Preparation, antioxidant and antimicrobial evaluation of hydroxamated degraded polysaccharides from Enteromorpha prolifera

Enzymatic degraded polysaccharides from Enteromorpha prolifera inhibit the growth of THP-1 cells and induce apoptosis via the mitochondrial pathway

Polysaccharides from Enteromorpha prolifera (EP) is a kind of sulfated polysaccharides with complex structure. Several reports have showed that EP play roles in antioxidant and anti-inflammatory, while, whose function in anti-leukemia is still poorly understood. In this work, EPH were the hydrolysis products of EP by ulvan lyase EPL15085, which displayed lower molecular weight and enhanced sulfate groups than EP. Importantly, EPH exhibited effective inhibitory effect on the human leukemia monocyte cell line, THP-1 cells, however, the EP treated group showed no significant change. Results of JC-1 staining and ROS assay showed mitochondrial dysfunction after EPH treatment, and the increased rate of Bax/Bcl ultimately activated Caspase family proteins to induce apoptosis, indicating the mitochondrial pathway was involved. This study demonstrates the enzymatic products of EP showed enhanced effect on anti-leukemia, which would provide insights for approaches to uncover novel physiological functions of marine polysaccharides and potential therapy for acute myeloid leukemia patients.

Recent advances in fucoidan-based improved delivery systems: Structure, carrier types and biomedical applications

Consumer demand for nutritional supplements has fueled the rapid growth of the functional food market. However, ensuring the stability of functional factors in harsh environments remains a major challenge. The development of encapsulation systems is regarded as an effective method for enhancing the stability of functional factors, encapsulation carriers can offer protection for these functional factors. However, the selection of materials remains a significant constraint in the construction of delivery systems. Therefore, developing new encapsulation materials is crucial for advancing delivery systems, preserving the stability of functional factors, and ensuring public health. Fucoidan, a sulfated marine polysaccharide, has garnered significant attention in the field of encapsulation due to its notable advantages, including its remarkable bioactivity, biocompatibility, and targeted binding properties. Fucoidan-improved delivery systems provide new strategies for encapsulation of functional factors. This review first describes the structure of fucoidan, its modification and lists the applications of modified fucoidan, and assesses its feasibility for enhancing delivery systems. Second, it summarizes several common encapsulation technologies and methods, and outlines various carrier types based on fucoidan. Finally, it elucidates recent advances in the biomedical applications of fucoidan-improved delivery systems. Notably, it also presents the challenges and future prospects of this promising field.

Efficient degradation of the polysaccharide extracted from Enteromorpha prolifera by using a novel polysaccharide lyase family 28 enzyme with high activity

The polysaccharides originated from Enteromorpha species exhibited versatile physiological activities and great potential in food and medicine industries. The oligosaccharides, which prepared from polysaccharide by enzymatic hydrolysis, retained the excellent activity as polysaccharide, and then revealed better solubility, bioavailability and effectiveness. However, there are few reports on Enteromorpha polysaccharide (EP)-degrading enzymes for efficient degradation of EP and high-valued utilization of Enteromorpha biomass. Herein, a novel EP-degrading enzyme, EPD1, was identified and heterologously expressed. It could efficiently hydrolyze the EP with high activity (985.755 U/mg) and exhibited optimal activity at 50 °C and a pH of 10.0. The Km value of EPD1 was 7.5512 mg·mL-1 and the Vmax value was 4.9109 μmol·min-1·mL-1. Furthermore, EPD1 demonstrated cold adaptation as evidenced by minimal activity loss following incubation at temperatures below 30 °C for 1 h. HPLC and ESI-MS analysis revealed that EPD1 could produce disaccharides, trisaccharides and tetrasaccharides as the final degradation products from EPs. In conclusion, a novel EP-degrading enzyme with high activity and excellent performance was identified and it can expand the database of EP-degrading enzymes and provide the possibility to make full use of EPs.

Water-soluble polysaccharides extracted from Enteromorpha prolifera/PVA composite film functionalized as ε-polylysine with improved mechanical and antibacterial properties

The issue of environmental protection has received sustained and widespread attention. In order to reduce environmental pollution related to traditional plastics, it is an incessant demand to design novel environment-friendly food packaging materials with excellent performance. Sulfated polysaccharide extracted from the "green tide" marine pollution Enteromorpha prolifera (SPE) has been innovatively transformed into a film-forming material for better utilization. The insufficient mechanical properties and limited functionalities, however, hinder its wide application. In this study, polyvinyl alcohol (PVA) was blended to enhance its mechanical properties and ε-polylysine (ε-PL) was incorporated to endow it with antimicrobial performance. A novel and biodegradable film composed of SPE, PVA, and ε-PL was fabricated by casting method. We further determined the physicochemical properties of composited films. Mechanical performance test revealed the tensile strength of SPE-PVA-PL films increased from 5.56 MPa to 6.65 MPa and the E% increased from 128.8 % to 246.9 % compared with that of SPE-PVA films. Antimicrobial tests showed the excellent antibacterial activity of SPE-PVA-PL films against representative microbial species, Staphylococcus aureus and Escherichia coli. The results of this study suggested that the SPE-based composite film has the potential to be used as a potential food packaging and wound dressing materials.

A critical review on pharmacological properties of sulfated polysaccharides from marine macroalgae

The marine ecosystem contains an assorted range of organisms, among which macroalgae stands out marine resources as an invaluable reservoir of structurally diverse bioactive compounds. Marine macroalgae are considered as primary consumers have gained more attention for their bioactive components. Sulfated polysaccharides (SPs) are complex polymers found in macroalgae that play a crucial role in their cell wall composition. This review consolidates high-tech methodologies employed in the extraction of macroalgal SPs, offering a valuable resource for researchers focuses in the pharmacological relevance of marine macromolecules. The pharmacological activities of SPs, focusing on their therapeutic action by encompassing diverse study models are summarized. Furthermore, in silico docking studies facilitates a comprehensive understanding of SPs interactions with their binding sites providing a valuable insight for future endeavors. The biological properties of algal SPs, along with a brief reference to mode of action based on different targets are presented. This review utilizes up-to-date research discoveries across various study models to elucidate the biological functions of SPs, focusing on their molecular-level mechanisms and offering insights for prospective investigations. Besides, the significance of SPs from seaweeds is highlighted, showcasing their potential beneficial applications in promoting human health. With promising biomedical prospects, this review explores the extensive uses and experimental evidence supporting the important roles of SPs in various fields.

