Unlocking the potential of beta-glucans: a comprehensive review from synthesis to drug delivery carrier potency

Modernization and lifestyle changes have resulted in a number of diseases, including cancer, that require complicated and thorough treatments. One of the most important therapies is the administration of antibiotics and medicines. This is known as chemotherapy for cancer, and it is a regularly utilised treatment plan in which the medications used have negative side effects. This has resulted in extensive research on materials capable of delivering pharmaceuticals to particular targets over an extended period of time. Biopolymers have often been preferred as effective drug delivery carriers. Of these, β-glucan, a natural polysaccharide, has not been extensively studied as a drug delivery carrier, despite its unique properties. This review discusses the sources, extraction techniques, structures, and characteristics of β-glucan to provide an overview. Furthermore, the different methods employed to encapsulate drugs into β-glucan and its role as an efficient drug, SiRNA and Plasmid DNA carrier have been elaborated in this article. The capacity of β-glucan-based to specifically target and alter tumour-associated macrophages, inducing an immune response ultimately resulting in tumour suppression has been elaborated. Finally, this study aims to stimulate further research on β-glucan by thoroughly describing its many characteristics and demonstrating its effectiveness as a drug delivery vehicle.

Coating effect of renatured triple-helix lentinan on the morphology and antimicrobial activity of ZnO synthesized by hydrothermal method

Polysaccharides are considered to be ideal green raw materials for enhancing biocompatibility and dispersion effects of nanoparticles. In this study, we coated and dispersed ZnO nanoparticles (NPs) using the denaturation-renaturation process of a triple helix glucan lentinan (LNT), induced by changes in pH value within the reaction system. Various ZnO/LNT composites with different particle sizes and crystal morphologies were prepared and characterized. The results demonstrated that renatured LNT (r-LNT) effectively encapsulated the {101̄0} crystal planes of ZnO, preventing crystal growth during the renaturation process and resulting in smaller, uniformly dispersed nanoparticles. Among the samples, ZnO/r-LNT-2 exhibited significantly higher antimicrobial activity, and it had a certain inhibitory effect on various plant pathogens. It also displayed the highest inhibitory effect against Candida albicans, with a minimum inhibitory concentration (MIC) of up to 8 μg mL-1. Consistently, ZnO/r-LNT-2 generated the highest amount of reactive oxygen species (ROS), thus exhibiting the most effective antimicrobial activity. However, excessive introduction of the dispersant LNT may reduce these activities. This study provides a foundation for further exploring the detailed mechanism of ROS generation catalyzed by ZnO and for harnessing the full potential of this type of antimicrobial agent.

Effect of the β-glucan from Lentinus edodes on colitis-associated colorectal cancer and gut microbiota

Colorectal cancer is the third most common cancer in the world, and therapies with safety are in great need. In this study, the β-glucan isolated from Lentinus edodes was successfully fractionated into three fractions with different weight-average molecular weight (M_w) by ultrasonic degradation and used for the treatment of colorectal cancer. In our findings, the β-glucan was successfully degraded with the M_w decreased from 2.56 × 10⁶ Da to 1.41 × 10⁶ Da, exhibiting the triple helix structure without conformation disruption. The in vitro results indicate that β-glucan fractions inhibited colon cancer cell proliferation, induced colon cancer cell apoptosis, and reduced inflammation. The in vivo results based on Azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model demonstrate that the lower-molecular weight β-glucan fraction showed stronger anti-inflammatory and anti-colon cancer activities by reconstructing intestinal mucosal barrier, increasing short chain fatty acids (SCFAs) content, regulating metabolism of gut microbiota, and rebuilding the gut microbiota structure with the increased Bacteroides and the decreased Proteobacteria at the phylum level, as well as with the decreased Helicobacter and the increased Muribaculum at the genus level. These findings provide scientific basis for using the β-glucan to regulate gut microbiota as an alternative strategy in the clinical treatment of colon cancer.

