Preparation, structural characterization and bioactivities of Se-containing polysaccharide: A review

Recent advances in dietary polysaccharides from Allium species: Preparation, characterization, and bioactivity

Allium plants, including garlic, onions, shallots, and leeks, belong to the Alliaceae family and are utilized as vegetable, medicinal, and ornamental plants. These plants are consumed both raw and cooked and are noted in traditional medicine for their antibacterial, antitumor, and diuretic properties. Allium plants are a rich source of polyphenols, organosulfur compounds, flavonoids, alkaloids, and polysaccharides, which contribute to their health benefits. As consumer interest in the association between diet and health grows, there is an increasing market demand for foods that promote health, particularly those rich in dietary fiber or non-starch polysaccharides. Allium polysaccharides (APS) have molecular weights of 1 × 103-1 × 106 Da containing small amounts of pectin, glucofructan, or glycoproteins and large amounts of fructans. APS, despite its complex structure, is one of the principal active components of Allium plants but is often overlooked, which restricts its practical application. This paper provides a comprehensive overview of the extraction and purification, structural and functional characteristics, bioactivities, structure-function relationships, and chemical modifications of APS, as well as the effects of APS processing and storage. Additionally, this paper outlines future research directions for APS, which will inform its development and application in the food, pharmaceutical, and cosmetic industries.

Preparation, characterization and evaluation of microwave-assisted synthesized selenylation Codonopsis pilosula polysaccharides

In this work, the selenylation Codonopsis pilosula polysaccharide (Se-CPPS) were synthesized using an optimized microwave-assisted method. Then, physicochemical properties, including molecular weight, particle size, valence state of selenium, antioxidant capacity, release mechanism of selenium under gastrointestinal conditions, as well as their effects on HT-29 cell viability were comprehensively investigated. The results demonstrated that Se-CPPS with the highest selenium content (21.71 mg/g) was synthesized using 0.8% nitric acid concentration under microwave conditions of 90 min at 70 °C. FTIR and XPS analysis revealed that Se was bound to the polysaccharide chain in the form of O-Se-O and O-H···Se, with a valence state of either 0 or +4. In vitro investigations on antioxidant activity and selenium release capacity indicated that selenization not only enhanced the antioxidant activity of CPPS but also endowed Se-CPPS with robust selenium release capability in simulated gastric digestion. The effects of Se-CPPS on HT-29 cells was further investigated by CCK-8 method. The results showed that the selenide modification effectively reduced the toxicity of Na2SeO3 and enhanced the viability of CPPS. The findings of this study offer valuable methodological guidance for the synthesis of Se-polysaccharides with superior functional properties.

Chemically modified seaweed polysaccharides: Improved functional and biological properties and prospective in food applications

Seaweed polysaccharides are natural biomacromolecules with unique physicochemical properties (e.g., good gelling, emulsifying, and film-forming properties) and diverse biological activities (e.g., anticoagulant, antioxidant, immunoregulatory, and antitumor effects). Furthermore, they are nontoxic, biocompatible and biodegradable, and abundant in resources. Therefore, they have been widely utilized in food, cosmetics, and pharmaceutical industries. However, their properties and bioactivities sometimes are not satisfactory for some purposes. Modification of polysaccharides can impart the amphiphilicity and new functions to the biopolymers and change the structure and conformation, thus effectively improving their functional properties and biological activities so as to meet the requirement for targeted applications. This review outlined the modification methods of representative red algae polysaccharides (carrageenan and agar), brown algae polysaccharides (fucoidan, alginate, and laminaran), and green algae polysaccharides (ulvan) that have potential food applications, including etherification, esterification, degradation, sulfation, phosphorylation, selenylation, and so on. The improved functional properties and bioactivities of the modified seaweed polysaccharides and their potential food applications are also summarized.

Recent progress in Porphyra haitanensis polysaccharides: Extraction, purification, structural insights, and their impact on gastrointestinal health and oxidative stress management

Porphyra haitanensis, a red seaweed species, represents a bountiful and sustainable marine resource. P. haitanensis polysaccharide (PHP), has garnered considerable attention for its numerous health benefits. However, the comprehensive utilization of PHP on an industrial scale has been limited by the lack of comprehensive information. In this review, we endeavor to discuss and summarize recent advancements in PHP extraction, purification, and characterization. We emphasize the multifaceted mechanisms through which PHP promotes gastrointestinal health. Furthermore, we present a summary of compelling evidence supporting PHP's protective role against oxidative stress. This includes its demonstrated potent antioxidant properties, its ability to neutralize free radicals, and its capacity to enhance the activity of antioxidant enzymes. The information presented here also lays the theoretical groundwork for future research into the structural and functional aspects of PHP, as well as its potential applications in functional foods.

Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV-visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Extraction, structure, pharmacological activity, and structural modification of Lilium polysaccharides

Polysaccharides primarily composed of glucose, arabinose, rhamnose, xylose, and galactose are pharmacologically active ingredients in Lilium. The pharmacological activities shown by polysaccharides from Lilium include antioxidant, anti-tumor, immunomodulatory, hypoglycemic, bacteriostatic, and radiation protection effects. This review provides a comprehensive summary of the distribution of Lilium medicinal resources in China, current extraction and purification methods of Lilium polysaccharide (LP), the strategies used for analyzing the polysaccharide structure and monosaccharide composition in LP, and the pharmacological activities and structural modification of LP. This review provides a basis for the development and clinical application of LP along with the conservation and utilization of Lilium resources.

Selenium Modification of Natural Products and Its Research Progress

The selenization of natural products refers to the chemical modification method of artificially introducing selenium atoms into natural products to interact with the functional groups in the target molecule to form selenides. Nowadays, even though scientists in fields involving organic selenium compounds have achieved numerous results due to their continuous investment, few comprehensive and systematic summaries relating to their research results can be found. The present paper summarizes the selenization modification methods of several kinds of important natural products, such as polysaccharides, proteins/polypeptides, polyphenols, lipids, and cyclic compounds, as well as the basic principles or mechanisms of the selenizing methods. On this basis, this paper explored the future development trend of the research field relating to selenized natural products, and it is hoped to provide some suggestions for directional selenization modification and the application of natural active ingredients.

