Duoduo Xu

Charaterization and immunomodulatory activities of polysaccharide isolated from Pleurotus eryngii

A water-soluble polysaccharide (EPA-1) from Pleurotus eryngii was obtained using DEAE-52 and Sephadex G-50 columns. The properties, structure and immunomodulatory activity of EPA-1 were studied. The results demonstrated that EPA-1 was a homogeneous polysaccharide with the molecular weight of 9.97×104Da. EPA-1 consisted of Man, Glc and Gal in a molar ratio of 2.2:1.0:3.2. The characterized fragment structures of EPA-1 were found to be consisting of seven sugar residues and two branches by GC-MS, FTIR and NMR analyses. Among them, the (1→6)-linkedGal residue was the main linkage mode of EpA-1 and composed of its backbone. Activity tests indicated that EPA-1 significantly induced macrophage to release the immune activity factor of NO, TNF-α, IL-1 and IL-6 through activation of signal protein of p38, ERK, JNK in MAPKs and translocation of nuclear NF-κΒ, indicating EPA-1 to possess good immunoregulatory activity.

A polysaccharide from cultured mycelium of Hericium erinaceus and its anti-chronic atrophic gastritis activity.

A polysaccharide named EP-1 was found by screening cultured mycelium of Hericium erinaceus, which was extracted and subjected to precipitation with ethanol, hollow-fiber ultrafiltration and ion-exchange chromatography. The polysaccharide has a molecular weight of approximately 3100Da and is composed of glucose, mannose and galactose, thus being a heteroglycan. EP-1 has a backbone of α-d-Glc(1→3) and β-d-Glc(1→3). The β-d-Glc(1→3) and α-d-Gal-(1→3) were regarded as branches attached to the C-4 position. The α-d-Man was regarded as a terminal residue. The anti-CAG activity was evaluated in experimental systems using a cell model for identification. The polysaccharide significantly inhibited the growth of MC cells obtained from human gastric mucosa epithelium (GES-1) cells transformed by MNNG, which were used as a chronic atrophic gastritis cell model. It also interfered with the MC cells by inducing cell cycle arrest. Thus, EP-1 shows potential for the development of new functional foods and drugs.

Flavonoids from litchi( Litchi chinensis Sonn.) seeds and their inhibitory activities on α -glucosidase

With the bioactivity-guided method, a new flavanone glycoside, together with nine known flavonoids were isolated from 50% aqueous ethanol of litchi(Litchi chinensis Sonn.) seeds. The chemical structure of the new compound was elucidated via 1D and 2D nuclear magnetic resonance(NMR) techniques and mass spectrometry to be (2S)-pinocembrin-7-O-(6″-O-α-L-arabinosyl-β-D-glucopyranoside)(1), and the nine known compounds were determined to be quercetin(2), phlorhizin(3), pinocembrin-7-O-glucoside(4), kaempferol-7-O-β-D-glucopyranoside(5), onychin(6), nairutin(7), narcissin(8), pinocembrin-7-O-[(6″-O-β-D-glucopyranoside)-β-D-glucopyranoside](9) and pinocembrin-7-O-[(2″,6″-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside](10). Some of the isolated flavonoids were tested for their inhibitory effects on α-glucosidase. And compounds 2 and 3 showed stronger inhibitory activity than positive control.

Studies on the characteristic and activity of low-molecular fragments from zymosan.

Zymosan was hydrolysed with HCl and fractionated by ultrafiltration and dialysis to obtain water-soluble fragments A, B and C. Physical and chemical analyses showed that these fractions are composed primarily of glucose and have molecular weights of 8 kDa, 5 kDa and 2 kDa, respectively. A glycosidic linkage analysis indicated that they are mainly composed of β-1,3-glucans. Fragment A, which has the highest molecular weight, contains approximately 30% β-1,6-linked glucans, but fragment C is almost entirely composed of linear β-1,3-glucan chains. The anti-chronic atrophic gastritis activity experiments showed that fragment A has significant activity, the activity of zymosan is quite low and the activities of fragments B and C are in between those of fragment A and zymosan.

A Method for Determining the Content of Glycoproteins in Biological Samples.

The glycoprotein purified from the mycelium extract of Tremella fuciformis was marked with iodine through the iodine substitution reaction. The content of iodine, which is indicative of the amount of the marked tremella glycoprotein (ITG), was detected with Inductively coupled plasma mass spectrometry (ICP-MS). The method was found to be stable, sensitive, and accurate at detecting the content of iodine-substituted glycoprotein, and was used in the quantitative analysis of biological samples, including blood and organs. Different biological samples were collected from rats after oral administration of ITG, and were tested for iodine content by ICP-MS to calculate the amount of ITG in the samples. The results suggested that ICP-MS is a sensitive, stable, and accurate method for detection of iodinated glycoproteins in blood and organs.

A method for determining polysaccharide content in biological samples

Difficulties in the determination of polysaccharide content in biological samples has been one of the bottlenecks limiting the development of polysaccharides pharmacokinetics, greatly due to the complicated chemical structure of these compounds. In this study, we established a simple, reproducible and reliable method for the determination of polysaccharide content in biological samples. Polysaccharides were replaced by fluorescein isothiocyanate (FITC) and iodine to generate a complex. The iodine content in the complex was measured by inductively coupled plasma-mass spectrometry (ICP-MS) to indirectly reflect polysaccharide content. We investigated the stability of the complex, carried on methodological validation and proceeded to determine the polysaccharide content in rat blood and organs after oral administration of iodine substituted polysaccharides using ICP-MS. The results showed that the iodine complex was stable in vivo and in vitro. In the bioavailability of polysaccharides, after 1h, the absorption rate of polysaccharides in blood was the highest, reaching 5.84%. After 3h, the bioaccessibility was differently distributed in various organs, reaching 1% on average across organs.