Unraveling the web of defense: the crucial role of polysaccharides in immunity

The great potential of polysaccharides in immunological regulation has recently been highlighted in pharmacological and clinical studies. Polysaccharides can trigger immunostimulatory responses through molecular identification, intra- and intercellular communication via direct or indirect interactions with the immune system. Various immunostimulatory polysaccharides or their derivative compounds interacts at cellular level to boost the immune system, including arabinogalactans, fucoidans, mannans, xylans, galactans, hyaluronans, fructans, pectin and arabinogalactans, etc. These natural polysaccharides are derived from various plants, animals and microbes. A unique structural diversity has been identified in polysaccharides, while monosaccharides and glucosidic bonds mainly confer diverse biological activities. These natural polysaccharides improve antioxidant capacity, reduce the production of pro-inflammatory mediators, strengthen the intestinal barrier, influence the composition of intestinal microbial populations and promote the synthesis of short-chain fatty acids. These natural polysaccharides are also known to reduce excessive inflammatory responses. It is crucial to develop polysaccharide-based immunomodulators that could be used to prevent or treat certain diseases. This review highlights the structural features, immunomodulatory properties, underlying immunomodulatory mechanisms of naturally occurring polysaccharides, and activities related to immune effects by elucidating a complex relationship between polysaccharides and immunity. In addition, the future of these molecules as potential immunomodulatory components that could transform pharmaceutical applications at clinical level will also be highlighted.

Improving the shelf life of minced beef by Cystoseira compressa polysaccharide during storage

A polysaccharide extracted from the brown alga Cystoseira compressa (CCPS) was evaluated as a food additive to extend the shelf-life of raw beef meat. The antioxidant potential of CCPS was demonstrated by its inhibition of β-carotene bleaching (64.28 %), superoxide radicals (70.12 %), and hydroxyl radicals (93 %) at a concentration of 10 mg/ml. The polysaccharide also showed antibacterial activity with MIC values between 6.25 mg/ml and 50 mg/ml against five foodborne pathogenic bacteria. Furthermore, CCPS exhibited excellent functional, foaming, and emulsifying properties. Furthermore, microbiological and chemical effects of CCPS at concentrations equivalent to 1 MIC (CCPS-1), 2 MIC (CCPS-2), and 4 MIC (CCPS-3) were conducted. Chemical analyses showed that treated beef had significantly reduced TBARS levels below 2 mg MDA/kg at day 14. The treatment also decreased carbonyl groups, improved heme iron transformation, inhibited microbial growth (p < 0.05), and kept MetMb levels below 40 % by day 14. Moreover, two multivariate approaches, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were effectively used to analyze the results characterizing the main attributes of the stored meat samples. In conclusion, these findings demonstrated that CCPS could be employed as a functional and bioactive component in the meat industry.

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.

Improvement of antibacterial activity of polysaccharides via chemical modification: A review

Antibiotic residue and bacterial resistance induced by antibiotic abuse have seriously threatened food safety and human healthiness. Thus, the development and application of safe, high-efficiency, and environmentally friendly antibiotic alternatives are urgently necessary. Apart from antitumor, antivirus, anti-inflammatory, gut microbiota regulation, immunity improvement, and growth promotion activities, polysaccharides also have antibacterial activity, but such activity is relatively low, which cannot satisfy the requirements of food preservation, clinical sterilization, livestock feeding, and agricultural cultivation. Chemical modification not only provides polysaccharides with better antibacterial activity, but also promotes easy operation and large-scale production. Herein, the enhancement of the antibacterial activity of polysaccharides via acetylation, sulfation, phosphorylation, carboxymethylation, selenation, amination, acid graft, and other chemical modifications is reviewed. Meanwhile, a new trend on the application of loading chemically modified polysaccharides into nanostructures is discussed. Furthermore, possible limitations and future recommendations for the development and application of chemically modified polysaccharides with better antibacterial activity are suggested.

Structural characterization and anti-inflammatory effects of Enteromorpha prolifera polysaccharide-Fe/Zn complexes

The structure of polysaccharide has a great influence on its biological functions, and the chelation with metal ions is an effective way to change polysaccharide structural configuration. Herein, the structure of Enteromorpha prolifera polysaccharide (EP)-Fe/Zn complexes were characterized and the results showed that the iron (III) existed in form of β-FeOOH in EP-Fe (III) complex and the zinc (II) existed in form of C-O-Zn in EP-Zn (II) complex. Besides, the chelation with iron (III) or zinc (II) completely changed the apparent forms, and improved the thermal stability of EP. Furthermore, the anti-inflammatory activities of EP, EP-Fe and EP-Zn were proved by a lipopolysaccharide (LPS)-induced RAW264.7 macrophages model. The results showed that EP, EP-Fe (III) and EP-Zn (II) could decrease the mitochondrial membrane potential and the secretion of NO and cytokines induced by LPS. One of the anti-inflammatory mechanisms of EP, EP-Fe (III) and EP-Zn (II) was that they could inhibit mitogen-activated protein kinase (MAPK) signaling pathway via increasing its inhibitor content in cells. Collectively, the research suggested that the chelation with iron (III) or zinc (II) could change the structure and improve the anti-inflammatory activities of EP.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

Polysaccharides are promising biomolecules with lowtoxicity and diverse bioactivities in food processing and clinical drug development. However, an essential prerequisite for their applications is the fine structure characterization. Due to the complexity of polysaccharide structure, partial degradation is a powerful tool for fine structure analysis, which can effectively provide valid information on the structure of backbone and branching glycosidic fragments of complex polysaccharides. This review aims to conclude current methods of partial degradation employed for polysaccharide structural characterization, discuss the molecular mechanisms, and describe the molecular structure and solution properties of degraded polysaccharides. In addition, the effects of polysaccharide degradation on the conformational relationships between the molecular structure and bioactivities, such as antioxidant, antitumor, and immunomodulatory activities, are also discussed. Finally, we summarize the prospects and current challenges for the partial degradation of polysaccharides. This review will be of great value for the scientific elucidation of polysaccharide fine structures and potential applications.