Synthesis of Se polysaccharide catalyzed by sulfonic acid functionalized ionic liquids: Synergism effect of anion/cation

The rational design and construction of controllable selenylation strategy are important for the study on the structure-activity relationship of Se polysaccharides. Herein, selenized Artemisia sphaerocephala polysaccharides (SePASs) were synthesized by using sulfonic acid functionalized ionic liquids (SFILs) as catalysts in order to study the regulation of the cation/anion constitute on the selenylation efficiency and Se polysaccharide structure. Impressively, SFILs could promote the efficient substitution of seleno-group on the polysaccharide backbone through the synergistic catalysis by cation/anions (Se content up to 5582.7 μg/g). Further, reaction mechanism and potential dissolution effect was supported by DFT calculation and polarized light microscopy. ¹³C NMR and FT-IR spectra analysis of SePASs exhibited that selenite existed in polysaccharides and the substitution position occured at C-6. SEC-MALLS, monosaccharide composition results revealed that strong acidity of SFILs lead to the driving forces toward low molecular mass polysaccharide fragments and synergistic effect of anion/cations in SFILs (-SO₃H group of cations as proton donor, anions as nucleophile) showed regulation on average molecular mass. In addition, the strong attractions between the seleno-groups generated agglomeration of polysaccharide chain, which was proved by applying AFM analysis. Therefore, this work provided a new insight for manipulate Se content and M_W of Se polysaccharides.

Preparation of Biocompatible Manganese Selenium-Based Nanoparticles with Antioxidant and Catalytic Functions

The specificity of the tumor microenvironment (TME) severely limits the effectiveness of tumor treatment. In this study, we prepared a composite nanoparticle of manganese dioxide and selenite by a one-step redox method, and their stability under physiological conditions was improved with a bovine serum protein modification to obtain MnO₂/Se-BSA nanoparticles (SMB NPs). In the SMB NPs, manganese dioxide and selenite endowed the SMB NPs with acid-responsive and catalytic, and antioxidant properties, respectively. The weak acid response, catalytic activity, and antioxidant properties of composite nanoparticles were verified experimentally. Moreover, in an in vitro hemolysis assay, different concentrations of nanoparticles were incubated with mouse erythrocytes, and the hemolysis ratio was less than 5%. In the cell safety assay, the cell survival ratio was as high as 95.97% after the co-culture with L929 cells at different concentrations for 24 h. In addition, the good biosafety of composite nanoparticles was verified at the animal level. Thus, this study helps to design high-performance and comprehensive therapeutic reagents that are responsive to the hypoxia, weak acidity, hydrogen peroxide overexpression nature of TME and overcome the limitations of TME.

Synthesis and cytotoxic activities of selenium nanoparticles incorporated nano-chitosan

New system compromising of chitosan nanoparticles encapsulated pre-synthesized selenium nanoparticles in the presence of 5-fluorouracil was successfully prepared and used for cancer antiproliferation. Selenium nanoparticles were synthesized using ascorbic acid as reducing agent under mild condition. Chitosan nanoparticles were prepared via ionic gelation technique using sodium tri-polyphosphate. Characterization of the prepared nanoparticles was carried out using FTIR, TEM, XRD, TGA and dynamic light scattering (DLS). The results displayed the formation of selenium nanoparticles with an average size 20 nm and chitosan nanoparticles with an average size 207 and 250 nm for neat nano-chitosan and chitosan incorporated 5-fluorouracil/selenium nanoparticles, respectively. The encapsulated nanocomposites were tested for treatment of cancer cell of human colorectal carcinoma (HCT-116), human liver carcinoma (HepG-2), and human breast adenocarcinoma MCF-7. The results indicated the potent cytotoxic activities of all nanocomposite toward the tested cells with enhanced anticancer activity rather than the single drug or neat selenium nanoparticle. All composites were tested against non-tumor fibroblast-derived cell line (BJ) and demonstrated very low cytotoxicity.

A Se-enriched Grifola frondosa polysaccharide induces macrophage activation by TLR4-mediated MAPK signaling pathway

Se-polysaccharide (Se-GFP-22) from Se-enriched Grifola frondosa has double and cooperative activities of polysaccharide and Se. To delineate the underlying mechanism and signaling cascade involved in immune-stimulatory property of Se-GFP-22, the production of cellular mediators and key proteins in signaling pathway was examined. Results showed that Se-GFP-22 exhibited no cytotoxic and had a high capacity to promote macrophage phagocytosis, up-regulate interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and nitric oxide (NO) productions, as well as the relative messenger RNA (mRNA) expressions. In Se-GFP-22-induced macrophages, intracellular superoxide dismutase (SOD) activity was significantly increased to protect cells from oxidative injury. However, Se-GFP-22 induced macrophage activation was suppressed when the toll-like receptor 4 (TLR4) signaling pathway was blocked by a specific TLR4 inhibitor. According to the western blot analysis and the use of specific inhibitors against the mitogen-activated protein kinases (MAPK) signaling pathway, we speculated that Se-GFP-22 activated RAW264.7 macrophages through the TLR4-mediated MAPK signaling pathway. This study provides a molecular basis for the potential of Se-GFP-22 as a novel immune-stimulatory agent.

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (M_w) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

Ameliorative effect of Berberidis radix polysaccharide selenium nanoparticles against carbon tetrachloride induced oxidative stress and inflammation

Berberidis radix polysaccharide (BRP) extracted as capping agents was applied to prepare BRP-selenium nanoparticles (BRP-SeNPs) in the redox reaction system of sodium selenite and ascorbic acid. The stability and characterization of BRP-SeNPs were investigated by physical analysis method. The results revealed that BRP were tightly wrapped on the surface of SeNPs by forming C-O⋯Se bonds or hydrogen bonding interaction (O-H⋯Se). BRP-SeNPs presented irregular, fragmented and smooth surface morphology and polycrystalline nanoring structure, and its particle size was 89.4 nm in the optimal preparation condition. The pharmacologic functions of BRP-SeNPs were explored in vitro and in vivo. The results showed that BRP-SeNPs could heighten the cell viabilities and the enzyme activity of GSH-Px and decrease the content of MDA on H2O2-induced AML-12 cells injury model. In vivo tests, the results displayed that BRP-SeNPs could increase the body weight of mice, promote the enzyme activity like SOD and GSH-Px, decrease the liver organ index and the hepatic function index such as ALT, AST, CYP2E1, reduce the content of MDA, and relieve the proinflammation factors of NO, IL-1β and TNF-α in CCl4-induced mice injury model. Liver tissue histopathological studies corroborated the improvement of BRP-SeNPs on liver of CCl4-induced mice. The results of Western blot showed that BRP-SeNPs could attenuate oxidant stress by the Nrf2/Keap1/MKP1/JNK pathways, and downregulate the proinflammatory factors by TLR4/MAPK pathway. These findings suggested that BRP-SeNPs possess the hepatoprotection and have the potential to be a green liver-protecting and auxiliary liver inflammation drugs.

