The study evaluated the chemical composition, molecular weight, and antioxidant activity of ulvan extracted from Ulva papenfussii and Ulva lactuca. The results revealed distinct differences in the monosaccharide composition, sulfate content, and uronic acid levels between ulvans from both species, with ulvan from U. papenfussii exhibiting higher levels of iduronic acid and sulfate (16.39 ± 0.45 %w/w and 28.46 + 3.63 %w/w). Ulvan was fractionated using anion exchange chromatography (DEAE) based o