Structural characterization of sulfated arabinans extracted from Cladophora glomerata Kützing and their macrophage activation

The crude and fractionated polysaccharides (F 1 and F 2 ) mostly consisted of carbohydrates (62.8–74.5%) with various amounts of proteins (9.00–17.3%) and sulfates (16.5–23.5%), including different levels of arabinose (41.7–54.4%), galactose (13.5–39.0%), glucose (0.80–10.6%), xylose (6.84–13.4%), and rhamnose (0.20–2.83%).

Based on the size exclusion chromatography (SEC) profiles, the crude and fractions mainly contained one peak with shoulders having molecular weight ( M w ) ranges of 358–1,501 × 10 3 . The F 1 fraction stimulated RAW264.7 cells to produce considerable amounts of nitric oxide and cytokines compared to the crude and F 2 fraction. The backbone of the most potent immunostimulating fraction (F 1 ) was α-(1→4)-L-arabinopyranoside with galactose and xylose residues as branches at O-2 position, and sulfates mainly at O-2 position as well.