Alginate Oligosaccharides Research Articles

Low Molecular Weight Alginate Oligosaccharides as Alternatives to PEG for Enhancement of the Diffusion of Cationic Nanoparticles Through Cystic Fibrosis Mucus.

Airway mucus is a major barrier to the delivery of lipid-based nanoparticles in chronic airway diseases such as cystic fibrosis (CF). Receptor-Targeted Nanocomplexes (RTN), comprise mixtures of cationic lipids and bifunctional peptides with receptor-targeting and nucleic acid packaging properties. The aim of this study is to improve the mucus-penetrating properties of cationic siRNA and mRNA RTNs by combining them with low molecular weight alginate oligosaccharides, OligoG and OligoM. Cationic RTNs formulated with either alginate become strongly anionic, while PEGylated messenger RNA (mRNA) and short interfering RNA (siRNA) RTNs remain cationic. Both alginates enhance mucus diffusion rates of cationic siRNA and mRNA RTNs in a static mucus barrier diffusion model, with OligoG particularly effective. PEGylation also enhance mucus diffusion rates of siRNA RTNs but not mRNA RTNs. Electron microscopy shows that RTNs remained intact after mucosal transit. The transfection efficiency of OligoM-coated mRNA RTNs is better than those coated with OligoG or PEG, and similar to cationic RTNs. In siRNA RTN transfections, OligoM is better than OligoG although 1% PEG is slightly better than both. The combination of cationic RTNs and alginate oligosaccharides represents a promising alternative to PEGylation for epithelial delivery of genetic therapies across the mucus barrier while retaining transfection efficiency.

A combined analysis of transcriptome and proteome reveals the regulation mechanism of alginate oligosaccharides on alleviating energy deficit in postharvest strawberry

Strawberry exhibits a very short shelf life due to its rapid softening and decay, resulting in postharvest loss. Our previous study showed that AOS, an eco-friendly nontoxic natural product, plays a role in preserving the freshness of strawberries by regulating ABA content and its signaling pathway. Considering the critical role that energy deficit plays in the senescence process of fruits, coupled with the potential influence of plant hormones on energy metabolism. In this study, the molecular mechanism of strawberry postharvest senescence in response to AOS treatment was further explored from the perspective of energy metabolism regulation. This was achieved through a two-layered approach, integrating the direct determination of energy-related substances with a comprehensive joint analysis of transcriptome and proteome data. AOS treatment significantly delayed the loss of ATP, ADP, and AMP contents compared to control fruit, implying that maintaining cell energy is a crucial factor in AOS postponing senescence in strawberry. Subsequently, the mechanisms were further revealed by transcriptome and proteome analysis. Overall, 255 DEGs were screened from the AOS group, mainly related to carbohydrate and energy metabolism, defense, plant hormone, and secondary metabolism. Additionally, A total of 227 proteins were identified that were differentially expressed in the AOS group, and the majority were related to carbohydrate and energy metabolism (85 proteins). Two omics data implied that AOS could effectively regulate the energy metabolism system to maintain the cellular energy level of harvested strawberry during storage, ultimately leading to longer shelf life. Therefore, our findings provide comprehensive information regarding the molecular mechanism underlying the postharvest storage of strawberry treated with AOS. From our results, it can be concluded that AOS postharvest treatment is very useful for keeping fruit quality and extending shelf life by maintaining a higher energy level.

