Kjellmaniella crassifolia for the Prevention of Ultraviolet B-Induced Oxidative Stress in HaCaT Keratinocytes.

Ultraviolet B (UVB) radiation induces oxidative stress, contributing to skin damage and elevating the risk of chronic skin disorders. In response to growing interest in natural alternatives to synthetic compounds, this study evaluated the photoprotective effects of Kjellmaniella crassifolia ethanol extract (KCE) in UVB-exposed HaCaT keratinocytes. The cytotoxicity/cytoprotective activity of KCE was assessed using MTT, and DCF-DA assays to measure cell viability and intracellular reactive oxygen species (ROS), respectively. Apoptotic cell death was examined through nuclear staining, Annexin V/PI assays, and mitochondrial membrane potential analysis via JC-1 staining. Western blot results indicated that KCE suppressed the mitochondrial-mediated apoptotic pathway, reduced phosphorylation of MAPK and NF-κB, and activated the Nrf2/HO-1 antioxidant signaling pathway. Overall, these findings demonstrate that KCE effectively attenuates UVB-induced oxidative stress and apoptosis, highlighting its potential as a natural bioactive ingredient for skin protection in cosmeceutical applications.