Roasted and green coffee extracts show antioxidant and cytotoxic activity in myoblast and endothelial cell lines in a cell specific manner

Coffee is one of the most highly consumed beverages with potential beneficial health implications, however its molecular mechanism of action has not been completely elucidated yet. To that cause, the polyphenolic composition of different coffee extracts (from Light, Medium and Dark roasts as well as green beans) was examined by UHPLC-HRMS analysis, indicating chlorogenic acids isomers as the main constituents. In the following step, the toxicity of the extracts was tested in myoblasts and endothelial cells and differential toxicity of green and roasted samples was displayed as the myoblasts were more sensitive to green coffee extracts, in contrast to the endothelial cells. Subsequently, biologically relevant, non-cytotoxic extract concentrations were administered to explore their potential effect on cell redox status using flow cytometry and spectrophotometric assays. The results indicated that all coffee extracts improved cell redox status, however differences were observed between the two different cell lines tested, implying that coffee compounds display cell- and tissue-specificity. Glutathione levels were increased in almost all cases up to 70%, while the roasting degree affected the free radical scavenging potential of the extracts and their ability to protect from macromolecular oxidation as exhibited by the differences in ROS, CARB and TBARS levels, especially in the myoblasts.