Chunyan Yan

Isolation, purification, and structural characterization of a novel polysaccharide from Ganoderma capense.

The mushrooms of the genus Ganoderma are popular for their important biological activities, such as antioxidation, anti-inflammatory, antitumour, antiulcer, antiviral, etc. Ganoderma capense is one of the important members of this fungus family, which possesses potential pharmacological properties. There is a dearth of information on the biochemical constituents of G. capense. The present study aimed to isolate, purify, and characterize the structure of the polysaccharide obtained from the mycelia of G. capense. A novel water-soluble polysaccharide (GCP50-1) was obtained from the dried powder of submerged fermentation mycelia of G. capense by extraction with hot water and further successive purification through diethylaminoethyl (DEAE) Sepharose CL-6B and Sephadex G-75 column chromatography. The average molecular weight of the polymer was 1.5 × 10(4)Da determined by a high performance gel permeation chromatography (HPGPC), and its specific optical rotation was be [α]₂₅(D)=+170°. The structural feature of GCP50-1 was investigated by monosaccharide analysis, partial acid hydrolysis, methylation analysis, periodic acid oxidation, gas chromatography-mass spectrometry (GC-MS), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy. The results obtained from the analyses indicated that GCP50-1 was an α-D-glucan with the main backbone chain of (1→4)-α-D-glucopyranosyl residue interspersed with (1→4, 6)-α-D-glucopyranosyl residue and the side chain attached to the O-6 position with (1→)-α-D-glucopyranosyl residue. This was the first report on the detailed structure elucidation of this novel polysaccharide from G. capense mycelia powder.

Structural characterization and DPPH· radical scavenging activity of a polysaccharide from Guara fruits

The crude polysaccharides were extracted from fruits of Psidium guajava Linn. by hot water. After removal of proteins, isolation and purification by DEAE-52 Cellulose chromatography and Sephadex G-75 gel filtration, a polysaccharide (GP70-2) was obtained and structurally characterized. GP70-2 has a relative molecular weight of 74 kDa and was composed of D-galactose and L-arabinose in the ratio of 1:1, with a specific optical rotation of [a]D(25) = +101°. Structural characterization of this novel polysaccharide was carried out using infrared spectroscopy, methylation analyses, and NMR studies ((1)H, (13)C, (1)H-(1)H-COSY, HMQC, and HMBC). Based on the above data, the following structure was assigned to the repeated core unit of GP70-2: [Formula: see text]. This polysaccharide showed a concentration dependent DPPH· radical scavenging activity.

Structural characterization, α-glucosidase inhibitory and DPPH scavenging activities of polysaccharides from guava.

To explore the chemicals responsible for the health benefits of guava, water-soluble polysaccharides were extracted including GP90 and P90. They exhibited excellent α-glucosidase inhibition activity with an EC50 of 2.27μg/mL and 0.18mg/mL. This suggests that their activities were 1379- and 17-fold higher than the positive control. The DPPH scavenging activities of GP90 was even higher than Vc at some concentrations. Upon further isolation, a novel polysaccharide termed GB90-1B was obtained. Monosaccharide analysis, methylation analysis, and NMR were used to analyze the structural characterization of GB90-1B. Structural analysis revealed that its backbone consisted of (1→5)-linked-α-l-arabinose, (1→2,3,5)-linked-α-l-arabinose and (1→3)-linked-α-l-arabinose. Branch linkages included (1→6)-linked-α-d-glucose, (1→)-linked-α-d-glucose and (1→)-linked-α-l-arabinose. The structure of the repeating unit of GP90-1B was predicted.

Purification, structural characterization and in vitro antioxidant activity of a novel polysaccharide from Boshuzhi

A novel polysaccharide, designated GCPB-1b, was obtained from the alkaline extract of the submerged fermentation culturing mycelium powder of Boshuzhi, Ganoderma capense. This polysaccharide was purified by ion-exchange and gel-permeation column chromatography and is a glucan (MW 2847Da). GCPB-1b has a specific optical rotation of [α]D(25)=+154° (c 1.0, H2O). Based on monosaccharide analysis, partial acid hydrolysis, periodic acid oxidation-Smith degradation, methylation analysis, Fourier transform-infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy, the backbone of GCPB-1b was composed of (1→4)-linked-α-d-glucose residues and (1→4,6)-linked-α-d-glucose residues. Furthermore, GCPB-1b had 1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging ability (EC50 3.23μM) according to antioxidant activity tests which was greater than other antioxidants. These data suggest that GCPB-1b holds promise as an anti-aging functional food.

