Comparison of Maillard-Type Glycated Collagen with Alginate Oligosaccharide and Glucose: Its Characterization, Antioxidant Activity, and Cytoprotective Activity on H2O2-Induced Cell Oxidative Damage

Expression and characterization of colanic acid-degrading enzyme from Escherichia phage phi92 and analysis of its hydrolysate composition and structure

Colanic acid (CA), an exopolysaccharide synthesized by bacteria, is known for its potential to extend the lifespan of nematodes. However, its high viscosity poses practical application challenges, which can be mitigated by employing colanic acid-degrading enzymes (CAEs). This study presents the expression and characterization of a novel CAE from Escherichia phage phi92, used for the production of CA oligosaccharides (CAOSs). Optimal CAE expression conditions were identified as induction at 20 °C for 24 h with 0.1 mM IPTG. The enzyme showed maximal activity at 55 °C and pH 6.0, with stability in the range of 4-50 °C and pH 4.0-7.0. Structural characterization of CAOSs was performed using GC-MS, LC-MS and NMR spectroscopy, revealing the composition of hexasaccharide and dodecasaccharide units, with CAE cleaving the β-1,4 glycosidic linkage between glucose and fucose. CAOSs were found to mitigate oxidative stress and inflammation induced by H2O2 in RAW 264.7 macrophages, inhibiting NO and MDA production while enhancing CAT activity. Additionally, CAOSs modulated the mRNA expression of pro-inflammatory (IL-1β, COX-2) and anti-inflammatory (IL-10, HO-1) factors. This study deepens the understanding of CAE and facilitates the preparation of CA oligomers for applications in food, cosmetics, and pharmaceuticals.

Procyanidin B2 targeted CCR7 expression to inhibit the senescence-associated secretory phenotype through the NF-κB pathway to promote osteogenic differentiation of periodontal ligament stem cells in periodontitis

Periodontitis is recognized as a chronic inflammatory disease, with aging emerging as a significant risk factor. Cellular senescence plays a crucial role in the biological process of aging. The senescence-associated secretory phenotype (SASP) is characterized by a series of pro-inflammatory factors, chemokines, and proteases, which are hallmark characteristics of senescent cells. These factors collectively alter the local environment, impacting the function of periodontal ligament stem cells (PDLSCs). Procyanidin B2 (PB2), the main dimer of oligomeric procyanidins, possesses antioxidant, anti-inflammatory, and anti-cancer properties. The molecular mechanisms through which PB2 exerts its protective effects against periodontitis remain incompletely understood. Therefore, this research aimed to investigate the effects and underlying mechanisms of PB2 on the osteogenic differentiation of PDLSCs within an inflammatory environment. To simulate a chronic inflammatory condition, PDLSCs were stimulated with Porphyromonas gingivalis Lipopolysaccharide (Pg. LPS). The findings indicated that PB2 significantly alleviated the inflammatory responses, enhanced the activity of antioxidant enzymes, and upregulated the osteogenic differentiation of PDLSCs stimulated by Pg. LPS. RNA sequencing (RNA-Seq) revealed that Pg. LPS influenced the cell cycle, cellular senescence, and NF-κB signaling pathways. In contrast, PB2 treatment reduced the number of senescent cells and diminished the expression of senescence-associated proteins and genes. Western blot analysis verified that PB2 also decreased the levels of CCR7 and suppressed the NF-κB signaling pathways. In conclusion, PB2 targeted CCR7 expression to inhibit the SASP through NF-κB signaling pathway, demonstrating its anti-inflammatory and osteogenic properties, positioning PB2 as a promising therapeutic option for the adjuvant treatment of periodontitis.

