Orally administered Gentiana dahurica arabinogalacturonan alleviates CCl₄-induced acute liver injury in mice by reaching liver and kidney tissue

Gentiana dahurica Fisch. (Qinjiao), a traditional medicine used for "damp-heat" ailments, contains polysaccharides whose in vivo fate and mechanistic contribution remain unclear. This study investigated the hepatoprotective effects and systemic behavior of a structurally defined arabinogalacturonan (GDP) which was isolated from G. dahurica . Oral administration of GDP significantly alleviated CCl₄-induced acute liver injury in mice by reducing serum biochemical indices (alanine aminotransferase and aspartate aminotransferase et al.), and three pro-inflammatory cytokines. It also restored hepatic antioxidant enzymes (superoxide dismutase, reduced glutathione, catalase et al.) and improved histopathology. Furthermore, fluorescein isothiocyanate labeling of GDP (FGDP) was developed to track GDP in vivo. In vivo imaging revealed specific FGDP accumulation in the liver and kidneys, follow by fecal excretion. Pharmacokinetic analysis demonstrated rapid absorption (peak time ~1 h) and prolonged residence (mean residence time ~ 24.7 h). This current research provides direct evidence that bioactive G. dahurica polysaccharide targets key organs and correlates with its hepatoprotective mechanisms. It also established a robust fluorescence-labeling strategy for complex plant polysaccharide pharmacokinetics. • GDP showed hepatoprotective effect against CCl₄- induced liver injury. • The FITC-labeled method revealed that GDP accumulated in the liver and kidney. • Pharmacokinetics revealed GDP was excreted mainly via the gastrointestinal tract.