Abstract

Introduction: Type 2 diabetes mellitus (T2DM) is frequently associated with dyslipidemia, which corresponds to the increase in the triglycerides and fatty acid concentrations in tissues, such as the skeletal muscle. The use of herbal medicines as Uncaria tomentosa (Ut) has been proposed as an auxiliary treatment for patients with T2DM. In this study, it was evaluated the effect of Ut and its compounds on the reactive oxygen species (ROS) production and in the expression of genes present in the insulin signaling pathway of skeletal muscle cells, exposed to the free fatty acid palmitate (PA), which consists a central event involved in T2DM pathogenesis. Methods: Cells were cultured in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% fetal bovine serum (FBS), at 37°C humidified atmosphere and 5% CO2. The cells were incubated with PA in different concentrations, in the presence or absence of 250 μg/ml Ut aqueous extract, for 2, 6 or 24 h. After these periods, oxidative stress was evaluated by fluorescence spectroscopy and the gene expression by quantitative polymerase chain reaction (q-PCR) in real-time. Results: The treatment of cells with Ut aqueous extract, for 6 h, followed by exposure to 500 μM PA, caused 38% less ROS formation than those incubated with only PA. Although, the gene expression of IRS1 was three times more in cells treated with Ut than those incubated with 500 μM PA. Conclusion: The Ut extract promoted an increase in cell viability and gene expression of proteins involved in insulin signaling pathway, reduced cell death and attenuated ROS formation in cultures incubated with 500 μM PA, protecting cells from the fatty acid lipotoxicity.