Molecular mass and chain conformation of carboxymethylated derivatives of beta-glucan from sclerotia of Pleurotus tuber-regium

Exploring β-glucan as a micro-nano system for oral delivery targeted the colon

The critical role of oral colon-specific delivery systems (OCDDS) is important for delivering active agents to the colon and rectum specifically via the oral route. The use of micro/nanostructured OCDDS further improves drug stability, bioavailability, and retention time, leading to enhanced therapeutic effects. However, designing micro/nanoscale OCDDSs is challenging due to pH changes, enzymatic degradation, and systemic absorption and metabolism. Biodegradable natural polysaccharides are a promising solution to these problems, and β-glucan is one of the most promising natural polysaccharides due to its unique structural features, conformational flexibility, and specific processing properties. This review covers the diverse chemical structures of β-glucan, its benefits (biocompatibility, easy modification, and colon-specific degradation), and various β-glucan-based micro/nanosized OCDDSs, as well as their drawbacks. The potential of β-glucan offers exciting new opportunities for colon-specific drug delivery.

A wet-adhesive carboxymethylated yeast β-glucan sponge with radical scavenging, bacteriostasis and anti-inflammatory functions for rapid hemostasis

Local hemostats still face obstacles to efficiently achieving hemostasis and promoting wound healing. Herein, a series of multifunctional well-degradable hemostatic sponges based-on carboxymethylated yeast β-glucan (CMYG) were fabricated by lyophilization. The porous CMYG sponge not only could absorb blood quickly (44.12 g/g), but also possessed unexpected tissue adhesion (∼30 kPa), and it represented good biocompatibility in vitro on fibroblasts and red blood cells. Notably, compared with the commercial Celox™, the CMYG sponge achieved more rapid hemostasis and significantly reduced blood loss in liver injury rat models by rapid wound block. Interestingly, the developed sponge showed an outstanding effect on antioxidant, anti-infection, anti-inflammatory, and cell proliferation, which are beneficial for further wound repair. Overall, these results suggest that the CMYG sponge is a promising candidate for the clinical management of uncontrollable hemorrhage and the further development of wound dressing materials throughout skin defect repair.

Fabrication of phytic acid-modified wheat straw platform and its pH-responsive release performance for the pesticide imidacloprid

For the effective utilization of pesticides and the treatment of abundant waste wheat straw (WS) resources, an eco-friendly composite PA-WS platform was prepared by modification of WS with phytic acid (PA).

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.

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).

Enhancement of antitumor activities in sulfated and carboxymethylated polysaccharides of Ganoderma lucidum

Two water-soluble derivatives, sulfated and carboxymethylated Ganoderma lucidem polysaccharides, coded as S-GL and CM-GL, were prepared using derivatization of water-insoluble polysaccharides (GL-IV-I) extracted from the fruit body of G. lucidem . The degree of substitution (DS) of S-GL and CM-GL was 0.94 and 1.09, respectively. The weight-average molecular mass (Mw) of GL-IV-I, S-GL, and CM-GL was determined with light scattering to be 13.3x10(4), 10.1x10(4), and 6.3x10(4), respectively. S-GL and CM-GL inhibited the in vitro proliferation of Sarcoma 180 (S-180) tumor cells in a dose-dependent manner, with an IC50 value of 26 and 38 microg/mL, respectively. They also inhibited the growth of S-180 solid tumors implanted in BALB/c mice, with low toxicity to the animals. Flow cytometric studies revealed that treatment of S-GL and CM-GL with S-180 tumor cells could mediate the cell-cycle arrest in the G2/M phase. The expression of Bax increased, and the expression of Bcl-2 decreased dramatically, as shown by immuno-histochemical staining of S-180 tumor tissue excised from the animals. The sulfated and carboxmethylated groups in the polysaccharides played an important part in enhancing their antitumor activities, leading to the potential to be developed into antitumor drugs.

Chemical modification and antitumor activities of two polysaccharide-protein complexes from Pleurotus tuber-regium

Two water-soluble polysaccharide-protein complexes, extracted from Pleurotus tuber-regium sclerotia, were modified chemically to obtain their sulfated and carboxymethylated derivatives. While C6 position of glucan was fully substituted, C2, C3, and C4 were only partially substituted by sulfate groups. C3, C4, and C6 position of glucan were partially substituted during the carboxymethylation. Chain conformation and antitumor activity of the native samples and their derivatives were studied. The native samples and derivatives existed in sphere conformation, and showed potent in vitro antitumor activities. Water-solubility and introduction of ionic groups played important roles in enhancing the antitumor activities of the polysaccharide-protein complexes.

