Oral Centella asiatica Extract Attenuates UVB-Induced Skin Photoaging via Antioxidant, Anti-Inflammatory, and Extracellular Matrix-Preserving Effects in Hairless Mice

<i>Centella asiatica</i> exhibits antioxidant, anti-inflammatory, and dermal-regenerative activities, yet the in vivo efficacy of an orally administered, dose-standardized extract against ultraviolet B (UVB)-induced photoaging has not been fully elucidated. This study investigated the protective effects of a chemically standardized <i>C. asiatica</i> extract (sCAE; 70 mg/g asiaticoside) in UVB-irradiated Skh:HR-1 hairless mice. Animals received oral sCAE (40 or 80 mg/kg/day) for eight weeks during repeated UVB exposure. Comprehensive assessments-including skin biophysical measurements, histological analysis, ELISA, and gene expression profiling-were performed to characterize dose-dependent responses. sCAE significantly reduced wrinkle formation, transepidermal water loss, malondialdehyde accumulation, and pro-inflammatory cytokines, while enhancing skin hydration, elasticity, antioxidant enzyme activities, and collagen expression. It also restored hyaluronic acid, ceramide, and their biosynthetic genes, and suppressed matrix metalloproteinase-1 and -9. Notably, the higher dose (80 mg/kg) consistently shifted key parameters toward normal levels, demonstrating a clear dose-response effect. These findings provide the first integrative in vivo evidence that orally administered, asiaticoside-standardized <i>C. asiatica</i> extract mitigates UVB-induced photoaging by concurrently improving barrier lipids, extracellular matrix integrity, inflammation, and oxidative stress, supporting its potential as a nutricosmetic agent for skin health.