Ulvan from Ulva lactuca Promotes Keratinocyte Migration, Adhesion, and Photoprotection Against UVB Damage

Abstract

Ulvan, a sulfated polysaccharide extracted from the sea lettuce, is gaining wider appreciation for its health-promoting and medicinal qualities. In the current study, Ulva lactuca was collected from the coastal site of Monastir, Tunisia. Ulvan was extracted and characterized using Fourier-transform infrared (FTIR) spectroscopy, confirming the presence of characteristic sulfate and carboxyl groups. The antiradical, antioxidant activity, and carbohydrate content were also estimated. The photoprotective effects of ulvan were evaluated in human keratinocyte (HaCaT) cells exposed to UVB radiation. Pre-treatment with ulvan (25 and 50 µg/mL) significantly enhanced cell viability, reduced reactive oxygen species (ROS) production, preserved lysosomal function, and inhibited apoptosis. Additionally, ulvan enhanced cell migration and enhanced adhesion on extracellular matrix proteins, including laminin, collagen I, poly-L-lysine, vitronectin, and fibrinogen, demonstrating its role in maintaining cellular integrity under UVB stress. An enriched-ulvan emulsion was formulated. SPF evaluation suggested limited sunscreen effectiveness. Therefore, the photoprotective effects are mediated via antioxidant and cytoprotective mechanisms. This result support its potential as a natural marine-derived ingredient for functional cosmetic and dermatological products.