Progress in the Surface Functionalization of Selenium Nanoparticles and Their Potential Application in Cancer Therapy

As an essential micronutrient, selenium participates in numerous life processes and plays a key role in human health. In the past decade, selenium nanoparticles (SeNPs) have attracted great attention due to their excellent functionality for potential applications in pharmaceuticals. However, the utilization of SeNPs has been restricted by their instability and low targeting ability. Since the existing reviews mainly focused on the applications of SeNPs, this review highlights the synthesis of SeNPs and the strategies to improve their stability and targeting ability through surface functionalization. In addition, the utilization of functionalized SeNPs for the single and co-delivery of drugs or genes to achieve the combination of therapy are also presented, with the emphasis on the potential mechanism. The current challenges and prospects of functionalized SeNPs are also summarized. This review may provide valuable information for the design of novel functionalized SeNPs and promote their future application in cancer therapy.

Sulfonated, oxidized pectin-based double crosslinked bioprosthetic valve leaflets for synergistically enhancing hemocompatibility and cytocompatibility and reducing calcification

Clinically frequently-used glutaraldehyde (GA)-crosslinked bioprosthetic valve leaflets (BVLs) are still curbed by acute thrombosis, malignant immunoreaction, calcification, and poor durability. In this study, an anticoagulant heparin-like biomacromolecule, sulfonated, oxidized pectin (SAP) with a dialdehyde structure was first obtained by modifying citrus pectin with sulfonation of 3-amino-1-propane sulfonic acid and then oxidating with periodate. Notably, a novel crosslinking approach was established by doubly crosslinking BVLs with SAP and the nature-derived crosslinking agent quercetin (Que), which play a synergistic role in both crosslinking and bioactivity. The double crosslinked BVLs also presented enhanced mechanical properties and enzymatic degradation resistance owing to the double crosslinking networks formed via CN bonds and hydrogen bonds, respectively, and good HUVEC-cytocompatibility. The in vitro and ex vivo assay manifested that the double-crosslinked BVLs had excellent anticoagulant and antithrombotic properties, owing to the introduction of SAP. The subcutaneous implantation also demonstrated that the obtained BVLs showed a reduced inflammatory response and great resistance to calcification, which is attributed to quercetin with multiple physiological activities and depletion of aldehyde groups by hydroxyl aldehyde reaction. With excellent stability, hemocompatibility, anti-inflammatory, anti-calcification, and pro-endothelialization properties, the obtained double-crosslinked BVLs, SAP + Que-PP, would have great potential to substitute the current clinical GA-crosslinked BVLs.

Recent advances in medicinal and edible homologous polysaccharides: Extraction, purification, structure, modification, and biological activities

110 kinds of traditional Chinese medicines can be used for medicine and food from Chinese pharmacopoeia in 2021. With the deepening of research in recent years, medicinal and edible homologous (MEH) traditional Chinese medicines have great development and application prospects in many fields. Polysaccharides are one of the major and representative pharmacologically active macromolecules in traditional Chinese medicines with MEH. Moreover, traditional Chinese medicines with MEH have become the main source of natural polysaccharides with safety, high efficiency, and low side effects. Increasing researches have confirmed that MEH polysaccharides (MEHPs) have multiple biological activities both in vitro and in vivo methods, such as antioxidant, immunomodulatory, anti-tumor, anti-aging, anti-inflammatory, hypoglycemic, hypolipidemic activities, and regulating intestinal flora. Additionally, different raw materials, extraction, purification, and chemical modification methods result in differences in the structure and biological activities of MEHPs. The purpose of the present review is to provide comprehensively and systematically reorganized information in the extraction, purification, structure, modification, biological activities, and potential mechanism of MEHPs to support their therapeutic effects and health functions. New valuable insights and theoretical basis for the future researches and developments regarding MEHPs were proposed in the fields of medicine and food.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

Synthesis, characterization, and evaluation of microwave-assisted fabricated selenylation Astragalus polysaccharides

Selenylation Astragalus polysaccharides (Se-APS) was fabricated by an optimized microwave-assisted method. Their physicochemical properties, antioxidant capacities and selenium (Se) release rate under gastrointestinal conditions were determined. Se-APS with the highest Se content (18.8 mg/g) was prepared in 0.4 % nitric acid, under the microwave conditions of 90 min and 80 °C. FTIR and XPS spectra indicated that Se was bound to the polysaccharide chain in the form of O-Se-O and O-H···Se, and most of Se⁺⁴ was reduced to Se⁰. Meanwhile, the micromorphology of Se-APS became clusters, loose and porous, which decreased its hydrodynamic particle size and negative surface charges. Besides, Se-APS displayed strong scavenging capacities towards ABTS and superoxide anion free radicals than Na₂SeO₃, and showed higher Se release rate (12.52 ± 0.31 %) under intestinal fluid comparing with gastric fluid (3.14 ± 0.38 %) during 8 h in vitro digestion. The results provided efficient preparation method references for selenylation polysaccharides, and broaden the application fields of APS.

Pumpkin Skin Polysaccharide–Zn(II) Complex: Preparation, Characterization, and Suppression of Inflammation in Zebrafish

In this study, pumpkin (Cucurbita moschata) skin polysaccharide–zinc(II) (PSP−Zn) complex was successfully prepared. The structure and physicochemical properties of PSP and PSP−Zn were analyzed. The anti-inflammatory activity of PSP and PSP−Zn was investigated in zebrafish larvae induced by copper sulphate. PSP and PSP−Zn consisted of rhamnose, arabinose, galactose, glucose, and galacturonic acid. The molecular weight (Mw) of PSP and PSP−Zn were 3.034 × 10⁶ and 3.222 × 10⁶ Da, respectively. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) analysis results suggested that the chemical modification of zinc might occur through hydroxyl groups of PSP. The PSP−Zn complex had lamellar texture, smooth surface morphology, and larger particle size. X-ray Diffraction (XRD) analysis revealed that both PSP and PSP−Zn were semi-crystalline substances. PSP−Zn solution showed superior stability in a weak acid and alkaline environment, especially at pH = 6.0. Moreover, PSP and PSP−Zn showed a good inhibitory effect on inflammation cells in zebrafish. Real-time quantitative polymerase chain reaction (RT-PCR) result suggested that the anti-inflammatory mechanism of PSP and PSP−Zn were through downregulation of the expression of nitric oxide synthase 2b (nos2b), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and nuclear factor-kappa B2 (NF-κB2). The present study indicated that PSP−Zn is expected to be a safe and efficient novel zinc supplement with anti-inflammatory activity.

