Chemical modification, characterization and bioactivity of Chinese lacquer polysaccharides from lac tree Rhus vernicifera against leukopenia induced by cyclophosphamide

The effect of carboxymethylation on the macromolecular conformation of the (1 → 3)-β -D-glucan of curdlan in water

The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.

Gallic Acid-Laminarin Conjugate Is a Better Antioxidant than Sulfated or Carboxylated Laminarin

A 12.4 kDa laminarin (LM) composed of β(1→3)-glucan with β(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin–Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H₂O₂-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.

In vivo immunological activity of carboxymethylated-sulfated (1→3)-β-D-glucan from sclerotium of Poria cocos

β-Glucans are one of the polysaccharides known as biological response modifiers extracted from the sclerotium of Poria cocos which has been used for several decades as Traditional Chinese Medicine. Due to its ability to activate immune system, it can be applied in chemotherapy after being chemically modified. In this study, sulfated (1→3)-β-D-glucan (S-P), carboxymethyl (1→3)-β-D-glucan (CMP), and carboxymethylated-sulfated (1→3)-β-D-glucan (S-CMP), which are (1→3)-β-D-glucan derivatives were synthesized. The current study was aimed to investigate in vivo potential immunological activity of S-CMP in mice. In addition, mice were separately treated with S-P, CMP and S-CMP to evaluate the relationship between single and multiple functional groups. Interestingly, S-CMP exhibited the best in vivo immunological activities and the highest inhibition rate against the implanted HepG2 tumor in BALB/c mice, with significant increase in serum hemolysin antibody titer, spleen antibody production as well as delayed type hypersensitivity compared with S-P and CMP. Furthermore, it was assumed that simultaneous introduction of carboxymethyl and sulfate groups also had great potential effect on antioxidant activity, as substantial decrease in malondialdehyde (MDA) content was remarked. Therefore, it may suggest that S-CMP has better immunological and anti-tumor effects on mice in vivo.

Characterization and antioxidant activities of degraded polysaccharides from Poria cocos sclerotium

Poria cocos F.A.Wolf is a Chinese traditional medicine used to treat chronic gastritis, edema, nephrosis, gastric atony, and acute gastroenteric catarrh. Polysaccharides are the main active component of P. cocos. We obtained polysaccharides PCP-1, PCP-2, and PCP-3 from the degradation of P. cocos polysaccharides (PCP) with different concentrations of H2O2 solution. Molecular weights were determined by high performance size exclusion chromatography. HPLC analysis of monosaccharide composition confirmed that PCP-1, PCP-2, and PCP-3 are heteropolysaccharides composed of glucose and arabinose. IR spectra indicated obvious characteristic peaks of polysaccharides. The antioxidant activities of these polysaccharides were evaluated by established in vitro systems, including scavenging activity of hydroxyl radicals, ABTS radicals, and ferrous ions. The degradation polysaccharides exhibited obvious and concentration-dependent antioxidant properties. In addition, DNA binding analysis showed that PCP-1 had a stronger capacity than other polysaccharides to interact with DNA. However, each polysaccharide had a certain capacity for DNA damage protection.

Chemical modification and antioxidant activities of polysaccharide from mushroom Inonotus obliquus

Chemical modification polysaccharides exerted potent biological property which was related to the physicochemical properties. In the present study, polysaccharides from Inonotus obliquus were modified by suflation, acetylation and carboxymethylation. The physicochemical and antioxidant properties of I. obliquus polysaccharide (IOPS) and its derivatives were comparatively investigated by chemical methods, gas chromatography, size exclusion chromatography, scanning electron micrograph, infrared spectra and circular dichroism spectra, and ferric reducing power assay and lipid peroxidation inhibition assay, respectively. Results showed that physicochemical and antioxidant properties of IOPS were differed each other after the chemical modification of suflation, acetylation and carboxymethylation. Among the three derivatives, acetylationed polysaccharide (Ac-IOPS) resulted in lower molecular weight distribution, lower intrinsic viscosity, a hyperbranched conformation, higher antioxidant abilities on ferric-reducing power and lipid peroxidation inhibition activity compared with the native polysaccharide IOPS. Ac-IOPS might be explored as a novel potential antioxidant for human consumption.

Effects of lacquer polysaccharides, glycoproteins and isoenzymes on the activity of free and immobilised laccase from Rhus vernicifera

The purified polysaccharides, glycoproteins, and isoenzymes of Rhus laccase, and crude enzymes, from Chinese lacquer (Rhus vernicifera sap) were used to determine their influence on the enzymic activity of Rhus laccase on several substrates (4-phenylenediamine, isoeugenol and coniferyl alcohol). No product identity changes were observed when these components were added singularly or in combination to the enzymic reactions (only relative product yields varied significantly), however, the polysaccharides (GP1 and GP2) and glycoprotein (stellacyanin, St) exhibited negative effects, and the two isoenzymes (L1 and L2) exhibited positive synergistic effects, on the activity of Rhus laccase. With respect to the activity of the crude enzymes, the negative effects of GP1, GP2 and St were greater than the positive effects of L1 and L2, compared with free Rhus laccase on its own (using 4-phenylenediamine as substrate), the estimated inhibitory effect (of GP1, GP2 and St) being by at least a factor of 50 (even with the positive effect of L1 and L2). This contributes to understanding of lacquer storage stability and drying rates. Immobilisation of crude enzymes using a variety of techniques (using natural and modified polysaccharides, and an inorganic support) where evaluated using isoeugenol as substrate. Agar embedding and zirconium chloride chelation methods resulted in the highest substrate conversion levels. The yields and products of isoeugenol catalysis using Vietnamese crude enzymes/purified Rhus laccase and commercial Denilite laccase were also compared and contrasted with their Chinese lacquer sap equivalents.

