Structural Characteristics and Antioxidant Activities of Polysaccharide Extracted from Ulva fasciata Green Seaweed

In this study, the structural characteristics of a polysaccharide extracted from the Ulva fasciata green seaweed were determined using the chemical composition analytical methods combined with IR, MS, and NMR spectra. The results showed that the polysaccharide consists of two major repeating disaccharide units designated as ulvanobiuronic acid 3-sulfate type A (A3s) [→4)-β-D-GlcA-(1 → 4)-α-L-Rha 3S-(1→] and type B (B3s) [→4)-α-LIdoA-(1 → 4)-α-L-Rha 3s(1→]. This kind of polysaccharide exhibited a significant in vitro antioxidant activity. This study demonstrated that the Ulva fasciata green algae can be considered as a source of bioactive ulvan.