Aiping Liu

Structural characterization and antidiabetic activity of a glucopyranose-rich heteropolysaccharide from Catathelasma ventricosum.

Polysaccharides, which are the main bioactive constituents of edible mushrooms, have been shown to have a variety of useful biological activities. In this study, a polysaccharide fraction from the edible mushroom Catathelasma ventricosum was purified using anion exchange and size exclusion chromatographies. The structure of the resulting polysaccharide, named CVP-1S, was characterized on the basis of partial acid hydrolysis, periodic acid oxidation, methylation analysis, gas chromatography-mass spectrometry, Fourier-transform infrared spectroscopy, 1D/2D NMR spectroscopy, scanning electron microscopy, and atomic force spectroscopy. The results showed that CVP-1S is a heteropolysaccharide consisting of glucose (94.2%), galactose (3.51%) and fucose (1.3%) with a molecular weight of 1.5×10(4)Da. Its backbone is mainly linked by (1→6)-β-d-Glcp glycosidic bonds, and branches are attached to the backbone through 1,3-linked glycosidic bonds. CVP-1S was also found to have antioxidant, hypoglycemic, and hypolipidemic activities in the streptozoicin-induced diabetic mouse model. From these results, we conclude that CVP-1S should receive further attention as a potential agent for the treatment and prevention of diabetes.

Nutritional composition of boletus mushrooms from Southwest China and their antihyperglycemic and antioxidant activities.

Thirteen samples representing five species were collected from different provinces of Southwest China, and their chemical composition, antihyperglycemic activity, and antioxidant activity were evaluated. These mushrooms had high crude protein (21.72-30.59g/100g dw) and total carbohydrate (49.18-62.58g/100g dw) contents, but low crude fat contents (1.96-7.87g/100g dw). They also accumulated notable quantities of potassium, zinc, sodium, magnesium and copper from the soil. The potassium content, in particular, was 18.75-39.21 times that found in the soil at the collection site. The natural habitat of these mushrooms, especially the mineral content of the soil, seems to have more influence on the mineral content of these mushrooms than their species. Most of the samples possessed antihyperglycemic and antioxidant activities. Suillellus luridus showed the highest antioxidant activity and antihyperglycemic activities, suggesting that S. luridus shows potential for development as a dietary nutritional supplement.

Characterization and antioxidant activities of polysaccharides from thirteen boletus mushrooms

Water-soluble polysaccharides were extracted from the caps and stipes of thirteen boletus mushrooms representing five different species collected in Southwest China. Investigations of their structures and antioxidant activities allowed an evaluation of structure-function relationships. The polysaccharides were composed mainly of the monosaccharides arabinose, xylose, mannose, glucose and galactose. Most samples displayed a broad molecular weight range, with significant differences observed between the molecular weight ranges of the polysaccharides from the caps and the stipes. FT-IR spectral analysis of the polysaccharides revealed that most of polysaccharides from boletus mushrooms (except Boletus edulis) contained a pyranose ring. The antioxidant activities of the polysaccharides in stipes showed a significant correlation with their monosaccharide composition, and were also related to their molecular weight and anomeric configuration. Suillellus luridus collected in Pingwu, Mianyang, Sichuan, China had remarkably superior antioxidant activity and might be developed as a natural antioxidant.

Synthesis and antidiabetic activity of selenium nanoparticles in the presence of polysaccharides from Catathelasma ventricosum

Selenium nanoparticles (SeNPs) were prepared by adding Catathelasma ventricosum polysaccharides (CVPs) to the redox system of selenite and ascorbic acid. Taking particle size as an investigation index, the optimal synthesis conditions of CVPs-SeNPs were obtained by orthogonal test. Herein, the diameter, morphology, and stability of the CVPs-SeNPs were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, the antidiabetic activities of CVPs-SeNPs were evaluated by STZ (streptozocin)-induced diabetic mice. The obtained results showed that, optimum synthesis conditions of CVPs-SeNPs were: ultrasonic time 60min, concentration of Vc 0.04M, reaction time 2h, pH7.0. Under these conditions, mean diameter of the synthesized CVPs-SeNPs was around 49.73nm. TEM of CVPs-SeNPs prepared in optimal conditions showed individual and spherical nanostructure. CVPs-SeNPs (particle size of about 50nm) could be stable for approximately 3months at 4°C, but only 1month at 25°C. The results on serum profiles and antioxidant enzymes levels revealed that CVPs-SeNPs had a potential antidiabetic effect. In addition, CVPs-SeNPs showed significantly higher antidiabetic activity (p<0.05) than other selenium preparations such as SeNPs, selenocysteine, sodium selenite.

