Characterization of arabinogalactan-rich mucilage from Cereus triangularis cladodes

•High yield polysaccharides extraction from Cereus triangularis cladodes.•Arabinogalactan from Cereus triangularis cladodes with Araf/Galp=0.67 ratio.•High molecular weight mucilage from Cereus triangularis cladodes.•Antioxidant properties of arabinogalactan. Cereus triangularis (Cactaceae) is a cactus used in food decoction as a traditional medicine in the North region of Madagascar to reduce stomach ache and intestinal diseases. Hydrocolloids were sequentially extracted from its cladodes with a yield of 24% (240mg/g based on dried cladodes powder). Structural analyses has revealed that this polysaccharide with a molecular mass of 8430,000g/mol was mainly composed of a galactan backbone of a (1→4) linked β-d-Galp residues probably substituted at position 3 by l-arabinofuranosyl residues. In vitro antioxidant activity of this arabinogalactan-rich fraction was detected and quantified by radical DPPH scavenging, hydroxyl radical scavenging, radical anion superoxide scavenging and reducing power method.