Ultrafiltration isolation, structure and effects on H1N1-induced acute lung injury of a heteropolysaccharide from Houttuynia cordata

Previous studies showed that crude Houttuynia cordata polysaccharides (CHCP) exerted therapeutic effects on acute lung injury induced by influenza A virus (IAV) in mice. Here, an acidic heteropolysaccharide from H. cordata, named HCPM (Mw, 19.1 kDa), was obtained directly from CHCP using sequential ultrafiltration membrane columns. The backbone of HCPM was consisted of 1, 3, 6-8-Manp, 1, 4-alpha-GalpA, 1, 2-alpha-Rhap, and 1, 2, 4-alpha-Rhap, with main branches of glucan, arabinan, and galactan substituted at C-3 of 1, 3, 6-8-Manp or C-4 of 1, 2, 4-alpha-Rhap. The structural information was further validated by oligosaccharide sequencing analysis using UPLC-ESI-MS. Furthermore, HCPM exhibited a potent anti-complementary activity with CH50 value of 254.1 +/- 7.8 mu g/mL in vitro and significantly attenuated IAV-induced lung and gut injuries in vivo by inhibiting viral replication, reducing inflammatory responses, and suppressing complement overactivation. These results sug-gested that HCPM might be a key H. cordata substance for pulmonary infection treatment.

Automated summary

A study found that an acidic heteropolysaccharide, HCPM, extracted from Houttuynia cordata, has a therapeutic effect on acute lung injury induced by influenza A virus. HCPM can reduce inflammation and complement overactivation by inhibiting viral replication and regulating immune responses, thus alleviating lung and gut injuries.