Impact of hydrolysis conditions on the detection of mannuronic to guluronic acid ratio in alginate and its derivatives

Optimization of hydrolysis conditions of alginate based on high performance liquid chromatography

Alginate is the most abundant polysaccharide compound in brown algae, which is widely used in various fields. At present, the determination of the content of alginate is mostly carried out using sulfuric acid and trifluoroacetic acid hydrolysis followed by the determination of the content, but the results are not satisfactory, and there are problems such as low hydrolysis degree and low recovery rate. Therefore, in this study, based on the optimization of high performance liquid chromatographic conditions for pre-column derivatization of 1-phenyl-3-methyl-5-pyrazolone (PMP), the hydrolysis effects of sulfuric acid, trifluoroacetic acid (TFA), oxalic acid, and formic acid were compared and the hydrolysis conditions were optimized. The results showed that formic acid was the best hydrolyzing acid. The optimal hydrolysis conditions were 95 % formic acid at 110 °C for 10 h. The hydrolysis effect was stable, with high recovery and low destruction of monosaccharides, which made it possible to introduce formic acid into the subsequent polysaccharide hydrolysis. The pre-column derivatization high performance liquid chromatography method established in this study was accurate and reliable, and the hydrolysis acid with better effect was screened, which provided a theoretical basis for the subsequent determination of alginate content.

Estimation of alginate purity and M/G ratio by methanolysis coupled with anion exchange chromatography

Alginates are industrially relevant polysaccharides widely used in the food and biomedical industries for their excellent gelling properties. The growing emphasis on the valorization of marine resources has evidenced the need for alternative methods for the determination of both alginate content and the M/G ratio. This study describes the application of acid methanolysis and separation by anion exchange chromatography. Five samples, including alginates extracted from Saccharina latissima, Ascophyllum nodosum, a certified standard, and two poly-uronates (Poly-M and Poly-G), were analysed for their M/G ratio and alginate content at different treatment conditions, and compared with other conventionally used or reference methods (NMR, FTIR, and colorimetric methods). Quantitative estimation of alginate was relatively accurate at optimum conditions (4 h at 100 °C), as compared with the certified standard or with other colorimetric methods. M/G ratios were not significantly different from those determined after the reference method (1H NMR) or compared to FTIR protocols. The results evidence that methanolysis may be applied to simultaneously estimate the purity and M/G ratio of alginate-rich samples in a single analysis.

Directed preparation, structure-activity relationship and applications of alginate oligosaccharides with specific structures: A systematic review

The alginate oligosaccharides (AOS) possess versatile activities (such as antioxidant, anti-inflammatory, antitumor, and immune-regulatory activities) and have been the research topic in marine bioresource utilization fields. The degree of polymerization (DP) and the β-D-mannuronic acid (M)/α-L-guluronic acid (G)-units ratio strongly affect the functionality of AOS. Therefore, directed preparation of AOS with specific structures is essential for expanding the applications of alginate polysaccharides and has been the research topic in the marine bioresource field. Alginate lyases could efficiently degrade alginate and specifically produce AOS with specific structures. Therefore, enzymatic preparation of AOS with specific structures has drawn increasing attention. Herein, we systematically summarized the current research progress on the structure-function relation of AOS and focuses on the application of the enzymatic properties of alginate lyase to the specific preparation of various types of AOS. At the same time, current challenges and opportunities for AOS applications are presented to guide and improve the preparation and application of AOS in the future.

Recent advances in the production, properties and applications of alginate oligosaccharides - a mini review

Alginate oligosaccharides (AOS) made from the degradation of alginate, to some extent, makes up for the poor solubility and bioavailability of alginate as a macromolecular substance and possess several beneficial biological activities that are absent in alginate. These properties include prebiotic, glycolipid regulatory, immunomodulatory, antimicrobial, antioxidant, anti-tumor, promoting plant growth and other activities. Consequently, AOS has significant potential for use in the agricultural, biomedical, and food industries, and has been the focus of research in the field of marine biological resources. This review comprehensively covers methods (physical, chemical, and enzymatic methods) for the production of AOS from alginate. More importantly, this paper reviews recent advances in the biological activity and potentially industrial and therapeutic applications of AOS, providing a reference for future research and applications of AOS.