Structure characterization and bioactivity of neutral polysaccharides from different sources of Polygonatum Mill

Polygonati rhizoma (PR), a traditional medical and edible product, is rich in polysaccharides and exhibits physiological activity, including antioxidant, hypoglycemic and hypolipidemic properties. Neutral polysaccharides have been reported to be one of the main active ingredients of Polygonatum, with many of these fractions being responsible for the biological activity. This behavior was shown to be closely connected to the chemical structure, monosaccharide composition, and glycosidic bond type. There are few reports on the chemical constituents of the neutral polysaccharides from different sources of PR. In this study, neutral polysaccharides of PR from four different regions of China (Chun'an (Zhejiang), Xixia (Henan), Danfeng (Shanxi), and Pan'an (Zhejiang)), named CAZJ, XXHN, DFSX, and PAZJ, respectively, were isolated by anion-exchange and gel-permeation chromatography. Structures of the four polysaccharides were investigated. The results showed that all of them were mainly glucose and mannose, while the monosaccharide composition and content of polysaccharides from different sources varied. The molecular weights of CAZJ, XXHN, DFSX, and PAZJ were 14.119, 22.352, 18.127, and 15.699 kDa, respectively. Infrared spectra illustrated the existence of α-glycosidic bond and β-glycosidic bond in the polysaccharides. CAZJ, XXHN, and DFSX possessed a pyranose ring structure, whereas PAZJ had a furanose ring structure. Congo red test indicated that XXHN, DFSX, and PAZJ had a triple-helix structure. X-ray diffraction showed that the polysaccharides consisted of crystalline and amorphous regions. All four polysaccharides exhibited different degrees of antioxidant and hypoglycemic activities with a dose-dependent manner in the 1.0-10.0 mg/mL concentration range. Correlation analysis revealed that the bioactivities of polysaccharides was significantly related to monosaccharide composition, uronic acid, and protein content. The results suggested that neutral polysaccharides could be used as potential natural antioxidants and hypoglycemic agents for functional and nutraceutical applications.

Beta-d-glucan-based drug delivery system and its potential application in targeting tumor associated macrophages

Use of polysaccharides as carriers in drug delivery system is a hot topic, especially those with specific recognition of immune cells, enabling them to be applied in targeting delivery system. β-d-glucans are naturally occurring non-digestible polysaccharides with immunomodulatory activities that have attracted increasing attention to serve as therapeutic agents or immune-adjuvants. Being able to be specifically recognized by immune cells like macrophages, β-d-glucans can be developed as promising carriers for targeting delivery with stability, biocompatibility and specificity when applied in immunotherapy. Targeting tumor associated macrophages (TAMs) is an emerging strategy for cancer immunotherapy since it exerts anti-cancer effects based on modulating body immunity in tumor microenvironment (TME). This new strategy does not require high concentration of drugs to kill cancer cells directly and lessen tumor recurrence by creating unique immune memory for malignant cells. In this review, construction strategies of polysaccharide-based drug delivery system of three types of β-d-glucan including non-yeast and yeast β-d-glucans as well as hyper-branched β-d-glucan are discussed with reference to their branching characteristics and conformation. The applications of these β-d-glucans as nano-carrier for drug delivery targeting TAMs are also discussed.

Structural characterization of polysaccharides with potential antioxidant and immunomodulatory activities from Chinese water chestnut peels

Chinese water chestnut peels are a kind of vegetable processing waste containing many active components such as polysaccharides, the structure of which remains unknown. To elucidate the structure of polysaccharides from Chinese water chestnut peels, two polysaccharides named WVP-1 and WVP-2 were isolated. WVP-1 (3.16 kDa) consisted of mannose (1.75 %), glucose (84.69 %), galactose (6.32 %), and arabinose (7.24 %), while WVP-2 (56.97 kDa) was composed of mannose (3.18 %), rhamnose (1.52 %), glucuronic acid (1.42 %), galacturonic acid (4.83 %), glucose (11.51 %), galactose (36.02 %), and arabinose (41.53 %). Linkage and NMR data indicated that WVP-1 was composed mainly of →4)-α-d-Glcp(1→ and a certain proportion of →3)-β-d-Glcp-(1→, including linear and branched polysaccharides simultaneously. WVP-2 was a pectin-like polysaccharide with →4)-α-d-GalpA6Me-(1→ units and the branch points of →3,4)-α-l-Arap-(1→, →3,6)-β-d-Galp-(1→. WVP-2 exhibited stronger potential antioxidant and immunomodulatory activities than WVP-1 in vitro. These results provide a foundation for the further study of polysaccharides from Chinese water chestnut peels.