A search for hepatoprotective activity of aqueous extract of Rhus coriaria L. against oxidative stress cytotoxicity

The protective effects of different concentrations of aqueous extract of Rhus coriaria L. fruit (75 and 100 microg/ml) and also gallic acid (100 microM) as one of its main components were examined against oxidative stress toxicity induced by cumene hydroperoxide (CHP) in isolated rat hepatocytes. Both extract concentrations and gallic acid (100 microM) significantly (P<0.05) protected the hepatocyte against all oxidative stress markers including cell lysis, ROS generation, lipid peroxidation, glutathione depletion, mitochondrial membrane potential decrease, lysosomal membrane oxidative damage and cellular proteolysis. Aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) were more effective than gallic acid (100 microM) in protecting hepatocytes against CHP induced lipid peroxidation (P<0.05). On the other hand gallic acid (100 microM) acted more effective than aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) at preventing hepatocyte membrane lysis (P<0.05). In addition H(2)O(2) scavenging effect of both extract concentrations (75 and 100 microg/ml) were determined in hepatocytes and compared with gallic acid (100 microM). Gallic acid (100 microM) was more effective than aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) at H(2)O(2) scavenging activity (P<0.05).

Carboxymethylated beta-glucan derived from Poria cocos with biological activities

Water-insoluble beta-(1-3)-D-glucan isolated from the sclerotium of Poria cocos hardly exhibits biological activity. Therefore, it is advantageous to produce a value-added product from P. cocos. We extracted the beta-(1-3)-D-glucan from the sclerotium of P. cocos and synthesized a carboxymethylated derivative. The structural and physiological properties of the derivative were investigated. The carboxymethylation of the polysaccharides was confirmed by Fourier transform infrared spectroscopy, and the degree of substitution (DS) and molecular weight were obtained by the potentiometric titration and gel permeation chromatography (GPC) analysis, respectively. The carboxymethylation caused the enhancement of in vitro bile acid binding capacity of the polysaccharides, which would be explained by the improved water solubility and structural changes caused by carboxymethylation. In addition, in vitro antiradical capacity of the derivative was observed by the method of 2,2-diphenyl-1-picrylhydrazyl (DPPH).

Biological activities of extracts from sumac (Rhus spp.): a review

Sumac is the common name for a genus (Rhus) that contains over 250 individual species of flowering plants in the family Anacardiaceae. These plants are found in temperate and tropical regions worldwide, often grow in areas of marginal agricultural capacity, and have a long history of use by indigenous people for medicinal and other uses. The research efforts on sumac extracts to date indicate a promising potential for this plant family to provide renewable bioproducts with the following reported desirable bioactivities: antifibrogenic, antifungal, antiinflammatory, antimalarial, antimicrobial, antimutagenic, antioxidant, antithrombin, antitumorigenic, antiviral, cytotoxic, hypoglycaemic, and leukopenic. As well, the bioactive components can be extracted from the plant material using environmentally benign solvents that allow for both food and industrial end-uses. The favorable worldwide distribution of sumac also suggests that desirable bioproducts may be obtained at the source, with minimal transportation requirements from the source through processing to the end consumer. However, previous work has focussed in just a few members of this large plant family. In addition, not all of the species studied to date have been fully characterized for potential bioactive components and bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better understand the full potential of the Rhus genus as part of global green technology based on bioproducts and bioprocesses research programs.

Purification and characterization of hydrosoluble components from the sap of Chinese lacquer tree Rhus vernicifera

Continuous gradient elution chromatography (CGEC) was employed to purify and separate enzymes and polysaccharides from the sap of Rhus vernicifera Chinese lacquer tree. There are three different molecules with laccase enzyme activity. Two are enzymes of each other (L1, and L2), whereas the third (RL) is an entirely separate entity. Two polysaccharides (GP1 and GP2) were also found. The Rhus laccase (RL), and isoenzymes L1 and L2, have peak molecular masses of 109,100, 120,000, 103,000 respectively; each has four copper atoms per molecule, and the pI values were 8.2, 8.6, and 9.1, respectively. The structure of the laccases was studied by Fourier-transform infrared (FT-IR) and Matrix-assisted laser desorption/ionization time-of flight (MALDI-TOF) mass spectrometry. The typical amide I (1646cm(-1)) and amide II (1545cm(-1)) bands were observed. The results from MALDI-TOF were similar to those from CGEC, but the molecular mass from the MALDI-TOF was significantly different from that obtained from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Synthesis and characterization of carboxymethylated cyclosophoraose, and its inclusion complexation behavior

Carboxymethylated cyclosophoraoses (CM-Cys) were synthesized by chemical modification of a family of neutral cyclosophoraoses isolated from Rhizobium leguminosarum biovar trifolii. Structural analyses of the CM-Cys were carried out using NMR and FTIR spectroscopies, and the molecular weight distributions were confirmed with MALDI-TOF mass spectrometry. Based on structural characterization, native cyclosophoraoses were successfully substituted with carboxymethyl groups at the OH-4 and OH-6 of the glucose residues with degrees of substitution (DS) ranging from 0.012 to 0.290. CM-Cys was also used as a host for the inclusion complexation with hydrobenzoin (HB) and N-acetyltryptophan (N-AcTrp) as guest molecules. NMR spectroscopic analyses of the complexes showed that the CM-Cys induced chemical shifts of some protons of the guest molecules upon the complexation. Phase solubility studies of the guest molecules by CM-Cys were performed using HPLC, and the results were compared with those of native cyclosophoraoses. The solubility of HB and N-AcTrp was enhanced by the CM-Cys about 5.1- and 299-fold, respectively.