Inhibitory effect of polysaccharides isolated from Angelica sinensis on hepcidin expression

Ethnopharmacological relevanceAngelica sinensis polysaccharide is an important bioactive component of Angelica sinensis (Oliv.) Diels that has been used in traditional Chinese medicine for treating gynecological disorders and anemia.Aim of the studyPrevious study indicated that Angelica sinensis polysaccharide (ASP) may promote plasma iron levels by suppressing the expression of hepcidin, a negative regulator of body iron metabolism, in the liver. The present study aims to clarify the inhibitory effect of ASP on hepcidin expression as well as the involved mechanisms.Materials and MethodsASP (1 g/kg) or vehicle (normal saline) was intragastrically administrated to rats everyday for 14 d. Intraperitoneal injections of recombinant human erythropoietin (rhEPO, 2000 U/kg) were given to positive control group. Erythropoietin and hepcidin levels in serum at different time points were determined by enzyme-linked immunosorbent assay. Western blot was used to investigate the expression of 6 pertinent signal proteins in liver.ResultsASP significantly reduced hepcidin expression by inhibiting the expression of signal transducer and activator of transcription 3/5 (STAT3/5) and mothers against decapentaplegic protein 4 (SMAD4) in liver and stimulating the secretion of erythropoietin, which further down-regulated hepcidin by repressing CCAAT/enhancer-binding protein α (C/EBPα), SMAD4, and the phosphorylation process of STAT3/5.ConclusionsASP can suppress the expression of hepcidin in normal rats, and may be used in the treatments of hepcidin-induced diseases.