Antioxidant and antimicrobial activity of xylan–chitooligomer–zinc complex

Functionalities of Tremella fuciformis Polysaccharides Modified with Gallic Acid

This research aimed to modify polysaccharides extracted from the edible mushroom Tremella fuciformis with gallic acid (GA) and to complex them with zinc ions. The functionalities of the modified Tremella fuciformis polysaccharides (TFPs) were investigated. Regarding antioxidant activity, TFP-GA demonstrated effective scavenging activity against DPPH radicals, nitric oxide, and hydrogen peroxide. Additionally, TFP-GA exhibited superior reducing ability toward Fe3+ and enhanced chelating activity toward Fe2+ compared to unmodified TFP. Notably, the TFP-GA conjugate outperformed GA in Fe2+-chelating activity. In terms of antimicrobial activity, the TFP-GA-Zn complex showed significantly improved antimicrobial effectiveness against S. aureus and E. coli compared to TFP-GA.

Toward Enhanced Antioxidant and Protective Potential: Conjugation of Corn Cob Xylan with Gallic Acid as a Novel Approach

Maize ranks as the second most widely produced crop globally, yielding approximately 1.2 billion tons, with corn cob being its primary byproduct, constituting 18 kg per 100 kg of corn. Agricultural corn production generates bioactive polysaccharide-rich byproducts, including xylan (Xyl). In this study, we used the redox method to modify corn cob xylan with gallic acid, aiming to enhance its antioxidant and protective capacity against oxidative stress. The conjugation process resulted in a new molecule termed conjugated xylan-gallic acid (Xyl-GA), exhibiting notable improvements in various antioxidant parameters, including total antioxidant capacity (1.4-fold increase), reducing power (1.2-fold increase), hydroxyl radical scavenging (1.6-fold increase), and cupric chelation (27.5-fold increase) when compared with unmodified Xyl. At a concentration of 1 mg/mL, Xyl-GA demonstrated no cytotoxicity, significantly increased fibroblast cell viability (approximately 80%), and effectively mitigated intracellular ROS levels (reduced by 100%) following oxidative damage induced by H2O2. Furthermore, Xyl-GA exhibited non-toxicity toward zebrafish embryos, offered protection against H2O2-induced stress, and reduced the rate of cells undergoing apoptosis resulting from H2O2 exposure. In conclusion, our findings suggest that Xyl-GA possesses potential therapeutic value in addressing oxidative stress-related disturbances. Further investigations are warranted to elucidate the molecular structure of this novel compound and establish correlations with its pharmacological activities.

New Insights into the In Vitro Antioxidant Routes and Osteogenic Properties of Sr/Zn Phytate Compounds

Sr/Zn phytate compounds have been shown interest in biomaterial science, specifically in dental implantology, due to their antimicrobial effects against Streptococcus mutans and their capacity to form bioactive coatings. Phytic acid is a natural chelating compound that shows antioxidant and osteogenic properties that can play an important role in bone remodelling processes affected by oxidative stress environments, such as those produced during infections. The application of non-protein cell-signalling molecules that regulate both bone and ROS homeostasis is a promising strategy for the regeneration of bone tissues affected by oxidative stress processes. In this context, phytic acid (PA) emerged as an excellent option since its antioxidant and osteogenic properties can play an important role in bone remodelling processes. In this study, we explored the antioxidant and osteogenic properties of two metallic PA complexes bearing bioactive cations, i.e., Sr²⁺ (SrPhy) and Zn²⁺ (ZnPhy), highlighting the effect of the divalent cations anchored to phytate moieties and their capability to modulate the PA properties. The in vitro features of the complexes were analyzed and compared with those of their precursor PA. The ferrozine/FeCl₂ method indicated that SrPhy exhibited a more remarkable ferrous ion affinity than ZnPhy, while the antioxidant activity demonstrated by a DPPH assay showed that only ZnPhy reduced the content of free radicals. Likewise, the antioxidant potential was assessed with RAW264.7 cell cultures. An ROS assay indicated again that ZnPhy was the only one to reduce the ROS content (20%), whereas all phytate compounds inhibited lipid peroxidation following the decreasing order of PA > SrPhy > ZnPhy. The in vitro evaluation of the phytate's osteogenic ability was performed using hMSC cells. The results showed tailored properties related to the cation bound in each complex. ZnPhy overexpressed ALP activity at 3 and 14 days, and SrPhy significantly increased calcium deposition after 21 days. This study demonstrated that Sr/Zn phytates maintained the antioxidant and osteogenic properties of PA and can be used in bone regenerative therapies involving oxidative environments, such as infected implant coatings and periodontal tissues.

