An inulin-type fructan isolated from Artemisia japonica and its anti-arthritic effects

•A homogeneous polysaccharide (MWP) were isolated and purified from Artemisia japonica.•MWP is a typical inulin type fructan.•MWP can significantly alleviate the severity of collagen induced arthritis in mice. Inulin is a type of polysaccharide with nutritional and functional properties and possesses various bioactivities. In this study, we isolated and purified a water-soluble polysaccharide (MWP) from Artemisia japonica. MWP has a molecular weight of 3.1kDa as calculated by High Performance Gel Permeation Chromatography (HPGPC) and is comprised of fructose and glucose. Methylation analysis, infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectra demonstrated that MWP is a typical inulin-type fructan. Oral administration of MWP (200mg/kg) significantly attenuated the clinical parameters of collagen-induced arthritis (CIA) in DBA/1 mice compared with untreated mice, and a histopathologic analysis indicated less joint damage and inflammatory cell infiltration in mice treated with MWP. The anti-arthritic effects of MWP were associated with reduced serum levels of the interleukins IL-17A and IL-6. These results demonstrate that MWP significantly reduced symptoms in CIA mice and suggest that inulin would be a valuable anti-arthritic agent warranting further investigation.