Quality control and immunological activity of lentinan samples produced in China

Lentinan is widely used as a therapeutic agent for treatment of malignant tumors in clinical practice. The chemical structure of lentinan is highly associated with its biological activity. In this study, the correlation between the structure of lentinan and its immune activity was investigated to assess the function of key parameters that can influence quality control of lentinan. The results showed that the batch-to-batch consistency of two lentinan samples was satisfactory, indicating the stability of production process of lentinan. However, although the chemical composition and triple-helical conformation (THC) of the tested samples were relatively similar, their Mw, polydispersity index (PDI), and Rg_z remarkably varied due to different production processes. In vitro immunomodulatory assay reflects that lentinan could stimulate the macrophages phagocytic capacity. Meanwhile, lentinan samples could improve the spleen and thymus indices, promote the proliferation of lymphocytes and adjust for the percentages of CD4+ and CD8+ T cells in vivo. Furthermore, the immunomodulatory effect of lentinan sample B (Mw: 650,700 g/mol) was superior than that of the sample A (Mw: 4,818,700 g/mol). It was noted that the Mw should be detected as a necessary index for quality control of lentinan to ensure stability and effectiveness of the production process.

Synthesis of gold-silver nanoalloys under microwave-assisted irradiation by deposition of silver on gold nanoclusters/triple helix glucan and antifungal activity

Polysaccharides are ideal green synthetic raw materials to improve the biocompatibility of metal nanoparticles. However, polysaccharides generally have weak reducibilities, being challenging supports for the direct preparation of Ag nanoparticles. In this work, gold nanoclusters were prepared using a triple helix glucan (Lentinan) via microwave-assisted synthesis and subsequently employed as seeds for the synthesis of a series of Ag-Au alloy nanoparticles (Ag-AuNPs). The results showed that gold nanoclusters can remarkably speed up the preparation of Ag-AuNPs without the addition of any other chemicals. The particle size of Ag-AuNPs increased at increasing Ag contents in the alloy. Results of UV-vis, transmission electron microscope (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) suggested that Ag⁺ was quickly reduced to irregular silver nanoparticles (with gold nanoparticles as seeds), then gradually form more regular nano-alloys. Additionally, X-ray diffraction (XRD) and zeta potential results suggested that Ag-AuNPs could entrap the hydrophobic cavity of triple helix polysaccharides during the renaturation process. The nanocomposites exhibited good antifungal activity and low cytotoxicity to RAW264.7, Hela and LO2 cell lines in vitro.

Adjuvant Therapy With Mushroom Polysaccharides for Diabetic Complications

Background

Diabetic complications seriously endanger the health of most diabetic patients around the world. Most chemical hypoglycemic agents have adverse effects and are unable to improve the progression of diabetic complications. In recent years, a number of medicinal herbs have become increasingly popular for the treatment of diabetic complications due to their relative safety. Polysaccharides extracted from medicinal herbs with multiple pharmacological activities and low toxicity have been reported to be useful in the treatment of diabetic complications.

Methods

Primary studies with keywords including polysaccharide and diabetic complications were retrieved from the Web of Science and NCBI databases and were read and analyzed.

Results

Mushroom polysaccharides were proven to have positive effects on diabetic complications.

Conclusions

We studied the effects of mushroom polysaccharides on hyperglycemia and as adjuvant therapies for diabetic complications and summarized the applications and limitations of mushroom polysaccharides to better understand their application for the treatment of diabetic complications.

