Polysaccharides from the root tubers of Curcuma wenyujin ameliorate cholestatic liver injury associated with remodeling gut microbiota and restoring bile acid homeostasis.

BACKGROUND: The root tuber of Curcuma wenyujin Y. H. Chen et C. Ling (taxonomically a synonym of the accepted species Curcuma aromatica Salisb.; hereafter C. wenyujin) has been prescribed in Chinese medicine for over a millennium to promote bile flow and alleviate jaundice. While its lipophilic constituents have received considerable attention, the bioactive potential of its water-soluble polysaccharides remains unclear. METHODS: A polysaccharide-enriched fraction (CWP) was isolated from C. wenyujin by hot-water extraction followed by enzymatic starch removal and dialysis. Its structural features were characterized by high performance gel permeation chromatography (HPGPC), high-performance anion-exchange chromatography with a pulsed amperometry detector (HPAEC-PAD), fourier transform infrared (FT-IR), and proton nuclear magnetic resonance (1H NMR). Hepatoprotective effects were evaluated in an α-naphthyl isothiocyanate (ANIT)-induced cholestasis model in mice. Underlying mechanisms were investigated using label-free hepatic proteomics, 16S rRNA gene sequencing, and targeted bile acid profiling by liquid chromatograph mass spectrometer (LC-MS/MS). RESULTS: CWP was characterized as a mannose- and glucose-rich polysaccharide-enriched fraction (average Mw 5.89 kDa; mannose 47.05 mol%, glucose 33.67 mol%) containing both α- and β-glycosidic configurations. Oral administration of CWP significantly reduced serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bile acids (TBA) at both doses tested, and attenuated hepatocyte necrosis and inflammatory infiltration in ANIT-challenged mice. Mechanistically, CWP upregulated bile acid synthesis enzymes (Cyp27a1), efflux transporters (Mrp2/3/4), and detoxification enzymes (Ugt1a1, Cyp3a11), leading to a reduction in hepatotoxic Tauro-β-muricholic acid (T-β-MCA) (from 22.0% to 14.6%) and an increase in cytoprotective ursodeoxycholic acid (UDCA). In the gut, CWP selectively suppressed Enterobacter while enriching Lactobacillus and Adlercreutzia, changes that correlated with the improved bile acid profile. CWP also inhibited hepatic NF-κB activation and neutrophil infiltration, and restored ileal tight-junction proteins (ZO-1, Occludin). CONCLUSION: CWP alleviates ANIT-induced cholestatic liver injury by restoring hepatic bile acid clearance, selectively remodeling the gut microbiota, and suppressing inflammation across the gut-liver axis. These results support further development of CWP as a functional macromolecule for managing cholestatic liver diseases.