Process and applications of alginate oligosaccharides with emphasis on health beneficial perspectives

Alginates are linear polymers comprising 40% of the dry weight of algae possess various applications in food and biomedical industries. Alginate oligosaccharides (AOS), a degradation product of alginate, is now gaining much attention for their beneficial role in food, pharmaceutical and agricultural industries. Hence this review was aimed to compile the information on alginate and AOS (prepared from seaweeds) during 1994-2020. As per our knowledge, this is the first review on the potential use of alginate oligosaccharides in different fields. The alginate derivatives are grouped according to their applications. They are involved in the isolation process and show antimicrobial, antioxidant, anti-inflammatory, antihypertension, anticancer, and immunostimulatory properties. AOS also have significant applications in prebiotics, nutritional supplements, plant growth development and others products.

Potential Food and Nutraceutical Applications of Alginate: A Review

Alginate is an acidic polysaccharide mainly extracted from kelp or sargassum, which comprises 40% of the dry weight of algae. It is a linear polymer consisting of β-D-mannuronic acid (M) and α-L-guluronic acid (G) with 1,4-glycosidic linkages, possessing various applications in the food and nutraceutical industries due to its unique physicochemical properties and health benefits. Additionally, alginate is able to form a gel matrix in the presence of Ca²⁺ ions. Alginate properties also affect its gelation, including its structure and experimental conditions such as pH, temperature, crosslinker concentration, residence time and ionic strength. These features of this polysaccharide have been widely used in the food industry, including in food gels, controlled-release systems and film packaging. This review comprehensively covers the analysis of alginate and discussed the potential applications of alginate in the food industry and nutraceuticals.

Preparation and potential applications of alginate oligosaccharides

Alginate, a linear polymer consisting of β-D-mannuronic acid (M) and α-L-guluronic acid (G) with 1,4-glycosidic linkages and comprising 40% of the dry weight of algae, possesses various applications in the food and nutraceutical industries. However, the potential applications of alginate are restricted in some fields because of its low water solubility and high solution viscosity. Alginate oligosaccharides (AOS) on the other hand, have low molecular weight which result in better water solubility. Hence, it becomes a more popular target to be researched in recent years for its use in foods and nutraceuticals. AOS can be obtained by multiple degradation methods, including enzymatic degradation, from alginate or alginate-derived poly G and poly M. AOS have unique bioactivity and can bring human health benefits, which render them potentials to be developed/incorporated into functional food. This review comprehensively covers methods of the preparation and analysis of AOS, and discussed the potential applications of AOS in foods and nutraceuticals.

Effect of Gum Tragacanth-Sodium Alginate Active Coatings Incorporated With Epigallocatechin Gallate and Lysozyme on the Quality of Large Yellow Croaker at Superchilling Condition

This research was done to investigate the synergistic interactions of the gum tragacanth (GT)–sodium alginate (SA) active coatings, incorporated with epigallocatechin gallate and lysozyme, on the quality of large yellow croaker (Larimichthys crocea) during superchilling storage at −3°C. Results showed that the GT-SA active coatings, containing epigallocatechin gallate [EGCG (E), 0.32% w/v], and lysozyme [LYS (L), 0.32% w/v] have reduced the total viable count, psychrophilic bacteria, and Pseudomonas spp. by about 1.55 log CFU/g, 0.49 log CFU/g, and 1.64 log CFU/g compared to the control at day 35. The GT-SA active coatings containing EGCG and LYS were effective in lowering the formations of off-odor compounds such as total volatile basic nitrogen (TVB-N), malondialdehyde (MDA), and off-favor amino acid (histidine). The solid phase microextraction gas chromatography-mass spectrometer (SPME-GC/MS) was applied to characterize and to quantify the volatile compounds of large yellow croaker samples during superchilling storage, while the relative content of the fishy flavor compounds (including 1-octen-3-ol and acetoin) was significantly reduced in the active coatings treated samples. Furthermore, the GT-SA active coatings containing EGCG and LYS treatments was found to be more effective in retarding the migration of water based on magnetic resonance imaging (MRI) results and in maintaining the organoleptic quality of large yellow croaker in superchilling storage at −3°C according to the sensory evaluation results. The results showed that the GT-SA active coating containing EGCG and LYS was effective to be used as a fish preservative to improve the quality and to prolong the shelf life of large yellow croaker in a superchilling storage for at least 7 days.