Recent Advances in Chain Conformation and Bioactivities of Triple-Helix Polysaccharides

Natural polysaccharides derived from renewable biomass sources are regarded as environmentally friendly and sustainable polymers. As the third most abundant biomacromolecule in nature, after proteins and nucleic acids, polysaccharides are also closely related with many different life activities. In particular, β-glucans are one of the most widely reported bioactive polysaccharides and are usually considered as biological response modifiers. Among them, β-glucans with triple-helix conformation have been the hottest and most well-researched polysaccharides at present, especially lentinan and schizophyllan, which are clinically used as cancer therapies in some Asian countries. Thus, creation of these active triple-helix polysaccharides is beneficial to the research and development of sustainable "green" biopolymers in the fields of food and life sciences. Therefore, full fundamental research of triple-helix polysaccharides is essential to discover more applications for polysaccharides. In this Review, the recent research progress of chain conformations, bioactivities, and structure-function relationships of triple-helix β-glucans is summarized. The main contents include the characterization methods of the macromolecular conformation, proof of triple helices, bioactivities, and structure-function relationships. We believe that the governments, enterprises, universities, and institutes dealing with the survival and health of human beings can expect the development of natural bioproducts in the future. Hence, a deep understanding of β-glucans with triple-helix chain conformation is necessary for application of natural medicines and biologics for a sustainable world.

Molecular Characterization of Arabinoxylan from Wheat Beer, Beer Foam and Defoamed Beer

This research was to explore the distribution and some molecular characterization of arabinoxylan in wheat beer (B), beer foam (BF) and defoamed beer (DB) because of the crucial influences of arabinoxylan on wheat beer and its foam. The purified arabinoxylan from B, BF, and DB were fractionated by ethanol of 50%, 67%, 75%, and 80%. The monosaccharide composition, substitution degree (Ara/Xyl ratio, A/X), and average degrees of polymerization (avDP) of arabinoxylan were investigated. Molecular weight and microstructure were also involved in this study by GPC-LLS and SEM, respectively. Under the same ethanol concentration, the arabinoxylan content in the BF was higher than the other two, respectively, and it was precipitated in BF fraction with 50% ethanol which accounted for 80.84% of the total polysaccharides. Meanwhile, the greatest substitution degree (A/X) and highest value of avDP of the arabinoxylan was found in all beer foam fractions regardless of the concentration of ethanol used. The average degrees of polymerization (avDP) of arabinoxylan displayed a significant difference (p < 0.05) among B, BF, and DB. Furthermore, arabinoxylan presented varied microstructure with irregular lamellas and spherical structures and the weight-average molecular weight (Mw) of arabinoxylan showed the lowest values in BF, while the largest values were shown in DB. Therefore, arabinoxylan was more accumulated in beer foam, especially in 50% ethanol, characterised by greater value of A/X and avDP, as well as lower Mw. It was suggested that the arabinoxylan played important roles in maintaining wheat beer foam characteristics.

Self-Assembled Exopolysaccharide Nanoparticles for Bioremediation and Green Synthesis of Noble Metal Nanoparticles

Continuing efforts have been made to explore novel exopolysaccharides (EPSs) for valuable applications. In this research, we report for the first time that a novel non-glucan EPS named EPS-605 can self-assemble to form spherical nanosize particles of ∼88 nm in diameter, expanding both the range of EPS type and structural type that EPSs self-assemble into. Characterization of EPS-605 shows that it is composed of mannose, glucose, and galactose with several modifications including acylation, phosphorylation, sulfation, and carboxylation, and a highly negative charge. EPS-605 showed a record biosorption capability for Pb²⁺, Cu²⁺, Cd²⁺, and methylene blue as compared to that of other reported EPSs, biosorbents, and nanosorbents. The adsorption ability of EPS-605 is affected by pH, temperature, the initial adsorbate concentration, the contact time, and the presence of background electrolytes. The mechanism of EPS-605 adsorbing heavy metals seems to be different to that for dyes. Moreover, EPS-605 can serve as the reductant in the synthesis of Au nanoparticles (AuNPs) and AgNPs enabling good monodispersity within the shortest time (of 30 min) compared to that from other EPSs and without any extra pretreatment. Our research advances the development of novel EPSs and provides a new, eco-friendly, and renewable platform for both the bioremediation and green synthesis of nanomaterials.