Influence of consumption of unsaturated alginate oligosaccharides on the gut microbiota and the intestinal mucosal immunity homeostasis in immunocompromised mice

Influence of consumption of unsaturated alginate oligosaccharides on the gut microbiota and the intestinal mucosal immunity homeostasis in immunocompromised mice

Direct Preparation of Alginate Oligosaccharides from Brown Algae by an Algae-Decomposing Alginate Lyase AlyP18 from the Marine Bacterium Pseudoalteromonas agarivorans A3

Alginate oligosaccharides (AOs), derived from alginate degradation, exhibit diverse biological activities and hold significant promise in various fields. The enzymatic preparation of AOs relies on alginate lyases, which offers distinct advantages. In contrast to the conventional use of sodium alginate derived from brown algae as the substrate for the enzymatic preparation of AOs, AO preparation directly from brown algae is more appealing due to its time and energy efficiency. Thus, the identification of potent alginate lyases and cost-effective brown algae substrates is crucial for optimizing AO production. Herein, we identified and characterized an alginate lyase, AlyP18, capable of efficiently decomposing algae, from a marine bacterium Pseudoalteromonas agarivorans A3 based on secretome analysis. AlyP18 is a mesothermal, endo-type and bifunctional alginate lyase with high enzymatic activity. Two brown algae substrates, Laminaria japonica roots and Macrocystis pyrifera, were used for the AO preparation by AlyP18. Upon optimization of AlyP18 hydrolysis parameters, the substrate degradation efficiency and AO production reached 53% and ~32% for L. japonica roots, respectively, and 77% and ~46.5% for M. pyrifera. The generated AOs primarily consisted of dimers to pentamers, with trimers and tetramers being dominant. This study provides an efficient alginate lyase and alternative brown algal feedstock for the bioconversion of high-value AOs from brown algae.

Preserving refrigeration and shelf life quality of hardy kiwifruit (Actinidia arguta) with alginate oligosaccharides preharvest application.

Alginate oligosaccharide (AOS) is a bioactive carbohydrate known for its preservation properties. However, the efficacy of preharvest AOS treatment in maintaining the postharvest quality of hardy kiwifruit (Actinidia arguta) has not been previously reported. This study explores the effects of preharvest AOS treatment (80mg L-1) on A. arguta fruit, assessing visual quality, physiological attributes, aroma, and antioxidant capacity during refrigeration and shelf life. Results showed that AOS treatment maintained higher lightness, chroma, firmness, and antioxidant levels (total phenolics, flavonoids, ascorbic acid, and glutathione), along with antioxidant enzyme activities (peroxidase, catalase, and ascorbate peroxidase). Specifically, AOS-treated fruit had 9% higher chroma and double the firmness after 60 days of refrigeration. AOS treatment reduced ripening and senescence, with 25% lower soluble solids content, 22% lower respiration rate, 30% lower ethylene production, and 35% lower malondialdehyde content. Electronic nose analysis indicated that AOS treatment suppressed changes in fruit aroma and off-odor development, maintaining significantly higher quality during the shelf life period. These findings demonstrate the effectiveness of AOS as a sustainable method to extend shelf life and preserve the quality of A. arguta fruit, enhancing its market value and consumer appeal. PRACTICAL APPLICATION: The research on using alginate oligosaccharides (AOS) for preharvest treatment of hardy kiwifruit (Actinidia arguta) has practical applications in the food industry. By extending the shelf life and preserving the quality of the fruit during storage, this method can help reduce postharvest losses and improve the market value and consumer appeal of A. arguta fruit. This sustainable preservation technique offers an eco-friendly alternative to traditional methods, enhancing the freshness and nutritional quality of the fruit available to consumers.

Application of 28.1 kDa Alginate Oligosaccharide Improves the Yield and Quality of Grain in Rice

AbstractWe conducted a phase‐wise study to evaluate the efficacy of the gamma ray‐produced oligosaccharides of alginate and chitosan in enhancing the yield in rice. Initially, we irradiated the dry powder of alginate and chitosan with 200–500 kGy dose of gamma ray to produce their oligosaccharides. Subsequently, we assessed efficiency of the aqueous solution (50–400 ppm) of these oligosaccharides to stimulate the growth in rice seedling. The elicitors which stimulated the seedling growth were later tested in the field for their ability to enhance the growth and yield in rice under six different treatment regimens. In the next two seasons we evaluated the elicitor and treatment regimen, which enhanced the yield and yield contributing factors, at a larger scale. The observations suggest that 200 ppm of alginate oligosaccharide (28.1 kDa) produced by 500 kGy of gamma ray enhances the yield in rice by 13% and improves the seed quality when sprayed during seedling, pre‐flowering and grain‐filling stages. Such treatment improves the overall growth and development of the plant, which probably enhances the yield and grain quality of the produce.

