Transport mechanism and subcellular localization of a polysaccharide from Cucurbia Moschata across Caco-2 cells model

Demonstration of the effective intestinal immunity activity of a high branched rhamnogalacturonan-I type pectin polysaccharide from wolfberry via exploration its interaction with mechanical barrier

Rhamnogalacturonan-I type pectin polysaccharide from wolfberry has immunity activity, but its intestinal immunity activity and structure-activity relationship in the small intestine was still unclear. This study comparatively investigated the intestinal immune activity of wolfberry-derived high and low branched Rhamnogalacturonan-I type pectin polysaccharides (H-LBP and L-LBP) and explored the interaction mechanism with mechanical barrier. In the normal mechanical barrier model, both H-LBP and L-LBP could cross mechanical barrier with transport rates of 23.2 % and 25 %, thereby directly enhancing macrophage viability and phagocytic ability after crossing the mechanical barrier. The transport mechanism of H-LBP in mechanical barrier included the clathrin- and caveolin-mediated pathways. In the damaged mechanical barrier model, H-LBP could significantly enhance mechanical barrier integrity, reduce the production of neurotransmitter (NO) and inflammatory cytokine (TNF-α), thereby exerting indirectly intestinal immune activity. Transcriptome analysis showed that the interaction mechanism between H-LBP and damaged mechanical barrier mainly involved signaling pathway regulating cell growth and survival (PI3K-AKT). Western blot experiment and molecular docking simulation confirmed that H-LBP could reduce the expression of p-PI3K, p-AKT and cleaved Caspase3. H-LBP had stronger directly and indirectly intestinal immune activity than L-LBP. These findings were useful for the application of H-LBP in improving intestinal immunity oral formulations.

Effect of steaming on the selenium form, structure, and bioavailability of selenopolysaccharides from Chlamys nobilis

To investigate the effect of steam processing on the form, structure and biological properties of selenopolysaccharides in the Chlamys nobilis, we conducted purification and compositional analysis of both raw and steamed samples. The results showed that the raw (SS-3) and steamed (SZ-3) groups had the highest selenium content in the purified fraction. Comparison of the structural characterization shows that selenium can exist in both O-Se-O and Se-O-C chemical bonds, but the absorption strength of the chemical bonds decreased after steam treatment, and steaming can convert β-type pyranose to α-type in selenopolysaccharides. In vitro simulation of gastrointestinal digestion, SZ-3 fractions showed a higher bioaccessibility compared to SS-3 fractions, and also the cellular transport and uptake rates of selenium SZ-3 > SS-3 > sodium selenite were significant in the Caco-2 cell model. In conclusion, steaming can alter the structure and selenium content of selenopolysaccharides without affecting their bioavailability.

Natural deep eutectic solvents-platostoma palustre polysaccharides/ polyvinyl alcohol nano-electrospun membranes: Fabrication, characterization, transdermal property and bioactivity

Conventional wet facial masks face critical environmental and functional limitations, including reliance on non-biodegradable polymers, preservative-dependent formulations, and inefficient transdermal delivery of bioactive macromolecules. This study developed eco-friendly nanofibrous facial membranes by integrating natural deep eutectic solvents (NADES) with electrospinning to enhance Platostoma palustre polysaccharide (PPP) delivery. The L-proline/lactic acid NADES (L-proLA) increased PPP solubility 51.63-fold through hydrogen-bond disruption, confirmed by FT-IR analysis and Kamlet-Taft parameters (α = 2.904). Electrospinning with polyvinyl alcohol (PVA) created 40-150 nm diameter nanofibers (DPNMs) enabling dual transdermal mechanisms: lactic acid's stratum corneum disruption and sustained nanofiber release. DPNM-12 achieved 10.11 ± 0.13 mg/cm2 cumulative skin permeation in 24 h. The membranes demonstrated 95.36 ± 0.17 % Staphylococcus aureus and 93.59 ± 0.15 % Escherichia coli inhibition, suppressed macrophage nitric oxide by 75.8 %, and maintained >90 % fibroblast viability. Utilizing food-grade biodegradable components (PVA, NADES) eliminated organic solvents, establishing a green platform for polysaccharide-based skincare. This technology addresses conventional masks limitations by combining antimicrobial/anti-inflammatory functions with scalable eco-friendly production.