Extended chain conformation of β-glucan and its effect on antitumor activity

Extended chain conformation of β-glucan visualized by AFM, and its molecular weight- and chain conformation-dependent antitumor activity.

Progress in rigid polysaccharide-based nanocomposites with therapeutic functions

Nanocomposites engineered by incorporating versatile nanoparticles into different bioactive β-glucan matrices display effective therapeutic functions.

The structure of mushroom polysaccharides and their beneficial role in health

Mushroom is a kind of fungus that has been popular for its special flavour and renowned biological values. The polysaccharide contained in mushroom is regarded as one of the primary bioactive constituents and is beneficial for health. The structural features and bioactivities of mushroom polysaccharides have been studied extensively. It is believed that the diverse biological bioactivities of polysaccharides are closely related to their structure or conformation properties. In this review, the structural characteristics, conformational features and bioactivities of several mushroom polysaccharides are summarized, and their beneficial mechanisms and the relationships between their structure and bioactivities are also discussed.

Transfection efficiency and internalization of the gene carrier prepared from a triple-helical β-glucan and polydeoxyadenylic acid in macrophage RAW264.7 cells

The stability and gene transfection efficiency of poly(dA)–s-LNT complexes strongly depend on the base length of poly(dA) in the target DNA sequence.

Construction of selenium nanoparticles/β-glucan composites for enhancement of the antitumor activity

We report on a green procedure for the stabilization of selenium nanoparticles (SeNPs) by a naturally occurring β-glucan with triple helical conformation known as Lentinan (t-LNT) in water after denaturing into single chains (s-LNT) at 140 °C. The results demonstrated that the s-LNT can interact with SeNPs through Se-O-H interaction. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectra, UV/vis, X-ray diffraction (XRD) and dynamic light scattering (DLS) showed that s-LNT coated SeNPs to form a stable nano-composite Se/s-LNT, leading to good dispersion of SeNPs. Especially, the as-prepared Se/s-LNT composite in the solution could remain homogeneous and translucent for 30 days without any precipitates. Different size distribution of SeNPs was prepared by simply controlling the concentrations of selenite sodium and the corresponding reducing agent ascorbic acid. The size effect of SeNPs on anti-tumor activity was revealed that the SeNPs with more evenly particle size distribution show the higher anticancer activity.

Assembly of single-stranded polydeoxyadenylic acid and β-glucan probed by the sensing platform of graphene oxide based on the fluorescence resonance energy transfer and fluorescence anisotropy

Based on the fluorescence resonance energy transfer (FRET) and fluorescence anisotropy (FA), the present study reported proof-of-principle for a highly sensitive and rapid detection technique that can be precisely utilized for investigating the self-assembly of polydeoxyadenylic acid (poly(dA)) and β-glucan, and the interactions of the poly(dA)-β-glucan complex on the surface of graphene oxide (GO). Due to the noncovalent assembly of fluorescein amidite (FAM)-labeled poly(dA) and GO via π-π stacking, the fluorescence of (FAM)-labeled poly(dA) as a molecular aptamer beacon (MAB) was completely quenched by GO. Conversely, the addition of single-stranded lentinan (s-LNT) resulted in the significant restoration of fluorescence due to the formation of poly(dA)-s-LNT complexes with a stiff rod-like structure, which had a weak affinity to GO and kept the dyes away from GO. However, relatively weak fluorescence restoration was observed by adding another single-stranded curdlan (s-CUR) for positive control, indicative of complex formation with higher binding ability to GO. The fluorescence anisotropy (FA) was also combined to confirm the occurrence with different increments of anisotropy relative to the free poly(dA), which could be conveniently extended for detecting the assembly of other biomolecules with higher sensitivity.

