Jun-Hui Wang

Structural characterisation, physicochemical properties and antioxidant activity of polysaccharide from Lilium lancifolium Thunb.

A novel polysaccharide fraction (LP2-1) was isolated and purified from the edible bulbs of Lilium lancifolium Thunb. by DEAE cellulose chromatography and Sephacryl S-400 size-exclusion chromatography. The structural characterisation, physicochemical properties and antioxidant activity of LP2-1 were investigated. The results showed that LP2-1 had an average molecular weight of approximately 8.52×10(3)kDa and was mainly composed of l-rhamnopyranose, d-arabinofuranose, d-glucopyranose and d-galactopyranose in the molar ratio of 1.88:2.13:1.00:2.50, and major functional groups of LP2-1 were COO and OH. The viscoelastic properties of LP2-1 systems exhibited a gel-like behaviour, with storage modulus higher than loss modulus, and both moduli increased with increasing Ca(2+) concentration. In addition, LP2-1 had DPPH and hydroxyl radicals scavenging activities, and also had the strong reducing power and chelating activity on ferrous ion. These results suggest that LP2-1 has good antioxidant activity and can be used in food industry.

Structural analysis and antioxidant activities of polysaccharide isolated from Jinqian mushroom.

Jinqian mushroom is a precious edible mushroom with delicious taste and high nutritional value. In this paper, a polysaccharide fraction JQPs was isolated and purified from the fruiting body of Jinqian mushroom. The chemical structure, chain conformation and antioxidant activities of JQPs were investigated. The results indicated that JQPs was mainly composed of glucose with trace amounts of xylose. The backbone of JQPs consisted of β-(1 → 3)-D-glucan with β-(1 → 6)-glucosyl side chain. The chain conformation analysis showed that JQPs was a triple helical polysaccharide. The antioxidant activity tests in vitro revealed that JQPs exhibited high DPPH radical and ABTS radical scavenging activities, moderate superoxide radical and hydroxyl radical scavenging activities, low reducing power and Fe(2+) chelating activities. The results suggested that JQPs could be used as a potential natural antioxidant.

Physicochemical properties and antioxidant activities of polysaccharide from floral mushroom cultivated in Huangshan Mountain.

In this paper, a polysaccharide fraction (FMPS) was purified from the floral mushroom cultivated in Huangshan Mountain for the first time. Physicochemical properties and antioxidant activities of FMPS were investigated. FMPS had an average molecular weight of 7.2×10(5)Da and was composed of glucose. On the basis of FT-IR, NMR and methylation analysis, the repeating unit of FMPS was established as (1→3)-linked β-d-glucopyranosyl backbone with 1-linked β-d-glucopyranosyl branches substituted at O-6 position of (1→3)-linked β-d-glucopyranosyl residues. The advanced structure studies indicated that FMPS was a triple-helical polysaccharide. The main hydrodynamic radius (Rh) of FMPS was 23.4nm and it could form a stable system with water in 1.2×10(-2)g/mL solutions. In addition, FMPS exhibited high DPPH radical scavenging activities (79.46% at 5mg/mL) and hydroxyl radical scavenging activities (74.18% at 5mg/mL), as well as Fe(2+)chelating activities and ABTS radical scavenging activities to some extent.

An acetylated galactomannoglucan from the stems of Dendrobium nobile Lindl

A water-soluble polysaccharide DNP-W2 composed of glucose, mannose, and galactose in the molar ratio of 6.1:2.9:2.0 had been isolated from the stems of Dendrobium nobile. Its molecular weight was 1.8 x 10(4) Da determined by HPGPC. Structural features of DNP-W2 were investigated by a combination of chemical and instrumental analysis, including FTIR, GC, GC-MS, periodate oxidation-Smith degradation, methylation analysis, partial acid hydrolysis, and NMR spectroscopy. The results showed that DNP-W2 is a 2-O-acetylgalactomannoglucan and has a backbone consisting of (1-->4)-linked beta-D-Glcp, (1-->6)-linked beta-D-Glcp, and (1-->4)-linked beta-D-Manp, with branches at O-6 of (1-->4)-linked beta-D-Glcp and beta-D-Manp. The branches are composed of alpha-D-Galp. The acetyl groups are substituted at O-2 of (1-->4)-linked Manp. Preliminary tests in vitro reveals that DNP-W2 can stimulate ConA- and LPS-induced T and B lymphocyte proliferation.

