Wenbing Yao

Characterization and antioxidant activity of two low-molecular-weight polysaccharides purified from the fruiting bodies of Ganoderma lucidum

Two low-molecular-weight polysaccharides, GLP(L)1 and GLP(L)2, purified from a crude Ganoderma lucidum polysaccharide preparation GLPP were investigated for their physicochemical properties, structure characterization and antioxidant activities. The results indicated that GLP(L)1 was a glucan with an average molecular weight of 5.2kDa, while GLP(L)2 was composed of glucose, galactose and mannose in a ratio of 29:1.8:1.0 with the average molecular weight of 15.4kDa. GLP(L)1 and GLP(L)2 had similar structure characteristic which contained linkages such as -->3)-Glcp-(1-->, -->4)-Glcp-(1-->, -->6)-Glcp-(1-->, -->3,6)-Glcp-(1-->, and -->4,6)-Glcp-(1--> in the percentage ratio of 21.9:20.3:23.7:24.0:3.7 and 23.0:34.6:7.0:14.1:3.0 in the backbone or branches, respectively. Antioxidant results showed that both GLP(L)1 and GLP(L)2 exhibited antioxidant activities while GLP(L)1 was more effective in free radicals scavenging and Fe(2+) chelating. Low-molecular-weight polysaccharide seems to play an important role in the exploration of natural antioxidants in food industry and pharmaceuticals.

Characterization and hypoglycemic effect of a polysaccharide extracted from the fruit of Lycium barbarum L.

Diabetes mellitus is a group of complicated metabolic disorders characterized by high blood glucose level and inappropriate insulin secreting capacity due to decreased glucose metabolism and pancreatic β cell mass or dysfunction of β cells. Thus, improving glucose metabolism and preserving β cell mass and function might be useful for the treatment of diabetes. In this study, a novel acidic polysaccharide LBP-s-1 extracted from Lycium barbarum L. was obtained by purification using macroporous resin and ion-exchanged column. Monosaccharide composition analysis indicated that LBP-s-1 was comprised of rhamnose, arabinose, xylose, mannose, glucose, galactose, galacturonic acid in the molar ratio of 1.00:8.34:1.25:1.26:1.91:7.05:15.28. The preliminary structure features of LBP-s-1 were investigated by FT-IR, (1)H NMR and (13)C NMR. In vitro and in vivo hypoglycemic experiments showed that LBP-s-1 had significant hypoglycemic effects and insulin-sensitizing activity through increasing glucose metabolism and insulin secretion and promoting pancreatic β cell proliferation. Preliminary mechanisms were also elucidated.

Aqueous extract of the Chinese medicine, Danggui‐Shaoyao‐San, inhibits apoptosis in hydrogen peroxide‐induced PC12 cells by preventing cytochrome c release and inactivating of caspase cascade

Danggui‐Shaoyao‐San (DSS), a traditional Chinese medicine used for centuries for the enhancement of womens health, has been shown to display therapeutic efficacy on senile dementia. In the present study, using a rat pheochromocytoma (PC12) cell line, the effect of DSS on hydrogen peroxide (H2O2) induced apoptosis was studied. The apoptosis in H2O2‐induced PC12 cells was accompanied by downregulation of Bcl‐2, upregulation of Bax, the release of mitochondrial cytochrome c into cytosol, and sequential activation of caspase‐9 and −3. DSS was able to suppress all these changes and eventually protected against H2O2‐induced apoptosis. Taken together, these results suggest that treatment of PC12 cells with DSS can block H2O2‐induced apoptosis by the regulation of Bcl‐2 family members, as well as suppression of cytochrome c release and caspase cascade activation.

Metabolic engineering of Bacillus subtilis for the efficient biosynthesis of uniform hyaluronic acid with controlled molecular weights.