Antidiabetic activities of polysaccharides from Anoectochilus roxburghii and Anoectochilus formosanus in STZ-induced diabetic mice

Six polysaccharides were extracted from different parts (whole plants, roots and leaves) of Anoectochilus roxburghii and Anoectochilus formosanus (ARPs, ARPs-1, ARPs-2, AFPs, AFPs-1 and AFPs-2). Their primary characteristics were identified and their antidiabetic activities were evaluated in STZ-induced diabetic mice. Root polysaccharides (ARPs-1and AFPs-1) and leaf polysaccharides (ARPs-2 and AFPs-2) were distinct from each other in terms of the Mws, monosaccharide compositions and functional groups. Notably, the primary structures of ARPs and AFPs were similar to those of ARPs-1and AFPs-1, respectively. In animal experiment, after feeding with polysaccharides samples, the body weight, blood glucose, glycogen, insulin, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), malondiadehyde (MDA) and antioxidant enzyme activities in liver and kidney of mice were tested to investigate the antidiabetic activities. All polysaccharides exhibited varying antidiabetic activities (antihyperglycemic, antioxidant and antihyperlipidemic activities), which were closely related to their primary characteristics. Furthermore, root polysaccharides with higher Mws and glucose content in both A. roxburghii and A. formosanus, exhibited better antidiabetic activities than leaf polysaccharides, and ARPs which showed the best antidiabetic activities had the potential to be used as functional food or medicine for diabetes treatment.

Antidiabetic activity of polysaccharides from Suillellus luridus in streptozotocin-induced diabetic mice

Three polysaccharides were extracted from Suillellus luridus (Suilu.A, Suilu.C and Suilu.S) by the hot water-extraction (1:40, w/v) and ethanol precipitation. Their preliminary structures were characterized and their antidiabetic activities were evaluated to obtain the most active component. The results of high performance gel permeation chromatography (HPGPC) and gas chromatograph (GC) showed that the main molecular weight of Suilu.A, Suilu.C and Suilu.S were 6383, 8172, 10,710 Da, and these polysaccharides were composed of arabinose, xylose, mannose, glucose and galactose, with the highest glucose contents (41.90%-49.09%) and the lowest xylose contents (2.06%-4.36%). Besides, the structures of them were proved by Fourier transform infrared (FT-IR). Further, the antidiabetic effects of three polysaccharides were evaluated in diabetic mice (induced by injecting streptozotocin, 100 mg/kg, i.p). The results showed that these polysaccharides all exhibited potential antidiabetic effects. Especially, when diabetic mice were treated with Suilu.C (150 mg/kg·bw), all antidiabetic indexes and pathologic morphologies of liver, kidney were normalized, which indicated Suilu.C possessed higher antidiabetic activity than other two polysaccharides and was valuable for the diabetes treatment.

A Minireview of the Methods for Listeria monocytogenes Detection

Listeria monocytogenes (LM) is recognized as an opportunistic, foodborne pathogen that leads to the disease listeriosis. Although the incidence of listeriosis is low, listeriosis has a high mortality rate. LM can survive the most common stresses present during food processing steps, and it causes contamination in many food products. Consequently, most countries have endorsed strong restrictions on LM in food products, especially in ready-to-eat products. Conventional culture-based methods are currently the gold standard for testing, but their inefficiency can no longer meet the needs of batch inspection. As a result, a sensitive, fast, and reliable method for LM detection is required. There are many rapid detection methods for LM that are based on different principles, and an overview of the methods of LM detection is addressed here, with an emphasis on chromatographic, immunological, and aptamer-based techniques. Additionally, the prospect of developing novel LM detection methods is discussed.

Synthesis and antidiabetic properties of chitosan-stabilized selenium nanoparticles

Chitosan-stabilized selenium nanoparticles (CTS-SeNPs) were prepared through the reduction of selenite acid with ascorbic acid. The optimal synthesis conditions of CTS-SeNPs were obtained by orthogonal experiments. Besides, the size, morphology and stability of CTS-SeNPs were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM) and dynamic light scattering (DLS). The results showed that, the CTS-SeNPs with diameter of about 54 nm could be obtained under the optimal conditions (temperature of 25 °C, reaction time of 2 h, Vc concentration of 0.04 M and the CTS concentration of 1.0 mg/mL). CTS-SeNPs were uniform spherical and could be stable for approximately 60 days at 4 °C. Further, the antidiabetic activities of CTS-SeNPs in streptozotocin (STZ)-induced diabetic mice were investigated as well. The results revealed that CTS-SeNPs at a dose of 2.0 mg Se/kg bw exhibited higher antidiabetic activity than other doses of CTS-SeNPs and other selenium compounds with the same selenium content.