Degradation of Natural Undaria pinnatifida into Unsaturated Guluronic Acid Oligosaccharides by a Single Alginate Lyase.

Here, we report on a bifunctional alginate lyase (Vnalg7) expressed in Pichia pastoris, which can degrade natural Undaria pinnatifida into unsaturated guluronic acid di- and trisaccharide without pretreatment. The enzyme activity of Vnalg7 (3620.00 U/mL-culture) was 15.81-fold higher than that of the original alg (228.90 U/mL-culture), following engineering modification. The degradation rate reached 52.75%, and reducing sugar reached 30.30 mg/mL after combining Vnalg7 (200.00 U/mL-culture) and 14% (w/v) U. pinnatifida for 6 h. Analysis of the action mode indicated that Vnalg7 could degrade many substrates to produce a variety of unsaturated alginate oligosaccharides (AOSs), and the minimal substrate was tetrasaccharide. Site-directed mutagenesis showed that Glu238, Glu241, Glu312, Arg236, His307, Lys414, and Tyr418 are essential catalytic sites, while Glu334, Glu344, and Asp311 play auxiliary roles. Mechanism analysis revealed the enzymatic degradation pattern of Vnalg7, which mainly recognizes and attacks the third glycosidic linkage from the reducing end of oligosaccharide substrate. Our findings provide a novel alginate lyase tool and a sustainable and commercial production strategy for value-added biomolecules using seaweeds.

Genome Analysis of a Potential Novel Vibrio Species Secreting pH- and Thermo-Stable Alginate Lyase and Its Application in Producing Alginate Oligosaccharides.

Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity (<98.4%), ANI value (<71.9%), and dDDH value (<23.9%) clearly indicated that the isolate represented a potential novel species of the genus Vibrio. The genome contained two chromosomes with lengths of 3,007,948 bp and 874,895 bp, respectively, totaling 3,882,843 bp with a G+C content of 46.5%. Among 3482 genes, 3332 protein-coding genes, 116 tRNA, and 34 rRNA sequences were predicted. Analysis of the amino acid sequences showed that the strain encoded 73 carbohydrate-active enzymes (CAZymes), predicting seven PL7 (Alg1-7) and two PL17 family (Alg8, 9) alginate lyases. The extracellular alginate lyase from strain HB236076 showed the maximum activity at 50 °C and pH 7.0, with over 90% activity measured in the range of 30-60 °C and pH 6.0-10.0, exhibiting a wide range of temperature and pH activities. The enzyme also remained at more than 90% of the original activity at a wide pH range (3.0-9.0) and temperature below 50 °C for more than 2 h, demonstrating significant thermal and pH stabilities. Fe2+ had a good promoting effect on the alginate lyase activity at 10 mM, increasing by 3.5 times. Thin layer chromatography (TLC) and electrospray ionization mass spectrometry (ESI-MS) analyses suggested that alginate lyase in fermentation broth could catalyze sodium alginate to produce disaccharides and trisaccharides, which showed antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophila, Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. This research provided extended insights into the production mechanism of alginate lyase from Vibrio sp. HB236076, which was beneficial for further application in the preparation of pH-stable and thermo-stable alginate lyase and alginate oligosaccharides.

