Eggplant (Solanum spp.) Fruits Dietary Polyphenols Upregulate the Expression of Glucose Transporter Protein in Palmitate-Induced Diabetic Cell Line C2C12

Abstract

Studies utilizing cell-based systems to investigate plant-based diets for diabetes management are gaining attention due to the adverse effects associated with commercially available drugs. However, the molecular mechanisms underlying the anti-diabetic effects of specific plant-derived products remain inadequately explored. The major aim of our study was to elucidate the molecular mechanisms by which bioactive compounds in the fruit of Solanum spp. influence key proteins associated with type 2 diabetes. The expressions of genes such as glucose transporter protein 4 (GLUT4), myocyte enhancer factor-2 (MEF-2A), and nuclear respiratory factor-1 (NRF-1) were investigated in a palmitate-induced C2C12 cell model of type 2 diabetes mellitus. The structures of these proteins were retrieved from the protein database, while bioactive compounds previously identified in Solanum spp. were obtained from PubChem site. Drug-likeness properties of these compounds (ligands) were assessed. The docked protein-ligand complexes were further analyzed using the Protein-Ligand Profiler web server. Our results showed that the studied compounds from Solanum spp. profoundly upregulated GLUT4 expression (9–19-fold increase) in the C2C12 cell line, thus surpassing the effects of the standard anti-diabetic drug metformin. Additionally, activities of antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase were elevated. Molecular docking showed that rutin, an abundant flavonoid from Solanum spp., had the highest binding affinity for the active sites of the target proteins. These findings provide new mechanistic insight into the anti-diabetic effects of Solanum spp., primarily due to its high rutin content, which plays a major role in the plant’s glucose-regulating and antioxidant actions. Our findings underscore the potential use of Solanum spp. as an affordable functional food for managing type 2 diabetes, especially in developing countries with limited resources for purchasing drugs. Although promising, our findings should be further validated by clinical studies.