Current advances and potential trends of the polysaccharides derived from medicinal mushrooms sanghuang

For thousands of years, sanghuang is distinctive as a general designation for a group of precious and rare Chinese medicinal mushrooms. Numerous investigations have revealed that polysaccharide is one of the important biological active ingredients of sanghuang with various excellent biological activities, including antioxidant, anti-aging, anti-tumor, immunomodulatory, anti-inflammatory, anti-diabetic, hepatoprotective, and anti-microbial functionalities. For the past two decades, preparation, structural characterization, and reliable bioactivities of the polysaccharides from fruiting bodies, cultured mycelia, and fermentation broth of sanghuang have been arousing extensive interest, and particularly, different strains, sources, and isolation protocols might result in obvious discrepancies in structural features and bioactivities. Therefore, this review summarizes the recent reports on preparation strategies, structural features, bioactivities, and structure-activity relationships of sanghuang polysaccharides, which will enrich the knowledge on the values of natural sanghuang polysaccharides and support their further development and utilization as therapeutic agents, vaccines, and functional foods in tonic and clinical treatment.

Structural characterization, acute toxicity assessment and protective effects of selenylated apple pectin on dextran sulfate sodium-induced ulcerative colitis

This study was aimed at investigating the structural characterization, acute toxicity and protective effect of selenylated apple pectin on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Selenylated apple pectin was characterized by ion chromatography, NMR and SEC-RI-MALLS. The acute toxicity and protective effect of selenylated apple pectin against UC were investigated by gavage administration in mice. The organ state and coefficients, inflammatory cytokine (IL-6, IL-10 and TNF-α) contents in serum, GSH-Px activity and MPO content in colon tissues were also evaluated. The results indicated that selenylated apple pectin was non-toxic and contained 244.28 μg_selenium per g. The monosaccharide composition with different molar ratios, different relative molecular weights and a weakened signal peak (CH₂-O group) at 3-4 ppm were observed after selenylation. The selenylated apple pectin showed the protective effect against UC by down-regulating IL-6 and TNF-α contents and up-regulating the IL-10 content in serum, as well as increasing the GSH-Px activity and decreasing the MPO content in colon tissues. Moreover, DSS-induced alterations were effectively recovered by a high-dose sample. These findings provide evidence in support of selenylated apple pectin as a novel dietary selenium supplement for UC protection.

Preparation, Physicochemical and Hypoglycemic Properties of Natural Selenium-Enriched Coarse Tea Glycoproteins

Various functional components in tea have been well developed, but less research has been explored on glycoproteins in tea. In this paper, three types of glycoprotein fractions, namely tea selenium-binding glycoprotein1-1 (TSBGP1-1), TSBGP2-1, and TSBGP3-1, respectively, were extracted and purified from selenium-enriched coarse green tea. Chemical analysis revealed that three fractions were glycoproteins, but their selenium content, molecular weight, and monosaccharide composition were significantly different. Fourier transforms infrared (FT-IR) analysis indicated that three fractions contained characteristic absorption peaks of glycoproteins but differed in secondary structural composition. Thermogravimetric (TG) analysis showed that the thermal stability of the three fractions was dramatically distinct. The in vitro hypoglycemic activity showed that TSBGPs significantly activated the insulin receptor substrate 2 (IRS2)/protein kinase B (Akt) pathway in LO2 cells, then enhanced glucose metabolism and inhibited gluconeogenesis, and finally ameliorated insulin resistance (IR) and glucose metabolism disorders. Furthermore, Pearson correlation analysis reveals that the hypoglycemic activity was significantly correlated with Se, protein, monosaccharide composition (especially glucose), molecular weight, and secondary structure. Our results show that Se-enriched tea glycoprotein is a desirable candidate for developing anti-diabetic food, and TSBGP-2 and TSBGP-3 had a better regulation effect. Our results can provide a research reference for the extraction, physicochemical property, and function of selenium-enriched plant glycoproteins.

Selenium-containing polysaccharides isolated from Rosa laevigata Michx fruits exhibit excellent anti-oxidant and neuroprotective activity in vitro

Selenium-containing polysaccharides have potential as an organic selenium dietary supplement, owing to their low toxicity, few side effects, and easy absorption attributes. In this study, we isolated two novel homogeneous selenium-containing polysaccharides from Rosa laevigata Michx fruits (Se-RLFPs). Results from primary structural analysis revealed that Se-RLFPs were α - pyranose, and were both composed of rhamnose, xylose, glucose with an average molecular weight of 24 and 16 KDa, respectively. Selenium contents in Se-RLFP-I and Se-RLFP-II were 16.49 μg/g and 21.61 μg/g, respectively. Results from analysis of antioxidant and neuroprotective activity of the polysaccharides revealed that Se-RLFPs had a radical scavenging effect. Specifically, they effectively protected SH-SY5Y cells from H₂O₂-induced damage by enhancing antioxidant enzyme activities (SOD), total antioxidant capacity (T-AOC) and suppressing malondialdehyde (MDA) levels. Western blots showed that the underlying mechanisms of action may be related to the Nrf2/HO-1 signaling pathway. Taken together, these results suggested that Se-RLFPs have potential as a pharmaceutical agent for treatment of neurodegenerative diseases (NDDs) or as a selenium-complementary ingredient in functional foods.

