Extraction, characterization, antioxidation and anti-inflammatory activity of polysaccharides from Bupleurum chinense based on different molecular weights

Bupleurum chinense polysaccharide has a wide range of biological activities. In this study, Bupleurum chinense polysaccharides (BPs), BPs-1 (30 kDa) and BPs-2 (2000 kDa) with different molecular weights were isolated and prepared by ultrafiltration interception method. The structures of BPs, BPs-1 and BPs-2 were characterised by monosaccharide composition, GC-MS, Fourier transform infra-red spectroscopy and nuclear magnetic resonance. The results showed that the monosaccharide composition of BPs with different molecular weights was the same, but the proportion was different. BPs, BPs-1 and BPs-2 were mainly connected by Glup-(1→,→2,4)-Araf-(1→,→6)-Glup-(1→). The anti-inflammatory activity screening experiment in vitro showed that BPs-1 had stronger anti-inflammatory effect. Antioxidant experiments showed that BPs-2 had high free radical scavenging activity. This study laid a foundation for elucidating the fine structure and structure-activity relationship of Bupleurum chinense polysaccharides and will promote the product development of Bupleurum chinense polysaccharides.