Carboxymethylation of a polysaccharide extracted from Ganoderma lucidum enhances its antioxidant activities in vitro

Molecular mechanisms of bioactive polysaccharides from Ganoderma lucidum (Lingzhi), a review

Ganoderma lucidum, commonly known as "Lingzhi" in Chinese, are well-known medicinal mushrooms. Lingzhi has been used in traditional Chinese herbal medicines for more than two thousand years. G. lucidum polysaccharides (GLPs) are present at high levels in G. lucidum cells and GLPs have molecular weights ranging from thousands to millions. GLPs have been widely studied for their various biological activities, such as antioxidant, antitumor, anti-inflammatory, antiviral, anti-diabetes, and immunomodulatory activities. The methods for GLPs extraction and characterization are mature, but the comprehensive research on the relationship between GLPs structure (i.e., molecular weight, tertiary structure, branching, substituents, and monosaccharide composition) and function is still quite limited. The aim of this review is to update and summarize the mechanisms of the various bioactive polysaccharides extracted from G. lucidum. The information presented on these bio-mechanisms should be valuable in the research and development of GLPs-derived therapeutics.

Carboxymethyl-botryosphaeran stabilized carbon nanotubes aqueous dispersion: A new platform design for electrochemical sensing of desloratadine

The polysaccharide carboxymethyl-botryosphaeran (CMB) was used to improve the dispersion of multi-walled carbon nanotubes (MWCNTs) in water. This feature was applied in modifying a glassy carbon electrode (GCE) to construct a sensitive voltammetric sensor for the determination of desloratadine (DESL), a tricyclic antihistamine. The morphology and spectroscopic behavior of the sensor were evaluated. The modified sensor was characterized as homogeneous, and presented a higher electroactive area and a lower charge transfer resistance compared to the unmodified GCE. Using linear sweep voltammetry at 25 mV s^-1, the developed sensor presented a sensitivity of 1.018 μA L μmol^-1 in the linear working range of 1.99-32.9 μmol L^-1, with a detection limit of 0.88 μmol L^-1 of DESL in 0.10 mol L^-1 potassium hydrogen-phosphate solution (pH 8.0). In addition, the sensor showed excellent repeatability with a relative standard deviation of only 1.02% for a sequence of 10 measurements. The sensor was successfully applied in the analysis of pharmaceutical preparations containing DESL, with equivalent results compared to a validated spectrophotometric method at the 95% confidence level. The sensor was also employed in the analysis of a spiked sample of DESL in rat serum.

Preparation, characteristics, and antioxidant activities of carboxymethylated polysaccharides from blackcurrant fruits

In the present study, the native polysaccharide (RNP) extracted from blackcurrant fruits was carboxymethylated. Physicochemical characteristics and antioxidant activities in vitro of RNP and three carboxymethylated polysaccharides (CRNPs) were determined. GC analysis proved that RNP and CRNPs were composed of the same six monosaccharides (galacturonic acid, rhamnose, arabinose, mannose, glucose and galactose), but the molar ratios of monosaccharides were different. HPLC demonstrated that the molecular weights of CRNPs were improved. The assays of the antioxidant properties indicated that CRNPs possessed stronger scavenging activities on radicals (hydroxyl and superoxide radicals) and better anti-lipid peroxidation activities, as well as better protection effects on erythrocyte hemolyses in vitro compared with RNP. The activities of CRNPs were significantly enhanced with the increase of the degree of substitution (DS). These results proved that the carboxymethylation could effectively increase the antioxidant activities of the polysaccharide.

Effect of Carboxymethylation and Phosphorylation on the Properties of Polysaccharides from Sepia esculenta Ink: Antioxidation and Anticoagulation in Vitro