Effects including photobiomodulation of galactomannan gel from Cassia grandis seeds in the healing process of second-degree burns

The epithelium recovery of skin-burned wounds has been currently achieved by several therapies, for example, hydrogel-based dressings and photobiomodulation therapy (PBMT). Thus, this work aimed to evaluate the healing activity of Cassia grandis seeds' galactomannan gel, associated or not with PBMT, in second-degree burns. Sixty male Wistar rats were assigned to four groups: Control (CG), Gel (GG), Laser/PBMT (LG), and Laser+Gel (GLG). Burns were made with an aluminum bar (90 °C), and submitted to clinical observations diary and area measurements at specific days. Microscopic analysis was based on histological criteria. The results showed that GG, LG, and GLG had a higher contraction rate (p < 0.05) than CG on the 14th experimental day, not differing from each other (∼95 %). At 21 days, all groups showed complete contraction (p > 0.05). Considering the histological results, LG and GLG showed excellent pro-wound healing properties after 14 days; at 21 days, all groups showed wound recovery compared to previous days. In view of the macroscopic and microscopic observations, the isolated treatments (Gel or Laser) effectively accelerated healing; however, the association (Laser+Gel) promoted re-epithelialization and stromal remodeling with better evolution of epithelium recovery due to the positive synergistic effect, thus emerging as a promising therapeutic alternative in the repair of burns.

Preparation of meaty flavor additive from soybean meal through the Maillard reaction

Meaty flavor additive was prepared from soybean meal hydrolysate and xylose in the method of Maillard reaction. Under the conditions of reaction temperature 120 ℃, time 120 min and cysteine addition 10%, the Maillard products had strong flavor of meat. The content of free amino acids was 4.941 μ mol/mL in the products. There were 50 volatile flavor substances in Maillard reaction products according to GC-MS analysis. 4 mercaptans, 4 sulfur substituted furans, 3 thiophenes, 7 furans, 6 pyrazine, 3 pyrrole, 1 pyrimidine, 7 aldehydes, 4 ketones, 7 esters, 2 alcohols and 2 acids were included. The Maillard reaction products also have strong antioxidant activity. The scavenging ability of FRAP, DPPH radical, hydroxyl radical and ABTS+ radical was 1.82%, 69.8%, 68.7% and 71.6% respectively. The products of Mailard reaction have potential to be used in food additives.

Effect of deacetylation of chitosan on the physicochemical, antioxidant and antibacterial properties activities of chitosan-mannose derivatives

BACKGROUND

The present study investigates the physical, chemical, and antibacterial properties of water-soluble chitosan derivatives. Preparation of the water-soluble chitosan derivatives was performed by the Maillard reaction (MR) between chitosan [with the degree of deacetylation (DD) being 50%, 70%, and 90%] and mannose. No organic reagent was used in the process. Systematic evaluations of the effects of chitosan DD on the reaction extent, the structure, the composition, as well as the physicochemical properties, antioxidant properties, and bacterial inhibitory properties of the finished chitosan-mannose MR products (Mc-mrps), were carried out.

RESULTS

Based on the experimental data obtained from Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, Pyrolysis-gas chromatography-mass spectrometry analysis, and 1 H-NMR, the Mc-mrps formed from chitosan with different DDs had different structures and components. An increase in the DD of chitosan led to a significant increase in the degree of reaction, color difference (△E), and solubility (P < 0.05). The zeta potential and particle size of the Mc-mrps were also influenced by the DD of chitosan. Additionally, the antimicrobial action against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), as well as antioxidant activity, were enhanced by the incorporation of mannose. This was also achieved by the increase of the DD of chitosan.

CONCLUSION

The results of the present study suggest that chitosan was derived with mannose to yield a novel, water-soluble polysaccharide with better antioxidant and antimicrobial activities. The DD of chitosan had a significant effect on the properties of the Mc-mrp, which can serve as a reference point for the subsequent preparation and application of such derivatives. © 2023 Society of Chemical Industry.

The Nutritional and Functional Properties of Protein Isolates from Defatted Chia Flour Using Different Extraction pH

This study aims to determine the effects of various alkaline pHs on the nutritional and functional properties of protein isolated from defatted chia flour (DCF). The DCF isolated using alkali extraction method at pH 8.5, 10.0, and 12.0 were coded as CPI-8.5, CPI-10.0, and CPI-12.0, respectively. The highest extraction yield and protein recovery yield was demonstrated by CPI-12.0 (19.10 and 59.63%, respectively), with a total protein content of 74.53%, and glutelin showed the highest portion (79.95%). The CPI-12.0 also demonstrated the most elevated essential (36.87%), hydrophobic (33.81%), and aromatic (15.54%) amino acid content among other samples. The DCF exhibited the highest water (23.90 gg-1) and oil (8.23 gg-1) absorption capacity, whereas the CPI-8.5 showed the highest protein solubility (72.31%) at pH 11. DCF demonstrated the highest emulsifying capacity at pH 11 (82.13%), but the highest stability was shown at pH 5 (82.05%). Furthermore, CPI-12.0 at pH 11 shows the highest foaming capacity (83.16%) and stability (83.10%). Despite that, the CPI-10.0 manifested the highest antioxidant capacity (DPPH: 42.48%; ABTS: 66.23%; FRAP: 0.19), as well as ACE-I (35.67%). Overall, the extraction pH had significant effects in producing chia protein isolates (CPI) with improved nutritional and functional qualities.

Polysaccharides from Passion Fruit Peels: From an Agroindustrial By-Product to a Viable Option for 5-FU-Induced Intestinal Damage

Gastrointestinal mucositis is a serious and dose-limiting toxic side effect of oncologic treatment. Interruption of cancer treatment due to gastrointestinal mucositis leads to a significant decrease in cure rates and consequently to the deterioration of a patient's quality of life. Natural polysaccharides show a variety of beneficial effects, including a gastroprotective effect. Treatment with soluble dietary fiber (SDF) from yellow passion fruit (Passiflora edulis) biomass residues protected the gastric and intestinal mucosa in models of gastrointestinal injury. In this study, we investigated the protective therapeutic effect of SDF on 5-FU-induced mucositis in male and female mice. Oral treatment of the animals with SDF did not prevent weight loss but reduced the disease activity index and preserved normal intestinal function by alleviating diarrhea and altered gastrointestinal transit. SDF preserved the length of the colon and histological damage caused by 5-FU. SDF significantly restored the oxidative stress and inflammation in the intestine and the enlargement and swelling of the spleen induced by 5-FU. In conclusion, SDF may be a promising adjuvant strategy for the prevention and treatment of intestinal mucositis induced by 5-FU.

