (CEEA 5747-2015). The aqueous extract was obtained by decoction in distilled water and subsequent lyophilization, obtaining the lyophilized aqueous extract of C. speciosa (EALCs). Firstly, Wistar rats were divided into 4 groups: negative control treated with saline solution (CS), positive control (CP), group treated with EALCs 200mg/kg, and group treated with EALCs 400mg/kg. The animals in the treated groups received C. speciosa lyophilized aqueous extract (200mg/kg and 400mg/kg) by gavage for 14 days. Subsequently, hypercholesterolemia was induced with a single intraperitoneal administration of Tyloxapol in the treated and positive control groups. All animals were euthanized 48 hours after administration of Tyloxapol, and blood was collected for biochemical analyzes (cholesterol, glucose, triglycerides, urea, and creatinine). In the second part of the study, the rats were divided into three groups: negative control group (CS), group treated with EALCs 200mg/kg and group treated with 400mg/kg. The negative control group received saline solution and the treated groups received the EALCs by gavage for 28 days. The blood collected after the euthanasia of the animals was used to determine blood levels of cholesterol and glucose. The liver and kidney were removed and used for preliminary evaluation of the species toxicity (mutagenicity and genotoxicity). The results obtained in this study were analyzed through the statistical software Graph Pad Prism 5.0. The lyophilized aqueous extract of C. speciosa was not able to prevent the increase of blood levels of cholesterol, but the dose of 200mg/kg significantly reduced the glucose levels in rats with Tyloxapolinduced hypercholesterolemia when compared to the positive control. The extract of the species did not alter the blood levels of cholesterol in normal rats, but significantly increased the glucose levels in the two doses tested. C. speciosa did not promote mutagenic changes both in hepatic and renal tissue. However, the extract EALCs 400mg/kg induced DNA damage in the hepatic tissue, suggesting genotoxic action. The results of this work do not confirm nor discard the hypocholesterolemic activity of C. speciosa, but provide important information regarding the safety of the population that regularly consumes the species.