To investigate the effect of carboxymethylation and phosphorylation modification on Sepia esculenta ink polysaccharide (SIP) properties, this study prepared carboxymethyl SIP (CSIP) with the chloracetic acid method, and phosphorylated SIP (PSIP) with the sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) method, on the basis of an orthogonal experiment. The in vitro antioxidant and anticoagulant activities of the derivatives were determined by assessing the scavenging capacity of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals, which activated the partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). The results showed that SIP was modified successfully to be CSIP and PSIP, and degrees of substitution (DSs) of the two products were 0.9913 and 0.0828, respectively. Phosphorylation efficiently improved the antioxidant property of SIP, and the IC₅₀ values of PSIP on DPPH and hydroxyl radicals decreased by 63.25% and 13.77%, respectively. But carboxymethylation reduced antioxidant activity of the native polysaccharide, IC₅₀ values of CSIP on the DPPH and hydroxyl radicals increased by 16.74% and 6.89%, respectively. SIP significantly prolonged the APTT, PT, and TT in a dose-dependent fashion, suggesting that SIP played an anticoagulant action through intrinsic, extrinsic, and common coagulation pathways. CSIP and PSIP both possessed a stronger anticoagulant capacity than SIP via the same pathways; moreover, CSIP was observed to be more effective in prolonging APTT and PT than PSIP.

Encapsulated Microparticles of (1→6)-β-d-Glucan Containing Extract of Baccharis dracunculifolia: Production and Characterization

β-Glucans are biomacromolecules well known, among other biological activities, for their immunomodulatory potential. Similarly, extracts of Baccharis dracunculifolia also possess biological properties and are used in folk medicine for the treatment of inflammation, ulcers, and hepatic diseases. Microparticles containing (1→6)-β-d-glucan (lasiodiplodan) and B. dracunculifolia extract were produced and characterized. A 23 factorial design was employed to define the conditions of production of microparticles by atomization. Lasiodiplodan associated with maltodextrin and gum arabic was studied as a matrix material. Microparticles of 0.4 μm mean size and high phenolics content (3157.9 μg GAE/g) were obtained under the optimized conditions. The microparticle size ranged from 0.23 to 1.21 µm, and the mathematical model that best represented the release kinetics of the extract was the Korsmeyer-Peppas model. Diffusional exponent (n) values of 0.64 at pH 7.7 and 1.15 at pH 2.61 were found, indicating particles with a non-Fickian or anomalous transport system, and Super Case II transport, respectively. Thermal analysis indicated that the microparticles demonstrated high thermal stability. The X-ray diffraction analyses revealed an amorphous structure, and HPLC-DAD analysis showed microparticles rich in phenolic compounds: caffeic acid, p-coumaric acid, and catechin. The microparticles obtained comprise a new biomaterial with biological potential for applications in different fields.

Fungal Exocellular (1-6)-β-d-glucan: Carboxymethylation, Characterization, and Antioxidant Activity

Exocellular (1→6)-β-d-glucan (lasiodiplodan) produced by the fungus Lasiodiplodia theobromae MMPI was derivatized by carboxymethylation using different concentrations of a derivatizing agent. Lasiodiplodan was derivatized by carboxymethylation in an attempt to increase its solubility and enhance its biological activities. Carboxymethylglucans with degrees of substitution (DS) of 0.32, 0.47, 0.51, 0.58, and 0.68 were produced and characterized. FTIR analysis showed a band of strong intensity at 1600 cm⁻¹ and an absorption band at 1421 cm⁻¹, resulting from asymmetric and symmetrical stretching vibrations, respectively, of the carboxymethyl group COO- in the carboxymethylated samples. Thermal analysis showed that native lasiodiplodan (LN) and carboxymethylated derivatives (LC) exhibited thermal stability up to 200–210 °C. X-ray diffractometry demonstrated that both native and carboxymethylated lasiodiplodan presented predominantly an amorphous nature. Scanning electron microscopy revealed that carboxymethylation promoted morphological changes in the biopolymer and increased porosity, and alveolar structures were observed along the surface. The introduction of carboxymethyl groups in the macromolecule promoted increased solubility and potentiated the hydroxyl radical-scavenging activity, suggesting a correlation between degree of substitution and antioxidant activity.