Effect of Locust Bean Gum-Sodium Alginate Coatings Combined with High CO2 Modified Atmosphere Packaging on the Quality of Turbot (Scophthalmus maximus) during Refrigerated Storage

This research was conducted to investigate the effect of active coatings composed of locust bean gum (LBG) and sodium alginate (SA) containing daphnetin emulsions (DEs) combined with modified atmosphere packaging (MAP) on the microbiological and physicochemical properties of turbot during 4 °C refrigerated storage for 32 days. The results revealed that LBG-SA-DE coatings together with high CO₂ MAP (60% CO₂/35% N₂/5% O₂) maintained the total viable count (TVC) of H₂S-producing bacteria in 4–6 lg CFU/g, which is lower than the limit (7 lg CFU/g). In addition, LBG-SA-DE coatings together with high CO₂ MAP (60% CO₂/35% N2/5% O₂) inhibited the production of odor compounds, including thiobarbituric acid (TBA), trimethylamine-nitrogen (TMA-N), K value, and total volatile basic nitrogen (TVB-N). The low-field NMR analysis (LF-NMR) and magnetic resonance imaging (MRI) indicated that LBG-SA-DE coatings together with high CO₂ MAP (60% CO₂/35% N₂/5% O₂) treatments could delay the release of water located in muscle fiber macromolecules or convert it into free water based on muscle fiber destruction, thus maintaining the water content and migration. The results of the sensory evaluation showed that turbot treated with LBG-SA-DE coatings together with MAP could maintain its freshness during refrigerated storage.

Calcium bridging drives polysaccharide co-adsorption to a proxy sea surface microlayer

Saccharides comprise a significant mass fraction of organic carbon in sea spray aerosol (SSA), but the mechanisms through which saccharides are transferred from seawater to the ocean surface and eventually into SSA are unclear. It is hypothesized that saccharides cooperatively adsorb to other insoluble organic matter at the air/sea interface, known as the sea surface microlayer (SSML). Using a combination of surface-sensitive infrared reflection-absorption spectroscopy and all-atom molecular dynamics simulations, we demonstrate that the marine-relevant, anionic polysaccharide alginate co-adsorbs to an insoluble palmitic acid monolayer via divalent cationic bridging interactions. Ca2+ induces the greatest extent of alginate co-adsorption to the monolayer, evidenced by the ∼30% increase in surface coverage, whereas Mg2+ only facilitates one-third the extent of co-adsorption at seawater-relevant cation concentrations due to its strong hydration propensity. Na+ cations alone do not facilitate alginate co-adsorption, and palmitic acid protonation hinders the formation of divalent cationic bridges between the palmitate and alginate carboxylate moieties. Alginate co-adsorption is largely confined to the interfacial region beneath the monolayer headgroups, so surface pressure, and thus monolayer surface coverage, only changes the amount of alginate co-adsorption by less than 5%. Our results provide physical and molecular characterization of a potentially significant polysaccharide enrichment mechanism within the SSML.

Metabolic Effects of a Hydrophobic Alginate Derivative and Tetrahydrolipstatin in Rats Fed a Diet Supplemented with Palm Fat and Cholesterol

The effects of octadecylamide of alginic acid (amidated alginate) and tetrahydrolipstatin on serum and hepatic cholesterol, and the faecal output of fat and sterols, were investigated in rats. Amidated alginate is a sorbent of lipids, tetrahydrolipstatin is an inhibitor of pancreatic lipase. Rats were fed diets containing cholesterol and palm fat at 10 and 70 g/kg, respectively. Palm fat was provided by coconut meal. Amidated alginate at 40 g/kg diet significantly decreased serum total cholesterol, low-density lipoprotein and hepatic cholesterol, and hepatic lipids and increased the faecal output of fat and coprostanol. Tetrahydrolipstatin at 300 mg/kg diet significantly decreased low-density lipoprotein cholesterol and hepatic lipids and increased the faecal output of fat. The intake of feed was not significantly influenced; however, the weight gains in rats fed amidated alginate were lower than in rats of the control group. Both amidated alginate and tetrahydrolipstatin modified the fatty acid profile in excreta lipids. Concentrations of saturated fatty acids were decreased and those of unsaturated fatty acids increased. Despite different modes of action, amidated alginate and tetrahydrolipstatin were equally efficient in removing the dietary fat from the body.