Effect and potential mechanism of modified citrus pectin in 3D printing-based cartilage tissue engineering

Modified citrus pectin (MCP) is widely used as a dietary supplement in the food and pharmaceutical industries with pleiotropic bioactivities. Particularly, MCP has effects on chondroprotection and phenotype maintenance of chondrocyte. Here, after confirming its chondroprotective effect in a partial-thickness articular cartilage (AC) defect, the distributions of MCP in cartilage and chondrocytes were investigated using fluorescence labeled-MCP. Then the potential of it in cartilage tissue engineering (CTE) was studied using 3D-printed scaffolds of hybrid hydrogel (GelMA/HAMA/MCP) of MCP, methacryloydylated-gelatin (GelMA) and hyaluronic acid (HAMA). Finally, the mechanism of the scaffolds on chondrogenesis were analyzed through transcriptome sequencing. It was found that MCP could penetrate cartilage, enter chondrocytes and accumulate in lysosome by binding with Gal-3. MCP could promote the proliferation and maintain the phenotype of chondrocytes in continuous passage culture. Mechanistically, MCP-based scaffold could upregulate the expression of genes of chondrogenic markers and growth factors, downregulate genes related to inflammation or degeneration mediators, and modulate autophagy pathways to maintain homeostasis of chondrocytes. Ultimately, MCP-based scaffolds could support chondrocytes adhesion, proliferation, ECM deposition, and enhance the chondrogenesis of the engineered cartilage. Together, our results demonstrate that MCP has great potential in three-dimensional bioprinting (3DBP)-based CTE to enhance the cartilage regeneration.

Modulating the Protein Corona on Nanoparticles by Finely Tuning Cross-Linkers Improves Macrophage Targeting in Oral Small Interfering RNA Delivery

The protein corona (PC) plays an important role in regulating the in vivo fate of nanoparticles (NPs). Modulating the surface chemical properties of NPs to control PC formation provides an alternative impetus for the oral delivery of small interfering RNA (siRNA). Herein, using tripolyphosphate (TPP), hyaluronic acid, and poly-γ-glutamic acid as cross-linkers, three types of mannose-modified trimethyl chitosan-cysteine (MTC)-based NPs with distinct surface chemistries were prepared to encapsulate siRNA via ionic gelation. The MTC-based NPs that were cross-linked exclusively with TPP (MTC/TPP/siRNA NPs) exhibited greater thiol group accessibility on their surfaces, resulting in a stronger affinity for apolipoprotein (APO) B48 during translocation across intestinal epithelia. Moreover, intracellular transport of MTC/TPP/siRNA NPs via the endoplasmic reticulum and Golgi apparatus further increased adsorption of APOB48, a key component of chylomicrons, which follow a similar transport pathway. Benefiting from the elevated APOB48 levels within the PC, the orally delivered MTC/TPP/siRNA NPs showed higher uptake by hepatic macrophages and better therapeutic efficacy for acute liver injury. Our results elucidate the role of NP surface chemical characteristics and translocation mechanisms across intestinal epithelia in forming oral PC, providing valuable insights for designing NPs that achieve effective oral gene delivery by customizing PC formation in vivo.

Absorption Patterns of Fucoidan Oligosaccharides from Kjellmaniella crassifolia in the Caco-2 Monolayer Cell Model and Their Pharmacokinetics in Mice

Oligosaccharides possess characteristics such as low molecular weight, good solubility, and high bioavailability, which make them better absorbed than fucoidan. This study hypothesizes that fucoidan oligosaccharides can be absorbed by intestinal epithelial cells and quickly enter the bloodstream, with a rapid absorption rate. In this study, fucoidan oligosaccharides were obtained through acid degradation and Bio Gel column separation. By analyzing the chemical composition and molecular weight, oligosaccharides with smaller molecular weights and simpler monosaccharide compositions were selected for further research. A cell model and pharmacokinetic studies in mice were established to analyze the absorption patterns of the oligosaccharides. The results showed that after acid degradation and column separation, high-molecular-weight oligosaccharides SPF1 with a molecular weight range of 1.63 × 104 to 2.14 × 105 Da and the low-molecular-weight oligosaccharides SPF2 with a molecular weight range of 244.22 to 1545.36 Da were obtained. In cell transport and uptake experiments, the transport of SPF1 and SPF2 was positively correlated with time and negatively correlated with concentration. The transport rates of SPF1 and SPF2 ranged from 20% to 70%, with Papp values greater than 1 × 10-5 cm/s. In the pharmacokinetics study, the blood concentration of the oligosaccharides in mice was simulated and analyzed using DAS 2.0, which indicated that the fucoidan oligosaccharides exhibited good absorption characteristics in vivo and in vitro. Therefore, fucoidan oligosaccharides with smaller molecular weights are more easily absorbed, which provides a theoretical basis for the application of fucoidan oligosaccharides.