Bacillus subtilis was engineered into an efficient hyaluronic acid (HA) producer by introducing two inducible artificial operons carrying HA synthase gene from Pasteurella multocida and precursor genes encoding enzymes involved in synthesis of the sugar precursors. A two-stage induction strategy was established for metabolic engineering of recombinant B. subtilis to efficiently produce uniform HA with controlled molecular weights. Strain TPG223 produced larger HA molecules (yield=6.8 g/L; molecular weight=4.5 MDa) than strain PG6181 (yield=2.4 g/L; molecular weight=13 KDa), indicating that the enzymes involved in the synthesis of UDP-glucuronic acid are essential for HA biosynthesis. Strain TPG223 was able to synthesize HA molecules ranging in molecular weight from 8 KDa to 5.4 MDa indicating that size control is achievable in vivo through appropriate tools. The work reported here not only advanced mechanisms research of size control in vivo, but also could be an attractive alternative for commercial preparation of uniform size-defined HA.

Structure characterization, chemical and enzymatic degradation, and chain conformation of an acidic polysaccharide from Lycium barbarum L.

An acidic polysaccharide, named as p-LBP, was isolated from Lycium barbarum L. by water extraction and purified by decoloration, ion exchange chromatography, dialysis and gel chromatography, successively. The primary structure analysis was determined by HPAEC-PAD, HPSEC, FT-IR, GC-MS, and NMR. The results showed p-LBP was a homogeneous heteropolysaccharide as a pectin molecule with an average molecular weight of 64kDa p-LBP was an approximately 87nm hollow sphere in 0.05mol/L sodium sulfate solution determined by HPSEC-MALLS, DLS and TEM. A discussion of degradation patterns gave the detailed structural information of p-LBP. Therefore, the results from degraded fragments elucidated that the backbone of p-LBP was formed by →4-α-GalpA-(1→, repeatedly. Partial region was connected by →4-α-GalpA-(1→ and →2-α-Rhap-(1→, alternatively. On the C-4 of partial →2-α-Rhap-(1→ residues existed branches forming by →4-β-Galp-(1→, →3-β-Galp-(1→ or →5-α-Araf-(1→, while on the C-6 of partial →3-β-Galp-(1→ residues existed secondary branches forming by terminal-α-Araf, terminal-β-Galp or →3-α-Araf-(1→.

Characterization of a Novel Polysaccharide from Tetraploid Gynostemma pentaphyllum Makino

A novel heteropolysaccharide (GPP-TL) was isolated from tetraploid Gynostemma pentaphyllum (Makino) leaf by hot water extraction and anion-exchange and gel permeation chromatography approaches. GPP-TL had a molecular weight of 9.3 × 10(3) Da and was primarily composed of glucose, galactose, and arabinose, with a molar ratio of 43:5:1, respectively. The chemical structure of GPP-TL was characterized using chemical and instrumental analyses. The results indicated the presence of (1→4)-α-d-glucopyranosyl, (1→4)-β-d-galactopyranosyl, (1→4,6)-linked-α-d-glucopyranosyl, and terminal 1→)-α-d-glucopyranosyl moieties in a molar ratio of 5.7:1:1.5:1, respectively. The results indicated that GPP-TL had glucose and galactose residues in the main chain with (1→6)-linked branches at glucose residues. In addition, GPP-TL exhibited scavenging capacities against hydroxyl, peroxyl, and DPPH radicals in vitro and had a stronger bile acid-binding ability than psyllium on a same-weight basis.

Effects of sulfation on the physicochemical and functional properties of a water-insoluble polysaccharide preparation from Ganoderma lucidum.