Effect of locust bean gum-sodium alginate coatings incorporated with daphnetin emulsions on the quality of Scophthalmus maximus at refrigerated condition

In this study, the microbiological, physicochemical, and flavor changes of turbot (Scophthalmus maximus) coated with a composite active coating of locust bean gum (LBG) and sodium alginate (SA) supplemented with daphnetin emulsions (0.16, 0.32, 0.64 mg·mL^-1) were determined during 18 days of refrigerated storage (4 ± 1 °C). Results showed that LBG-SA coatings containing 0.32 mg·mL^-1 daphnetin emulsions could significantly lower the total viable count (TVC), psychrophiles, Pseudomonas spp. and H₂S-producing bacteria counts, and inhibit the productions of off-flavor compounds including the total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and ATP-related compounds. 32 volatile compounds were identified by solid phase microextraction combined with gas chromatography-mass spectrometer method (SPME-GC/MS) during refrigerated storage and the treated turbot samples significantly lowered the relative content of fishy flavor compounds. Further, the LBG-SA coatings containing daphnetin could also delay the myofibril degradation of the turbot samples. These results indicated that the LBG-SA coatings with 0.32 mg·mL^-1 daphnetin were a potential alternative way to improve the quality of turbot during refrigerated storage.

Effect of Phlorotannins from Brown Seaweeds on the In Vitro Digestibility of Pig Feed

Phlorotannins have been reported to have positive effects on pig health, including improved gut health and digestibility. In this study, we investigate the effect of phenolics found in two brown seaweeds, Ascophyllum nodosum and Fucus serratus, on in vitro dry matter digestibility of seaweeds and commercial pig feed. Phlorotannin extracts and whole seaweeds were supplemented into pig feed to test their effect on digestibility. Solid-phase extraction was used to purify the phenolics to phlorotannins. The results showed a slight decrease in the digestibility of pig feed that was found to be significant when phlorotannin extracts were added from either seaweed. However, when whole A. nodosum was added to the pig feed, the effect on digestibility was less pronounced. Specifically, no significant difference in digestibility was observed at inclusion rates up to 5%, and thereafter results varied. A difference in digestibility was also observed in the same species at the same inclusion rate, collected from different seasons. This suggests that other compounds, e.g., polysaccharides, are having an effect on digestibility when whole seaweeds are supplemented to animal feed. This research has also highlighted the need to base supplementation on phenolic concentration as opposed to a standardised percentage inclusion of seaweeds to ensure that digestibility is not adversely affected.

Bergaptol from blossoms of Citrus aurantium L. var. amara Engl inhibits LPS-induced inflammatory responses and ox-LDL-induced lipid deposition

Aberrant activation of inflammation and excess accumulation of lipids play pivotal roles in atherosclerosis (AS) progression. Constituents from Citrus aurantium Linn variant amara Engl (CAVA) were effectively investigated for their various bioactivities, especially anti-inflammation. Bergaptol (BER) is particularly abundant in Citrus products. Accumulating studies have confirmed its predominant anti-cancer and antioxidant functions, whereas few studies focused on its antiatherogenic functions. In the current study, BER was isolated from CAVA for the first time. Macrophages were stimulated with lipopolysaccharides (LPSs) or oxidized low-density lipoproteins (ox-LDL) to mimic inflammatory responses and AS development. BER treatment significantly inhibited LPS-induced production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and gene expression of inducible nitric oxide synthase (iNOS), IL-6, TNF-α, interleukin-1 beta (IL-1β) and cyclooxygenase-2 (COX-2). BER also potently blocked LPS-induced mitogen-activated protein kinase (MAPK) phosphorylation and nuclear factor-kappa B (NF-κB) activation, as evidenced by the inhibitory effects on c-Jun N-terminal kinase (JNK), P38, P65, IκBα and IκKα/β phosphorylation, and NF-κB nuclear translocation. Furthermore, BER treatment markedly mitigated ox-LDL-induced foam cell formation by inhibiting scavenger receptor class A type I (SRA1) and cluster of differentiation 36 (CD36)-dependent cholesterol uptake. In conclusion, BER might be a novel therapeutic agent for AS prevention through inhibiting inflammatory responses and cholesterol uptake.

