Structural characterization and α-glycosidase inhibitory activity of a novel polysaccharide fraction from Aconitum coreanum.

α-Glycosidase is an essential target for the management of postprandial serum glucose in diabetic patients. Therefore, the interest has been growing in the screening of α-glycosidase inhibitor from natural resource. In the present study, the structure and α-glycosidase inhibitory activity of a polysaccharide (named as ACPP-1) from Aconitum coreanum were investigated. Based on the results from high performance gel permeation chromatography, GC-MS and 1D/2D nuclear magnetic resonance spectroscopy, ACPP-1 was a highly-linear polysaccharide with a molecular weight of 34.0 kD and containing over 90 % of glucose. It was composed of (1→4)-α-d-Glcp and α-Araf. ACPP-1 exhibited a dose-dependent inhibitory eff ;ect against α-glycosidase activity in vitro and the IC50 value was ∼0.8 mg/mL. In oral starch tolerance test, treatment with ACPP-1 (800 mg/kg) significantly improved the starch tolerance in mice. Taken together, this study provided a potential intervention and management for postprandial hyperglycemia by the polysaccharide fraction from A. coreanum.

Bupleurum chinense polysaccharide inhibit adhesion of human melanoma cells via blocking ß1 integrin function.

Adhesive interaction contributes toward tumor metastasis and the transmembrane glycoprotein receptor, integrin has been recognized to mediate the adhesion to extracellular matrix thus upregulating tumor metastasis. In the current study, we evaluated the anti-adhesive mechanisms of a water-soluble polysaccharide (BCP) extracted from Bupleurum chinense. BCP inhibited integrin-mediated adhesion of human melanoma A375 cells to fibronectin but had no effects on nonspecific adhesion to poly-l-lysine. BCP also reduced ß1 integrin ligand affinity for GST-FNIII9-10 proteins. The adhesion-dependent formation of F-actin stress fiber and focal adhesion (FA) was also inhibited by BCP treatment. The inhibition of BCP on integrin-mediated signaling is probably through inhibiting phosphorylation of focal adhesion kinase (FAK) and paxillin. Collectively, our current findings indicated that BCP may be a potential therapy for melanoma metastasis due to its inhibitory effects on integrin function.

Macrophage activation induced by the polysaccharides isolated from the roots of Sanguisorba officinalis.

CONTEXT: Macrophage, involved at all stages of immune response, is an important component of the host defense system. Polysaccharides exist almost ubiquitously in medical plants and most of them possess immunomodulation and macrophage activation properties. OBJECTIVE: This study elucidates the effects on macrophage activation and molecular mechanism induced by the polysaccharides (SOPs) from the roots of Sanguisorba officinalis Linne (Rosaceae). MATERIALS AND METHODS: Polysaccharides (SOPs) from the roots of S. officinalis were obtained by water extraction and ethanol precipitation. Physicochemical characterization of SOPs was analyzed by phenol-sulfuric acid, m-hydroxydiphenyl, Bradford method, and gas chromatography. Phagocytic capacity of RAW 264.7 macrophages incubated with SOPs (25 and 100 µg/ml) was determined by the aseptic neutral red method. Macrophages were incubated with SOPs (25 and 100 µg/ml), and the TNF-α and NO the secretion were measured using ELISA kit and Griess reagent, respectively. In addition, TNF-α and iNOS transcripts were evaluated by semi-quantitative RT-PCR, and NF-κB signaling activation was detected by Western blot assay. RESULTS: SOPs enhanced the phagocytosis capacity of macrophages to aseptic neutral red solution and increased TNF-α and NO secretion. The amounts of TNF-α and iNOS transcript were increased significantly at the mRNA level when macrophages were exposed to SOPs. Meanwhile, the stimulation of macrophages by SOPs induced phosphorylation of p65 at serine 536 and a marked decrease of IκB expression. DISCUSSION AND CONCLUSION: These results suggested that SOPs exhibited significant macrophage activation properties through NF-κB signaling pathway and could be considered as a new immunopotentiator.

Inhibition of inflammatory injure by polysaccharides from Bupleurum chinense through antagonizing P-selectin.

P-selectin-mediated adhesion between endothelium and neutrophils is a crucial process leading to acute inflammatory injure. Thus, P-selectin has been considered as promising target for therapeutics of acute inflammatory-related diseases. In the present study, the water-soluble polysaccharides (BCPs) were isolated from Bupleurum chinense, and we evaluated their therapeutical effects on acute inflammatory injure and antagonistic function against P-selectin-mediated neutrophil adhesion. Our results showed that BCPs significantly impaired the leukocyte infiltration and relieve lung injury in LPS-induced acute pneumonia model. BCPs significantly blocked the binding of P-selectin to neutrophils and inhibited P-selectin-mediated neutrophils rolling along CHO-P cell monolayer. The result from in vitro protein binding assay showed a direct evidence indicating that BCPs-treatment significantly eliminated the interaction between rhP-Fc and its physiological ligand PSGL-1 at protein level. Together, these results provide a novel therapeutical strategy for amelioration of inflammation-related disease processes by polysaccharides from B. chinense.

Two new proanthocyanidins from the leaves of Garcinia multiflora.

Two new proanthocyanidins, namely garcinianin A (1) and garcinianin B (2), together with two known compounds (3 and 4) were isolated from the leaves of Garcinia multiflora Champ. Their structures were elucidated on the basis of spectroscopic analysis.