Antioxidant and Antiproliferative Activities of Modified Polysaccharides Originally Isolated from Morchella Angusticepes Peck

Polysaccharides extracted from Morchella angusticepes Peck (PMEP) were chemically modified to obtain sulfated, carboxymethylated, and acetyled derivatives. Results showed that the acetyled derivatives with the degree of substitution (0.40 ± 0.07) exerted higher antioxidant ability than native polysaccharides, demonstrating inhibitory effects on growth of human hepatoma cells (EC₅₀  = 0.710 ± 0.002 mg/mL) and human colon cancer cells (EC₅₀  =  1.229 ± 0.008 mg/mL). It indicated that the acetylation was a favorable way to enhance the bioactivities of PMEP. PRACTICAL APPLICATION: Polysaccharides extracted from Morchella angusticepes Peck (PMEP) have many health-promoting properties. Chemical modifications could improve the bioactivities of polysaccharides. We demonstrated that acetylation enhanced the cellular antioxidant and antiproliferative activities of PMEP. The results support further research that explores clinical utility, and may justify ex vivo and in vivo designs toward that end.

Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review

Ganoderma lucidum (Reishi) is a popular medicinal mushroom and has been used in oriental medicine because of its promoting effects on health and life expectancy. G. lucidum contains various compounds with a high grade of biological activty, which increase the immunity and show antitumour, antimicrobial, anti-inflammatory, antioxidant and acetylcholinesterase inhibitory activity. Several of these substances belong to the triterpenoids and polysaccharides classes. Proteins, lipids, phenols, sterols, etc. are also present. In the present review, an extensive overview of the presence of antitumour, antimicrobial, antioxidant and antiacetylcholinesterase compounds in G. lucidum extracts will be given, along with an evaluation of their therapeutic effects.

Acetylation Modification Improves Immunoregulatory Effect of Polysaccharide from Seeds of Plantago asiatica L

The current study was conducted to investigate effects of acetylated Plantago asiatica L. polysaccharides (Ac-PLCPs) on their immunoregulatory activities in bone-marrow-derived dendritic cells (DCs) model. Influences of natural Plantago asiatica L. crude polysaccharide (PLCP) and Ac-PLCPs on inducing phenotypic and functional maturation on DCs were determined. The results showed that Ac-PLCPs with degree of substitution (DS) from 0.06 to 0.1 could not only stimulate the expression of surface molecules major histocompatibility complex class II (MHC II), cluster of differentiation 86 (CD86), and CD80 on DCs (P<0.01) but also increase the secretion of cytokine IL-12p70 (P<0.01). The endocytosis activity of DCs was attenuated by Ac-PLCPs treatment (P<0.01), while the mRNA expressions of chemokine receptors CCR7 and CXCR4 in DCs were significantly increased (P<0.01). Besides, DCs treated with the Ac-PLCPs showed extremely strong T cell proliferation stimulating activity (P<0.01). These data showed that Ac-PLCPs had higher maturation-stimulating activity on DCs than PLCP, which indicated that acetylation modification improved the immunoregulatory effect of PLCP.

Structural Characterization of Mannoglucan from Dendrobium nobile Lindl and the Neuritogenesis-Induced Effect of Its Acetylated Derivative on PC-12 Cells

A water-soluble polysaccharide (JCS1) was isolated from the stems of Dendrobium nobile Lindl. JCS1 was structurally characterized using a combination of chemical and spectral analysis, including methylation analysis, partial acid hydrolysis, Fourier-transform infrared (FTIR) spectroscopy, gas chromatography (GC), GC-mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. The molecular weight was estimated to be 2.3 × 10⁴ Da using high-performance gel permeation chromatography (HPGPC). The sugar composition analysis indicated it was composed of glucose, mannose, xylose, and arabinose in a 40.2:2.3:1.7:1.0 molar ratio. The structure analysis showed that JCS1 was a mannoglucan with a backbone consisting of (1→4)-linked β-Manp and (1→4)-linked α-Glcp with branches at C-6 of (1→4)-linked α-Glcp residues. The branches were composed of T-α-Glcp, 1,4-α-Xylp, and T-α-Araf. In vitro bioactivity tests revealed that the acetylated derivative of JCS1, YJCS1, induced neuritogenesis of PC-12 cells. These results demonstrate that YJCS1 might be a promising bioactive polysaccharide for development as a drug candidate for the possible prevention and treatment of neurodegeneration diseases.