Amphiphilic colloidal particles/Ca2+ reinforced edible agar nanocomposite film by multiple cross-linking/microphase separation strategies

The agar (AG) film exhibited poor mechanical and water-resistant properties which limited its application for food packaging. The structural modification of AG nanocomposite film greatly impacts their macroscopic properties. In this paper, edible AG nanocomposite films were achieved by incorporating colloidal particles based on conjugates of whey protein isolate (WPI) and alginate oligosaccharides (AOS) as the nanofiller to obtain the micro-phase separation structure and the multiple cross-linking network with the synergistic interactions of the Ca2+ crosslinking. Firstly, WPI-AOS colloidal particles were synthesized through the Wet-heating Maillard reaction. Good compatibility between WPI-AOS colloidal particles and AG was exhibited, resulting in improved mechanical and water-resistant properties of AG composite films. Compared to pure AG film, the tensile strength (TS) of the agar composite film with 10% WPI-AOS colloidal particles increased significantly to 81.87 MPa from 24.02 MPa, and the elongation at break (EAB) also improved to 46.25% from 18.65%. The moisture content (MC), water solubility (WS), and water vapor permeability (WVP) of the AG composite film decreased by 33.1%, 18.0%, and 22.4% respectively. In addition, the multiple cross-linking network hindered the relative sliding between the AG molecular chain, which resulted in improved thermal stability of the composite film. Using soft colloidal particles as nanofillers to fabricate edible films for improving their properties is an effective and promising strategy.

Efficient Production of an Alginate Lyase in Bacillus subtilis with Combined Strategy: Vector and Host Selection, Promoter and Signal Peptide Screening, and Modification of a Translation Initiation Region.

Alginate lyases (ALys) whose degrading products, alginate oligosaccharides, exhibit various outstanding biochemical activities have aroused increasing interest of researchers in the marine bioresource field. However, their predominant sourcing from marine bacteria, with limited yields and unclear genetic backgrounds, presents a challenge for industrial production. In this study, ALys (Aly01) from Vibrio natriegens SK 42.001 was expressed in Bacillus subtilis (B. subtilis), a nonpathogenic microorganism recognized as generally safe (GRAS). This accomplishment was realized through a comprehensive strategy involving vector and host selection, promoter and signal peptide screening, and engineering of the ribosome binding site (RBS) and the N-terminal coding sequence (NCS). The optimal combination was identified as the pP43NMK and B. subtilis WB600. Among the 19 reported strong promoters, PnprE exhibited the best performance, showing intracellular enzyme activities of 4.47 U/mL. Despite expectations, dual promoter construction did not yield a significant increase. Further, SPydhT demonstrated the highest extracellular activity (1.33 U/mL), which was further improved by RBS/NCS engineering, reaching 4.58 U/mL. Finally, after fed-batch fermentation, the extracellular activity reached 18.01 U/mL, which was the highest of ALys with a high molecular weight expressed in B. subtilis. These findings are expected to offer valuable insights into the heterologous expression of ALys in B. subtilis.

Alginate oligosaccharide supplementation improves boar semen quality under heat stress

Heat stress is a serious problem that affects animal husbandry by reducing growth and reproductive performance of animals. Adding plant extracts to the diet is an effective way to help overcome this problem. Alginate oligosaccharide (AOS) is a natural non-toxic antioxidant with multiple biological activities. This study analyzed the potential mechanism of AOS in alleviating heat stress and improving semen quality in boars through a combination of multiple omics tools. The results indicated that AOS could significantly increase sperm motility (P < 0.001) and sperm concentration (P < 0.05). At the same time, AOS improved the antioxidant capacity of blood and semen, and increased blood testosterone (P < 0.05) level. AOS could improve the metabolites in sperm, change the composition of gut microbiota, increase the relative abundance of beneficial bacteria such as Pseudomonas (P < 0.01), Escherichia-Shigella (P < 0.05), Bifidobacterium (P < 0.01), reduce the relative abundance of harmful bacteria such as Prevotella_9 (P < 0.05), Prevotellaceae_UCG-001 (P < 0.01), and increase the content of short chain fatty acids. Proteomic results showed that AOS increased proteins related to spermatogenesis, while decreasing heat shock protein 70 (P < 0.05) and heat shock protein 90 (P < 0.01). These results were verified using immunofluorescence staining technology. There was a good correlation among sperm quality, sperm metabolome, sperm proteome, and gut microbiota. In conclusion, AOS can be used as a feed additive to increase the semen quality of boars to enhance reproductive performance under heat stress.