Fabrication of detonation nanodiamond@sodium alginate hydrogel beads and their performance in sunlight-triggered water release

Agricultural water use accounts for around 70% of total water use in the world. Enhancing agricultural water use efficiency is a key way to cope with water shortage. Here, sunlight-responsive hydrogel beads consisting of sodium alginate (SA) matrix and detonation nanodiamond (DND) were fabricated by an ion gelation technique, which has potential applications in controlled water release. The interaction between the DND and SA matrix was investigated by Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD). UV-vis diffuse reflectance spectra verified DND can absorb solar energy in the UV, visible and even near-infrared regions. DND dispersed in the hydrogel matrix can absorb sunlight and generate heat, increasing the temperature of the matrix and resulting in slow release of water from the elastic beads. In addition, the effects of DND content and pH were systematically studied to evaluate their water adsorption properties. The swelling kinetics of DND@SA hydrogel beads in distilled water could be fitted well with a pseudo-second-order kinetic model. Six consecutive cycles of water release-reswelling indicated that their easy regeneration and reusability. The novel and eco-friendly hydrogel beads should be applicable to on-demand, sequential, and long-term release of water via light exposure.

Optimization of the extraction, preliminary characterization, and anti-inflammatory activity of crude polysaccharides from the stems of Trapa quadrispinosa

A novel method was developed using pressurized-assisted extraction (PAE) to efficiently extract crude Trapa quadrispinosa polysaccharides (TQCPS) from plant stems, and the extraction process was optimized using response surface methodology (RSM). At a water-to-material fixed ratio of 30 mL g⁻¹, the highest yield of 3.72 ± 0.13% was obtained under the optimum conditions of extraction time of 32 min, extraction temperature at 47 °C, and extraction pressure at 1.87 Mpa, which were in agreement with the predicted value of 3.683%. Compared with conventional hot water extraction (HWE), the PAE method remarkably enhanced the extraction yield with the further advantages of short extraction time and low extraction temperature. The preliminary characteristics of TQCPS were analyzed through UV-vis, FT-IR, and chemical composition analysis. In subsequent anti-inflammatory studies, when RAW 264.7 mouse macrophage cells were treated with TQCPS, satisfactory anti-inflammatory activity was observed, and TQCPS significantly suppressed the release of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) and synchronously restrained the expression levels of inducible nitric oxide synthase (iNOS), TNF-α, and IL-6 mRNA induced by lipopolysaccharide (LPS) in a dose-dependent manner. These results indicate that PAE is a technology that can be used for efficient extraction of polysaccharides from medicinal plants, and TQCPS can be explored as a potential anti-inflammatory agent in medicine.

The high-yield TQCPS extracted by PAE presented good anti-inflammatory activity.

The impacts of natural polysaccharides on intestinal microbiota and immune responses – a review

This paper presents a comprehensive review of the impacts of natural polysaccharides on gut microbiota and immune responses as well as their interactions.

Selenium Pretreatment Alleviated LPS-Induced Immunological Stress Via Upregulation of Several Selenoprotein Encoding Genes in Murine RAW264.7 Cells

This study was conducted to profile selenoprotein encoding genes in mouse RAW264.7 cells upon lipopolysaccharide (LPS) challenge and integrate their roles into immunological regulation in response to selenium (Se) pretreatment. LPS was used to develop immunological stress in macrophages. Cells were pretreated with different levels of Se (0, 0.5, 1.0, 1.5, 2.0 μmol Se/L) for 2 h, followed by LPS (100 ng/mL) stimulation for another 3 h. The mRNA expression of 24 selenoprotein encoding genes and 9 inflammation-related genes were investigated. The results showed that LPS (100 ng/mL) effectively induced immunological stress in RAW264.7 cells with induced inflammation cytokines, IL-6 and TNF-α, mRNA expression, and cellular secretion. LPS increased (P < 0.05) mRNA profiles of 9 inflammation-related genes in cells, while short-time Se pretreatment modestly reversed (P < 0.05) the LPS-induced upregulation of 7 genes (COX-2, ICAM-1, IL-1β, IL-6, IL-10, iNOS, and MCP-1) and further increased (P < 0.05) expression of IFN-β and TNF-α in stressed cells. Meanwhile, LPS decreased (P < 0.05) mRNA levels of 18 selenoprotein encoding genes and upregulated mRNA levels of TXNRD1 and TXNRD3 in cells. Se pretreatment recovered (P < 0.05) expression of 3 selenoprotein encoding genes (GPX1, SELENOH, and SELENOW) in a dose-dependent manner and increased (P < 0.05) expression of another 5 selenoprotein encoding genes (SELENOK, SELENOM, SELENOS, SELENOT, and TXNRD2) only at a high level (2.0 μmol Se/L). Taken together, LPS-induced immunological stress in RAW264.7 cells accompanied with the global downregulation of selenoprotein encoding genes and Se pretreatment alleviated immunological stress via upregulation of a subset of selenoprotein encoding genes.