The sulfation of a water-insoluble Ganoderma lucidum polysaccharide (GLP) was successfully carried out with chlorosulfonic acid-pyridine in dimethyl formamide to prepare three sulfated GLP derivatives, named sGLP1, sGLP2, and sGLP3. The chemical structure of the sulfated GLP was confirmed by Fourier transform infrared and (13)C NMR analyses. The sGLPs were evaluated for their water solubility, degree of substitution (DS), antioxidant properties, and bile acid-binding capacities. The results showed that sulfation improved the water solubility of GLP and increased its scavenging capacities against hydroxyl and superoxide anion radicals, hydrogen peroxide-scavenging activity, Fe(II) chelating ability, reducing power, and bile acid-binding capacities. It was also observed that the DS may influence the physicochemical and functional properties of sGLPs. For instance, the sulfated GLP with the lowest DS had the greatest bile acid-binding capacity, and the sGLP that had the highest DS showed the lowest bile acid-binding ability under the experimental conditions. The results from this study suggested that sulfation is a possible approach to obtain novel water-soluble derivatives of GLP with improved physicochemical, functional, and biological properties for potential utilization in functional foods or supplemental products.

Characterization and antioxidant activity of a polysaccharide extracted from Sarcandra glabra.

Response surface methodology (RSM) was employed to optimize the parameters for polysaccharide extracted from the aerial parts of Sarcandra glabra (SGP). The optimum conditions were predicted as follows, ratio of water to raw material at 30, extracting temperature at 85 °C, extracting duration at 3 h, and yield was estimated at 4.55%. The experimental yield of SGP under the optimum conditions was 4.49±0.09%. A homogenous polysaccharide (SGP-1) was obtained by purification using DEAE-cellulose-52 and Sephacryl S-400 column chromatography. SGP-1 showed a single symmetrical peak in high performance size-exclusion chromatography (HPSEC) and the average molecular weight (Mw) was estimated to be 1.06×10(4) Da. It was composed of glucose, galactose, and mannose in a ratio of 8.38:3.13:1 determined by gas chromatography (GC). The in vitro antioxidant tests showed that SGP-1 has significant inhibition effects on hydroxyl, superoxide anion, DPPH, ABTS radicals in a dose-dependent manner. This study indicated that SGP-1 could be used as a potential natural antioxidant.

Structure, chain conformation, and immunomodulatory activity of the polysaccharide purified from Bacillus Calmette Guerin formulation.

A polysaccharide, coded as BDP, purified from the injection powder of Bacillus Calmette Guerin (BCG) polysaccharide and nucleic acid, was composed mainly of α-D-(1→4)-linked glucan with (1→6)-linked branches and trace amounts of fucose and mannose from the results of FT-IR, HPAEC-PAD and NMR spectrum. The Mw, Mn, Mz, and [Formula: see text] were determined to be 1.320×10(5)g/mol, 1.012×10(5)g/mol, 2.139×10(5)g/mol, and 21.8±3.2%nm by using HPSEC-MALLS, respectively. The ν value from [Formula: see text] was calculated to be 0.52±0.01, which firstly clarified that BDP existed as random coils in 0.9% NaCl aqueous solution. AFM and SEM combined with Congo-red test also revealed that the polysaccharide was irregular globular like or curly structure. Furthermore, in vitro tests on RAW264.7 murine macrophages cells revealed that BDP exhibited significant immunomodulatory activity.

Characterization of a monoPEG20000-Endostar

In this study, we investigated the PEG attachment site of mono-PEGylated Endostar, a modified recombinant human endostatin approved in China for lung cancer. N-terminal site-directed mono-PEGylation of Endostar was accomplished using mPEG-propionaldehyde derivatives (Mw=20 kDa) under slightly acidic pH conditions (pH 5.5). One-step cation exchange chromatography was used to purify the mono-PEGylated Endostar. Following tryptic digestion, the peptide fragment containing PEG was separated by SDS-PAGE. Barium iodide staining and Western blotting were used to detect the PEG moiety and the N-terminus of Endostar, respectively. The peptide fragment stained by barium iodide showed a positive response to anti-(His) 6 mAb, demonstrating that PEG was located at the N-terminus of Endostar. LC/MS was applied to verify the occurrence of mono-PEGylation at the N-terminus of Endostar.