Dendrobium officinale polysaccharide promotes M1 polarization of TAMs to inhibit tumor growth by targeting TLR2.

Promoting M1 polarization of tumor-associated macrophages (TAMs) is an effective pathway for malignant tumor therapy. In this study, we aimed to demonstrate whether homogeneous Dendrobium officinale polysaccharide (DOP) could promote M1 polarization of TAMs to inhibit tumor growth, and how it promoted. Results exhibited that DOP could inhibit the tumor growth and promote the M1 polarization of TAMs in tumor-bearing mice. Macrophage depletion and replenishment experiment clearly proved that the inhibitory effect of DOP on tumor growth is dependent on promoting M1 polarization of TAMs. Moreover, we found that DOP could reach tumor microenvironment (TME) and directly bind to TAMs to promote its M1 polarization via targeting toll-like receptor 2 (TLR2) after oral administration. These results clarified that DOP could remarkably inhibit the tumor growth of tumor-bearing mice via directly targeting the TLR2 of TAMs to promote its M1 polarization.

Structural characterization and hepatoprotective activity of a galactoglucan from Poria cocos.

To find the polysaccharide with hepatoprotective activity from Poria cocos and clarify its structure, a galactoglucan (PCP-1C) with a molecular weight of 17 kDa was purified from the Poria cocos sclerotium by column chromatography and activity evaluation in the present work. It was composed of galactose, glucose, mannose, and fucose in a molar percentage of 43.5: 24.4: 17.4: 14.6. Structural characterization showed that PCP-1C has a backbone consisted of 1,6-α-D-Galp, which branches composed of 1,3-ß-D-Glcp, 1,4-ß-D-Glcp, 1,6-ß-D-Glcp, T-ß-D-Glcp, T-α-D-Manp, T-α-L-Fucp and 1,3-α-L-Fucp. In vivo experiments found that PCP-1C can apparently improve the damage of liver tissue in CCl4-treated mice and relieve oxidative stress and inflammation. PCP-1C also reduced the expression of CAR and CYP2E1 in the liver. These findings indicated strong hepatoprotective effect of PCP-1C, which was attributed to the reduction of CCl4 metabolism via inhibiting the CAR/CYP2E1 signal pathway.

Physicochemical, morpho-structural, and biological characterization of polysaccharides from three Polygonatum spp.

Polygonatum species, including P. cyrtonema, P. kingianum, and P. sibiricum, are edible plants with medicinal purposes, which have long been consumed as food due to their high nutritional value. In this study, polysaccharides from P. cyrtonema (PCP), P. kingianum (PKP) and P. sibiricum (PSP) were obtained, and their physicochemical properties and in vitro biological activities were investigated. Our results demonstrated that PCP, PKP, and PSP consist of major fructose and minor glucose, galacturonic acid, and galactose in different molar ratios with the molecular weights of 8.5 × 103 Da, 8.7 × 103 Da, and 1.0 × 104 Da, respectively. The three polysaccharides had triple-helical structures with ß-d-Fruf, α-d-Glcp, α-d-Galp sugar residues, and an O-acetyl group, and displayed peak-shaped structures in different sizes. They also exhibited thermal, shear-thinning behavior and viscoelastic properties, and PCP presented the highest viscoelasticity. Moreover, they exerted strong free radical-scavenging abilities, and significant reducing capacity. PCP was the strongest, followed by PSP and then PKP. They significantly promoted the polarization of the M1 macrophage, with the effect of PCP ranking first. All three had similar effects on GLP-1 secretion. It is, therefore, necessary to identify the various roles of these three Polygonatum polysaccharides as functional agents based on their bioactivities and physicochemical properties.

Polysaccharides from Dendrobium huoshanense stems alleviates lung inflammation in cigarette smoke-induced mice.

The present work investigated the inhibitory activity of the polysaccharide from cultivated Dendrobium huoshanense (cDHP) on lung inflammation in cigarette smoke (CS)-induced mouse model. cDHP was mainly composed of mannose and glucose in a molar ratio of 1.89: 1.00, and had a backbone with linkages of 1,4-Manp, 1,4-Glcp, 1,4,6-Manp and 1-Glcp. Hematoxylin and Eosin (HE) staining and immunohistochemistry analysis showed that cDHP can increase alveolar number, thicken alveolar wall, inhibit pulmonary bulla formation and decrease inflammatory cell infiltration as compared to the model group. ELISA determination revealed that cDHP can inhibit CS-induced enhancement in TNF-α and IL-1ß secretion in serum and lung. These results suggested that cDHP can resist CS-induced lung inflammation. Further, the phosphorylation analysis of p65, IκB, p38 and JNK as well as the DNA binding activity analysis of NF-κB and AP-1 implied that the anti-inflammation function of cDHP is mediated via regulating NF-κB and MAPK signaling.

Digestive behavior of Dendrobium huoshanense polysaccharides in the gastrointestinal tracts of mice.

With fluorescent end-labeling method, a homogenous Dendrobium huoshanense polysaccharide (GXG) that was orally administrated to mice was found to be degraded into a stable fragment (dGXG) in the stomach, where dGXG was propelled into the small intestine and absorbed into the systemic circulation. The residual GXG in the stomach could pass through the gastrointestinal tract and was excreted into faeces with a very slow fermentation in the large intestine. The simulated digestion of GXG indicated that the acidic pH condition in the gastric fluid was responsible for GXG degradation, which was supported by the oral digestion of dGXG. Chemical analysis not only showed a change in the molar ratio of monosaccharide compositions and glycosidic linkage types, but also found the loss of the sugar residue (1→4)-linked Galp after the acid treatment of GXG, suggesting that the cleavage of glycosidic linkage, especially (1→4)-linked Galp linkage, resulted in GXG degradation in the gastrointestinal tract.