Structural characterization and anti-inflammatory effects of Angelica pubescens polysaccharide APRP50-2-1 in rheumatoid arthritis.

Throughout the history of traditional Chinese medicine, Angelica pubescens has been extensively employed to treat inflammatory arthritis. However, little is known about the anti-rheumatoid arthritis (RA) effects of A. pubescens polysaccharides. In this study, four crude polysaccharides (APR50, APR70, APR90, and APRB) were isolated from A. pubescens radix, and the rat model of collagen-induced arthritis (CIA) was established to evaluate the anti-RA effects of A. pubescens polysaccharides. A. pubescens polysaccharides could effectively reduce the degree of paw swelling in CIA rats, among which the effect of APR50 was comparable to that of methotrexate. A homogenous polysaccharide APRP50-2-1 was purified from APR50. Structural characterization indicated that APRP50-2-1 was primarily composed of glucose, mannose, galactose, and arabinose. The main skeleton of APRP50-2-1 consisted of →4)-α-D-Glcp-(1→, →6)-α-D-Glcp-(1→, and →6,4)-α-D-Galp-(1→ residues. The branched chains of →4)-α-D-Glcp-(1→ and →3)-β-D-Manp-(1→ were substituted at O-4 of →4,6)-α-D-Galp-(1→. APRP50-2-1 inhibited the proliferation and promoted the apoptosis of MH7A cells by down-regulating the expression of the anti-apoptotic protein B-cell lymphoma-2 (BCL2) and up-regulating the expression of the pro-apoptotic protein BCL2-associated X (BAX). In conclusion, A. pubescens polysaccharides had significant anti-RA effects in rat CIA model, among which APR50 and APRP50-2-1 possessed the promising prospects of ameliorating RA.