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 230 kDa 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.