Efeito do extrato etanólico de Lippia dulcis Trev. Sobre a glicemia em jejum e fatores de risco associados em ratos Wistar diabéticos

Abstract

Diabetes Mellitus (DM) is a metabolic disease characterized by failure in the production or deficiency of insulin in the body, the hormone responsible for glucose metabolism. Lippia dulcis Trev. is a shrubby plant from the Verbenaceae family, known as sweet mint or sweet grass in the North of Brazil. It is traditionally used to treat DM. Considering the empirical use of this plant and the search for natural alternatives to control diabetes, this research aimed to evaluate the hypoglycemic activity of the Ethanol Extract from the dried aerial parts of Lippia dulcis Trev. (EELD) in Wistar rats induced type 2 DM by alloxan. The extract was obtained by Soxhlet and the chemical composition of EELD was analyzed using High Performance Liquid Chromatography – HPLC. The compounds were identified using the literature. The acute oral toxicity of the extract was evaluated using 6 female Wistar rats, three of which received EELD at 2,000 mg/kg, and three were used as controls. For the hypoglycemic effect experiments, 20 male Wistar rats were used, divided into four groups (n=5), Negative Control (Group I), Positive Control (Group II), EELD 100 mg/Kg (Group III) and EELD 500 mg /Kg (Group IV), the latter two being those that received EELD concentrations of 100 mg/kg and 500 mg/kg, respectively. Treatments were administered by gavage for 21 days. Every 7 days, the animals' weight and fasting blood glucose levels were evaluated. After 21 days of treatment, the animals' blood was collected for biochemical analysis (TGP, TGO, urea and creatinine). The result of the EELD chemical analysis indicated the presence of phenolic and phenylpropanoid compounds. The ethanolic extract of L. dulcis showed no signs of toxicity in animals that received 2,000 mg/kg. When evaluating the hypoglycemic effect of EELD, there was a statistical difference between the treated groups, where Groups II, III and IV differed from Group I (Negative Control). The animals treated with both concentrations of L. dulcis extract maintained an average blood glucose level during the 21 days of treatment, showing a slight reduction in this parameter on the 21st day. Regarding weight status, there was a statistical difference in weight gain between the evaluation days, demonstrating that the loss in the groups was gradual from the first week of experiments. It was observed that animals treated with EELD at 100 mg/Kg and 500 mg/Kg showed an average weight gain on the 21st day. In the biochemical evaluation, the levels of TGO, TGP and urea showed no statistical difference between the groups, unlike serum creatinine levels, which were considered within normal limits only in animals treated with the extracts. These results indicate that EELD may be associated with the improvement of certain problems of chronic hyperglycemia. Therefore, it is necessary to complement these results with additional studies, in order to contribute to the knowledge of the plant's therapeutic activities. Furthermore, it is essential to conduct a more detailed phytochemical analysis of EELD, enabling the quantification of L. dulcis phenolic compounds, expanding the data provided in this research.