Enhanced Growth Inhibition and Apoptosis Induction in Human Colon Carcinoma HT-29 Cells of Soluble Longan Polysaccharides with a Covalent Chemical Selenylation

The selenylated polysaccharides chemically belong to the organic Se-conjugated macromolecules and have recently been attracting more and more attention due to their potential to promote body health or prevent cancers. Longan (Dimocarpus longan L.), as a subtropical fruit, contains soluble and non-digestible polysaccharides that are regarded with health care functions in the body. In this study, the longan polysaccharides (LP) were obtained via enzyme-assisted water extraction, and then chemically selenylated using a reaction system composed of HNO₃–Na₂SeO₃ to yield two selenylated products, namely, SeLP1 and SeLP2, with Se contents of 1.46 and 4.79 g/kg, respectively. The anti-cancer effects of the three polysaccharide samples (LP, SeLP1, and SeLP2) were thus investigated using the human colon cancer HT-29 cells as the cell model. The results showed that SeLP1 and SeLP2 were more able than LP to inhibit cell growth, alter cell morphology, cause mitochondrial membrane potential loss, increase intracellular reactive oxygen and [Ca²⁺]_i levels, and induce apoptosis via regulating the eight apoptosis-related genes and proteins including Bax, caspases-3/-8/-9, CHOP, cytochrome c, DR5, and Bcl-2. It was thereby proven that the selenylated polysaccharides could induce cell apoptosis via activating the death receptor, mitochondrial-dependent, and ER stress pathways. Collectively, both SeLP1 and SeLP2 showed higher activities than LP in HT-29 cells, while SeLP2 was consistently more active than SeLP1 in exerting these assessed anti-cancer effects on the cells. In conclusion, this chemical selenylation covalently introduced Se into the polysaccharide molecules and caused an enhancement in their anti-cancer functions in the cells, while higher selenylation extent was beneficial to the activity enhancement of the selenylated products.

A Novel Selenium Polysaccharide Alleviates the Manganese (Mn)-Induced Toxicity in Hep G2 Cells and Caenorhabditis elegans

Manganese (Mn) is now known to have a variety of toxicities, particularly when exposed to it in the workplace. However, there are still ineffective methods for reducing Mn's hazardous effects. In this study, a new selenium polysaccharide (Se-PCS) was developed from the shell of Camellia oleifera to reduce Mn toxicity in vitro and in vivo. The results revealed that Se-PCS may boost cell survival in Hep G2 cells exposed to Mn and activate antioxidant enzyme activity, lowering ROS and cell apoptosis. Furthermore, after being treated with Se-PCS, Caenorhabditis elegans survived longer under Mn stress. daf-16, a tolerant critical gene, was turned on. Moreover, the antioxidant system was enhanced as the increase in strong antioxidant enzyme activity and high expression of the sod-3, ctl-2, and gst-1 genes. A variety of mutations were also used to confirm that Se-PCS downregulated the insulin signaling pathway. These findings showed that Se-PCS protected Hep G2 cells and C. elegans via the insulin/IGF-1 signaling pathway and that it could be developed into a promising medication to treat Mn toxicity.

Polysaccharides as Potential Anti-tumor Biomacromolecules —A Review

Cancer, as one of the most life-threatening diseases, has attracted the attention of researchers to develop drugs with minimal side effects. The bioactive macromolecules, such as the polysaccharides, are considered the potential candidates against cancer due to their anti-tumor activities and non-toxic characteristics. The present review provides an overview on polysaccharides' extraction, isolation, purification, mechanisms for their anti-tumor activities, structure-activity relationships, absorption and metabolism of polysaccharides, and the applications of polysaccharides in anti-tumor therapy. Numerous research showed extraction methods of polysaccharides had a significant influence on their activities. Additionally, the anti-tumor activities of the polysaccharides are closely related to their structure, while molecular modification and high bioavailability may enhance the anti-tumor activity. Moreover, most of the polysaccharides exerted an anti-tumor activity mainly through the cell cycle arrest, anti-angiogenesis, apoptosis, and immunomodulation mechanisms. Also, recommendations were made to utilize the polysaccharides against cancer.

Effects of selenylation modification on the antioxidative and immunoregulatory activities of polysaccharides from the pulp of Rose laevigata Michx fruit

Selenylation modification has been widely utilized to improve the activity of polysaccharides and to develop novel sources of selenium (Se) supplements. A purified pulp polysaccharide of Rose laevigata Michx fruit (PPRLMF-2) was selenized into Se-PPRLMF-2 in this study. PPRLMF-2 + Se was formulated by Na₂SeO₃ according to the Se content of Se-PPRLMF-2. To investigate the effects of selenylation modification on the structure and functions of PPRLMF-2, the characteristics, antioxidative and immunoregulatory activities of PPRLMF-2 before and after selenylation were compared. The results showed that compared with PPRLMF-2, Se-PPRLMF-2 became an irregular fibrous network, and its Mw decreased and C-6 substitution predominated in ¹³C NMR spectra. Se-PPRLMF-2 significantly increased chemical antioxidant activity and reduced the oxidative damage of erythrocytes, which was not due to Se alone. Se-PPRLMF-2 significantly increased immunomodulatory activity on macrophages, which was related to Se alone. Se-PPRLMF-2 could be a good potential source of antioxidants, immune enhancers and dietary Se supplements.

Preparation and structural properties of selenium modified heteropolysaccharide from the fruits of Akebia quinata and in vitro and in vivo antitumor activity

Cancer is a complex disease, and blocking tumor angiogenesis has become one of the most promising approaches in cancer therapy. Here, an exopoly heteropolysaccharide (AQP70-2B) was firstly isolated from Akebia quinata. Monosaccharide composition indicated that the AQP70-2B was composed of rhamnose, glucose, galactose, and arabinose. The backbone of AQP70-2B consisted of →1)-l-Araf, →3)-l-Araf-(1→, →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →2,5)-l-Araf-(1→, →4)-d-Glcp-(1→, →6)-d-Galp-(1→, and →1)-d-Rhap residues. Based on the close relationship between selenium and anti-tumor activity, AQP70-2B was modified with selenium to obtain selenized polysaccharide Se-AQP70-2B. Then, a series of methods for analysis and characterization, especially scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS), indicated that Se-AQP70-2B was successfully synthesized. Furthermore, zebrafish xenografts and anti-angiogenesis experiments indicated that selenization could improve the antitumor activity by inhibiting tumor cell proliferation and migration and blocking angiogenesis.

