Structural characterization and anti-osteoporosis effect of an arabinomannan from Anemarrhena asphodeloides Bge

To discover the polysaccharide with anti-diabetic osteoporosis (DOP) activity and clarify its structure, an ara-binomannan (PAAP-1B) with a molecular weight of 14.0 kDa was isolated from Anemarrhena asphodeloides Bge. using column chromatography. It consists of arabinose, mannose, and galactose in a molar ratio of 6:3:1. PAAP-1B has a backbone composed of 1,5-alpha-Araf, 1,4-8-Manp, and 1,6-8-Galp residues that are branched at C3 of alpha-Araf and 8-Galp residues. The side chains are T-alpha-Araf, T-alpha-Manp, T-8-Galp, and 1,6-8-Galp. PAAP-1B attenuated DOP and reduced ferroptosis in the femurs and tibias of alloxan-induced mice. It also suppressed ferroptosis in advanced glycation end product-induced osteoblasts by decreasing 4-hydroxynonenal, malondialdehyde, mito-chondrial reactive oxidative species levels, and lipid peroxidation, while reversing the downregulation of solute carrier family 7 membrane 11 and glutathione expression.