Preparation and identification of an antioxidant peptide from wheat embryo albumin and characterization of its Maillard reaction products

Wheat embryo albumin (WEA) extracted from wheat embryo possesses multiple effects including antioxidant, anti-inflammatory, and immunoregulatory effects. In this study, a single factor experiment was conducted to determine the optimal enzymolysis conditions of WEA. Five components (F1-F5) were obtained via ultrafiltration, among which F3 (molecular weight 3-5 kDa) displayed the best antioxidant activity. WEA and F3 were characterized by transmission electron microscopy, scanning electron microscopy, circular dichroism spectrum analysis, and amino acid composition tests. Results revealed that F3 significantly increased the contents of β-tablets, aromatic amino acids, and hydrophobic amino acids compared to WEA. LC-MS/MS analysis demonstrated that F3 had more tyrosine and histidine moieties than WEA. Moreover, analysis of the Maillard reaction products (MRPs) showed that F3-MRPs had strong browning strength, ultraviolet absorption, higher number of free amino acids, and umami amino acid ratio compared with WEA. In conclusion, enzymolysis can improve the functional properties of WEA, which broadens the application spectrum of WEA in food and pharmaceutical fields. PRACTICAL APPLICATION: This study provides a new approach for identifying potential antioxidants and developing functional foods from WEA, and broadens the application spectrum of wheat germ resources.

Enteromorpha polysaccharide-zinc replacing prophylactic antibiotics contributes to improving gut health of weaned piglets

This research aimed to study whether Enteromorpha polysaccharide-zinc (EP-Zn) can act as an alternative to antibiotics in weaned piglet feeds. Two hundred and twenty-four weaned piglets from 14 pens were randomly assigned into 1 of 2 groups according to their body weight and litter size (7 pens/group). The piglets in the antibiotics group were fed with olaquindox at 400 mg/kg and enduracidin at 800 mg/kg basal diet, and piglets in the EP-Zn group were fed with EP-Zn at 800 mg/kg basal diet. One piglet per pen was selected to collect samples after 14 d of feeding. Results showed that EP-Zn supplementation significantly increased the plasma anti-oxidants level compared with the antibiotics group. However, a nonsignificant difference was observed in growth performance between treatment groups. Additionally, the intestinal tight junction (TJ) protein expression and the histopathologic evaluation data showed that EP-Zn contributed to improving intestinal development. Further, piglets in the EP-Zn group had a lower level of intestinal inflammation-related cytokines including IL-6 (P < 0.001), IL-8 (P < 0.05), IL-12 (P < 0.05) and tumor necrosis factor-α (TNF-α) (P < 0.001), and showed an inhibition of the phosphorylation nuclear transcription factor-kappa B (p-NF-κB) (P < 0.05) and total NF-κB (P < 0.001) level in the jejunal mucosa. Taken together, it is supposed that EP-Zn, to some extent, would be a potent alternative to prophylactic antibiotics in improving the health status of weaned piglets.

Structural characteristics and improved in vitro hepatoprotective activities of Maillard reaction products of decapeptide IVTNWDDMEK and ribose