Structural characterization and antioxidant activity of a novel heteropolysaccharide from the submerged fermentation mycelia of Ganoderma capense.

A novel heteropolysaccharide (GCPB-2) with a molecular mass of 1.03×10(5)Da was isolated from the submerged fermentation culturing mycelia powder of Lingzhi, Ganoderma capense, by DEAE-52 cellulose, DEAE Sepharose CL-6B, and Sephadex G-75 column chromatography. Its chemical structure was characterized for the first time. The antioxidant activity was evaluated by two antioxidant assay methods. The result of this study introduced G. capense as a possible valuable source that helped to exhibit some antioxidant properties. The homogeneous polysaccharide was composed of xylose and arabinose in the molar ratio of 1:1, and showed a specific optical rotation of [α]D(25)=+161° (c 1.0, H2O). Monosaccharide analysis, partial acid hydrolysis, periodic acid oxidation, methylation analysis, gas chromatography-mass spectrometry (GC-MS), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy ((1)H, (13)C, HMQC and HMBC) were conducted to elucidate its structure. The backbone of GCPB-2 was composed of (1 → 4)-linked-β-D-xylopyranose residues which branched at O-3. The two branches consisted of (1 → 3)-linked-β-L-arabinopyranose terminated with β-D-xylopyranose residues, and (1 → 4)-linked-β-L-arabinopyranose terminated with β-D-arabinopyranose residues. In the in vitro antioxidant assay, GCPB-2 was found to possess 1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activity with an EC50 value of 0.379 μM. The findings of this study indicated that GCPB-2 possesses the hydroxyl radical-scavenging activity, which provided an experimental evidence to support the G. capense as functional foods in some Asian countries. To understand better the bioactivity of GCPB-2, the antioxidant activity should be further investigated to find out its mechanism in future work.

Structural characterization and antioxidant activity of a heteropolysaccharide from Ganoderma capense

In this work, crude polysaccharide extracts were obtained from mycelia of the edible fungus Ganoderma capense (Lloyd) Teng. After removal of proteins by the Sevage method, fractionation and purification by anion-exchange and gel-permeation chromatography, a polysaccharide (GCPB-3) was isolated. The relative molecular weight of GCPB-3 was 124kDa determined by high performance gel permeation chromatography (HPGPC). The homogeneous polysaccharide was composed of d-xylose and l-arabinose in the ratio of 1:1, and showed a specific optical rotation of [α]D(25)=+145°(c 1.0, H2O). Its structural features were determined by monosaccharide analysis, partial acid hydrolysis, methylation analysis, periodic acid oxidation, gas chromatography-mass spectrometry (GC-MS), Fourier transform-infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy ((1)H, (13)C, HMQC and HMBC). The results characterized GCPB-3 as a heteropolysaccharide with backbone consisting of β-l-Arap and β-d-Xylp, linked with 1→4 sugar bonds. Interestingly, GCPB-3 showed some DPPH•- and hydroxy-radical scavenging activities.

Antidiabetic effects of Morus alba fruit polysaccharides on high-fat diet- and streptozotocin-induced type 2 diabetes in rats

ETHNOPHARMACOLOGICAL RELEVANCE Type 2 diabetes mellitus (T2DM) is becoming a serious threat to human health. The fruit of Morus alba L. is widely used as a traditional Chinese medicine for the treatment of DM, dizziness, tinnitus, insomnia, and premature graying, as well as to protect the liver and kidneys. Several studies have demonstrated that the aqueous extracts of the roots bark, leaves, and ramuli of mulberry, which are known to contain polyphenols and polysaccharides, have antihyperglycemic and antihyperlipidemic activities. The aim of the present study was to further investigate the active polysaccharides from M. alba fruit by evaluating the antidiabetic activities of different fractions on T2DM rats and elucidate the mechanism underlying these activities. MATERIALS AND METHODS Diabetic rats were treated with two fractions of M. alba fruit polysaccharides (MFP50 and MFP90). The disease models were induced by a high-fat diet and low dose injection of streptozotocin and were compared to normal rats and metformin-treated diabetic rats. After seven weeks, the fasting blood glucose (FBG), oral glucose tolerance test (OGTT), fasting serum insulin (FINS) levels, homeostasis model of assessment-insulin resistance (HOMA-IR), glycated serum protein (GSP), and serum alanine transaminase (ALT) levels, as well as serum lipid profiles and histopathological changes in the pancreas were measured. Next, the expressions of the insulin signaling pathway were measured by western blot analysis to elucidate the potential mechanism underlying these antidiabetic activities. RESULTS After seven weeks of treatment, a significant reduction in the FBG levels, OGTT-area under the curve (OGTT-AUC), FINS, HOMA-IR, ALT, and triglyceride (TG) values of the MFP50 group was observed. On the other hand, in the MFP90 group, the FBG, OGTT-AUC, FINS, HOMA-IR, GSP, and TG levels were significantly reduced. The level of high-density lipoprotein cholesterol (HDL-c) and the proportion of HDL-c to total cholesterol (TC) significantly increased in the MFP50 group. Moreover, MFP50 and MFP90 induced repair of damaged pancreatic tissues of the diabetic rats. The hypoglycemic effect of MFP50 was more stable than MFP90, whereas the hypolipidemic effect of MFP90 was slightly better than MFP50. Moreover, the expression levels of InsR, IRS-2, Akt and GLUT4 in the MFP90 group significantly increased relative to that of the T2DM group. CONCLUSIONS MFP50 and MFP90 have markedly antihyperglycemic and antihyperlipidemic effects and can clearly relieve diabetes symptoms in the T2DM rat model. The M. alba fruit polysaccharides may potentially be utilized as an effective treatment for T2DM. Further research into the structures of active M. alba fruit polysaccharides and their mechanisms in promoting antidiabetic effects are underway.