Alginate oligosaccharide-induced intestinal morphology, barrier function and epithelium apoptosis modifications have beneficial effects on the growth performance of weaned pigs

Background

Alginate oligosaccharide (AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function, as well as epithelium apoptosis.

Methods

Twenty-four weaned pigs were distributed into two groups (n = 12) and received either a basal diet (control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose (0.1 g/kg body weight) was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later.

Results

Our results showed that inclusion of AOS in the diet for 2 wk increased (P < 0.05) the average daily body weight gain in weaned pigs. Notably, AOS supplementation ameliorated the intestinal morphology and barrier function, as suggested by the enhanced (P < 0.05) intestinal villus height, secretory immunoglobulin A content and goblet cell counts. Compared to the control group, AOS ingestion both decreased (P < 0.05) the total apoptotic percentage and increased (P < 0.05) the proportion of S phase in the intestinal epithelial cells. Furthermore, AOS not only up-regulated (P < 0.05) the B-cell lymphoma-2 (BCL2) transcriptional level but also down-regulated (P < 0.05) the B-cell lymphoma-2-associated X protein (BAX), cysteinyl aspartate-specific proteinase-3 (caspase-3) and caspase-9 transcriptional levels in the small intestine.

Conclusions

In summary, this study provides evidence that supplemental AOS beneficially affects the growth performance of weaned pigs, which may result from the improved intestinal morphology and barrier function, as well as the inhibited enterocyte death, through reducing apoptosis via mitochondria-dependent apoptosis.

Fabrication of Composite Beads Based on Calcium Alginate and Tetraethylenepentamine-Functionalized MIL-101 for Adsorption of Pb(II) from Aqueous Solutions

In this work, a tetraethylenepentamine (TEPA)-grafted metal-organic framework material (MIL-101) was synthesized. The introduction of TEPA increased the abundance of functional groups on the MIL-101. As a powdery adsorbent, MIL-101-TEPA can be difficult to separate. In order to solve this problem, we combined MIL-101-TEPA with sodium alginate (SA) and injected the mixture into a CaCl₂ solution to solidify the powder into beads with a particle size of 3 mm. The easily recovered adsorbent was applied to the adsorption of Pb(II) from water. The structure and characterization of the adsorbent were investigated through scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). We also optimized the adsorption conditions. The results of the study showed that the adsorption process was chemisorptive and endothermic in nature. The maximum adsorption capacity of the composite beads was 558.6 mg/g. Meanwhile MIL-101-TEPA@CA showed good repeatable utilization.

Alginate oligosaccharide enhances intestinal integrity of weaned pigs through altering intestinal inflammatory responses and antioxidant status