Sensory improvement and antioxidant enhancement in silver carp hydrolysate using prebiotic oligosaccharides: insights from the Maillard reaction

Our previous studies have highlighted the potential of silver carp hydrolysate (SCH) in managing chronic diseases. Unfortunately, its fishy smell and bitter taste limited consumer acceptance. Prebiotic oligosaccharides are often used as dietary supplements, ignoring their role as carbonyl ligands in the Maillard reaction to enhance food's sensory and antioxidant properties. This study aimed to improve SCH's sensory attributes and investigate its physicochemical properties and antioxidant activities using prebiotic oligosaccharides via the Maillard reaction. The results showed that xylo-oligosaccharide (XOS) had the highest reactivity among the oligosaccharides tested, and it greatly enhanced the taste and flavor of SCH, as well as its antioxidant activities (0.45 to 16.5 times). Specifically, XOS effectively reduced the fishy smell and bitter taste, imparting a caramel-like flavor and overall acceptability to SCH. The improved flavor profile was attributed to the increased presence of sulfur-containing and nitrogen oxide volatile flavor compounds, such as benzothiazole, methional, and furans, which also contributed to antioxidant effects. Sensory evaluation results indicated that SCH obtained from papain exhibited a stronger bitter taste than that obtained from alcalase. Additionally, XOS imparted a reddish-brown color to SCH due to the higher browning intensity. This study is the first to demonstrate that XOS in the Maillard reaction can effectively improve the undesirable flavor and taste of SCH while enhancing its antioxidant activities, providing a theoretical basis for developing SCH as a market-acceptable functional food ingredient.

Antioxidant potential and protective effect of modified sea cucumber peptides against H2O2-induced oxidative damage in vitro HepG2 cells and in vivo zebrafish model

In this study, modified sea Cucumber Peptides (SCP) were prepared by reacting with xylooligosaccharide (XOS) and alginate oligosaccharides (AOS) via glycation. Free radical inhibitory and inhibition of oxidative stress of modified SCP was evaluated using human hepatocellular carcinoma (HepG2) cells and zebrafish embryos. LC-MS analysis revealed that SCPs mainly consist of 40 active peptides, with an average molecular weight of 1122.168 Da and an average length of 11 amino acid residues. For amino acid composition, L-Asparagine, L-Methionine, and L-Aspartic Acid were dominant amino acids in SCP. The result showed that the antioxidant ability of SCP against 2,2-Diphenyl-1-picrylhydrazyl (DPPH), superoxide anion radical (O-2), and Hydroxyl Radical (OH) was significantly improved after modification. In HepG2 cells, the modified SCP showed stronger protection than native SCP native against H2O2-induced oxidative stress by enhancing cell viability and reducing radical oxygen species (ROS) generation. The inhibition effect of SCP was increased after modification with XOS and AOS by 13 % and 19 % respectively. Further studies displayed that the activity of antioxidative enzymes, including Superoxide dismutase (SOD), Glutathione Peroxidase (GPx), and catalase (CAT), was remarkably enhanced, whereas malondialdehyde (MDA) level was reduced compared with native SCP and H2O2-treated groups, thus, improving the intracellular antioxidant defenses. The gene expression analysis showed that the mechanism underlying the modified SCP protective effect may be linked with the capability to regulate Nuclear factor-erythroid factor 2-related factor 2 (NRF2) gene expression. The protective effect of modified SCP against H2O2 in vitro was confirmed in vivo by reduced toxicity in zebrafish embryos via improvement of mortality rate, hatching rate, heart beating rate, and deformities of the zebrafish model. However, SCPAOS conjugate displayed greater antioxidant potentials compared to the SCPXOS, the different effects between SCPAOS and SCPXOS could be due to their different antioxidant activity. Thus, modified SCP could be potentially used as a novel nutraceutical in the preparation of anti-aging food and medicine.

Maillard-type glycated collagen with alginate oligosaccharide suppresses inflammation and oxidative stress by attenuating the expression of LPS receptors Tlr4 and Cd14 in macrophages