Effect of carboxymethylation on rheological and drug release characteristics of Terminalia catappa gum

The carboxymethylation of galactomannans, arabinogalactans, arbinoxylan, etc is known to modify solubility, swelling index, rheological behaviour, powder characteristics, etc. Therefore, an attempt had been made to study the effect of carboxymethylation on Terminalia catappa (TC) gum. For this, modified Williamson synthesis reaction was utilized employing Quality by Design (QbD) approach. Grafting of carboxymethyl group on Terminalia catappa was confirmed by ATR-FTIR, H¹NMR and DSC analyses. The rheological attributes revealed that the carboxymethylation of TC lowers the viscosity, enhance thermal stability (high activation energy), disentanglement was near to re-entanglement, and weak gelling characteristic. However, the soluble fluconazole loaded gel formulation of CMTC showed diffusion based kinetic model indicating good reservoir for effective application on skin/tissue surfaces.

Anti-fatigue activity of a Lachnum polysaccharide and its carboxymethylated derivative in mice

The present study was designed to evaluate the anti-fatigue activity of an exopolysaccharide LEP-1b and its carboxymethylated derivative CLEP-1b from a Lachnum sp. Carboxymethylation was confirmed through FT-IR and ¹³C NMR spectroscopies, which showed that the (-CH₂COOH) group was attached to an oxygen (O) atom of the hydroxyl group on (C-3) of LEP-1b. Each treatment group LEP-1b and CLEP-1b at doses (50, 100, 200mg/kg, respectively) ameliorated physical fatigue and extended exhaustive swimming time in mice. Results of the fatigue related biochemical markers showed that LEP-1b and CLEP-1b at doses (50, 100, 200mg/kg, respectively) increased the content of hepatic glycogen and decreased the level of serum urea nitrogen and lactic acid. Additionally, LEP-1b and CLEP-1b enhanced the antioxidant enzymes' activities and reduced the lipid peroxidation. Moreover, results revealed that CLEP-1b had higher anti-fatigue activity than LEP-1b at same doses but without statistical significance, especially CLEP-1b (200mg/kg) had strong anti-fatigue effects. Therefore, LEP-1b and CLEP-1b can potentially be exploited as a kind of healthcare compound to combat fatigue and to boost physical strength.

Ganoderma lucidum polysaccharides encapsulated in liposome as an adjuvant to promote Th1-bias immune response

Liposome-based vaccine delivery systems are known to enhance immune responses. Ganoderma lucidum polysaccharides (GLP) have been widely studied as immunomodulator and it could be as inducers of strong immune responses. In the research, GLP and ovalbumin (OVA) were encapsulated into liposome as vaccine and inoculated to mice. The magnitude and kinetics of the humoral and cellular immune responses were investigated. The results showed that GLP-OVA-loaded liposomes (GLPL/OVA) could induce more powerful antigen-specific immune responses than each single-component formulation. Mice immunized with GLPL/OVA displayed higher antigen-specific IgG antibodies, better splenocytes proliferation, higher cytokine secretion by splenocytes and significant activation of CD3+CD4+ and CD3+CD8+ T cells. Thus the GLPL/OVA formulation produced a heightened humoral and cellular immune response, with an overall Th1 bias. Enhanced immune responses elicited by the GLPL/OVA formulation might be attributed to effective activation and mature of DC in draining lymph nodes. Overall, these findings indicate that GLPL have the potential to enhance immune responses as vaccine delivery systems.

Reviews on Mechanisms of In Vitro Antioxidant Activity of Polysaccharides

It is widely acknowledged that the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) induced oxidative stress will cause significant damage to cell structure and biomolecular function, directly or indirectly leading to a number of diseases. The overproduction of ROS/RNS will be balanced by nonenzymatic antioxidants and antioxidant enzymes. Polysaccharide or glycoconjugates derived from natural products are of considerable interest from the viewpoint of potent in vivo and in vitro antioxidant activities recently. Particularly, with regard to the in vitro antioxidant systems, polysaccharides are considered as effective free radical scavenger, reducing agent, and ferrous chelator in most of the reports. However, the underlying mechanisms of these antioxidant actions have not been illustrated systematically and sometimes controversial results appeared among various literatures. To address this issue, we summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms.