Preventive effect of a galactoglucomannan (GGM) from Dendrobium huoshanense on selenium-induced liver injury and fibrosis in rats

This study was carried out to investigate the preventive effects of galactoglucomannan (GGM), a homogeneous polysaccharide from Dendrobium huoshanense, on liver injury and fibrosis induced by sodium selenite. Sprague-Dawley rats injected subcutaneously with sodium selenite at the dosage of 3.28 mgkg(-1) b.wt. were set as the model groups. Rats treated with sodium selenite at the dosage of 3.28 mgkg(-1) b.wt. and GGM at 50-200 mgkg(-1) b.wt. were set as the prevention groups. Biochemical and histological analysis showed that GGM significantly ameliorated selenite-induced liver injury and fibrosis in rats. Oral administration of GGM effectively attenuated the toxicity of selenite to liver tissue, which was judged both by the decreased activities of serum hepatic enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), and by liver histopathological examination. Meanwhile, GGM also reduced the levels of H(2)O(2) and malondialdehyde (MDA), elevated the levels of GSH, restored the fluidity of hepatic plasma membrane, and retained the activities of endogenous enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST). The prevention of selenite-induced liver injury and fibrosis by GGM was further supported by the reduced expression of transforming growth factor-β1 (TGF-β1) and type I collagen. These results suggested that GGM may be developed into a novel antifibrotic agent for the prevention of liver injury and fibrosis.

Structure and bioactivity of a polysaccharide extracted from protocorm-like bodies of Dendrobium huoshanense

The crude polysaccharides of Dendrobium huoshanense were fractionated by anion-exchange chromatography and gel permeation chromatography, giving one homogeneous fraction DHP-4A with molecular weight of 2.32 × 10(5)Da. UV spectrum indicated that there was no existence of proteins and nucleic acids in DHP-4A. Monosaccharide analysis revealed that DHP-4A was made up of glucose, arabinose, mannose and rhamnose with a molar ratio of 13.8:3.0:6.1:2.1. The backbone of DHP-4A consisted of (1 → 6)-linked glucose, (1 → 6)-linked mannose and (1 → 3,6)-linked mannose. The βL-Rhap-(1 → 2)-β-L-Rhap-(1 → 4)-β-D-Manp-(1 → and α-L-Araf-(1 → 3)- α-L-Araf -(1 → 3)-α-L-Araf-(1 → were regarded as the branches attached to the C-3 position of (1 → 6)-linked mannose in the backbone. The sugar residue sequence was further determined by NMR spectra including (1)H NMR, (13)C NMR, HSQC and HMBC. Pharmacological tests showed that DHP-4A can significantly stimulate RAW 264.7 macrophage cells to secrete NO, TNF-α, IL-6 and IL-10 via activation of p38, ERK, JNK and translocation of nuclear NF-κB, indicating this polysaccharide possesses good immunoregulatory activity.

Isolation and prebiotic activity of water-soluble polysaccharides fractions from the bamboo shoots (Phyllostachys praecox)

The water-soluble polysaccharides from bamboo shoots (Phyllostachys praecox) (WBP) were isolated, and the characterizations as well as prebiotic activities were investigated. The yield of WBP was 7.58±0.31% under optimal hot-water extraction conditions. Two fractions, i.e., WBP-1 and WBP-2 with molecular weight of 83.50kDa and 80.08kDa, respectively, were purified by chromatography. Both the polysaccharides fractions were identified as heteropolysaccharides-protein complexes composed of 15 kinds of common amino acids in protein part and rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios in polysaccharide part. The existence of α- and β-glycosidic linkages between the sugar units was confirmed by FTIR and NMR spectra. Compared with the blank control and the reference of FOS, WBP-1 and WBP-2 significantly increased the numbers of Bifidobacterium adolescentis and Bifidobacterium bifidum (P<0.05), which contributed to the production of organic acids, suggesting that the polysaccharides have potential prebiotic properties.