Alginate Oligosaccharides Enhance Gut Microbiota and Intestinal Barrier Function, Alleviating Host Damage Induced by Deoxynivalenol in Mice

BackgroundAlginate oligosaccharides (AOS) exhibits notable effects in terms of anti-inflammatory, antibacterial, and antioxidant properties. Deoxynivalenol (DON) has the potential to trigger intestinal inflammation by upregulating pro-inflammatory cytokines and apoptosis, thereby compromising the integrity of the intestinal barrier function and perturbing the balance of the gut microbiota. ObjectivesWe assessed the impact of AOS on mitigating DON-induced intestinal damage and systemic inflammation in mice. MethodsAfter a 1-wk acclimatization period, the mice were divided into 4 groups. For 3 wk, the AOS and AOS + DON groups were gavaged daily with 200 μL of AOS [200 mg/kg body weight (BW)], whereas the CON and DON groups received an equivalent volume of sterile Phosphate-Buffered Saline (PBS). Subsequently, for 1 wk, the DON and AOS + DON groups received 100 μL of DON (4.8 mg/kg BW) daily, whereas the control (CON) and AOS groups continued receiving PBS. ResultsAfter administering DON via gavage to mice, there was a significant decrease (P < 0.05) in body weights compared with the CON group. Interestingly, AOS exhibited a tendency to mitigate this weight loss in the AOS + DON group. In the feces of mice treated with both AOS and DON, the concentration of DON significantly increased (P < 0.05) compared with the DON group alone. Histological analysis revealed that DON exposure caused increased intestinal damage, including shortened villi and eroded epithelial cells, which was ameliorated by presupplementation with AOS, alleviating harm to the intestinal barrier function. In both jejunum and colon tissues, DON exposure significantly reduced (P < 0.05) the expression of tight junction proteins (claudin and occludin in the colon) and the mucin protein mucin 2, compared with the CON group. Prophylactic administration of AOS alleviated these reductions, thereby improving the expression levels of these key proteins. Additionally, AOS supplementation protected DON-exposed mice by increasing the abundance of probiotics such as Bifidobacterium, Faecalibaculum, and Romboutsia. These gut microbes are known to enhance (P < 0.05) anti-inflammatory responses and the production of short-chain fatty acids (SCFAs), including total SCFAs, acetate, and valerate, compared with the DON group. ConclusionsThis study unveils that AOS not only enhances gut microbiota and intestinal barrier function but also significantly mitigates DON-induced intestinal damage.

Effect of Alginate Oligosaccharides on Oxidative Reactions in Sweet Basil During Low-Temperature Storage

This study aimed to investigate the antioxidant effect of alginate oligosaccharides (AOS) on sweet basil leaves preserved at low temperatures. This investigation was divided into 3 treatments and 3 replications using a completely randomized design (CRD) experiment. Specifically, the effects of dipping basil leaves in AOS solutions at different concentrations (100 and 200 mg L−1) and in distilled water (control) for 1 min were compared. Cell deterioration due to cold storage was investigated based on the variation in oxidative reactions in the cells, causing an accumulation of free radicals. The AOS-treated sweet basil leaves had a 12-day shelf life, compared to just 9 days for those in the control group. Those treated with AOS at 100 mg L−1 exhibited the lowest levels of phenylalanine ammonia-lyase, lipoxygenase, hydrogen peroxide, peroxidase and malondialdehyde content. On the contrary, the contents of phenolic compounds, polyphenol oxidase, catalase and superoxide dismutase increased in the treated leaves during storage compared to those observed in the control treatment. HIGHLIGHTS Alginate oligosaccharides (AOS) enhanced antioxidant effects in sweet basil leaves stored at low temperatures. Basil leaves treated with AOS at 100 and 200 mg L⁻¹ had an extended shelf life of 12 days, compared to 9 days for untreated controls. AOS treatment reduced oxidative stress markers, including phenylalanine ammonia-lyase, lipoxygenase, hydrogen peroxide, peroxidase, and malondialdehyde. AOS-treated leaves showed increased phenolic compounds, polyphenol oxidase, catalase, and superoxide dismutase activity. AOS treatment may mitigate chilling injury and improve postharvest quality in sweet basil leaves. GRAPHICAL ABSTRACT