Preparation of carboxylic acid-bearing polysaccharide nanofiber made from euglenoid β-1,3-glucans

This paper introduces a new strategy for creating surface modified polysaccharide nanofibers. To demonstrate proof of principle, the synthesis, structure, and self-assembly behavior of a carboxylic acid-bearing polysaccharide made from paramylon (β-1,3-glucan) and succinic anhydride were investigated. Examination by a combination of NMR, FT-IR, and SEC-MALLS confirmed that successful preparation of the desired succinylated paramylon without significant depolymerization. NMR, SEC-MALLS, visible absorption and CD spectroscopic analyses indicated that the paramylon derivative forms the triplex structure in solutions. SEM observation revealed that succinylated paramylon forms a nanofiber that has carboxylic acid on the surface.

Polysaccharide nanofiber made from euglenoid alga

We have fabricated a polysaccharide nanofiber made from paramylon (β-1,3-glucan), a storage polysaccharide stored as a micrometer-sized particle in the cell of euglenoid alga. Preparation of this nanofiber primarily hinges on the bottom-up approach. First, paramylon, which is originally present in the form of a bundle of nanofibers in a particle, was fibrillated to a randomly coiled polymer by dissolving the particle in a 1.0-mol/L NaOH aqueous solution. Second, the randomly coiled polymer was allowed to self-assemble into a triplex as the NaOH concentration was reduced to 0.25-0.20mol/L. Third, a 20-nm-width nanofiber made from the triplex emerged in the solution when the NaOH concentration was reduced to approximately 0.20mol/L.

Triple helical polysaccharide-induced good dispersion of silver nanoparticles in water

Silver nanoparticles were constructed by using triple helical polysaccharide (lentinan) dissolved in water as matrix for the first time. The structure, morphology, and size of the nanocomposites in the polysaccharide aqueous solutions were investigated with UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), and dynamic laser light scattering (DLS). The results revealed that the silver nanoparticles were attached to the polysaccharide chains through the strong noncovalent interactions, leading to the good dispersion of silver nanoparticles with mean radius of 6 nm in water. The silver nanoparticles were stable in the lentinan aqueous solution for 9 months. However, with an addition of NaOH, the polysaccharide with the imperfect helical structure broken partially by NaOH could aggregate in the alkali aqueous solution. The aggregation of the lentinan-bonded silver nanoparticles increased with an increase in the NaOH concentration, whereas the size of the silver nanoparticles barely changed, further confirming that the Ag nanoparticles were stable in this system. The aggregation was related to the conformation transition of the polysaccharide from the triple helix to random coil in the solution. A new method to detect the aggregates and aggregation rate was established according to the intensity of the maximum absorption peaks of the polysaccharide labeled by Ag nanoparticles in the UV spectrum.

Physicochemical properties and antitumor activities for sulfated derivatives of lentinan

Five fractions of lentinan, a beta-(1-->3)-D-glucan bearing beta-(1-->6)-d-glucopyranosyl branches, were treated with chlorosulfonic acid for 90 min at 60 degrees C in pyridine medium to synthesize water-soluble sulfated derivatives having the substitution degree of 1.44-1.76. The (13)C NMR spectra of the sulfated beta-glucans indicated that the C-6 position was preferentially substituted by the sulfate groups. The values of the weight-average molecular weight (M(w)), radius of gyration (s(2)(z)(1/2)), and intrinsic viscosity ([eta]) of the sulfated lentinan fractions were determined by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS) and viscometry in 0.15 M aq NaCl at 25 degrees C, respectively. The dependence of [eta] on M(w) for the sulfated lentinan was found to be [eta]=8.93 x 10(-3)M(w)(0.73+/-0.02) (mL/g) in 0.15 M aq NaCl (for M(w) ranging from 14.6 x 10(4) to 50.4 x 10(4)). On the basis of the Yamakawa-Fujii-Yoshizaki (YFY) theory, the conformational parameters of the sulfated lentinan were calculated as 950 nm(-1) for the molar mass per unit contour length (M(L)), 4.8 nm for the persistence length (q), and 13.9 for the characteristic ratio (C(infinity)), indicating relatively extended single flexible chains in solution. The sulfated glucan fractions exhibited in vitro antiproliferative activities against sarcoma 180 (S-180) cells, and their inhibition ratios were lower than that of the triple-helix lentinan, but higher than that for the one with single random-coil lentinan chains.