Structural identification and immunostimulating activity of a Laminaria japonica polysaccharide

In the present study, a new water-soluble polysaccharide (LJP-11) was obtained from Laminaria japonica by anion exchange DEAE-cellulose chromatography and Sephacryl S-500 chromatography. The average molecular weight of this polysaccharide was estimated to be about 2.89×10(6) Da by high performance liquid chromatography system. Gas chromatography showed that LJP-11 was composed of arabinose, mannose and glucose in a molar ratio of 1.0:1.16:6.33. LJP-11 contains a long backbone consisting of (1→4)-β-D-GlcpAc, (1→4)-α-D-Glcp, (1→6)-β-D-Glcp and (1→3,6)-α-D-Manp. The 1-linked β-L-Araf was linked to the C-6 of (1→3)-α-D-Manp and the sulfate group was attached to the C-4 of (1→6)-β-D-Glcp. Pharmacological tests displayed that LJP-11 can stimulate macrophages to release NO, IL-6, TNF-α and IL-10 as well as the up-regulation of their gene expressions, indicating LJP-11 has beneficial effects on immunostimulation. Moreover, LJP-11 exhibited positive effects on the translocation of NF-κB p65 from cytoplasm to nucleus and the phosphorylation of IκBα, ERK1/2, JNK1/2 and P38 in macrophages. These results suggested that the activation of MAPK and NF-κB signaling pathways is one of the mechanisms responsible for the immunostimulating activity of LJP-11.

Enzymatic fingerprints of polysaccharides of Dendrobium officinale and their application in identification of Dendrobium species

Enzymatic fingerprinting of polysaccharides from Dendrobium officinale was studied and applied to authenticate Dendrobium species. Results showed that Dendrobium officinale species from Anhui province, Fujian province, Yunnan province, Guangdong province and Guangxi province of China, could be identified by polysaccharide analysis using carbohydrate gel electrophoresis (PACE). However, the fingerprints of Dendrobium officinale from Jiangxi province, Hu’nan province and Wenzhou, Yandangshan and Fuyang in Zhejiang province were very similar. As far as the fingerprints of different Dendrobium species were concerned, the differences between Dendrobium officinale, Dendrobium huoshanense, Dendrobium moniliforme, Dendrobium devonianum, Dendrobium aphyllum, Dendrobium wilsonii and Dendrobium crystallinum were obvious. Moreover, the genetic relationships between different samples were analyzed by using principal component analysis and unweighted pair group method with arithmetic mean cluster analysis. Results suggested that polysaccharide fingerprint analysis by PACE has the potential to become a valuable new method for the identification and control of quality of herbal medicines in future.

Pectinase hydrolysis of Dendrobium huoshanense polysaccharide and its effect on protein nonenzymatic glycation

The aim of this study was to investigate the inhibitory effects of molecular weight alteration of Dendrobium huoshanense polysaccharide on protein nonenzymatic glycation. For this purpose, one homogeneous active polysaccharide DHPD1 with molecular weight 3.2 kDa was extracted from D. huoshanense. GC analysis showed that DHPD1 was mainly composed of glucose, arabinose, galactose in a molar ratio of 0.023:1.023:0.021 with a trace of mannose and xylose. In order to get DHPD1-derived fragments with different molecular weight, response surface methodology was employed to optimize the enzymatic degradation conditions. The maximum reducing sugar production (0.399 mg/mL) was obtained under an optimal condition including pectinase dosage 126 U/mL, reaction pH 4.46 and reaction temperature 48 °C. By applying this condition, three DHPD1-derived fragments with different molecular weights were obtained through changing the hydrolysis time. Infrared spectroscopy analysis indicated that the backbone structure of DHPD1 was not destroyed by pectinase hydrolysis. Monosaccharide composition analysis showed that pectinase preferred to liberate glucose from DHPD1. The inhibitory action of DHPD1 on protein nonenzymatic glycation reduced with the decrease of molecular weight.