Chemical and enzymatic hydrolysis of alginate: a review

Abstract Alginate is a brown seaweed-based linear polysaccharide of D – mannuronic acid and L – guluronic acid residues. Hydrolysis products of the polysaccharide, specifically oligosaccharides, have been receiving increasing interest, due to their significant bioactivity and potential utilisation routes. The bioactivity of alginate oligosaccharides is closely linked to structural characteristics, namely: molecular weight, degree of polymerisation, and ratio of the monomers (the M/G ratio). Hence, potential applications (such as utilisation as a biostimulant fertilizer) depend on these parameters. This review focuses on recent advances in producing alginate oligosaccharides using chemical or enzymatic methods. The literature survey includes utilisation of these methods at both laboratory and industrial scale. For the chemical methods, we assessed the standard laboratory scale procedures of alginate oligosaccharide production, the potential of scaling up to an industrial level, and the subsequent challenges. For the enzymatic route, we provide an overview of alginate lyases and the application perspectives of enzymatic hydrolysis of alginate.

A novel enzyme-assisted one-pot method for the extraction of fucoidan and alginate oligosaccharides from Lessonia trabeculata and their bioactivities

A novel enzyme-assisted one-pot method for the extraction of fucoidan and alginate oligosaccharides from Lessonia trabeculata and their bioactivities

The enhancement of wastewater purification efficiency in ecological floating bed aquaculture through alginate oligosaccharide treatment

The enhancement of wastewater purification efficiency in ecological floating bed aquaculture through alginate oligosaccharide treatment

Enhancing the rigidity of the catalytic pocket entrance to improve catalytic efficiency and thermal stability of alginate Lyase from Pseudoalteromonas

Alginate lyase plays a critical role in the production of alginate oligosaccharides (AOS), necessitating efficient activity and a certain level of thermal stability for industrial AOS production. In this study, through sequence alignment and structural analysis, a non-catalytic amino acid residue, Ala195, located at the entrance of the catalytic pocket was identified. This residue is crucial for the catalytic efficiency and thermal stability of Alg2944, a member of the polysaccharide lyase family 18. The specific activities of A195F, A195I, and A195L were enhanced by 1.84-, 1.39-, and 1.98-fold, respectively, while the thermal stability of mutants A195L and A195I showed significant improvements at 35 °C and 40 °C compared to the wild-type (WT) enzyme. Furthermore, molecular docking, structural analysis, and molecular dynamics (MD) simulations revealed that the enhanced specific activity and thermal stability of the A195L mutant can be attributed to the creation of a hydrophobic pocket, increased rigidity in the loop region, and a notably lower binding free energy of the A195L mutant (-45.96 ± 7.69 kcal/mol) compared to the WT (-38.40 ± 4.25 kcal/mol). These findings underscore the essential role of rigidity and hydrophobicity at the entrance of the catalytic pocket in ensuring both catalytic efficiency and thermal stability of alginate lyase.

Alginate Oligosaccharides Enhance Antioxidant Status and Intestinal Health by Modulating the Gut Microbiota in Weaned Piglets.

