Comparative Study of Sulfated Polysaccharides From Ulva Lactuca Grown in Tunisia and Morocco: in Vitro Antioxidant Activity and in Vivo Anti-Inflammatory and Anti-Ulcer Effects.

This study presents a comparative analysis of sulfated polysaccharides extracted from Ulva lactuca collected in Tunisia (PSUT) and Morocco (PSUM). FTIR confirmed the presence of sulfate groups, while GC-MS identified diverse sugar components. Both polysaccharides showed strong antioxidant activity, with DPPH and ABTS radical scavenging rates exceeding 50% at the highest concentrations. In a rat model of gastric ulceration, PSUT and PSUM significantly reduced inflammation and lymphocytic infiltration and lowered the activities of 5-lipoxygenase and myeloperoxidase. Treatment also produced clear antioxidant effects, decreasing hydrogen peroxide by 48% and 61% and reducing TBARS by 65% and 71%, respectively. In addition, both polysaccharides inhibited gastric H+/K+-ATPase and pepsin, contributing to notable anti-acidic effects and improved protection of the gastric mucosa. Mucin levels increased by 82% and 100%, while gastric mucus content rose by 32% and 71% for PSUT and PSUM. Overall, PSUM displayed stronger in vivo anti-inflammatory and gastroprotective activities, whereas PSUT showed slightly higher in vitro antioxidant capacity. These findings confirm that the geographic origin of U. lactuca influences the structural features of its polysaccharides and their biological effects. Although based on a single animal model and dose, this work offers a solid basis for future mechanistic and clinical investigations.