ABSTRACT
Arabinogalactans (AGs) are plant heteropolysaccharides with complex structures occasionally attached to proteins (AGPs). AGs in cell matrix of different parts of plant are freely available or chemically bound to pectin rhamnogalactan. Type I with predominantly ß-d-(1 â 4)-galactan and type II with ß-d-(1 â 3) and/or (1 â 6)-galactan structural backbones construct the two main groups of AGs. In the current review, the chemical structure of AGs is firstly discussed focusing on non-traditional plant sources and not including well known industrial gums. After that, processes for their extraction and purification are considered and finally their techno-functional and biological properties are highlighted. The role of AG structure and function on health advantages such as anti-tumor, antioxidant, anti-ulcer- anti-diabetic and other activites and also the immunomodulatory effects on in-vivo model systems are overviewed.
Subject(s)
Galactans , PectinsABSTRACT
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% (240 mg/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 â 4) linked ß-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.
