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Recently, Dendrobium officinale polysaccharide (DOP), a typical acetylated glucomannan, has been widely applied in functional foods owing to its excellent bioactivity. However, the insufficiency of studies on in vivo process severely limits the further utilization of DOP. The aim of this study was to systematically investigate the gastrointestinal digestive behaviour of DOP after oral administration by labelling it with two fluorescein aminopyrene-1,3,6-trisulfonic acids, trisodium salt (APTS) and cyanine 7.5 (Cy7.5). Combining the results of NIR imaging and HPGPC, we found that DOP was poorly absorbed directly in the prototype form; instead, DOP moved with the intestinal contents to the distal part of the intestine, where Bacteroides aggregated for a prolonged time and was metabolized to oligosaccharide-like substances. In contrast, the digestive degradation of DOP in pseudo-sterile mice with a targeted clearance of Bacteroides significantly weakened, which provided the basis and direction for the subsequent search for more specific metabolic pathways of DOP in vivo .

Angelica sinensis polysaccharide (ASP), one of the major active ingredients isolated from the roots of Angelica sinensis (Oliv.) Diels, possesses numerous bioactivities. The aim of the present study was to explore the mechanisms of ASP-mediated hypoglycemic effects in type 2 diabetic BALB/c mice induced by multiple low-dose streptozotocin (STZ) injections plus a long-term high-fat diet (HFD) feeding. The potential mechanism explicating the hepatoprotective effect was also considered. Specifically, serum and hepatic biochemical parameters were determined, as well as the key proteins involved in glucose metabolism and apoptosis. The multiple low-dose STZ injection plus HFD treatment induced significant hyperglycemia, hyperlipidemia and marked liver injury. Our results showed that ASP had beneficial effects in preventing hyperglycemia, stimulating insulin secretion, promoting hepatic glycogen synthesis, regulating adipokine release, reducing liver fat accumulation, and attenuating liver injury. Moreover, mechanistic studies illustrated that ASP could upregulate the expression of PPARγ and liver insulin signaling proteins, including IRS-2, PI3K, Akt, p-Akt and GLUT2, increase anti-apoptotic protein Bcl-2, decrease pro-apoptotic protein Bax expressions, and protect the mice against hepatic damage. These findings revealed the potential mechanisms of ASP-mediated therapeutic effects in diabetic mice. It suggested that ASP might be used in prescriptions or functional foods for the prevention or treatment of diabetes and liver diseases.

A crude polysaccharide was obtained by water extraction and ethanol precipitation from the root of Angelica sinensis (AS) to investigate its suppressive effect on hepcidin expression in rats with iron deficiency anemia (IDA). In this study, we showed that the Angelica sinensis polysaccharide (ASP) was mainly composed of arabinose, glucose and galactose in a molar ratio of 1 : 2.5 : 7.5, with the molecular weight of 72 900 Da and the sugar content of 95.1%. ASP markedly decreased hepcidin expression by suppressing the expression of JAK1/2, phospho-JAK1/2, phospho-SMAD1/5/8, phospho-ERK1/2, and promoting the expression of SMAD7 in the liver. These findings suggest that ASP can prevent the janus-kinase (JAK), son of mother against decapentaplegic (SMAD) and extracellular signal-regulated kinase (ERK) pathways to down-regulate hepcidin expression in IDA rats, and may be useful for the treatments of diseases induced by hepcidin over-expression.