Rongmin Yu

Structural Characterization of a Novel Polysaccharide from Pulp Tissues of Litchi chinensis and Its Immunomodulatory Activity

A novel polysaccharide (LCP50W) with a molecular weight of 4.72 × 10(4) Da was isolated from the pulp tissues of Litchi chinensis . The chemical structure of LCP50W was characterized using physicochemical and instrumental analyses. The results indicated that the main chain of LCP50W consisted of (1→3)-linked β-L-rhamnopyranosyl, (1→6)-linked α-D-glucopyranosyl, and (1→2,6)-linked α-D-glucopyranosyl residues, which branched at O-6. The three branches consisted of (1→2)-linked α-L-rhamnopyranosyl, (1→3)-linked α-D-galactopyranosyl, and (1→3)-linked α-L-mannopyranosyl residues, terminated with (1→)-linked α-L-arabinopyranosyl residues, respectively. The in vitro immunomodulatory assay revealed that LCP50W promoted the proliferation of mouse splenocytes and enhanced the cytotoxicity of NK cells. LCP50W boosted the secretion of Th1 cytokine IFN-γ while it inhibited the secretion of Th2 cytokine IL-4; it also enhanced the expression of T-bet while it inhibited the expression of GATA-3. Additionally, LCP50W promoted the development of cell cycle toward the S phase.

Structural Characterization and Biological Activities of a Novel Polysaccharide from Cultured Cordyceps militaris and Its Sulfated Derivative

A novel polysaccharide (CMPA90-1; compound 1) was isolated from the cultured fruiting bodies of Cordyceps militaris. The chemical structure of compound 1 was elucidated by acid hydrolysis, periodate oxidation, Smith degradation, and methylation analysis, along with Fourier transform infrared spectroscopy, high-performance anion-exchange chromatography coupled with pulsed amperometric detection, gas chromatography-mass spectrometry, and one-dimensional [(1)H and (13)C nuclear magnetic resonance (NMR)] and two-dimensional NMR (heteronuclear single-quantum coherence and heteronuclear multiple-bond correlation). Sulfation of compound 1 by the chlorosulfonic acid-pyridine (CSA-Pyr) method led to synthesis of its sulfated analogue (CMPA90-M1; compound 2). The ultrastructures of both compounds 1 and 2 were further characterized by scanning electron microscopy and atomic force microscopy. The results of antioxidant assays showed that compounds 1 and 2 exhibited free-radical-scavenging effects, ferrous-ion-chelating ability, and reducing power. Also, in the cytotoxicity assay, compounds 1 and 2 showed inhibitory activity against A549 cells, with IC50 values of 39.08 and 17.33 μg/mL, respectively.

Structure characterization and antioxidant activity of a novel polysaccharide isolated from pulp tissues of Litchi chinensis.

A novel polysaccharide (LCP50S-2) with antioxidant activity was isolated from Litchi chinensis Sonn. The structure of LCP50S-2 was elucidated on the basis of physicochemical and instrumental analyses, and its average molecular weight was determined by gel permeation chromatography to be 2.19 × 10(2) kDa. The backbone of LCP50S-2 was composed of (1→3)-linked β-L-rhamnopyranosyl residues, (1→4)-linked α-D-xylopyranosyl residues, (1→4)-linked β-D-glucopyranosyl residues, and (1→4)-linked α-D-glucopyranosyl residues which branched at O-6. The two branches consisted of α-L-arabinopyranosyl residues and (1→6)-linked β-D-galactopyranosyl residues terminated with α-L-arabinopyranosyl residues, respectively. In the in vitro antioxidant assay, LCP50S-2 was found to possess DPPH radical-scavenging activity and hydroxyl radical-scavenging activity with IC(50) values of 220 and 266 μg/mL, respectively.

Structure characterization and antioxidant activity of a novel polysaccharide isolated from Ginkgo biloba

A novel polysaccharide (GBP50S2) with antioxidant activity was isolated from Ginkgo biloba. The structure of GBP50S2 was elucidated on the basis of physico-chemical and instrumental analyses, and its average molecular weight (Mw=2.30x10(5)) was determined by gel permeation chromatography. The backbone of GBP50S2 was composed of (1-->4)-linked alpha-d-mannopyranosyl residues which branched at O-3. The three branches consisted of beta-l-rhamnopyranosyl residues, (1-->4)-linked alpha-d-galactopyranosyl terminated with beta-l-rhamnopyranosyl residues, and (1-->3,4)-linked alpha-d-mannopyranosyl terminated with beta-l-rhamnopyranosyl residues, respectively. In the in vitro antioxidant assay, GBP50S2 was found to possess DPPH radical-scavenging activity and hydroxyl radical-scavenging activity with an IC(50) value of 0.412 mg/mL and 0.482 mg/mL, respectively.

Antioxidant Activities of Hydrolysates of Arca Subcrenata Prepared with Three Proteases

In order to get products with antioxidant activity from Arca subcrenata Lischke, the optimal hydrolase and hydrolysis conditions were investigated in the paper. Three proteases (neutrase, alcalase and papain) were applied to hydrolyze the homogenate of A. subcrenata. An orthogonal design was used to optimize hydrolysis conditions, and the pH-stat methods was used to determine the degree of hydrolysis. Viewed from the angle of reducing power, such as scavenging activities against α,α-diphenyl-β-picrylhydrazyl (DPPH) radical and hydrogen peroxide, the antioxidant activities of the alcalase hydrolysate (AH) were superior to neutrase hydrolysate (NH) and papain hydrolysate (PH), and its EC50 values in DPPH radical and hydrogen peroxide scavenging effect were 6.23 mg/ml and 19.09 mg/ml, respectively. Moreover, compared with products hydrolyzed by neutrase and papain, the molecular mass of AH was lower and its content of amino acid of peptides was higher. Therefore, alcalase was selected as the optimal enzyme to produce active ingredients since its hydrolysate exhibited the best antioxidant activity among them and possessed large amount of potential active peptides.