Carboxymethylation modification, characterization of dandelion root polysaccharide and its effects on gel properties and microstructure of whey protein isolate

In the present study, a native polysaccharide (DP) with sugar content of 87.54 ± 2.01 % was isolated from dandelion roots. DP was chemically modified to obtain a carboxymethylated polysaccharide (CMDP) with DS of 0.42 ± 0.07. DP and CMDP were composed of the same six monosaccharides including mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose. The molecular weights of DP and CMDP were 108,200 and 69,800 Da, respectively. CMDP exhibited more stable thermal performance and better gelling properties than DP. The effects of DP and CMDP on the strength, water holding capacity (WHC), microstructure, and rheological properties of whey protein isolate (WPI) gels were investigated. Results showed that CMDP-WPI gels had higher strength and WHC than DP-WPI gels. With the addition of 1.5 % CMDP, WPI gel had a good three-dimensional network structure. The apparent viscosities, loss modulus (G"), and storage modulus (G') of WPI gels were increased with the polysaccharide addition, the influence of CMDP was remarkable compared to DP at the same concentration. These findings suggest that CMDP may be used as a functional ingredient in protein-containing food products.

Structure and Adsorption Performance of Cationic Entermorpha prolifera Polysaccharide-Based Hydrogel for Typical Pollutants: Methylene Blue, Cefuroxime, and Cr (VI)

Hydrogels with polysaccharides as high polymer substrates have surprising advantages in wastewater treatment with complex components. Therefore, in this study, polysaccharides named EPS were extracted from Enteromorpha prolifera, a coastal pollutant with a wide range of sources, and cationic modification was performed to obtain CAEPS, the hydrogel with a double network structure was prepared based on EPS and CAEPS. Meanwhile, the structural characteristic of EPS and CAEPS-based hydrogel were identified by HPLC, AFM, FT-IR, TGA, SEM-EDS, Pore size distribution, and WCA, which showed that the porosity, apparent (skeletal) density, and hydrophilicity of CAEPS-hydrogels. We used nonlinear isotherms to uncover the adsorption mechanism of hydrogel applied to the water environment containing three typical pollutants (Methylene blue, Cefuroxime, and Cr (VI)). The results showed that the adsorption isotherm of the two hydrogels fit the Langmuir isotherm model, which indicated the monolayer adsorption of the pollution factor onto EPS- and CAEPS-hydrogels. The maximum adsorption capacities of CAEPS-hydrogels were higher than EPS-hydrogels, which indicated the microstructure and adsorption performance of the CAEPS-hydrogel are strengthened.

Characterization and Antibacterial Activities of Carboxymethylated Paramylon from Euglena gracilis

Paramylon from Euglena gracilis (EGP) is a polymeric polysaccharide composed of linear β-1,3 glucan. EGP has been proved to have antibacterial activity, but its effect is weak due to its water insolubility and high crystallinity. In order to change this deficiency, this experiment carried out carboxymethylated modification of EGP. Three carboxymethylated derivatives, C-EGP1, C-EGP2, and C-EGP3, with a degree of substitution (DS) of 0.14, 0.55, and 0.78, respectively, were synthesized by varying reaction conditions, such as the mass of chloroacetic acid and temperature. Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) analysis confirmed the success of the carboxymethylated modification. The Congo red (CR) experiment, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetry (TG) were used to study the conformation, surface morphology, crystalline nature, and thermostability of the carboxymethylated EGP. The results showed that carboxymethylation did not change the triple helix structure of the EGP, but that the fundamental particles’ surface morphology was destroyed, and the crystallization area and thermal stability decreased obviously. In addition, the water solubility test and antibacterial experiment showed that the water solubility and antibacterial activity of the EGP after carboxymethylation were obviously improved, and that the water solubility of C-EGP1, C-EGP2, and C-EGP3 increased by 53.31%, 75.52%, and 80.96% respectively. The antibacterial test indicated that C-EGP3 had the best effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with minimum inhibitory concentration (MIC) values of 12.50 mg/mL and 6.25 mg/mL. The diameters of the inhibition zone of C-EGP3 on E. coli and S. aureus were 11.24 ± 0.15 mm and 12.05 ± 0.09 mm, and the antibacterial rate increased by 41.33% and 43.67%.

Depolymerized Fractions of Sulfated Galactans Extracted from Gracilaria fisheri and Their Antibacterial Activity against Vibrio parahaemolyticus and Vibrio harveyi

Various seaweed sulfated polysaccharides have been explored for antimicrobial application. This study aimed to evaluate the antibacterial activity of the native Gracilaria fisheri sulfated galactans (NSG) and depolymerized fractions against the marine pathogenic bacteria Vibrio parahaemolyticus and Vibrio harveyi. NSG was hydrolyzed in different concentrations of H₂O₂ to generate sulfated galactans degraded fractions (SGF). The molecular weight, structural characteristics, and physicochemical parameters of both NSG and SGF were determined. The results revealed that the high molecular weight NSG (228.33 kDa) was significantly degraded to SGFs of 115.76, 3.79, and 3.19 kDa by hydrolysis with 0.4, 2, and 10% H₂O₂, respectively. The Fourier transformed spectroscopy (FTIR) and ¹H− and ¹³C−Nuclear magnetic resonance (NMR) analyses demonstrated that the polysaccharide chain structure of SGFs was not affected by H₂O₂ degradation, but alterations were detected at the peak positions of some functional groups. In vitro study showed that SGFs significantly exerted a stronger antibacterial activity against V. parahaemolyticus and V. harveyi than NSG, which might be due to the low molecular weight and higher sulfation properties of SGF. SGF disrupted the bacterial cell membrane, resulting in leakage of intracellular biological components, and subsequently, cell death. Taken together, this study provides a basis for the exploitation and utilization of low-molecular-weight sulfated galactans from G. fisheri to prevent and control the shrimp pathogens.

Structural Characterization of Polysaccharides in Waste Liquor Produced by Wet Decortication of Sesame Seeds

The wet decortication of sesame seeds produces wastewater containing diverse minerals and organic pollutants that could be valuable resources for the food industry. This investigation aimed to reclaim, purify, and characterize the polysaccharides contained in the waste liquor from the sesame decortication industry. The purified polysaccharide fractions were characterized using monosaccharide analysis, GPC (high-performance gel permeation chromatography), FT-IR (Fourier-transform infrared) spectroscopy, methylation analysis, 1D and 2D Nucleai Magnetic Resonance (NMR) analysis, and thermal analysis. Four fractions were found (SSP-1,-2,-3, -4), of which SSP-2 was proportionately the largest and most interesting. The backbone of SSP-2 is mainly composed of (1→2,4)-β-_D-Xylp residues with side chains connected to the O-4 position, with many T-β-_D-Galp and (1→5)-α-_L-Araf residues, and fewer (1→4)-α-_D-Glcp, (1→2)-α-_L-Rhap, T-α-_L-Araf, and (1→2)-β-_D-GlcpA residues. An efficient method for removing the polysaccharides would simplify wastewater treatment while finding a use for them would benefit the sesame, food, and pharmaceutical industries.

