Maturation of bone marrow-derived dendritic cells by a novel beta-glucan purified from Paenibacillus polymyxa JB115

We investigated the immunostimulatory effects of a novel beta-glucan purified from Paenibacillus (P.) polymyxa JB115 on bone marrow-derived dendritic cells (DCs), a type of potent antigen-presenting cells. beta-glucan isolated from P. polymyxa JB115 enhanced the viability and induced the maturation of DCs. beta-glucan markedly increased the cytokine production of DCs and surface expression of DC markers. In addition, DCs treated with beta-glucan showed a higher capacity to stimulate allogeneic spleen cell proliferation compared to those treated with medium alone. These results demonstrate the effect of beta-glucan on DC maturation and may increase the use of beta-glucan.

Hypoglycemic activity of polysaccharide fractions containing ß-glucans from extracts of Rhynchelytrum repens (Willd.) C.E. Hubb., Poaceae

ß-Glucans are soluble fibers with physiological functions, such as interference with absorption of sugars and reduction of serum lipid levels. The objective of the present study was to analyze the distribution of ß-glucans in different tissues of the African grass species Rhynchelytrum repens and also to evaluate their hypoglycemic activity. Leaf blades, sheaths, stems, and young leaves of R. repens were submitted to extraction with 4 M KOH. Analysis of the fractions revealed the presence of arabinose, glucose, xylose, and traces of rhamnose and galactose. The presence of ß-glucan in these fractions was confirmed by hydrolyzing the polymers with endo-ß-glucanase from Bacillus subtilis, followed by HPLC analysis of the characteristic oligosaccharides produced. The 4 M KOH fractions from different tissues were subjected to gel permeation chromatography on Sepharose 4B, with separation of polysaccharides with different degrees of polymerization, the highest molecular mass (above 2000 kDa) being found in young leaves. The molecular mass of the leaf blade polymers was similar (250 kDa) to that of maize coleoptile ß-glucan used for comparison. The 4 M KOH fraction injected into rats with streptozotocin-induced diabetes showed hypoglycemic activity, reducing blood sugar to normal levels for approximately 24 h. This performance was better than that obtained with pure ß-glucan from barley, which decreased blood sugar levels for about 4 h. These results suggest that the activity of ß-glucans from R. repens is responsible for the use of this plant extract as a hypoglycemic drug in folk medicine.