Activities of the soluble and non-digestible longan (Dimocarpus longan Lour.) polysaccharides against HCT-116 cells as affected by a chemical selenylation

The soluble and non-digestible longan (Dimocarpus longan Lour.) polysaccharides (LP) with Se content less than 0.01 g/kg were extracted and selenylated chemically with the HNO₃–Na₂SeO₃ system, to prepare two selenylated products namely SeLP1 and SeLP2 with enhanced Se contents of 1.46 and 4.79 g/kg, respectively. LP, SeLP1, and SeLP2 were then measured and compared for their saccharide features and bioactivity in human colon carcinoma HCT-116 cells. Compared with LP, both SeLP1 and SeLP2 contained more neutral saccharides, but showed reduced uronic acid content and undetectable sulfate. Moreover, SeLP1 and especially SeLP2 in the cells showed higher activities than LP, reflected by their enhanced capacity to inhibit cell growth, alter cell morphology, and suppress cell colony formation. Compared with LP, SeLP1 and especially SeLP2 were also more capable of promoting intracellular reactive oxygen species and Ca²⁺ levels, causing mitochondrial membrane potential loss, or inducing cell apoptosis via up- and down-regulating the eight apoptosis-related genes and proteins. Overall, the performed chemical selenylation of LP resulted in obvious changes in these saccharide features and simultaneously enhanced the anti-cancer activity of the selenylated products against the cells clearly, while a higher selenylation extent of the selenylated products consistently caused higher activity towards the cells. The results of this study thus highlighted that this chemical selenylation is applicable when aiming to enhance the bioactivities of natural polysaccharides.

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Chemical selenylation of longan polysaccharides causes Se conjugation covalently.

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The selenylated polysaccharides have changes in saccharide features and sulfate.

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The selenylated polysaccharides have higher activities to HCT-116 cells.

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Higher polysaccharide selenylation consistently leads to activity increase in cells.

In Vitro Immuno-Modulatory Potentials of Purslane (Portulaca oleracea L.) Polysaccharides with a Chemical Selenylation

The soluble polysaccharides from a non-conventional and edible plant purslane (Portulaca oleracea L.), namely PSPO, were prepared by the water extraction and ethanol precipitation methods in this study. The obtained PSPO were selenylated using the Na₂SeO₃-HNO₃ method to successfully prepare two selenylated products, namely SePSPO-1 and SePSPO-2, with different selenylation extents. The assay results confirmed that SePSPO-1 and SePSPO-2 had respective Se contents of 753.8 and 1325.1 mg/kg, while PSPO only contained Se element about 80.6 mg/kg. The results demonstrated that SePSPO-1 and SePSPO-2 had higher immune modulation than PSPO (p < 0.05), when using the two immune cells (murine splenocytes and RAW 264.7 macrophages) as two cell models. Specifically, SePSPO-1 and SePSPO-2 were more active than PSPO in the macrophages, resulting in higher cell proliferation, greater macrophage phagocytosis, and higher secretion of the immune-related three cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β. Meanwhile, SePSPO-1 and SePSPO-2 were more potent than PSPO in the concanavalin A- or lipopolysaccharide-stimulated splenocytes in cell proliferation, or more able than PSPO in the splenocytes to promote interferon-γ secretion but suppress IL-4 secretion, or more capable of enhancing the ratio of T-helper (CD4⁺) cells to T-cytotoxic (CD8⁺) cells for the T lymphocytes than PSPO. Overall, the higher selenylation extent of the selenylated PSPO mostly caused higher immune modulation in the model cells, while a higher polysaccharide dose consistently led to the greater regulation effect. Thus, it is concluded that the employed chemical selenylation could be used in the chemical modification of purslane or other plant polysaccharides, when aiming to endow the polysaccharides with higher immuno-modulatory effect on the two immune cells.

Structure features, selenylation modification, and improved anti-tumor activity of a polysaccharide from Eriobotrya japonica

A homogeneous polysaccharide, EJP90-1, was isolated from the leaves of E. japonica by hot water extraction in this study. EJP90-1 (7702 Da) was a heteropolysaccharide mainly consisting of →5)-linked-α-L-Araf-(1→, →4)-linked-β-D-Manp-(1→, →2,4)-linked-α-L-Rhap-(1→, →4)-linked-α-D-Xylp-(1→, →4)-linked-β-D-Galp-(1→, →2)-linked-β-D-Galp-(1→, →6)-linked-β-D-Glcp-(1→, α-D-Glcp-(4→, and t-linked-α-L-Araf. EJP90-1 was found to show moderate anti-tumor activity at the cellular level. In order to improve the anti-tumor activity and the potential applications of EJP90-1, a typical sodium selenite-nitric acid (Na₂SeO₃-HNO₃) modification on EJP90-1 was carried out. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometer (EDS) analysis confirmed that Se was successfully introduced into the polymer chain of EJP90-1. The subsequent in vitro cytotoxicity evaluation showed the selenylation modification derivative (EJP90-1-Se) possessed significant antiproliferative activity against cancer cells (HepG2 and A549 cells) through inducing cell apoptosis. The anti-tumor activity of EJP90-1-Se was further confirmed by zebrafish models, which inhibited the proliferation and migration of HepG2 cells and the angiogenesis.

In Vitro Immunomodulation of the Polysaccharides from Yam (Dioscorea opposita Thunb.) in Response to a Selenylation of Lower Extent

The immunomodulation of chemically selenylated polysaccharides has been attracting more attention recently, but the corresponding performance of the yam polysaccharides (YPS) with lower selenylation extent remains, thus far, unsolved. In this study, the YPS was selenylated with Na₂SeO₃ under acidic conditions generated by HNO₃ to reach two lower selenylation extents, yielding two selenylated YPSs, namely SeYPS-1 and SeYPS-2 with selenium contents of 715 and 1545 mg/kg, respectively. The results indicated that YPS, SeYPS-1, and SeYPS-2 all had in vitro immuno-modulation when using RAW 264.7 macrophages and murine splenocytes as cell models. In detail, the three polysaccharide samples at dose levels of 5–160 μg/mL showed insignificant cytotoxicity to the macrophages and splenocytes with cell exposure times of 12–24 h, because of the measured values of cell viability larger than 100%. However, Na₂SeO₃ at dose levels of 1.3–3.25 μg/mL mostly caused obvious cytotoxic effects on the cells, resulting in reduced cell viability values or cell death, efficiently. The results demonstrated that, compared with YPS, both SeYPS-1 and SeYPS-2 at a lower dose level (5 μg/mL) were more active at promoting phagocytosis activity, increasing the CD4⁺/CD8⁺ ratio of the T-lymphocyte sub-population in the murine splenocyte, improving cytokine secretion, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α in the macrophages, or increasing interferon-γ secretion, but suppressing IL-4 production in the splenocytes. Consistently, SeYPS-2 has more potential than SeYPS-1 at exerting these assessed bioactivities in the cells. Thus, we conclude that a chemical modification of YPS using trace element Se at a lower selenylation extent could bring about higher immunomodulatory activity towards macrophages and splenocytes, while selenylation extent of YPS is a critical factor used to govern the assessed activity changes of YPS.

