A novel α-glucan from Glehniae Radix protects against gastric ulcer and modulates complement-coagulation and NF-κB signaling.

Abstract

BACKGROUND: Glehniae Radix is a traditional herb used to nourish yin (i.e., replenish body fluids and benefit the lung and stomach) and support gastric health. Although it is rich in polysaccharides, the contribution of these compounds to gastroprotection remains poorly understood. PURPOSE: This study aimed to evaluate the gastroprotective activity of Glehniae Radix polysaccharides (GLP), investigate the molecular pathways associated with its gastroprotective activity, and purify and structurally characterize homogeneous bioactive polysaccharide components contributing to this activity. STUDY DESIGN: The gastroprotective activity and associated molecular pathways of GLP were investigated using complementary in vivo and in vitro models. GLPE1-F was purified, structurally characterized, and evaluated for its biological activities and associated molecular pathways. METHODS: Pharmacological activities were assessed in an ethanol-induced rat gastric ulcer model, in GES-1 gastric mucosal cells, and in three zebrafish inflammation models (CuSO₄, LPS, tail amputation). Mechanisms were investigated using 4D-DIA proteomics, Western blotting, immunofluorescence, and time-course analysis. A homogeneous polysaccharide (GLPE1-F) was purified by anion-exchange and size-exclusion chromatography and characterized by HPGPC, HPLC, FT-IR, methylation analysis, and NMR. RESULTS: GLP significantly attenuated gastric mucosal hemorrhage and erosion in rats, preserved mucosal barrier integrity, and reduced inflammation and oxidative stress. In GES-1 cells, GLP enhanced cell proliferation while reducing apoptosis and ROS accumulation. GLP also mitigated inflammation in zebrafish models induced by CuSO₄, LPS, and tail amputation. 4D-DIA proteomics identified the complement-coagulation cascade and NF-κB signaling among the pathways affected by GLP treatment. GLP reduced the levels of complement-coagulation factors, including C1QA, MBL2, F12, F2, and C3, in RAW 264.7 macrophages, HepG2 hepatocytes, rat serum, and gastric tissue. NF-κB activation (IκBα/NF-κB phosphorylation and nuclear translocation) and the levels of TNF-α, IL-6, and IL-1β were also decreased following GLP treatment. GLPE1-F (Mw 6.986 kDa) was identified as a novel α-glucan with a backbone of →4)-α-D-Glcp-(1→ and C-6 branches consisting of α-D-Glcp-(1→ and α-D-Glcp-(1→6)-α-D-Glcp-(1→ units. GLPE1-F exhibited gastroprotective activity in rats, cytoprotective activity in GES-1 cells, and anti-inflammatory activity in zebrafish models, and modulated complement-coagulation and NF-κB signaling in rat and cellular experiments. CONCLUSIONS: This study identifies GLPE1-F as one of the bioactive components contributing to the gastroprotective activity of GLP and modulating the complement-coagulation cascade and NF-κB pathway, providing a scientific basis for its further development as a gastroprotective candidate.

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