Alginate oligosaccharide (AOS), prepared from depolymerised alginate, a natural polysaccharide occurring in the cell walls of brown algae, provides beneficial effects for intestinal health. However, the underlying mechanisms by which AOS supplementation maintains the intestinal integrity of weaned pigs remain obscure. Here, we aimed to determine how AOS modulates the intestinal integrity of weaned pigs. Twenty-four weaned pigs were assigned to two treatments: a control group (basal diet) and an AOS group (the basal diet supplemented with 100 mg kg-1 AOS). On day 15, eight pigs per treatment were randomly selected and sacrificed for serum and intestinal samples. We observed that AOS supplementation enhanced the intestinal integrity, as evidenced by the increased (P < 0.05) intestinal occludin protein abundance. Compared to the control group, AOS ingestion both elevated (P < 0.05) the jejunal and ileal catalase activity and decreased (P < 0.05) the duodenal and jejunal tumour necrosis factor-α concentration and mast cell tryptase expression. Furthermore, AOS down-regulated (P < 0.05) the duodenal toll-like receptor 4 (TLR4) and its down-stream signals, myeloid differentiation factor 88 (MyD88), interleukin-1 receptor-associated kinase 1 (IRAK1) and tumour necrosis factor receptor-associated factor 6 (TRAF6) mRNA levels, as well as jejunal nucleotide-binding oligomerisation domain protein 1 (NOD1) and its adaptor molecule, receptor-interacting serine/threonine-protein kinase 2 (RIPK2), mRNA levels. Additionally, phospho-nuclear factor-κB (p-NF-κB) p65 protein abundance in the duodenum and jejunum was down-regulated (P < 0.05) following AOS supplementation. According to the above results, the enhanced intestinal integrity in AOS-supplemented pigs appears to be associated with the elevated antioxidant capacity and the reduced mast cell degranulation, as well as the inhibited pro-inflammatory cytokines production via inhibiting the TLR4/NF-κB and NOD1/NF-κB signalling pathways.

Alginate oligosaccharide alleviates enterotoxigenicEscherichia coli-induced intestinal mucosal disruption in weaned pigs

Alginate oligosaccharide (AOS) is a non-toxic, non-immunogenic, non-carcinogenic and biodegradable product generated by depolymerisation of alginate, and exhibits various salutary properties.

Synthesis of Furandicarboxylic Acid Esters From Nonfood Feedstocks Without Concomitant Levulinic Acid Formation

5-Hydroxymethylfurfural (HMF) is a versatile intermediate in biomass conversion pathways. However, the notoriously unstable nature of HMF imposes challenges to design selective routes to chemicals such as furan-2,5-dicarboxylic acid (FDCA). Here, a new strategy for obtaining furans is presented, bypassing the formation of the unstable HMF. Instead of starting with glucose/fructose and thus forming HMF as an intermediate, the new route starts from uronic acids, which are abundantly present in many agro residues such as sugar beet pulp, potato pulp, and citrus peels. Conversion of uronic acids, via ketoaldonic acids, to the intermediate formylfuroic acid (FFA) esters, and subsequently to FDCA esters, proceeds without formation of levulinic acid or insoluble humins. This new route provides an attractive strategy to valorize agricultural waste streams and a route to furanic building blocks without the co-production of levulinic acid or humins.

Immune enhancement effects and extraction optimization of polysaccharides from Citrus aurantium L. var. amara Engl

The crude polysaccharides ofCitrus aurantiumL. var.amaraEngl (CAVAPs) were extracted and their bioactivities including DPPH radical scavenging activity, cytotoxicity to human breast cancer cells, MCF-7, as well as lung cancer cells, HCC827, and their immune-enhancement activity were evaluated.

Extraction, characterization and bioactivities of novel purified polysaccharides from Baphicacanthis Cusiae Rhizoma et Radix

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Two purified water-soluble polysaccharides (BCP) were isolated and separated from Baphicacanthis Cusiae Rhizoma et Radix.

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Characterization technology had been researched.

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Demonstrated that BCP-1 and BCP-2 had novel anti-inflammatory and antioxidant activities.

The purpose of this study was to investigate the extraction, characterization and bioactivities of purified water-soluble polysaccharides (BCP) from Baphicacanthis Cusiae Rhizoma et Radix. Based on the response surface methodology, the optimal extraction parameters were obtained as follows: extraction temperature of 60.0 °C, extraction time of 35.0 min, and ratio of water to raw material of 24.5 ml/g. Then, BCP was separated and purified by chromatography of DEAE-52 and Sephadex G-100, and obtained two purified fractions, named as BCP-1 and BCP-2. Their molecular weights were respectively 11.6 and 26.7 KDa with mainly composed of glucose, arabinose and galactose. BCP-2 had higher contents of sulfuric radical and uronic acid than BCP-1. Finally, their antioxidant and anti-inflammatory activities were evaluated. Both of BCP-1 and BCP-2 exhibited strong antioxidant activity in vitro, and the antioxidant of BCP-2 was better. Besides, they showed ideal anti-inflammatory activity in vitro and in vivo.