Alginate oligosaccharides (AOSs), which are an attractive feed additive for animal production, exhibit pleiotropic bioactivities. In the present study, we investigated graded doses of AOS-mediated alterations in the physiological responses of piglets by determining the intestinal architecture, barrier function, and microbiota. A total of 144 weaned piglets were allocated into four dietary treatments in a completely random design, which included a control diet (CON) and three treated diets formulated with 250 mg/kg (AOS250), 500 mg/kg (AOS500), and 1000 mg/kg AOS (AOS1000), respectively. The trial was carried out for 28 days. Our results showed that AOS treatment reinforced the intestinal barrier function by increasing the ileal villus height, density, and fold, as well as the expression of tight junction proteins, especially at the dose of 500 mg/kg AOS. Meanwhile, supplementations with AOSs showed positive effects on enhancing antioxidant capacity and alleviating intestinal inflammation by elevating the levels of antioxidant enzymes and inhibiting excessive inflammatory cytokines. The DESeq2 analysis showed that AOS supplementation inhibited the growth of harmful bacteria Helicobacter and Escherichia_Shigella and enhanced the relative abundance of Faecalibacterium and Veillonella. Collectively, these findings suggested that AOSs have beneficial effects on growth performance, antioxidant capacity, and gut health in piglets.

Alginate oligosaccharide improves 5-fluorouracil-induced intestinal mucositis by enhancing intestinal barrier and modulating intestinal levels of butyrate and isovalerate

Chemotherapy-induced mucositis (CIM) is the typical side effect of chemotherapy. This study investigates the potential of alginate oligosaccharide (AOS) in ameliorating CIM induced by 5-fluorouracil (5-FU) in a murine model and its underlying mechanisms. AOS effectively mitigated body weight loss and histopathological damage, modulated inflammatory cytokines and attenuated the oxidative stress. AOS restored intestinal barrier integrity through enhancing expression of tight junction proteins via MLCK signaling pathway. AOS alleviated intestinal mucosal damage by inhibiting TLR4/MyD88/NF-κB signaling pathway, downregulating the pro-apoptotic protein Bax and upregulating the anti-apoptotic protein Bcl-2. Moreover, AOS significantly enriched intestinal Akkermansiaceae and increased the production of short-chain fatty acids (SCFAs), most notably butyrate and isovalerate. Pre-treatment with butyrate and isovalerate also alleviated 5-FU-induced CIM. In conclusion, AOS effectively mitigated CIM through strenghthening intestinal barrier, attenuating inflammation, and modulating gut microbiota and intestianl levels of butyrate and isovalerate. These finding indicate that AOS could be potentially utilized as a supplemental strategy for prevention or mitigation of CIM.

Polyelectrolyte complex formation of alginate and chito oligosaccharide is influenced by their proportion and alginate molecular weight

Sodium alginate (SA) and chito oligosaccharide (COS) are widely used food additives in the food industry, and exploring their interaction to form polyelectrolyte complexes (PECs) may provide insights into food development. In the present study, the effects of viscosity-average molecular weight (Mv) and relative amounts of SA on the formation of sodium alginate/chito oligosaccharide polyelectrolyte (SCP) complexes were investigated. The results showed that the electrostatic interaction between -COOH and -NH2 and the hydrogen bonding between OH, were attributed to the formation of the SCP complexes. Then the formation and properties of SCP complexes were greatly dependent on the Mv and the relative amount of SA. SA with Mv of ≥2.16 × 106 Da could form spherical SCP complexes, while the SA/COS ratio (w/w) ≥ 0.8 was not conducive to the formation of SCP complexes. Moreover, the SCP complexes were more stable in the gastric environment than in the intestinal condition. In addition, 1.73 × 107 Da was the optimal Mv of SA for SCP complexes formation. This study contributed to a comprehensive understanding of the interaction between SA and COS, and shed light on the potential application of SA and COS formulation to develop new food products.