Yuxian You

The characterization, selenylation and antidiabetic activity of mycelial polysaccharides from Catathelasma ventricosum

The mycelial polysaccharide from Catathelasma ventricosum (mCVP-1S) was found to be a heteropolysaccharide with an average size of 230kDa composed mainly of β-glucopyranosyl residues. The selenylation of mCVP-1S, performed using an HNO3-Na2SeO3 method, produced a series of selenized mCVP-1Ss (SemCVP-1Ss). Varying the reaction time, temperature and Na2SeO3 dosage altered the yield and selenium content of the SemCVP-1Ss. NMR spectra showed substitution mostly at C-6, and Congo red tests indicated excessive selenylation might destroy the triple-helical structure of SemCVP-1Ss. The antidiabetic activities of SemCVP-1Ss with varying selenium contents (low, middle and high) were tested in streptozotocin-induced diabetic mice. In SemCVP-1Ss with triple-helical structure, increasing selenium content enhanced antidiabetic activity, but damage to the triple-helical structure weakened antidiabetic activity. The ability of SemCVP-1Ss to normalize key biochemical parameters in diabetic mice was greater than that of the polysaccharide from the fruiting body of C. ventricosum.

Structural characterization and antidiabetic activity of a glucopyranose-rich heteropolysaccharide from Catathelasma ventricosum.

Polysaccharides, which are the main bioactive constituents of edible mushrooms, have been shown to have a variety of useful biological activities. In this study, a polysaccharide fraction from the edible mushroom Catathelasma ventricosum was purified using anion exchange and size exclusion chromatographies. The structure of the resulting polysaccharide, named CVP-1S, was characterized on the basis of partial acid hydrolysis, periodic acid oxidation, methylation analysis, gas chromatography-mass spectrometry, Fourier-transform infrared spectroscopy, 1D/2D NMR spectroscopy, scanning electron microscopy, and atomic force spectroscopy. The results showed that CVP-1S is a heteropolysaccharide consisting of glucose (94.2%), galactose (3.51%) and fucose (1.3%) with a molecular weight of 1.5×10(4)Da. Its backbone is mainly linked by (1→6)-β-d-Glcp glycosidic bonds, and branches are attached to the backbone through 1,3-linked glycosidic bonds. CVP-1S was also found to have antioxidant, hypoglycemic, and hypolipidemic activities in the streptozoicin-induced diabetic mouse model. From these results, we conclude that CVP-1S should receive further attention as a potential agent for the treatment and prevention of diabetes.

Nutritional composition of boletus mushrooms from Southwest China and their antihyperglycemic and antioxidant activities.

Thirteen samples representing five species were collected from different provinces of Southwest China, and their chemical composition, antihyperglycemic activity, and antioxidant activity were evaluated. These mushrooms had high crude protein (21.72-30.59g/100g dw) and total carbohydrate (49.18-62.58g/100g dw) contents, but low crude fat contents (1.96-7.87g/100g dw). They also accumulated notable quantities of potassium, zinc, sodium, magnesium and copper from the soil. The potassium content, in particular, was 18.75-39.21 times that found in the soil at the collection site. The natural habitat of these mushrooms, especially the mineral content of the soil, seems to have more influence on the mineral content of these mushrooms than their species. Most of the samples possessed antihyperglycemic and antioxidant activities. Suillellus luridus showed the highest antioxidant activity and antihyperglycemic activities, suggesting that S. luridus shows potential for development as a dietary nutritional supplement.