Here, a novel decapeptide IVTNWDDMEK with Maillard reactivity derived from scallop Chlamys farreri mantle was identified. The structural characteristics and in vitro hepatoprotective effects of IVTNWDDMEK conjugated with ribose were further investigated. The changes in decapeptide structures were determined by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR), and atomic force microscopy (AFM), and the modification sites induced by Maillard reaction of IVTNWDDMEK and ribose were monitored by high performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). Maillard reaction products (MRPs) of IVTNWDDMEK-ribose demonstrate hepatoprotective benefits through the suppression of DNA damage and apoptosis induced by oxidative stress in human HepG2 cells in addition to enhancing the antioxidant activities. Moreover, after treatment with decapeptide-ribose MRPs, the activities of cellular antioxidative enzymes, such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rx) were remarkably increased, while the content of malondialdehyde (MDA) was decreased compared with H₂ O₂ ^- treated group, thereby enhancing the intracellular antioxidant defenses. These findings demonstrate the potential utilization of decapeptide IVTNWDDMEK-ribose MRPs as food antioxidants to suppress oxidative damage. PRACTICAL APPLICATION: In recent years, several food-derived bioactive peptides and their derivatives are regarded as good dietary antioxidants for reducing oxidative stress and improving liver function. Here, a novel Maillard reactive decapeptide IVTNWDDMEK, identified from scallop mantle hydrolysates by peptidomics in the previous study was synthesized. Then, the correlation between intercellular antioxidant activities and chemical structure changes of IVTNWDDMEK-ribose Maillard reaction conjugates was further studied. The preferable hepatoprotective activities of decapeptide IVTNWDDMEK-ribose MRPs indicated that these MRPs could be potentially utilized as food antioxidants or additives in the production of nutritional foods.

Molecular modification, structural characterization, and biological activity of xylans

The differences in the source and structure of xylans make them have various biological activities. However, due to their inherent structural limitations, the various biological activities of xylans are far lower than those of commercial drugs. Currently, several types of molecular modification methods have been developed to address these limitations, and many derivatives with specific biological activity have been obtained. Further research on structural characteristics, structure-activity relationship and mechanism of action is of great significance for the development of xylan derivatives. Therefore, the major molecular modification methods of xylans are introduced in this paper, and the primary structure and conformation characteristics of xylans and their derivatives are summarized. In addition, the biological activity and structure-activity relationship of the modified xylans are also discussed.

Enhancing the antioxidative effects of foods containing rutin and α-amino acids via the Maillard reaction: A model study focusing on rutin-lysine system

Rutin is a bioflavonoid found in many plants and derived foods, accordingly, rutin likely interacts with α-amino acids such as Lys, Ile, His or Glu to give Maillard reaction products (MRPs). The heated rutin-Lys system exhibited highest brown intensity and in vitro antioxidant activities. The 30-50 kDa rutin-Lys fraction had higher in vitro antioxidant activities than the other fractions, and at a dose of 0.4 mg/ml preserved over 90% cell viability for HepG2 cells exposed to H₂ O₂ . The dose-dependent protective effects against H₂ O₂ -induced oxidative stress of the rutin-Lys MRPs may involve the inhibition of reactive oxygen species generation, enhancement of the superoxide dismutase and catalase activities, along with the activation of the Nrf2-dependent pathway and upregulation of phase II antioxidant genes (including NQO1, HO-1, GCLG, and GCLM). PRACTICAL APPLICATIONS: Rutin is widely distributed in vegetables and grains. The Maillard reaction is a common reaction occurring during food processing, and produces Maillard reaction products (MRPs) with distinct processing and biological properties. This study shows that a 30-min thermal treatment at 120°C generates antioxidative MRPs in the rutin-Lys, rutin-His, rutin-Ile and rutin-Glu model systems, which can directly inhibit reactive oxygen species generation and enhance SOD and CAT activities while activating the Nrf2-dependent pathway and upregulating the expression of phase II detoxifying antioxidant genes. Therefore, for food systems containing phenolic antioxidants and proteins (such as rutin and Lys), one may enhance the antioxidant properties of these food systems through a 30-min thermal treatment at 120°C. Also, the resultant rutin-Lys MRPs may be isolated and used as commercial preparations of natural antioxidants.

Hemicellulose from Plant Biomass in Medical and Pharmaceutical Application: A Critical Review

BACKGROUND

Due to the non-toxicity, abundance and biodegradability, recently more and more attention has been focused on the exploration of hemicellulose as the potential substrate for the production of liquid fuels and other value-added chemicals and materials in different fields. This review aims to summarize the current knowledge on the promising application of nature hemicellulose and its derivative products including its degradation products, its new derivatives and hemicellulosebased medical biodegradable materials in the medical and pharmaceutical field, especially for inmmune regulation, bacteria inhibition, drug release, anti-caries, scaffold materials and anti-tumor.

METHODS

We searched the related papers about the medical and pharmaceutical application of hemicellulose and its derivative products, and summarized their preparation methods, properties and use effects.