Purification and comparative study of bioactivities of a natural selenized polysaccharide from Ganoderma Lucidum mycelia

The development of selenized polysaccharides is a promising strategy for the dietary selenium supplementation. The purpose of this research is to determine the influence of selenium on the structure and bioactivity of a polysaccharide fraction (MPN) isolated from Ganoderma lucidum mycelia. After biological selenium enrichment, the selenium content in the selenized polysaccharide (SeMPN) was 18.91 ± 1.8 μg/g. SeMPN had a slightly lower molecular weight than MPN, but the carbohydrate content and monosaccharide composition remained identical. Additionally, the band at 606 cm^-1 in MPN changed to 615 cm^-1 in SeMPN as revealed by FT-IR spectra. No significant changes were observed in the types and ratios of glycosidic linkages, as determined by NMR spectroscopy. Extracellular and intracellular antioxidant assays demonstrated that SeMPN was more effective than MPN in scavenging free radicals, inhibiting AAPH-induced erythrocyte hemolysis, and protecting catalase (CAT) and glutathione peroxidase (GSH-Px) activity in H₂O₂-injured PC12 cells. Additionally, SeMPN had a higher increase effect on RAW 264.7 cells's pinocytic and phagocytic capacity, as well as their production of NO, TNF-α, and IL-6. SeMPN could be as potential functional selenium supplementation.

Enhanced antitumor activity of inulin-capped Se nanoparticles synthesized using Jerusalem artichoke tubers

An inulin polysaccharide with a molecular weight of ~ 2600 Da was derived from Jerusalem artichoke tubers and referred to as "JAP". Previous studies have shown that inulin can improve glucose tolerance and the liver lipid profile; however, its antitumor activity remains to be examined in detail. Therefore, to investigate the possible improvement of the antitumor activity of JAP, a novel nanostructured biomaterial was constructed by capping Se nanoparticles with JAP using sodium selenite, via a redox reaction with ascorbic acid, and referred to as "JAP-SeNPs". Transmission electron microscopy revealed that the average diameter of JAP-SeNPs is ~ 50 nm, and the C:Se mass ratio in JAP-SeNPs was found to be 15.4:1 by energy-dispersive X-ray spectroscopy. The well-dispersed JAP-SeNPs exhibited a significant in vitro antiproliferative effect on mouse forestomach carcinoma cells at a concentration of 400 μg/mL when incubated for 48 h, with an inhibition rate of 41.5%. Moreover, 38.9% of later apoptotic cells were observed. These results reveal that a combination of Se and JAP can effectively enhance the antitumor activity of polysaccharides obtained from Jerusalem artichoke tubers.

Effects of seleno-Sesbania canabina galactomannan on anti-oxidative and immune function of macrophage

Seleno-polysaccharides have become a major topic for research owing to their high anti-oxidative capacity and immune-enhancing activities. In this study, galactomannan (GM) was isolated from Sesbania cannabina, and next modified using HNO₃-Na₂SeO₃ method to obtain six varieties of seleno-galactomannans (SeGMs). FT-IR and GPC results showed the changes in chemical structure of SeGMs, indicating successful combination of selenium and GM. By measuring superoxide dismutase and malondialdehyde, the SeGMs showed a stronger protective effect against H₂O₂-induced oxidative damage in vitro than unmodified GM using macrophage RAW264.7 cell as a model, and the effect of SeGMs-14 was prominent. However, the selenylation modification did not show any obvious effect on the immunomodulatory activity of GM, as determined by the index of tumor necrosis factor-α, interleukin-6, and interleukin-1β. Overall, the prepared SeGMs from galactomannan could potentially serve as a dietary supplement of Se or an organic antioxidant.

Selenium-Containing Polysaccharides—Structural Diversity, Biosynthesis, Chemical Modifications and Biological Activity

Selenosugars are a group of sugar derivatives of great structural diversity (e.g., molar masses, selenium oxidation state, and selenium binding), obtained as a result of biosynthesis, chemical modification of natural compounds, or chemical synthesis. Seleno-monosaccharides and disaccharides are known to be non-toxic products of the natural metabolism of selenium compounds in mammals. In the case of the selenium-containing polysaccharides of natural origin, their formation is also postulated as a form of detoxification of excess selenium in microorganisms, mushroom, and plants. The valency of selenium in selenium-containing polysaccharides can be: 0 (encapsulated nano-selenium), IV (selenites of polysaccharides), or II (selenoglycosides or selenium built into the sugar ring to replace oxygen). The great interest in Se-polysaccharides results from the expected synergy between selenium and polysaccharides. Several plant- and mushroom-derived polysaccharides are potent macromolecules with antitumor, immunomodulatory, antioxidant, and other biological properties. Selenium, a trace element of fundamental importance to human health, has been shown to possess several analogous functions. The mechanism by which selenium exerts anticancer and immunomodulatory activity differs from that of polysaccharide fractions, but a similar pharmacological effect suggests a possible synergy of these two agents. Various functions of Se-polysaccharides have been explored, including antitumor, immune-enhancement, antioxidant, antidiabetic, anti-inflammatory, hepatoprotective, and neuroprotective activities. Due to being non-toxic or much less toxic than inorganic selenium compounds, Se-polysaccharides are potential dietary supplements that could be used, e.g., in chemoprevention.

