A Potential Functional Food-Based Neuroprotective Strategy Using Mulberry Leaf Extract and Trolox Against H₂O₂-Induced Oxidative Stress in SH-SY5Y Cells

This study investigated the synergistic potential of mulberry leaf extract and Trolox against hydrogen peroxide (H₂O₂)-induced oxidative stress in SH-SY5Y cells. Cells were treated with the combination for 24 h prior to exposure to 200 µM H₂O₂. Cell viability was assessed using the MTT assay, while oxidative status was evaluated through measurements of intracellular reactive oxygen species (ROS), malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Sirtuin 1 (SIRT1) and apoptosis-related proteins, including p53, cyclic AMP response element-binding protein (CREB), Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2), were determined by Western blot analysis. The combination treatment markedly upregulated SIRT1 expression, which was associated with increased CREB and Bcl-2 expression alongside reduced p53 and Bax levels. Increased SIRT1 expression was also accompanied by significant reductions in ROS and MDA levels and restoration of antioxidant enzyme activities. Collectively, these effects contributed to attenuation of oxidative stress and apoptosis, resulting in improved cell viability. These findings may support the formulation as a promising functional food-based strategy against oxidative stress-induced neuronal damage. However, these results are based on an in vitro SH-SY5Y cell model and represent preliminary evidence, warranting further in vivo and clinical studies to confirm their translational potential.