Structural Characterization and Anti-Inflammatory Activity of a Bioactive Polysaccharide from Cistanche deserticola

A bioactive polysaccharide (CDP-D1) was isolated from the bulbs of Cistanche deserticola and purified by DEAE anion-exchange chromatography, yielding a purity of 95.5% and a recovery rate of 33.1%. It exhibits an irregular amorphous structure, with a porous and loose surface, and displays distinct shear-thinning behavior. Its molecular weight (MW) is 142.52 kDa, and its polydispersity index (Mw/Mn) is 1.77, confirming its heterogeneity. Gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analysis identified it as a heteropolysaccharide. Functional studies indicate that CDP-D1 mediates a protective effect against lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. CDP-D1 restored LPS-induced decreases in cell viability to near-normal levels and suppressed pro-inflammatory signaling by downregulating TLR4 mRNA, key cytokines (IL-1, IL-6, TNF-α), and their cascade amplification. Metabolomic analysis (PLS-DA) validated the reliability of the model and identified 420 metabolites. LPS induced metabolic suppression, whereas CDP-D1 reversed this trend. Key pathways regulated by CDP-D1 include glutathione metabolism and amino acid/nucleoside/purine metabolism, partially restoring metabolic homeostasis. These findings provide preliminary evidence that CDP-D1 modulates inflammatory responses in LPS-stimulated macrophages, potentially through regulation of oxidative stress and metabolic reprogramming, and warrant further investigation into its molecular mechanism of action.