An-qiang Zhang

Antioxidant activity of polysaccharide extracted from Pleurotus eryngii using response surface methodology.

Ultrasonic technology was applied for polysaccharide extraction from the fruiting bodies of P. Eryngii, and response surface methodology (RSM) was used to optimize the effects of processing parameters on polysaccharide extraction yield. Three independent variables were extraction time (A), ultrasonic power (B) and the ratio of solvent to sample (C), respectively. Results showed that the maximum yield of P. eryngii polysaccharide (PEPS) was obtained at an optimum condition: extraction time 39 min, ultrasonic power 517 W, the ratio of water to material 19 mL/g, and the PEPS extracting yield reached 34.3% under the conditions. PEPS were precipitated into three crude polysaccharides, PEPS30, PEPS60 and PEPS80, by different concentrations of ethanol respectively. The antioxidant activities of these three polysaccharides were evaluated. The results showed that PEPS80 had the best reducing power, DPPH radical scavenging ability and oxygen radical scavenging ability followed by PEPS60 and PEPS30.

Structural elucidation of a novel mannogalactan isolated from the fruiting bodies of Pleurotus geesteranus

A novel water-soluble polysaccharide named PGPB-1, with a molecular weight of 1.3 × 10(4)Da as determined by high-performance liquid chromatography (HPLC), was isolated from the fruiting bodies of Pleurotus geesteranus by boiling water as well as DEAE-Sepharose Fast Flow and High-Resolution Sephacryl S-300. On the bases of compositional analysis, methylation analysis and NMR spectroscopy ((1)H NMR, (13)C NMR, 2D-COSY, TOCSY, HMQC, HMBC and NOESY spectra) analysis, the structural elucidation of PGPB-1 consisted of a α-D-(1→6)-galactopyranan and a α-D-3-O-Me-D-galactosyl unit backbone with a α-D-Mannosyl unit on O-2 of the 2,6-di-O-substituted-D-galactosyl units. The repeating unit of the polysaccharide was established as: [formula in text] PGPB-1 also contains a minor proportion of 6-linked-D-Glcp.

Purification, chemical characterization, and antioxidant activity of a polysaccharide from the fruiting bodies of sanghuang mushroom (Phellinus baumii Pilát)

A purified water-soluble polysaccharide was isolated from the fruiting bodies of sanghuang mushroom (Phellinus baumii Pilát) using hot water extraction, DEAE Sepharose Fast Flow anion exchange and High-Resolution Sephacryl S-1000 gel-filtration chromatography. The purified polysaccharide was a complex β-d-glucan, with a molecular mass of 230 kDa. Fourier-transform infrared (FT-IR), methylation analysis, and NMR spectroscopy of sanghuang mushroom polysaccharide (PBF3) indicated that the polysaccharide contained (1→3)-β-d-, (1→4)-β-d-, and branched (1→3,6)-β-d-glucopyranosyl residues. On the basis of hydroxyl radical assay, superoxide radical assay, and DPPH radical assay, its antioxidant activities were investigated. PBF3 had significant effect on scavenging hydroxyl radicals, an equivalent inhibiting ability to vitamin C on superoxide radical, and a little lower scavenging activity on DPPH radical than vitamin C, and should be explored as a novel potential antioxidant.

Structural investigation of a novel heteropolysaccharide from the fruiting bodies of Boletus edulis

A novel water-soluble heteropolysaccharide, BEPF1, was isolated from the fruiting bodies of Boletus edulis with boiling water extraction and purified by Sephacryl S-300, with a molecular weight of 1.08×10(4)Da. Sugar composition of BEPF1 showed that it was composed of l-fucose, d-mannose, d-glucose and d-galactose in the ratio of 0.21:0.23:1.17:1.00. Methylation analysis together with (1)H, (13)C and 2D NMR spectroscopy established that BEPF1 was consisted of α-d-(1→6)-galactopyranan backbone with a terminal of α-l-fucosyl unit on O-2 of the 2-d-(2→6)-galactosyl units, β-d-(1→6)-4-O-Me-glucopyranan and β-d-(1→6)-glucopyranan backbone with a terminal β-d-glucosyl unit and it also contained a minor of 2,6-β-d-Mannopyranan residues.