RESULTS

Two hundred and twenty-seven papers were included in this review. Forty-seven papers introduced the extraction and application in immune regulation of nature hemicellulose, such as xylan, mannan, xyloglucan (XG) and β-glucan. Seventy-seven papers mentioned the preparation and application of degradation products of hemicellulose for adjusting intestinal function, maintaining blood glucose levels, enhancing the immunity and alleviating human fatigue fields such as xylooligosaccharides, xylitol, xylose, arabinose, etc. The preparation of hemicellulose derivatives were described in thirty-two papers such as hemicellulose esters, hemicellulose ethers and their effects on anticoagulants, adsorption of creatinine, the addition of immune cells and the inhibition of harmful bacteria. Finally, the preparations of hemicellulose-based materials such as hydrogels and membrane for the field of drug release, cell immobilization, cancer therapy and wound dressings were presented using fifty-five papers.

CONCLUSION

The structure of hemicellulose-based products has the significant impact on properties and the use effect for the immunity, and treating various diseases of human. However, some efforts should be made to explore and improve the properties of hemicellulose-based products and design the new materials to broaden hemicellulose applications.

Antioxidant and antimicrobial evaluation of carboxymethylated and hydroxamated degraded polysaccharides from Sargassum fusiforme

In order to improve the bioactivity of the polysaccharide from Sargassum fusiforme (PSF), the degraded polysaccharide (DPSF) was modified by carboxymethylation, yielding carboxymethylated degraded polysaccharides (CDPSF), which were further modified to generate hydroxamated derivatives (HCDPSF). Both CDPSF and HCDPSF were characterized by Fourier transform infrared spectroscopy. The molecular weight of CDPSF and HCDPSF was found to be 354 kDa and 375 kDa, respectively. The in vitro antioxidant activity of CDPSF and HCDPSF was evaluated by determining the radical scavenging ability and total antioxidant activity. The results indicated that the antioxidant activity of CDPSF and HCDPSF was significantly improved when compared to those of DPSF. Antimicrobial assays indicated that both CDPSF and HCDPSF possessed a marked antimicrobial ability, while DPSF did not exhibit such effects under the same conditions. Such polysaccharide derivatives have potentials in the pharmaceutical and food industries.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Antibacterial Hydrogels

Antibacterial materials are recognized as important biomaterials due to their effective inhibition of bacterial infections. Hydrogels are 3D polymer networks crosslinked by either physical interactions or covalent bonds. Currently, hydrogels with an antibacterial function are a main focus in biomedical research. Many advanced antibacterial hydrogels are developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs, and structural diversity. Here, an overview of the structures, performances, mechanisms of action, loading and release behaviors, and applications of various antibacterial hydrogel formulations is provided. Furthermore, the prospects in biomedical research and clinical applications are predicted.

Antimicrobial hydrogels: promising materials for medical application

The rapid emergence of antibiotic resistance in pathogenic microbes is becoming an imminent global public health problem. Local application of antibiotics might be a solution. In local application, materials need to act as the drug delivery system. The drug delivery system should be biodegradable and prolonged antibacterial effect should be provided to satisfy clinical demand. Hydrogel is a promising material for local antibacterial application. Hydrogel refers to a kind of biomaterial synthesized by a water-soluble natural polymer or a synthesized polymer, which turns into gel according to the change in different signals such as temperature, ionic strength, pH, ultraviolet exposure etc. Because of its high hydrophilicity, unique three-dimensional network, fine biocompatibility and cell adhesion, hydrogel is one of the suitable biomaterials for drug delivery in antimicrobial areas. In this review, studies from the past 5 years were reviewed, and several types of antimicrobial hydrogels according to different ingredients, different preparations, different antimicrobial mechanisms, different antimicrobial agents they contained and different applications, were summarized. The hydrogels loaded with metal nanoparticles as a potential method to solve antibiotic resistance were highlighted. Finally, future prospects of development and application of antimicrobial hydrogels are suggested.