Consumption of guava may have beneficial effects in type 2 diabetes: A bioactive perspective

The objectives of this study were to evaluate the anti-diabetic and anti-hyperlipidemic effects and relative mechanisms of guava polysaccharides (GPs) in rats with type 2 diabetic mellitus (T2DM). The chemical characterization and monosaccharide compositions of GPs, named as GP-1, GP-2, GP-3, and GP-4, were determined by PMP-HPLC and FT-IR. The results revealed that all GPs had the typical saccharide absorptions, and all were heteropolysaccharides. In addition, GPs efficiently decreased levels of fasting blood glucose, glucosylated serum protein, serum insulin, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride and serum alanine transaminase, improved oral glucose tolerance, and increased insulin sensitivity in rats with T2DM. Histopathological observations suggested that GP-1, GP-3, and GP-4 could alleviate injury in pancreatic islet cells, and Western blot analysis showed that these GPs upregulated gene expression of the insulin receptor, insulin receptor substrate 2, Akt, and glucose transporter type 4. Taken together, these data suggest that GPs may be beneficial in treating T2DM and reducing the risk of hyperlipidemia, vascular disease, and cirrhosis via the PI3K/Akt signaling pathway.

Endogenous n-3 Fatty Acids Alleviate Carbon-Tetrachloride-Induced Acute Liver Injury in Fat-1 Transgenic Mice

n-3 polyunsaturated fatty acids (PUFAs) are beneficial for numerous models of liver diseases. The probable protective effects of n-3 PUFA against carbon-tetrachloride- (CCl4-) induced acute liver injury were evaluated in a fat-1 transgenic mouse that synthesizes endogenous n-3 from n-6 PUFA. Fat-1 mice and their WT littermates were fed a modified AIN93 diet containing 10% corn oil and were injected intraperitoneally with a single dose of CCl4 or vehicle. CCl4 challenge caused severe liver injury in WT mice, as indicated by serum parameters and histopathological changes, which were remarkably ameliorated in fat-1 mice. Endogenous n-3 PUFA decreased the elevation of oxidative stress induced by CCl4 challenge, which might be attributed to the activation of Nrf2/keap1 pathway. Additionally, endogenous n-3 PUFA reduces hepatocyte apoptosis via suppressing MAPK pathway. These findings indicate that n-3 PUFA has potent protective effects against acute liver injury induced by CCl4 in mice, suggesting that n-3 PUFA can be used for the prevention and treatment of liver injury.

An O-acetyl-glucomannan from the rhizomes of Curculigo orchioides: Structural characterization and anti-osteoporosis activity in vitro

Osteoporosis is characterized by a reduction in bone mass and bone mineral density, which weakens the bone. Due to the side effects associated with drugs that are currently used to treat this disease, an increasing number of studies have focused on the research of effective ingredients derived from natural products. In particular, polysaccharides extracted from Chinese herbal medicines have received increasing attention. In this study, we isolated a homogeneous polysaccharide (COP90-1) from the dried rhizomes of Curculigo orchioides, a famous traditional Chinese medicine that is widely used in China, and determined its structure using the combined methods of chemical and spectral analyses. In addition, its effects on the proliferation and differentiation of primary mouse osteoblasts were assessed. The results showed that COP90-1 can effectively promote the proliferation and differentiation of primary osteoblasts in vitro. Additional studies are warranted to study the effects of this compound in vivo.