Hepatoprotective effect and structural analysis of Hedysarum polysaccharides in vivo and in vitro

The crude Hedysarum polysaccharides (HPS: HPS-50 and HPS-80) obtained from Radix Hedysari exhibited great pharmacological activities in our previous research. This study investigated the effects of HPS on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury (ALI) in mice and LPS-induced injury in LO2 cells, as well as the relationship between structural characteristics and hepatoprotective activities. The in vivo results showed that compared with HPS-80, HPS-50 showed stronger hepatoprotection, which improved histopathological changes to normal levels. HPS-50 significantly decreased the levels of ALT, AST, MPO, and MDA, increased the activities of SOD, CAT, and GSH, and suppressed the LPS/D-GalN-triggered production of TNF-α, IL-1β, and IL-6 (p < .05). The results in vitro showed that HPS-50-P (HPS-50-1, HPS-50-2, and HPS-50-3) purified from HPS-50 played significant protective roles against LPS-induced injury in LO2 cells by reducing cell apoptosis and relieving cell cycle arrest. HPS-50-2 restored the percentage of normal cells from 54.8% to 94.7%, and reduced the S phase cells from 59.40% to 47.05% (p < .01). By analyzing the structure of HPS-50-P, including monosaccharide composition, molecular weight, chain conformation, and surface morphology, we speculated that the best protective effect of HPS-50-2 might be attributed to its beta configuration, highest molecular weight, and high glucose and galactose contents. These findings indicate that HPS-50 might be a promising source of functional foods for the protection and prevention of ALI. PRACTICAL APPLICATIONS: In this study, the protective effect of HPS on ALI was evaluated from multiple perspectives, and HPS-50-2 was screened as a potential active ingredient. This study has two practical applications. First, it provides a new way to improve ALI, and a new option for patients to prevent and treat ALI. Second, this work also complements the pharmacological activity of Radix Hedysari and provides a basis for the development of Radix Hedysari as a functional food.