Ursolic Acid Hydrazide Based Organometallic Complexes: Synthesis, Characterization, Antibacterial, Antioxidant, and Docking Studies

In thecurrent research work,eleven metal complexes were synthesized from the hydrazide derivative of ursolic acid. Metal complexes of tin, antimony and iron were synthesized and characterized by FT-IR and NMR spectroscopy. The antibacterial and antioxidant activities were performed for these complexes, which revealed that the metal complexes synthesized are more potent than their parent compounds. We observed that antioxidant activity showed by triphenyltin complex was significant and least activity have been shown by antimony trichloride complex. The synthesized metal complexes were then evaluated against two Gram-negative and two Gram-positive bacterial strains. Triphenyl tin complex emerged as potent antibacterial agent with MIC value of 8 μg/ml each against Shigellaspp, Salmonella typhi and Staphylococcus aureus. While, the MIC value against Streptococcus pneumoniae is 4 μg/ml. Computational docking studies were carried out on molecular targets to interpret the results of antioxidant and antibacterial activities. Based on the results, it may be inferred that the metal complexes of ursolic acid are more active as compared to the parent drug and may be proved for some other pharmacological potential by further analysis.

Antimicrobial and antioxidant capacity of glucosamine-zinc(II) complex via non-enzymatic browning reaction

Coordination compounds play an important role in the life process, and have been widely used in food, cosmetics and pharmaceutical industry. Herein, we have developed a novel kind of glucosamine-zinc(II) complex (GlcN-ZC) for food additive using non-enzymatic browning reaction. The GlcN-ZC was characterized by FTIR and XRD. Moreover, UV absorbance changes, browning intensity, fluorescence changes, antioxidant activity and antimicrobial assessment of GlcN-ZC were also evaluated. Results showed the GlcN-ZC intermediate compounds were accumulated in non-enzymatic browning while prolonging heating time and melanoidins were produced in the final stage. The fluorescence changes confirmed that fluorophores were formed during the non-enzymatic reaction and fluorescence intensity reached a maximun at 60 min. The highest radical scavenging activity of GlcN-ZC formed after 180 min of heating was 79.2%. Furthermore, GlcN-ZC exhibited excellent antibacterial activity against E. coli and S. aureus. Therefore, GlcN-ZC can be used as a novel promising additive in the food industry.

Novel Soluble Dietary Fiber-Tannin Self-Assembled Film: A Promising Protein Protective Material

In this experiment, a natural promising protein protective film was fabricated through soluble dietary fiber (SDF)-tannin nanocluster self-assembly. FT-IR, XRD, and DSC tests were employed to investigate the interaction between the SDF and tannins before and after cross-linking induced by calcium ion. On the other hand, referring to the SEM and TEM results, the self-assembly process of the protein protective film could be indicated as follows: first, calcium ion, with its cross-ability, served as the "nucleus"; SDF and tannins were combined to prepare the nanoscale SDF-tannin clusters; then, the clusters were homogeneously deposited on the surface of protein to form a protective film by self-assembling hydrogen bond between tannin component of clusters as "adhesive" and protein in aqueous solutions under very mild conditions. Film thickness could also be controlled by tannin of different concentrations ranging from 114 to 1384 μm. Antibacterial test and in vitro cytotoxicity test proved that the film had a broad spectrum of antimicrobial properties and excellent cell biocompatibility, respectively, which might open up new applications in the food preservation and biomedical fields.

Behaviour of zinc complexes and zinc sulphide nanoparticles revealed by using screen printed electrodes and spectrometry

In this study, we focused on microfluidic electrochemical analysis of zinc complexes (Zn(phen)(his)Cl₂, Zn(his)Cl₂) and ZnS quantum dots (QDs) using printed electrodes. This method was chosen due to the simple (easy to use) instrumentation and variable setting of flows. Reduction signals of zinc under the strictly defined and controlled conditions (pH, temperature, flow rate, accumulation time and applied potential) were studied. We showed that the increasing concentration of the complexes (Zn(phen)(his)Cl₂, Zn(his)Cl₂) led to a decrease in the electrochemical signal and a significant shift of the potential to more positive values. The most likely explanation of this result is that zinc is strongly bound in the complex and its distribution on the electrode is very limited. Changing the pH from 3.5 to 5.5 resulted in a significant intensification of the Zn(II) reduction signal. The complexes were also characterized by UV/VIS spectrophotometry, chromatography, and ESI-QTOF mass spectrometry.