Oral absorption mechanisms of polysaccharides and potential as carriers for the construction of nano-delivery systems: A review

Polysaccharides have garnered increasing attention in recent years for their potential in oral drug delivery within biomaterials and pharmaceuticals, owing to their excellent physicochemical properties, bioactivity, and low toxicity. However, the absorption of polysaccharides encounters multiple challenges posed by the biological, chemical, mechanical, and immune barriers of the intestinal mucosa. Therefore, elucidating the mechanisms by which polysaccharides traverse the intestinal mucosa for oral absorption is essential for their further development and application. Current studies have identified several polysaccharide absorption pathways, including transcellular transport, paracellular transport, M cell and Peyer's patches mediated transport, and intestinal flora mediated transport. Furthermore, numerous studies have demonstrated that polysaccharides can enhance the solubility, gastrointestinal stability, and permeability of small molecule components, which significantly improves their bioavailability. More importantly, nano-delivery systems utilizing polysaccharides as carriers have shown great promise in enhancing the targeting of small molecule components, thereby opening new avenues for drug delivery applications. We hope this review will provide theoretical support and inspiration for a deeper understanding of oral absorption mechanisms and the potential of polysaccharides in the development of nano-delivery systems.

Study on the absorption characteristics of euscaphic acid and tiliroside in fruits of Rosa laxa Retz

The fruits of Rosa laxa Retz. (FRL) have a long history of medicinal use, known for their rich composition of flavonoids, polyphenols, amino acids, sugars, and other bioactive compounds. FRL exhibits pharmacological effects such as antioxidant, antiviral, antibacterial, and antitumor activities, making it a valuable resource with significant development potential in both the food and pharmaceutical industries. This study employed a response surface methodology combined with ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-TQ-MS) to optimize FRL extraction. Reflux extraction was determined to be the most effective method with the following optimized parameters: 65% ethanol extraction solvent, material-to-liquid ratio of 1:35 (g/mL), and extraction time of 140 min, resulting in the FRL extract (FRLE). Under these optimized conditions, the extracted amount was extract was 51.00 ± 1.07%, the average content of total polyphenols was 126.55 ± 2.61 mg/g, and the average content of euscaphic acid was 2.90 ± 0.08 mg/g, demonstrating the efficiency of the extraction method. Using the Caco-2 cell model, the study investigated the absorption characteristics of euscaphic acid and tiliroside within FRLE. Results indicated that with increasing time, the absorbed amount (Qr) of euscaphic acid and tiliroside gradually increased, with an efflux ratio (RB→A/A→B) of less than 1.5, suggesting bidirectional drug transport with no significant directionality. Upon the addition of P-glycoprotein (P-gp) inhibitors Verapamil (Ver) and Ciclosporin A (CsA), as well as the chelating agent ethylenebis (oxyethylenenitrilo) tetraacetic acid (EGTA), Qr and Papp values notably increased, indicating that these two components are P-gp substrates with cellular basolateral efflux transport. Additionally, optimal absorption efficiency was observed under weakly acidic conditions (pH 6.0). In conclusion, euscaphic acid and tiliroside in FRLE demonstrated good membrane permeability, primarily relying on passive diffusion for absorption. This study offers experimental insights into the intestinal absorption of FRL in vivo.

Calcium Transport Activity of UV/H2O2-Degraded Fucoidans and Their Structural Characterization

Calcium-chelated polysaccharides have been increasingly considered as promising calcium supplements. In this study, degraded fucoidans (DFs) with different molecular weights (Mws) were prepared after UV/H2O2 treatment; their calcium-chelating capacities and intestinal absorption properties were also investigated. The results showed that the calcium-chelating capacities of DFs were improved with a decrease in Mw. This was mainly ascribed to the increased carboxyl content, which was caused by free-radical-mediated degradation. Meanwhile, the conformation of DF changed from a rod-like chain to a shorter and softer chain. The thermodynamic analysis demonstrated that DF binding to calcium was spontaneously driven by electrostatic interactions. Additionally, DF-Ca chelates with lower Mw showed favorable transport properties across a Caco-2 cell monolayer and could effectively accelerate the calcium influx through intestinal enterocytes. Furthermore, these chelates also exhibited a protective effect on the epithelial barrier by alleviating damage to tight junction proteins. These findings provide an effective free-radical-related approach for the development of polysaccharide-based calcium supplements with improved intestinal calcium transport ability.

