Comparative Analysis of Polyphenol-Rich Extracts from Hamamelis virginiana Leaves and Bark: ROS Scavenging and Anti-Inflammatory Effects on Skin Cells

<i>Hamamelis virginiana</i> (witch hazel) is traditionally used in dermatology for its antibacterial and anti-inflammatory effects. However, the number of studies on its chemical composition and potentials in skin protection remains limited. This study aimed to investigate the qualitative and quantitative composition of polyphenolic compounds in the leaves and bark of the plant, as well as to explore their antioxidant, anti-inflammatory, and extracellular matrix (ECM)-protective activities in skin-relevant cell models. Human dermal fibroblasts and keratinocytes were exposed to oxidative and inflammatory stimuli and pretreated with leaf and bark extracts. ROS levels, antioxidant enzyme activity (SOD, GPx, CAT), pro-inflammatory cytokines (IL-6, IL-1β, TNF-α), and inhibition of collagenase, hyaluronidase, and elastase were assessed. Both extracts strongly reduced ROS levels, enhanced SOD activity, and significantly decreased pro-inflammatory cytokines. Bark extract also exhibited potent inhibitory activity against collagenase and elastase. UPLC-DAD-MS analysis revealed that both plant parts contained high levels of tannins; however, the leaf extract showed a more diverse composition, including more complex tannin forms and a significant amount of flavonoids from the quercetin and kaempferol class. In conclusion, <i>H. virginiana</i> leaf and bark extracts demonstrate multifunctional antioxidant and anti-inflammatory properties, supporting their potential use in cosmeceuticals and dermatological formulations targeting skin aging and inflammation.