Structural and biological study of carboxymethylated Phellinus linteus polysaccharides

Polysaccharides isolated from Phellinus linteus were chemically modified by carboxymethylation, and the structural and physiological properties of the derivative were investigated. 13C NMR spectroscopy showed that the polysaccharides extracted from P. linteus contained (1-3)-beta-glucans with a (1-6)-linkage. The carboxymetehylation of the P. linteus polysaccharides was confirmed by Fourier transform infrared spectroscopy, and the degree of substitution was obtained by the potentiometric titration, which was calculated to be 0.63. The bronchoalveolar lavage experiments showed that the carboxymethylated derivative raised the nitric oxide production. In addition, the carboxymethylation stimulated in vitro cytotoxic activity against the HT1080 cell line. Thus, the derivative exhibited the enhanced activity of immune systems, which would be explained by the improved water solubility and structural changes by carboxymethylation. However, a slight decrease in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the derivative was observed.

Natural and modified (1-->3)-beta-D-glucans in health promotion and disease alleviation

A number of polysaccharides with beta-glycosidic linkage are widespread in nature in a variety of sources. All have a common structure and the (1-->3)-beta-D-glucan backbone is essential. They have attracted attention over the years because of their bioactive and medicinal properties. In many cases their functional role is a mystery, in others it is well established. Because of their insoluble chemical nature, particulate (1-->3)-beta-D-glucans are not suitable for many medical applications. Various methods of changing or modifying the beta-D-glucan chemical structure and transforming it to a soluble form have been published. The beta-D-glucan bioactive properties can be affected positively or negatively by such modifications. This review examines beta-glucan sources in nature, health effects and structure-activity relationships. It presents the current state of beta-D-glucan solubilization methods and discusses their effectiveness and application possibilities for the future.

Comparison of curdlan and its carboxymethylated derivative by means of Rheology, DSC, and AFM

Curdlan was carboxymethylated in an aqueous alkaline medium using monochloroacetic acid as the etherifying agent. The structure of carboxymethylated curdlan (CMc) was analyzed by FT-IR and NMR spectroscopy, which revealed that the carboxymethyl group was introduced mainly at the C-6 position as well as at the C-2 and C-4 positions. Furthermore, CMc was compared with the native curdlan by using rheology and DSC methods. It was found that in water, both polysaccharides behaved as pseudoplastic fluids and fit the power law and Herschel-Bulkley rheological models well. Both the storage shear modulus G' and the loss shear modulus G'' of CMc aqueous solutions decreased and became more frequency dependent with decreasing concentration in comparison with the curdlan aqueous suspensions. The modulus-temperature curve also suggested that the gel characteristic of curdlan has been lost after chemical modification, which is consistent with the DSC results. AFM images revealed differences in the conformation of native and carboxymethylated curdlan, which changed from the aggregation of macromolecules to triple helices. All the experimental results suggest that the hydrogen bonds that bind curdlan with interstitial water to form the micelles have been destroyed completely and that the hydrophobic interactions related to the methylene groups at C-6 formed above 55 degrees C disappeared due to the introduction of the hydrophilic carboxymethyl group.

Chain conformation of sulfated derivatives of β-glucan from sclerotia of Pleurotus tuber-regium

Six water-insoluble (1-->3)-beta-D-glucan fractions TM8-1 to TM8-6 with weight-average molecular mass Mw ranging from 5.76 to 77.4x10(4) obtained from the sclerotia of Pleurotus tuber-regium were sulfated to produce the water-soluble fractions S-TM8-1 to S-TM8-6 with Mw from 6.0 to 64.8x10(4). The degree of substitution (DS) of S-TM8 fractions was analyzed by elemental analysis (EA) to be 1.14-1.74. The 13C NMR results indicated that the C-6 was fully substituted, and C-2, C-4 were partially substituted by the sulfo-groups. The Mw and the intrinsic viscosity [eta] of the S-TM8 fractions were measured, respectively, by size-exclusion chromatography combined with laser light scattering (SEC-LLS), LLS and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The dependences of [eta] and radius of gyration <s2>z(1/2) on Mw for the S-TM8 samples were found to be [eta]=1.89x10(-2) Mw(0.70) (cm3/g) and <s2>z(1/2)=1.12x10(-4) Mw(0.81) (nm) in the Mw range tested. Based on current theories for a wormlike chain model, the molar mass per unit contour length ML and persistence length q of the S-TM8 were calculated to be 990 nm(-1) and 8.5 nm, respectively. The relatively higher q value suggested a more expanded flexible chain of S-TM8 in PBS. The water-solubility and relatively expanded chain conformation of the STM8 fractions were considered to be significant to their antiviral activity.