Osteoporosis is a significant health adversity worldwide. We isolated a neutral polysaccharide, MOP-D2N1, from salt-steamed Morinda officinalis How rhizomes, and investigated its structural and anti-osteoporotic activity. MOP-D2N1 composed Ara, Rha, Gal, and Glc, with 95.8 % purity and a molecular weight of 97.902 kDa. The primary structure of MOP-D2N1 consisted mainly of →3,6)-β-D-Galp-(1→, →2,4)-α-L-Rhap-(1→, →2)-α-L-Rhap-(1→, →4)-β-D-Galp-(1→ with minor →4)-β-D-Glcp-(1→ components. The side chains consisted of α-L-Araf-(1→6)-β-D-Galp-(1→ linked to O-4 of →2)-α-L-Rhap-(1→, and α-L-Araf-(1→5)-α-L-Araf-(1→ was linked to O-6 of →3,6)-α-D-Galp-(1→. Administering MOP-D2N1 for nine weeks to dexamethasone-induced osteoporotic mice (n = 10) notably increased cortical bone thickness, mineralized bone area, and osteoblast number, alongside a reduction in osteoclast number on the cortical bone surface. The oxidative stress pathway was implicated in boosting osteogenic activity and restoration of bone quality. Hence, MOP-D2N1 may serve as a potential therapeutic agent for osteoporosis.
