Structural characterization and in vivo and in vitro anti-osteoporosis potential of two Psoralea corylifolia L. polysaccharides.

Psoralea corylifolia L. (PCL) has been widely used to improve osteoporosis for thousands of years, whereas the anti-osteoporosis activity of its polysaccharides has not been systematically reported. Here, we firstly proved that PCLP80 crude polysaccharides exhibited significant improvement effects (p < 0.05) about femur bone mineral density, bone trabecula, and muscle function performances including grip strengths, and forced swimming times in glucocorticoid-induced osteoporosis (GIOP) mice. Subsequently, a novel acidic (PCLP80-1) and a neutral (PCLP80-2) polysaccharides were purified from PCLP80 fraction, with molecular weights of 20.07 and 53.39 kDa, respectively. PCLP80-1 was proposed to mainly consist of →3,6)-β-D-Galp-(1→, →6)-β-D-Galp-(1→, β-D-Galp-(1→, →4)-α-D-GalpA-(1→, →3,4)-β-D-Glcp-(1→, and α-L-Araf-(1 → moieties. PCLP80-2 was mainly characterized by →4)-β-D-Manp-(1→, →4,6)-β-D-Manp-(1→, α-D-Manp-(1→, →4)-β-D-Glcp-(1→, α-D-Galp-(1 → together with a small amount of →3,6)-β-D-Galp-(1 → residues. Their advanced structures were further characterized. Moreover, PCLP80-1 and PCLP80-2 both showed obvious anti-osteoporosis activity and improvement of muscle function in GIOP mice. The mechanism about increasing osteoblastogenesis mainly involved in PI3K/AKT/mTOR pathway in MG63 cells, Wnt and Hippo pathways in MC3T3-E1 cells. Taken together, this would benefit to develop high efficacy and low toxicity agents from PCL for the prevention and treatment of osteoporosis.