Elucidation and biological activities of a new polysaccharide from cultured Cordyceps militaris

A novel low-molecular-weight polysaccharide (CMP-1) with antioxidant, immunostimulatory and antitumor activities was isolated from the cultured Cordyceps militaris. The structure of CMP-1 was elucidated by a combination of physicochemical and instrumental analyses, and its average molecular weight was 4.3 kDa. The backbone of CMP-1 was composed of (1 → 4)-linked α-D-glucopyranosyl, (1 → 6)-linked β-D-glucopyranosyl and (1 → 4)-linked β-D-glucopyranosyl residues which branched at O-6. The branches consisted of (1 → 3)-linked α-L-rhamnopyranosyl terminated with (1 → )-linked α-D-glucopyranosyl residues. The ultrastructure of CMP-1 was further investigated by scanning electron microscope (SEM). The antioxidant assays showed that CMP-1 exhibited free radical-scavenging effects, ferrous ions-chelating ability and reducing power. In vitro test revealed that CMP-1 could significantly stimulate the mouse splenocyte proliferation. The cytotoxicity assay showed that CMP-1 inhibited the proliferation of HT-29, HeLa, HepG2 and K562 cells, with the IC50 values of 137.66, 162.59, 176.29 and 364.01 μg/mL, respectively.

Purification, Characterization and in vitro Anti-Tumor Activity of Proteins from Arca subcrenata Lischke

Two purified proteins G-6 and G-4-2 were obtained from Arca subcrenata Lischke using the homogenization, salting-out with ammonium sulfate, ion-exchange chromatography and gel filtration chromatography techniques. The purity of G-6 and G-4-2 was over 96%, as measured by RP-HPLC. G-6 and G-4-2 were measured by SDS-PAGE and IEF-PAGE to have molecular weights of 8.2 kDa and 16.0 kDa, and isoelectric points of 6.6 and 6.1, respectively. The amino acid constituents of G-6 and G-4-2 were also determined. The existence of saccharides in G-6 was demonstrated by the phenol-sulfuric acid method. G-6 and G-4-2 inhibited the proliferation of human tumor cells in vitro. By MTT assay, the IC50 values of G-4-2 were 22.9 μg/mL, 46.1 μg/mL and 57.7 μg/mL against Hela, HL-60 and KB cell lines, respectively, and the IC50 value of G-6 against HL-60 cell line was measured to be 123.2 μg/mL.

Structural characterization and in vitro antitumor activity of a novel polysaccharide from Taxus yunnanensis

The shrub, Taxus yunnanensis is famed as the source of the important anticancer drug, paclitaxel. But research on its polysaccharides contents has been scarce. The present research aimed to investigate the polysaccharide content of T. yunnanensis leaves and study the antitumor activities of isolated polysaccharide(s) using human tumor cells (K-562 and MCF). A novel heteropolysaccharide (TMP70W) was isolated and purified by anion-exchange and gel-permeation chromatography. Its molecular weight was 36.94 kDa and structural features were elucidated by partial acid hydrolysis, periodate oxidation-Smith degradation, methylation analysis, GC-MS, HPAEC-PAD, FT-IR, and NMR. The repeating unit of TMP70W had a backbone composed of (1→5)-linked-α-l-Araf, (1→2,5)-linked-α-l-Araf, and (1→6)-linked-β-d-Galp with a branch of α-d-Glcp-(1→2)-α-d-Galp-(1→ at the position of C-2 of arabinose. TMP70W displayed mild cytotoxicity against K562 cells with the IC50 value of 39.63 ± 2.37 μg/mL and inhibitory activity against MCF-7 cells (32.08 ± 0.39% at the concentration of 400 μg/mL) in a concentration-dependent manner.

Isolation, characterization and bioactivities of a new polysaccharide from Annona squamosa and its sulfated derivative.

A new water-soluble polysaccharide, designated as ASPW80-1, was first isolated from the fruit pulp of Annona squamosa. The structure of ASPW80-1 was elucidated based on the physicochemical and instrumental analyses. The results indicated that ASPW80-1 was a homogeneous heteropolysaccharide with an average molecular weight of 2.29×10(5)Da. Another novel modified polysaccharide, the sulfated derivative of ASPW80-1 namely as ASPW80-M1, was also synthesized. The ultra-structures of both ASPW80-1 and ASPW80-M1 were further characterized by scanning electron microscopy and atomic force microscopy. The antioxidant assays showed that ASPW80-1 and ASPW80-M1 exhibited DPPH and hydroxyl radicals scavenging activities. The results of immunomodulatory assays in vitro showed that ASPW80-1 and ASPW80-M1 could markedly promote the proliferation of mouse splenocytes. These results proposed that ASPW80-M1 might be proposed to be developed as a potential value-added product with the activities of immunomodulator and free-radical inhibitors.

Biosynthesis and regulation of terpenoid indole alkaloids in Catharanthus roseus

Catharanthus roseus produces a wide range of terpenoid indole alkaloids (TIA). Many of them, such as vinblastine and vincristine, have significant bioactivity. They are valuable chemotherapy drugs used in combination with other drugs to treat lymphoma and leukemia. The TIA biosynthetic pathway has been investigated for many years, for scientific interest and for their potential in manufacturing applications, to fulfill the market demand. In this review, the progress and perspective of C. roseus TIA biosynthesis and its regulating enzymes are described. In addition, the culture condition, hormones, signaling molecules, precursor feeding on the accumulation of TIA, and gene expression are also evaluated and discussed.