Adsorption behavior and mechanism of Lead (Pb2+) by sulfate polysaccharide from Enteromorpha prolifera

Lead (Pb²⁺) pollution poses severe healthy and ecological risks to humans. In this work, sulfate polysaccharide from Enteromorpha prolifera (SPE) was utilized for Pb²⁺ adsorption from simulated intestinal fluid. In order to evaluate its adsorption behaviors comprehensively, batch adsorption of Pb²⁺ was investigated under different conditions. Results showed that SPE presents high adsorption ability for Pb²⁺ through chemical adsorption process and the maximum adsorption capacity for Pb²⁺ was 278.5 mg/g. And SPE exhibited higher removal efficiency (≥60%) for trace Pb²⁺ (<10 mg/L) compared to that of other adsorbents based on polysaccharide. Besides, its adsorption can be described by Langmuir isotherm and pseudo-second-order kinetic models. Further, XRD, FTIR, and XPS were used to characterize the possible interaction of Pb²⁺ with SPE, and the results showed that carboxyl and hydroxyl groups in SPE play more important role than that of sulfate group. Our work represents the first assessment of Pb²⁺ adsorption properties of SPE. This investigation highlights the potential application of SPE to protect the body from hazard of food-derived heavy metals.

Immunomodulatory activity of Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatwr seed polysaccharide fraction through the activation of the MAPK signaling pathway in RAW264.7 macrophages

Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatwr seed (SMS) is a wild legume used as food and medicine in many African countries. In the current study, a novel polysaccharide (SMSP2) was extracted from SMS using hot water and purified with DEAE-52 cellulose. Its structure was characterized, and the immunomodulatory activity and possible molecular mechanism in murine macrophage RAW264.7 were explored. The results revealed that SMSP2 was a uronic acid-rich polysaccharide (51.6%, w/w) with a molecular weight of 52.07 kDa. The neutral sugars were mainly arabinose, xylose, mannose, and galactose at a molar ratio of 1.00 : 0.84 : 0.90 : 0.07. Interestingly, SMSP2 treatment markedly promoted macrophage proliferation and phagocytosis and induced the expression of inflammatory mediators, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10. SMSP2-induced macrophage stimulation occurs through the activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, macrophage surface complement receptor 3 (CR3) might play an important role in SMSP2-induced macrophage activation. This study revealed that SMSP2 is a potent immunomodulator, which could be used as a functional food and a pharmaceutical adjuvant in treating immune-compromising diseases.

Enzyme-Mediated Reactions of Phenolic Pollutants and Endogenous Metabolites as an Overlooked Metabolic Disruption Pathway

It is generally recognized that phenol-containing molecules mainly undergo phase II metabolic reactions, whereas glucuronide and sulfate are conjugated to form water-soluble products. Here, we report direct reactions of phenolic pollutants (triclosan, alkylphenol, bisphenol A [BPA], and its analogues) and some endogenous metabolites (vitamin E [VE] and estradiol) to generate new lipophilic ether products (e.g., BPA-O-VEs and alkylphenol-O-estradiol). A nontargeted screening strategy was used to identify the products in human liver microsome incubations, and the most abundant products (BPA-O-VEs) were confirmed via in vivo exposure in mice. BPA-O-VEs were frequently detected in sera from the general population at levels comparable to those of glucuronide/sulfate-conjugated BPA. Recombinant human cytochrome P450s were applied to find that CYP3A4 catalyzed the formation of these newly discovered ether metabolites by linking the VE hydroxyl group to the BPA phenolic ring, leading to the significantly reduced antioxidative activities of BPA-O-VEs compared to VEs. The effects of the reaction on the homeostasis of reacted biomolecules were finally assessed by in vitro assay and in vivo mice exposures. The generation of BPA-O-VEs decreased the VE concentrations and increased the reactive oxygen species generation after exposure to BPA at environmentally relevant concentrations. The identified reactions provided an overlooked metabolic disruption pathway for phenolic pollutants.

Enzyme and microwave co-assisted extraction, structural characterization and antioxidant activity of polysaccharides from Purple-heart Radish

A novel method of simultaneous extraction and separation of diverse polysaccharides from Purple-heart Radish was developed by integrating EAE with MAATPE. The effects of different enzymes, the ATPS composition, extraction temperature, time etc. were investigated by single-factor experiments and RSM. Under the optimum conditions, the extraction yields of PTP, PBP and total polysaccharides were 9.107 ± 0.391%, 32.506 ± 0.046% and 41.613 ± 0.437%, respectively. By means of HPGPC and PMP-HPLC, Mw of PTP and Mw of PBP were 15935 Da and 27962 Da, respectively. PTP and PBP were mainly composed of mannose, glucuronic acid, aminogalactose, glucose, galactose and arabinose. Moreover, both polysaccharides exhibited stronger antioxidant activities for scavenging multiple radicals and anti-lipid peroxidation. Compared to the conventional extraction methods, EAE-MAATPE achieved higher extraction efficiency due to the synergistic effect between EAE and MAATPE leading to rupture and enzymolysis of cell. Thus, EAE-MAATPE provided an efficient alternative to simultaneous extraction of different polysaccharides from natural products.

Ulva (Enteromorpha) Polysaccharides and Oligosaccharides: A Potential Functional Food Source from Green-Tide-Forming Macroalgae

The high-valued utilization of Ulva (previously known as Enteromorpha) bioresources has drawn increasing attention due to the periodic blooms of world-wide green tide. The polysaccharide is the main functional component of Ulva and exhibits various physiological activities. The Ulva oligosaccharide as the degradation product of polysaccharide not only possesses some obvious activities, but also possesses excellent solubility and bioavailability. Both Ulva polysaccharides and oligosaccharides hold promising potential in the food industry as new functional foods or food additives. Studies on Ulva polysaccharides and oligosaccharides are increasing and have been the focus of the marine bioresources field. However, the comprehensive review of this topic is still rare and do not cover the recent advances of the structure, isolation, preparation, activity and applications of Ulva polysaccharides and oligosaccharides. This review systematically summarizes and discusses the recent advances of chemical composition, extraction, purification, structure, and activity of Ulva polysaccharides as well as oligosaccharides. In addition, the potential applications as new functional food and food additives have also been considered, and these will definitely expand the applications of Ulva oligosaccharides in the food and medical fields.