Optimization of extraction, characterization and antioxidant activity of polysaccharides from Brassica rapa L

The root of Brassica rapa L. has been traditionally used as a Uyghur folk medicine to cure cough and asthma by Uyghur nationality in Xinjiang Uygur Autonomous Region of China. In the present study, therefore, extraction optimization, characterization and antioxidant activity in vitro of polysaccharides from the root of B. rapa L. (BRP) were investigated. The optimal extraction conditions with an extraction yield of 21.48 ± 0.41% for crude BRP were obtained as follows: extraction temperature 93°C, extraction time 4.3h and ratio of extraction solvent (water) to raw material 75 mL/g. The crude BRP was purified by chromatographic columns of DEAE-52 cellulose and Sephadex G-100, affording three purified fractions of BRP-1-1, BRP-2-1 and BRP-2-2 with average molecular weight of 1510, 1110 and 838 kDa, respectively. Monosaccharide composition analysis indicated that BRP-1-1 was composed of mannose, rhamnose, glucose, galactose and arabinose, BRP-2-1 was composed of rhamnose, galacturonic acid, galactose and arabinose, and BRP-2-2 was composed of rhamnose and galacturonic acid in a molar ratio of 1.27: 54.92. Furthermore, the crude BRP exhibited relatively higher antioxidant activity in vitro than purified fractions; hence, it could be used as a natural antioxidant in functional foods or medicines.

Carboxymethylation of polysaccharides from Tremella fuciformis for antioxidant and moisture-preserving activities

The carboxymethylated polysaccharide (CATP), which derived from water-insoluble crude Tremella fuciformis polysaccharide (ATP), was prepared. And then the antioxidant and moisture-preserving activities of the samples were investigated. The results of chemical composition and FT-IR analysis showed the carboxymethylated modifications of polysaccharide were successful. The degree of substitution (DS) of four carboxymethylated derivatives were different with the molar of monochloroacetic acid. Their water solubility and biological activities were improved with the increase of DS. And moreover, a high antioxidant and moisture-preserving activities of CATPs was observed, so this derivative needs to be attention and studied in further. Results proved that the carboxymethylation could effectively enhance their potential biological properties of the polysaccharide.

Carboxymethylation of an exopolysaccharide from Lachnum and effect of its derivatives on experimental chronic renal failure

Carboxymethylated polysaccharide CLEP-1b was prepared from a single component (LEP-1b) of Lachnum YM281 exopolysaccharides by molecular modification with a degree of substitution (DS) of 0.286. Infrared result proved that the carboxymethylation of LEP-1b succeeded and (13)C NMR result showed that the carboxymethyl group (CH2COOH) was chemically linked to an oxygen (O) atom of the hydroxyl on C-3 of LEP-1b. LEP-1b could improve the histopathological status of kidney and significantly reduce the contents of serum creatinine (Scr) and blood urea nitrogen (BUN), and increase the contents of total protein and albumin. It could also enhance the activity of SOD, GSH-PX, CAT, GSH and decrease MDA contents in the nephridial and hepatic tissues. What's more, CLEP-1b showed more significant effects than LEP-1b at the same dosage. The research indicated that LEP-1b and CLEP-1b could mitigate the chronic renal failure of mice and the effects were closely associated with antioxidant activity.

Antioxidant activity of carboxymethyl (1→3)-β-d-glucan (from the sclerotium of Poria cocos) sulfate (in vitro)

(1→3)-β-d-glucan derived from Poria cocos hardly exhibits bioactivities. To extend its use, three types of (1→3)-β-d-glucan derivatives, which were sulfated (1→3)-β-d-glucan (S-P), carboxymethyl (1→3)-β-d-glucan (CMP) and carboxylmethyl (1→3)-β-d-glucan sulfate (S-CMP), were synthesized. Potential antioxidant activities of S-P, CMP and S-CMP were evaluated in vitro. The experiments of scavenging abilities of free radicals were carried out, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion and hydroxyl. Deeply study of the derivatives' inhibitory effect for lipid peroxidation, DNA oxidative damage, erythrocyte hemolysis, and malondialdehyde (MDA) production were determined. And S-CMP significantly (P<0.01) increased the antioxidant activity of β-glucan. These results showed that multiple modifications of polysaccharides may bring the derivatives with excellent properties and various applications.