Inflammation and oxidative stress contribute to noncommunicable diseases (NCDs), with macrophages playing pivotal roles. Glycated collagen through Maillard-type glycation holds promise for enhancing anti-inflammatory properties, but its mechanism remains unclear. This study investigates the cellular mechanism and aims to contribute to expanding collagen utilization. Collagen was glycated with alginate oligosaccharide (AO) and glucose (Glc: as a comparative case) at 60 °C and 35% relative humidity for up to 24 h (C-AO and C-Glc, respectively). The anti-inflammatory activities of both C-AO and C-Glc were evaluated using an LPS-stimulated macrophage model. 18 h AO-glycated collagen (C-AO18 h) was found to significantly reduce the production of nitric oxide and proinflammatory cytokines (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). In contrast, C-Glc did not exhibit enhanced anti-inflammatory activity during any of the glycation periods. The enhanced anti-inflammatory activity of C-AO18 h was attributed to its downregulating effect on LPS receptors (toll-like receptor 4, Tlr4; cluster of differentiation 14, Cd14) and myeloid differentiation primary response 88 (Myd88) mRNA expression, with suppression in receptor expression resulting in decreased phagocytic ability of macrophages against E. coli. In addition, compared with intact collagen, C-AO18 h exhibited improved antioxidant activity in the LPS-stimulated macrophage model, as it significantly upregulated superoxide dismutase (SOD) and catalase (CAT) activities while reducing malondialdehyde (MDA) levels. Overall, this study contributes to the development of collagen-based functional foods for mitigating inflammation and oxidative stress in NCDs.

Alginate oligosaccharide extends the service lifespan by improving the sperm metabolome and gut microbiota in an aging Duroc boars model

Introduction

Alginate oligosaccharide (AOS), as a natural non-toxic plant extract, has been paid more attention in recent years due to its strong antioxidant, anti-inflammatory, and even anti-cancer properties. However, the mechanism by which AOS affects animal reproductive performance is still unclear.

Methods

The purpose of this study is to use multi-omics technology to analyze the effects of AOS in extending the service lifespan of aging boars.

Results

The results showed that AOS can significantly improve the sperm motility (p < 0.05) and sperm validity rate (p < 0.001) of aging boars and significantly reduce the abnormal sperm rate (p < 0.01) by increasing the protein levels such as CatSper 8 and protein kinase A (PKA) for semen quality. At the same time, AOS significantly improved the testosterone content in the blood of boars (p < 0.01). AOS significantly improved fatty acids such as adrenic acid (p < 0.05) and antioxidants such as succinic acid (p < 0.05) in sperm metabolites, significantly reducing harmful substances such as dibutyl phthalate (p < 0.05), which has a negative effect on spermatogenesis. AOS can improve the composition of intestinal microbes, mainly increasing beneficial bacteria Enterobacter (p = 0.1262) and reducing harmful bacteria such as Streptococcus (p < 0.05), Prevotellaceae_UCG-001 (p < 0.05), and Prevotellaceae_NK3B31_group (p < 0.05). Meanwhile, short-chain fatty acids in feces such as acetic acid (p < 0.05) and butyric acid (p < 0.05) were significantly increased. Spearman correlation analysis showed that there was a close correlation among microorganisms, sperm metabolites, and sperm parameters.

Discussion

Therefore, the data indicated that AOS improved the semen quality of older boars by improving the intestinal microbiota and sperm metabolome. AOS can be used as a feed additive to solve the problem of high elimination rate in large-scale boar studs.

Glycation with uronic acid-type reducing sugar enhances the anti-inflammatory activity of fish myofibrillar protein via the Maillard reaction

The role of carboxyl group in uronic acid in enhancing the anti-inflammatory activity of fish myofibrillar protein (Mf) was investigated, when lyophilized Mf was reacted with various reducing sugars at 60 °C and 35% relative humidity through the Maillard reaction. After pepsin and trypsin digestion, the anti-inflammatory activity was evaluated by measuring the secretions of tumor necrosis factor-α, interleukin-6, interleukin-1β, and nitric oxide in lipopolysaccharide-stimulated RAW 264.7 macrophage. The anti-inflammatory activity of Mf was not affected by glycation with glucose or galactose, whereas strongly enhanced by glycation with uronic acid-type reducing sugars: glucuronic acid, galacturonic acid, and alginate oligosaccharide. These results indicate that the presence of carboxyl group in reducing sugar is important for enhancing the anti-inflammatory activity of Mf. This study also shows that the enhanced effect could depend upon the number of carboxyl group in bound reducing sugar.