Structural elucidation of a novel heteropolysaccharide from the fruiting bodies of Pleurotus eryngii.

A novel water-soluble heteropolysaccharide (PEPS1), with a molecular weight of 1.88×10(4) Da as determined by high performance liquid chromatography (HPLC), specifically size exclusion chromatography, was isolated from the fruiting bodies of Pleurotus eryngii by hot water extraction and further purification by DEAE Sepharose Fast Flow and Sephacryl S-300 and S-100 High-Resolution chromatography. By use of compositional analysis, methylation analysis, together with (1)H, (13)C NMR and 2D NMR spectroscopy including COSY, TOCSY, HMQC, HMBC and NOESY experiments, the PEPS1 was identified as a heteropolysaccharide that consists of a α-D-(1→6)-Galactopyranan backbone with a β-D-Mannosyl unit on O-2 of the 2,6-di-O-substituted-D-Galactosyl units, α-(1→6)-3-O-Me-D-Galactopyranan backbone with a terminal α-3-O-Me-D-Galactosyl unit and it also contained a minor 2,3,6-α-D-Galatopyranan units and 4-β-D-Mannopyranan residues.

Structure and chain conformation of a neutral polysaccharide from sclerotia of Polyporus umbellatus

A water-soluble heteropolysaccharide (PUP60W-1) was purified from the hot water extract of sclerotia of P. umbellatus by chromatography with DEAE Sepharose Fast Flow and Sephacryl S200 High-Resolution. The primary structure of PUP60W-1 was elucidated by GC, GC-MS and NMR. PUP60W-1 was identified as a highly branched polysaccharide composed of fucose, glucose and galactose in a ratio of 1.0:0.9:13.3. The main repeating unit was identified as α-(1→6)-d-galactopyranan backbone with substitution of terminal α-galactopyranosyl residues at O-2 for two out of every three main chain galactose residues. Its chain conformation was studied by atom force microscopy and size exclusion chromatography coupled with multiple detectors. The results revealed that PUP60W-1 had a molecular weight of 2.47×104Da with a polydispersity index of 1.04, and existed in water as compact sphere structures which could be disrupted into smaller spherical chain blocks after dispersion with sodium dodecyl sulfate.

Structure elucidation and antioxidant activity of a novel polysaccharide from Polyporus umbellatus sclerotia.

A novel water-soluble polysaccharide PUP60S2, with a molecular weight of 1.44×10(4)Da, was obtained from the sclerotia of Polyporus umbellatus by hot water extraction, ethanol precipitation, anion-exchange and size-exclusion chromatography. PUP60S2 was a polysaccharide comprised of about 22.3% glucuronic acid. Monosaccharide composition analysis showed that PUP60S2 was only comprised of glucose and glucuronic acid. Reduction of carboxyl groups, sugar analysis, methylation analysis, together with one and two dimension NMR spectra disclosed that the backbone of PUP60S2 consisted of (1→6)-β-d-glucopyranosyl, every second of which was substituted at O-3 by side chains consisting of terminal β-d-Glcp, (1→3)-β-d-Glcp, (1→3)-β-d-GlcpA, (1→4)-β-d-Glcp and (1→4)-β-d-GlcpA units. The antioxidant activity assay in vitro showed that PUP60S2 exerted a significant scavenging effect on DPPH, hydroxyl radical and superoxide radical in a dose-dependent manner.

Structural elucidation of a novel water-soluble fructan isolated from Wedelia prostrata

A new heteropolysaccharide, WPP60A, with a molecular weight of 2.4 kDa, was isolated from Wedelia prostrata by hot water extraction, and purified by DEAE Sepharose fast flow and Sephacryl S-200 high-resolution chromatography. Compositional analysis, and methylation analysis, combined with (1)H, (13)C NMR spectroscopy including 2D NMR (COSY, TOCSY, HMQC, NOESY, and HMBC) experiments demonstrated that WPP60A was composed of primarily fructose and low glucose. Results indicated that this new heteropolysaccharide consists of a repeating unit with the following structure: [Formula: see text].