Structural elucidation and osteogenic activity of a novel heteropolysaccharide from Alhagi pseudalhagi

Alhagi pseudalhagi, commonly known as camel thorn, is used as an indigenous medicinal plant in China. The present study was designed to elucidate the structure of a novel polysaccharide, APP90-2, isolated from Alhagi pseudalhagi and evaluate its osteogenic activity. A homogeneous polysaccharide (APP90-2) was obtained from A. pseudalhagi via DEAE-52 and Sephacryl S-100 columns, with a molecular weight of 5.9 kDa. Monosaccharide, GC-MS, and NMR analyses showed that APP90-2 consisted of α-l-Rhap-(1→, →3)-α-l-Araf-(1→, →5)-α-l-Araf-(1→, →4)-β-d-Xylp-(1→, α-d-Glcp-(1→, →3,5)-α-l-Araf-(1→, →4)-β-d-GlcAp-(1→, →4)-3-OAc-α-d-Glcp-(1→, →3)-α-d-Galp-(1→, →3)-β-d-GalAp-(1→, →4)-α-d-Galp-(1→, →6)-α-d-Manp-(1→, →4,6)-β-d-Galp-(1→, and →3,6)-β-d-Glcp-(1→ with relative molar ratios of 4.1:1.8:6.1:6.7:1.7:1.0:1.5:2.7:2.4:1.1:2.3:2.6:1.4:2.0. Morphological analyses revealed that APP90-2 interacted with Congo-red and had an obvious honeycomb structure. Additionally, APP90-2 significantly promoted proliferation, differentiation, and mineralization of MC3T3-E1 cells, indicating that APP90-2 exhibited pronounced osteogenic activity. Therefore, our findings suggest that A. pseudalhagi may be used as an alternative medicine or health supplement for the prevention and treatment of osteoporosis.