Making of Massoia Lactone-Loaded and Food-Grade Nanoemulsions and Their Bioactivities against a Pathogenic Yeast

Nanoemulsions (NEs) have been made for improving the delivery and disperse of bioactive compounds. In this study, it was found that the best ingredients for the stable Massoia lactone-loaded and food-grade NEs making were 560.0 µL of Tween-80, 240.0 µL of Span-80 and 200.0 µL of Massoia lactone. Then, 9.0 mL of distilled water was titrated into the mixture under continuous magnetic stirring (750 rotations min−1) with about 2 drops per second for 20 min. Finally, the system was treated by ultrasonication using an ultrasonic generator (180 W and 22 KHz) for 5 min. All the prepared particles with a mean droplet diameter of 43 nm were spherical, had uniform size distribution and were equally distributed in the Massoia lactone-loaded NEs. The obtained Massoia lactone-loaded nanoemulsions (NEs) were very stable without changes of the mean droplet diameter and polydispersity indexes (PDI) for over two months under different conditions. As with free Massoia lactone, Massoia lactone loaded in the NEs had high anti-fungal activity against Metschnikowia bicuspidate LIAO, a pathogenic yeast causing milky disease in the Chinese mitten crab by damaging its cell membrane and causing cellular necrosis. Massoia lactone loaded in the NEs also had the DPPH radical scavenging activity and the hydroxyl radical scavenging activity.

Dietary Enteromorpha polysaccharide-Zn supplementation regulates amino acid and fatty acid metabolism by improving the antioxidant activity in chicken

Background

Enteromorpha prolifera (E. prolifera) polysaccharide has become a promising feed additive with a variety of physiological activities, such as anti-oxidant, anti-cancer, anti-diabetic, immunomodulatory, hypolipidemic, and cation chelating ability. However, whether Enteromorpha polysaccharide-trace element complex supplementation regulates amino acid and fatty acid metabolism in chicken is largely unknown. This study was conducted to investigate the effects of E. prolifera polysaccharide (EP)-Zn supplementation on growth performance, amino acid, and fatty acid metabolism in chicken.

Methods

A total of 184 one-day-old Ross-308 broiler chickens were randomly divided into two treatment groups with 8 replicates, 12 chickens per replicate, and fed either the basal diet (control group) or basal diet plus E. prolifera polysaccharide-Zinc (400 mg EP-Zn/kg diet).

Results

Dietary EP-Zn supplementation significantly increased (P < 0.05) the body weight, average daily gain, muscle antioxidant activity, serum HDL level, and reduced serum TG and LDL concentration. In addition, dietary EP-Zn supplementation could modulate ileal amino acid digestibility and upregulate the mRNA expression of amino acid transporter genes in the jejunum, ileum, breast muscle, and liver tissues (P < 0.05). Compared with the control group, breast meat from chickens fed EP-Zn had higher (P < 0.05) Pro and Asp content, and lower (P < 0.05) Val, Phe, Gly, and Cys free amino acid content. Furthermore, EP-Zn supplementation upregulated (P < 0.05) the mRNA expressions of mTOR and anti-oxidant related genes, while down-regulated protein degradation related genes in the breast muscle. Breast meat from EP-Zn supplemented group had significantly lower (P < 0.05) proportions of Σn-3 PUFA, and a higher percentage of Σn-6 PUFA and the ratio of n-6/n-3 PUFA. Besides, EP-Zn supplementation regulated lipid metabolism by inhibiting the gene expression of key enzymes involved in the fatty acid synthesis and activating genes that participated in fatty acid oxidation in the liver tissue.

Conclusions

It is concluded that EP-Zn complex supplementation regulates apparent ileal amino acid digestibility, enhances amino acid metabolism, and decreases oxidative stress-associated protein breakdown, thereby improving the growth performance. Furthermore, it promotes fatty acid oxidation and restrains fat synthesis through modulating lipid metabolism-related gene expression.

Graphical abstract

Polysaccharides to combat viruses (Covid-19) and microbes: New updates

COVID-19, which is speedily distributed across the world and presents a significant challenge to public health, is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Following MERS coronavirus (MERS-CoV) and SARS, this is the third severe coronavirus outbreak in less than 20 years. To date, there are no exact agents and vaccines available for the treatment of COVID-19 that are clinically successful. Antimicrobial medications are effective in controlling infectious diseases. However, the extensive use of antibiotics makes microbes more resistant to drugs and demands novel bioactive agents' development. Polysaccharides are currently commonly used in the biomedical and pharmaceutical industries for their remarkable applications. Polysaccharides appear to have a wide range of anti-virus (anti-coronavirus) and antimicrobial applications. Polysaccharides are able to induce bacterial cell membrane disruption as they demonstrate potency in binding onto the surfaces of microbial cells. Here, the antiviral mechanisms of such polysaccharides and their success in the application of antiviral infections are reviewed. Additionally, this report provides a summary of current advancements of well-recognized polysaccharides as antimicrobial and anti-biofilm agents.

Antibacterial activity and action mechanism of a novel chitosan oligosaccharide derivative against dominant spoilage bacteria isolated from shrimp Penaeus vannamei

With the aim of exploring the potential application of a novel chitosan oligosaccharide derivative (COS-All-Tio) in shrimp preservation, six dominant spoilage bacteria in the spoiled shrimp (Penaeus vannamei) were isolated and identified as Shewanella putrefaciens (RMS1), S. putrefaciens (S2), Pseudomonas weihenstephanensis (P1), P. gessardii (P2), Aeromonas bestiarum (A1) and Aeromonas molluscorum (A2). The antibacterial effect of COS-All-Tio against the six bacterial isolates were studied. Bacterial inhibition zone determination, and minimum inhibitory concentration and minimum bactericidal concentration assays indicated that the antibacterial activity of COS-All-Tio was greatly improved when compared to that of chitosan oligosaccharide (COS). The antibacterial mechanism investigation against S. putrefaciens (RMS1) revealed that COS-All-Tio could inhibit bacterial growth by influencing of membrane integrity. Such disturbance of membrane structure resulted in the leakage of intracellular substance of the bacteria. A strong synergistic antibacterial effect against S. putrefaciens (RMS1) was observed when COS-All-Tio was used in combination with food preservatives (e.g. ε-polylysine hydrochloride). Therefore, COS-All-Tio might have potential in shrimp preservation.

Extraction Techniques, Biological Activities and Health Benefits of Marine Algae Enteromorpha prolifera Polysaccharide

There is increasing interest in the use of marine algae as functional food additives for improving human health. Enteromorpha (Ulva) prolifera (E. prolifera) is a seaweed green alga (Chlorophyta) that contains many bioactive compounds, of which polysaccharide is the main component. With the advancement of technology in the methods of extraction and analysis, recent studies in in vitro and animals model showed that polysaccharides derived from E. prolifera exert various biological activities, such as gut microbiota modulation, immunomodulation, antioxidant, antidiabetic, antimicrobial, and hypolipidemic. Research evidence has shown that methods of extraction and molecular modification, such as degradation, carboxymethylation, and sulfonation could alter the biological activities of polysaccharides. Therefore, in this review, we discussed the different extraction techniques, structural-activity relationship, and health benefits of sulfated polysaccharides derived from E. prolifera, and suggested future research avenues. This review helps to advance the extraction techniques and promote the application of marine algae polysaccharides as functional food and therapeutic agent.

