Avaliação da atividade antidiabética de extratos das cascas de Salacia impressifolia

Abstract

Considering the impact caused by metabolic changes such as diabetes in society, in the economy and in the lifestyle, it is of relevant importance the search for new therapeutic alternatives as natural products derived from plants. Therefore, this study aimed to evaluate the antidiabetic activity of Salacia impressifolia hexanic extract (EHSI) in experimental models in vitro and in vivo. Firstly, four extracts were obtained by sequential maceration from the most apolar solvent to the most polar. The chemical characterization of the EHSI by NMR evidenced the presence of priestimerin, tingenone, and α-and β-amirine as major compounds. The extracts obtained in sequential maceration (hexanic, ethyl acetate, methanolic, and hydroethanolic) were evaluated in vitro in order to quantificate the content of phenols, flavonoids, antioxidant activity, anti-glycating effect, and possible effects on the inhibition of enzymes involved in the process of absorption of carbohydrates and lipids. Cytotoxic assays and analyses of in vivo antidiabetic effect were carried out with the EHSI. The experiments were performed in vivo with male Balb/c mice. For the acute oral glucose tolerance test it was used non-diabetic mice and for the chronic diabetes assay it was performed diabetes induction through a high fat diet and an intraperitoneal injection of streptozotocin (35mg/kg) for 7 days. Mice with glycemia up to 250 mg/dL were considered diabetic and monitored for 25 days. Blood samples were collected by cardiac puncture on the last day of the experiment before sacrifice in order to dose biochemical markers. The hydroethanolic extract showed the highest content of phenolic compounds and higher antioxidant activity when compared to the hexanic extract. None of the four extracts significantly inhibited α-glucosidase enzyme. However, the HESI showed significant activity against lipase enzyme with IC50 of 13.03 ± 0.7 μg/mL and also inhibited glycation by oxidative and non-oxidative routes with IC50 of 19.6 ± 0.5 and 28.7 ± µg/mL. In the cell viability test the HESI obtained an IC50 of 12.26 μg/mL in the first 72 hours and in the acute toxicity test in vivo it was not able to promote death at the single concentration of 2000 mg/kg. In the in vivo acute effect evaluation assays, the HESI increased glucose uptake at 100 and 50 mg/kg and also decreased glycemia in diabetic animals when treated at the same concentrations for 25 days. In the biochemical analyzes, the HESI promoted a decrease in glucose, insulin, glutamic oxaloacetic transaminase (SGO-T), triglycerides and increased release of creatinine. In conclusion, the hexanic extract tested in the present study presents a great antiglycant potential in vitro and hypoglycemic in vivo, which corroborates the popular use in Amazonian folk medicine. The data obtained were important for the biological characterization of this extract and the possible application as herbal medicine for the treatment of diabetes.