Bauhinia forficata Link Protects HaCaT Keratinocytes from H2O2-Induced Oxidative Stress and Inflammation via Nrf2/PINK1 and NF-κB Signaling Pathways

Oxidative stress has been directly implicated in the pathogenesis of various skin disorders, making it a promising target for therapeutic intervention. <i>Bauhinia forficata</i> Link (BFL), commonly referred to as "plant insulin," is well known for its antioxidant and antihyperglycemic properties; however, its potential role in skin protection remains unexplored. In this study, we investigated the protective effects of BFL against H₂O₂-induced oxidative stress and inflammation in HaCaT keratinocytes. The major phytochemical constituents of BFL were identified by high-performance liquid chromatography (HPLC). Its antioxidant capacity was evaluated using 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-Diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and superoxide dismutase (SOD). In an H₂O₂-induced oxidative stress model, we assessed intracellular reactive oxygen species (ROS) levels and apoptosis using flow cytometry. Cellular respiration was analyzed using a Seahorse XFp analyzer, while molecular mechanisms were examined by reverse transcription polymerase chain reaction (RT-PCR) and western blotting. Our results demonstrated that BFL significantly reduced intracellular ROS levels and apoptosis, primarily by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/PINK1 pathway, which promoted mitochondrial quality control and redox homeostasis. Additionally, BFL suppressed inflammatory responses by downregulating the nuclear factor-κB (NF-κB) signaling pathway and reducing the secretion of pro-inflammatory cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha (TNF-α). These findings suggest that BFL is a potent antioxidant and anti-inflammatory agent, with potential as an adjunctive therapy for oxidative stress-related skin conditions.