Degraded polysaccharides from Porphyra haitanensis: purification, physico-chemical properties, antioxidant and immunomodulatory activities

To explore effect of the structural properties of porphyra haitanensis polysaccharide on its biological activity, degraded porphyra polysaccharides were separated and purified by Cellulose DEAE-52 and Sephadex G-100 chromatography, obtaining three purified components (P1, P2 and P3). All the three components were sulfate polysaccharides containing the repeating units of → 3) β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →, and → 3) β-D-galactose (1 → 4) α-L-galactose-6-S (1 →, and → 3) 6-O-methyl-β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →. The molecular weight of the three fractions was measured to be 300.3, 130.4 and 115.1 kDa, respectively. Their antioxidant activity was investigated by the determination of the free radical scavenging effect and ferric reducing power. It was found that P1, P2 and P3 possessed marked antioxidant activity. It was also found that they appreciably enhanced the proliferation, phagocytic ability and nitric oxide secretion in RAW264.7 cells. Lower molecular weight and higher sulfate content were beneficial to bioactivities of P. haitanensis polysaccharides. Overall, P2 and P3 possess superior immuno-modulatory activity to that of P1 and PHP. Thus, the current work will provide the basis for the better utilization of P. haitanensis to develop the related functional foods.

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.

Seaweed polysaccharides: Emerging extraction technologies, chemical modifications and bioactive properties

Nowadays, consumers are increasingly aware of the relationship between diet and health, showing a greater preference of products from natural origin. In the last decade, seaweeds have outlined as one of the natural sources with more potential to obtain bioactive carbohydrates. Numerous seaweed polysaccharides have aroused the interest of the scientific community, due to their biological activities and their high potential on biomedical, functional food and technological applications. To obtain polysaccharides from seaweeds, it is necessary to find methodologies that improve both yield and quality and that they are profitable. Nowadays, environmentally friendly extraction technologies are a viable alternative to conventional methods for obtaining these products, providing several advantages like reduced number of solvents, energy and time. On the other hand, chemical modification of their structure is a useful approach to improve their solubility and biological properties, and thus enhance the extent of their potential applications since some uses of polysaccharides are still limited. The present review aimed to compile current information about the most relevant seaweed polysaccharides, available extraction and modification methods, as well as a summary of their biological activities, to evaluate knowledge gaps and future trends for the industrial applications of these compounds.Key teaching pointsStructure and biological functions of main seaweed polysaccharides.Emerging extraction methods for sulfate polysaccharides.Chemical modification of seaweeds polysaccharides.Potential industrial applications of seaweed polysaccharides.Biological activities, knowledge gaps and future trends of seaweed polysaccharides.

Reviews on mechanisms of in vitro antioxidant, antibacterial and anticancer activities of water-soluble plant polysaccharides

Degenerative diseases such as cancer and cardiovascular diseases, and antimicrobial resistance are becoming prominent health problems needing utmost public health attention. Curative interventions such as the use of pharmaceutical drugs and alternative plant medicines are increasingly being explored. Plant polysaccharides have gained attention for their promising bioactivities such as antioxidant, antimicrobial and anticancer activities. Bioactive plant polysaccharides are also being preferred for their relatively few side effects compared to conventional pharmaceuticals. The elucidation of the bioactive potential of plant polysaccharides in disease treatment entails an understanding of the factors that determine their biofunctional properties using functional and mechanistic assays. This review summarizes the literature on the composition, structural, functional, and mechanistic determinations of the antioxidant, anticancer and antimicrobial activities of plant polysaccharides. The outcome of this review highlights the leading trends in the elucidation of the antioxidant, anticancer and antimicrobial activities of plant polysaccharides and underscores the promising health benefits of plant polysaccharides.

Degradation of Codium cylindricum polysaccharides by H2O2-Vc-ultrasonic and H2O2-Fe2+-ultrasonic treatment: Structural characterization and antioxidant activity

In this study, two degraded polysaccharides were obtained by H₂O₂-Vc-ultrasonic and H₂O₂-Fe²⁺-ultrasonic treatment from Codium cylindricum. The basic structure of polysaccharides was characterized and the relationship between structure and antioxidant activity was studied. FTIR spectrum indicated that the degraded polysaccharides had similar functional groups (OH, CH, CO group) with ordinary polysaccharides. LC-MS analysis showed that the degraded polysaccharides were composed of the same monosaccharide units (mannose, galactose, arabinose, glucose, ribose) with Codium cylindricum polysaccharides, but the molar ratio was different. Meanwhile, the molecular weight and morphological feature of polysaccharides had been changed after degradation. Additionally, the antioxidant activity assay revealed that two degraded polysaccharides with lower molecular weight possessed better antioxidant property than ordinary polysaccharides. These results suggested that the basic structure of polysaccharides had not been damaged by two degradation methods, while the antioxidant activity was significantly enhanced.

A novel zinc complex with antibacterial and antioxidant activity

Background

In order to enhance the antibacterial activity and reduce the toxicity of Zn²⁺, novel complexes of Zn(II) were synthesized.

Results

A water-soluble zinc-glucose-citrate complex (ZnGC) with antibacterial activity was synthesized at pH 6.5. The structure, morphology, characterization, acute toxicity, antibacterial and antioxidant activities, and in situ intestinal absorption were investigated. The results showed that zinc ion was linked with citrate by coordinate bond while the glucose was linked with it through intermolecular hydrogen bonding. The higher the molecular weight of sugar is, the more favorable it is to inhibit the formation of zinc citrate precipitation. Compared with ZnCl₂, ZnGC complex presented better antibacterial activity against Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative).

Conclusions

The results of acute toxicity showed no obvious toxicity in this test and in situ intestinal absorption study, suggesting that ZnGC complex could be used as a potential zinc supplement for zinc deficiency.