The role of Se content in improving anti-tumor activities and its potential mechanism for selenized Artemisia sphaerocephala polysaccharides

Drawing an instructive point on the correlation between Se content and anti-tumor effects is helpful to develop Se-polysaccharides with potential anti-tumor activities. In this work, Se content-related anti-tumor activities are assessed in vitro by multiple comparisons among Na2SeO3, Artemisia sphaerocephala polysaccharide (ASP), and selenized ASP (SeASPs, Se contents 4344-13 030 μg g-1) synthesized by a chemical modification method. The results suggest that SeASPs exhibit potent anti-proliferation activities against three kinds of tumor cells by inducing apoptosis and cell cycle arrest, which is positively correlated to Se content. Meanwhile, SeASPs display low cytotoxicity against normal cells as compared with Na2SeO3 and 5-FU. A mitochondrial membrane potential assay and western blotting analysis suggest that the SeASPs induce HepG2 cell apoptosis via mitochondrial and death receptor pathways, which is confirmed by the reduced mitochondrial membrane potential, upregulated Bax/Bcl-2 ratio, promoted Cyt C release, and increased expression level of caspase-3/-9/-8. In an in vivo anti-tumor assay, SeASP with a high Se content (13 030 μg g-1) also obviously inhibits H22 tumor growth in a dose-dependent manner, and a tumor suppression rate of 45.10% is observed. In addition, the results of ELISA analysis suggest that SeASPs obviously increase the concentration of serum NO, cytokines (IL-1β, IL-6, TNF-α), and Ig-G in a dose-dependent manner as compared with the control and ASP group. It could be concluded that adjusting the Se content might be an effective approach to improve the anti-tumor activities of Se-polysaccharides.

Molar mass effect in food and health

It is demanded to supply foods with good quality for all the humans. With the advent of aging society, palatable and healthy foods are required to improve the quality of life and reduce the burden of finance for medical expenditure. Food hydrocolloids can contribute to this demand by versatile functions such as thickening, gelling, stabilising, and emulsifying, controlling texture and flavour release in food processing. Molar mass effects on viscosity and diffusion in liquid foods, and on mechanical and other physical properties of solid and semi-solid foods and films are overviewed. In these functions, the molar mass is one of the key factors, and therefore, the effects of molar mass on various health problems related to noncommunicable diseases or symptoms such as cancer, hyperlipidemia, hyperglycemia, constipation, high blood pressure, knee pain, osteoporosis, cystic fibrosis and dysphagia are described. Understanding these problems only from the viewpoint of molar mass is limited since other structural characteristics, conformation, branching, blockiness in copolymers such as pectin and alginate, degree of substitution as well as the position of the substituents are sometimes the determining factor rather than the molar mass. Nevertheless, comparison of different behaviours and functions in different polymers from the viewpoint of molar mass is expected to be useful to find a common characteristics, which may be helpful to understand the mechanism in other problems.

Effects of Selenized Astragalus Polysaccharide on the Adhesion and Endocytosis of Nanocalcium Oxalate Dihydrate after the Repair of Damaged HK-2 Cells

An oxidative damage model of human proximal renal epithelial cells (HK-2) was established using oxalate damage. The repair effects of Astragalus polysaccharide (APS) and selenized APS (Se-APS) on damaged HK-2 cells were investigated. Differences in the adhesion and endocytosis of HK-2 cells to calcium oxalate dihydrate crystals with a size of approximately 100 nm before and after APS and Se-APS repair were also explored. The results showed that after being repaired by APS and Se-APS, HK-2 cells exhibited increased cell viability, restored cell morphology, reduced reactive oxygen species level, increased mitochondrial membrane potential, reduced phosphatidylserine eversion, and osteopontin expression. Moreover, the amount of adherent crystals on the cell surface decreased, but the amount of endocytic crystals increased. At the same concentration, Se-APS exhibited better repair effects on the damaged HK-2 cells than APS. All these findings revealed that Se-APS may be a potential drug candidate for inhibiting the formation of kidney stones.

Effect of chitosan oligosaccharide-conjugated selenium on improving immune function and blocking gastric cancer growth

Selenium (Se) is a potential chemopreventive or chemotherapeutic agent against malignant tumor. Selenium-oligosaccharides are important selenium source of dietary supplementation. Due to the insufficient natural production, it is therefore urgent to develop selenium-oligosaccharides by artificial synthesis. Chitosan, the N-deacetylated derivative of chitin, has been applied widely in biomedical field, owing to its nontoxicity, hydrophilicity, biocompatibility, and biodegradation. While chitosan is water insoluble at neutral pH, limiting its application in physiological conditions. Chitosan oligosaccharide (COS), the hydrolysate of chitosan, is readily soluble in water because of the shorter chain lengths of the oligomers and the free amino groups in the D-glucosamine units. This study was aimed at preparing COS-conjugated selenium (COS-Se) and examining the toxicity and ability on improving immune function and blocking gastric cancer growth. Our results demonstrated that COS-Se displayed directly co-mitogenic and mitogenic actions on mouse splenocytes proliferation in vitro. Besides, COS-Se treatment could effectively elevate phagocytosis and increase the secretion of anti-inflammatory cytokine in mouse peritoneal macrophages. Further in vivo experiments showed that COS-Se exhibited immuno-enhancing effects through promoting the phagocytic index, spleen index and thymus index with no obvious toxicity to Kunming mice. Moreover, COS-Se inhibited proliferation and metastasis of human gastric cancer cells, with non-toxic effects on the normal fibroblast cells in vitro. COS-Se supplementation could significantly repress the growth of gastric adenocarcinoma through reducing levels of CD34, vascular endothelial growth factor and matrix metalloproteinase-9 of nude mice. In conclusion, COS-Se was non-toxic and showed great potential as a functional food ingredient in cancer prevention.

The characterization and biological activities of synthetic N, O-selenized chitosan derivatives

Synthetic selenium polysaccharides with potential bioactivity have drawn great interest due to the SeO bonds existing in the structure. Herein, N, O-selenized N-(2-carboxyethyl) chitosan (sNCCS) was synthesized through carboxyethylation and selenylation. Various characterizations were performed to identify the structure of sNCCS, indicating that SeO bonds were formed both at the C-6 hydroxyl groups and the introduced C-2 carboxyethyl groups. The highest yield and selenium content of all sNCCS reached 84.5% and 1.553 mg/g, respectively. In vitro evaluation exhibited that sNCCS has excellent bile acid binding capacity, which was 1.63, 2.00, and 2.55-fold higher than that of N-(2-carboxyethyl) chitosan (NCCS). Moreover, it was found that higher selenium content could significantly enhance the antioxidant properties of sNCCS. Importantly, no obvious cytotoxic effect had been observed on Caco-2 cells. Taken together, sNCCS with desirable biological activity and non-cytotoxicity might be considered as an effective ingredient in the fields of food or medicine.