Purification and Biological Activities of Enzymatically Degraded Sargassum fusiforme Polysaccharides

Enzymatic hydrolysate of the crude polysaccharide (SFP) extracted from Sargassum fusiforme was purified by column DEAE-52 and Sephadex G-100 to yield four components, namely, ESFP1, ESFP2, ESFP3 and ESFP4. These components were characterized by chemical composition assay, GC/MS, HPGPC, UV and FT-IR techniques. The in vitro antioxidant activities of the four purified fractions were investigated by measuring their radical scavenging activity and reducing power. The results suggested that all the four components possess good antioxidant activities. Among them, ESFP1 was found to possess the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical-scavenging activity, and the greatest ferric reducing power. The immunomodulatory effect of these four polysaccharides was demonstrated by their ability to promote proliferation, and to enhance both phagocytic activity and NO release in a macrophage RAW264.7 model. The results revealed that the bioactivities of the polysaccharides are related to their molecular weight, and the uronic acid and sulfate contents.

Ulva prolifera Extract Alleviates Intestinal Oxidative Stress via Nrf2 Signaling in Weaned Piglets Challenged With Hydrogen Peroxide

Background

Ulva prolifera extract contains a variety of functional active substances. Whether these substances had any beneficial effects on the small intestine of weaned piglets under oxidative stress remained unknown.

Method

We explored the effects of U. prolifera extract on oxidative stress and related mechanisms in weaned piglets and intestinal porcine epithelial cells (IPEC-J2) challenged with hydrogen peroxide.

Results

U. prolifera extract was found to mainly consist of polyphenols and unsaturated fatty acids. U. prolifera extract increased total antioxidant capacity and superoxide dismutase (SOD) activity, while it decreased malondialdehyde content, in the serum of weaned piglets challenged with hydrogen peroxide. Moreover, U. prolifera extract increased mRNA expression of SOD and catalase, as well as the intestinal expression of nuclear NF-E2-related factor 2 (Nrf2), both in vitro and in vivo. Furthermore, U. prolifera extract decreased reactive oxygen species and improved mitochondrial respiration in IPEC-J2 cells treated with hydrogen peroxide. However, AMPK inhibition did not affect nuclear Nrf2 expression and only partially affected the effects of U. prolifera extract on oxidative stress.

Conclusion

We suggest that U. prolifera extract alleviates oxidative stress via Nrf2 signaling, but independent of AMPK pathway in weaned piglets challenged with hydrogen peroxide. These results shed new insight into the potential applications of U. prolifera extract as a therapeutic agent for the prevention and treatment of oxidative stress-induced intestinal diseases.

Carboxymethylation of polysaccharides: Synthesis and bioactivities

Polysaccharides are a structurally diverse class of biomolecules with a wide variety of bioactivities. Natural polysaccharides isolated from plants and fungi are used as raw materials in food and pharmaceutical industries due to their therapeutic properties, non-toxicity, and negligible side effects, but many natural polysaccharides possess low bioactivities when compared to synthetic medicines due to their structure and physicochemical properties. Literature studies revealed that carboxymethylation of polysaccharides enhances the bioactivities and water solubility of native polysaccharides significantly, and provide structural diversity and even the addition of new bioactivities. This review article mainly focuses on the recent research on carboxymethylation of polysaccharides including preparation, characterization, and bioactivities. This article also throws light on future directions and scope to develop new carboxymethylated polysaccharide derivatives for many industries such as food processing, cosmetics, nutraceuticals, and pharmaceutical industry.

Dietary seaweed (Enteromorpha) polysaccharides improves growth performance involved in regulation of immune responses, intestinal morphology and microbial community in banana shrimp Fenneropenaeus merguiensis

The present study was conducted to evaluate the effects of marine polysaccharides from seaweed Enteromorpha on growth performance, immune responses, intestinal morphology and microbial community in the banana shrimp Fenneropenaeus merguiensis. Two thousand and four hundred juvenile shrimps with an average body weight of 2.18 ± 0.06 g were fed for 42 d with diets containing different levels of Enteromorpha polysaccharides (EPS): 0 (control), 1, 2 and 3 g/kg as treatment groups, each of group was replicated three times with two hundred shrimps per replicate. Dietary supplementation of 1 g/kg EPS showed a consistent improvement in the final weight, weight gain, average daily gain rate (ADGR) and specific growth rate (SGR) (P < 0.05), while showed a decrease in the feed conversion ratio (FCR) of shrimp (P < 0.05). Besides, the total anti-oxidative capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), lysozyme (Lyz), alkaline phosphatase (ALP), and phenoloxidase (PO) activities in hemolymph were enhanced by dietary supplementation of 1 g/kg EPS (P < 0.05), while it reduced the hemolymph MDA content (P < 0.05). Shrimp fed 1 g/kg EPS supplemented diets up-regulated FmLyz, FmSOD5 and FmCLAP gene expression level of hepatopancreas and gill (P < 0.05), and also improved the intestinal FmLC2, FmLyz, FmSOD5 and FmCLAP gene expression levels (P < 0.05). In addition, shrimp fed diets containing 1 g/kg EPS increased the villus width (P < 0.05) and resulted in a higher villus surface area (P < 0.05). According to 16S rRNA sequencing results, dietary supplementation of 1 g/kg EPS tended to increase the relative abundance of Firmicutes at phylum level (P = 0.07) and decrease the relative abundance of Vibrio at genus level (P = 0.08). There was a significant positive correlation between the relative abundance of Firmicutes and mRNA expression of intestinal immune-related genes (P < 0.05). These findings revealed that dietary 1 g/kg EPS could improve growth performance, enhance nonspecific immunity and modulate intestinal function of banana shrimp F. merguiensis.

Structural characterization and anti-lung cancer activity of a sulfated glucurono-xylo-rhamnan from Enteromorpha prolifera

A sulfated glucurono-xylo-rhamnan (EP-3-H) was purified from a green alga, Enteromorpha prolifera. EP-3-H and its oligomers were characterized by high performance liquid chromatography, mass spectrometry and one and two-dimensional nuclear magnetic resource spectroscopy. The structural analysis showed EP-3-H has a backbone of glucurono-xylo-rhamnan, branches with glucuronic acid and sulfated at C3 of rhamnose and/or C2 of xylose. The inhibition of EP-3-H on human lung cancer A549 cell proliferation in vitro and its therapeutic effects in BALB/c-nu mice in vivo were determined to evaluate the anti-lung cancer activity of EP-3-H. The tumor inhibition level was 59 %, suggesting that EP-3-H might be a good candidate for the treatment of lung cancer. Surface plasmon resonance (SPR) studies revealed the IC₅₀ on the binding of fibroblast growth factors, (FGF1 and FGF2), to heparin were 0.85 and 1.47 mg/mL, respectively. These results suggest that EP-3-H inhibits cancer proliferation by interacting with these growth factors.