Glycogen and zinc-enriched ferritin as bioavailable nanoparticulate nutrients released from gastrointestinal digestion of pacific oyster (Crassostrea gigas)

Oyster is a low-carbon animal food enriched with protein, glycogen, and trace minerals. Nano-nutrients are increasingly perceived as an unignorable part of foods. Here, simulated gastrointestinal digestion released a considerable amount of nanoparticulate nutrients from raw and cooked oysters. They were identified as glycogen monomers with size of 20-40 nm and their aggregates, as well as 6 nm-sized bare cores of ferritin containing iron and zinc (4:1, w/w). FITC-labeling and flow cytometry unveiled the efficient uptake of oyster glycogen by polarized Caco-2 cells via macropinocytosis and receptor-mediated endocytosis. Calcein-fluorescence-quenching assay revealed divalent-metal-transporter-1- and macropinocytosis-mediated enterocyte iron absorption from oyster ferritin. Zinquin-fluorescence flow cytometry and ex-vivo mouse ileal loop experiments demonstrated the ready intestinal zinc absorption from oyster ferritin via macropinocytosis, as well as the good resistance of oyster ferritin to phytate's inhibition on zinc absorption. Overall, our results offer a new insight into the digestive and chemical properties of oysters.

Carboxymethylation of paramylon derived from Euglena gracilis and its hypoglycemic mechanism in diabetic mice

Paramylon is a polysaccharide primarily composed of β-1,3-glucan, characterized by its high crystallinity and insolubility in water. Enhancing its water solubility through structural modifications presents an effective strategy to unlock its biological activity. In this study, carboxymethylation was employed to produce carboxymethylated paramylon (CEP) with varying carboxyl concentrations. The successful introduction of carboxyl groups led to a notable improvement in water solubility. In vivo experiments demonstrated that CEP reduced fasting blood glucose levels by 24.42 %, improved oral glucose tolerance, and enhanced insulin sensitivity in diabetic mice. Additionally, CEP regulated lipid homeostasis and ameliorated liver damage. Through modulation of the adenosine monophosphate-activated protein kinase/phosphoinositide 3-kinase/protein kinase B pathway and the glucose-6-phosphatase/phosphoenolpyruvate carboxykinase pathway, CEP effectively regulated hepatic glucose absorption and production. Furthermore, CEP mitigated diabetes-induced lipid metabolism disorders. These findings suggest that CEP holds significant promise in ameliorating glucose metabolism disorder, indicating its potential as a novel hypoglycemic functional food.

Various steaming durations alter digestion, absorption, and fermentation by human gut microbiota outcomes of Polygonatum cyrtonema Hua polysaccharides

Introduction

Different steaming durations dramatically alter the structure of Polygonatum cyrtonema polysaccharides (PCPs). This study aimed to compare characteristics of digestion, absorption, and fermentation by gut microbiota across four representative PCPs from different steaming durations (0, 4, 8, and 12 h), each with unique molecular weights and monosaccharide profiles.

Methods

Chemical composition of the four PCPs was analyzed. Digestibility was evaluated using an in vitro saliva-gastrointestinal digestion model. Absorption characteristics were assessed with a Caco-2 monolayer model, and impacts on gut microbiota composition and short chain fatty acid (SCFA) levels were analyzed using in vitro fermentation with human gut microbiota.

Results

Longer steaming durations altered the chemical profiles of PCPs, reducing carbohydrate content (84.87-49.58%) and increasing levels of uronic acid (13.99-19.61%), protein (1.07-5.43%), and polyphenols (0.05-2.75%). Four PCPs were unaffected by saliva digestion but showed enhanced gastrointestinal digestibility, with reducing sugar content rising from 4.06% (P0) to 38.5% (P12). The four PCPs showed varying absorption characteristics, with P0 having the highest permeability coefficient value of 9.59 × 10-8 cm/s. However, all PCPs exhibited poor permeability, favoring gut microbiota fermentation. The four PCPs altered gut microbiota composition and elevated SCFA production, but levels declined progressively with longer steaming durations. All PCPs significantly increased the abundance of Bacteroidota, Firmicutes, and Actinobacteriota, making them the dominant bacterial phyla. Additionally, all PCPs significantly increased the abundance of Bifidobacterium, Prevotella, and Faecalibacterium compared to the control group, which, along with Bacteroides, became the dominant microbiota. Increasing the steaming duration led to a reduction in Prevotella levels, with PCPs from raw rhizomes showing the highest relative abundance at 24.90%. PCPs from moderately steamed rhizomes (4 h) led to a significant rise in Faecalibacterium (7.73%) among four PCPs. P8 and P12, derived from extensively steamed rhizomes (≥8 h), exhibited similar gut microbiota compositions, with significantly higher relative abundances of Bacteroides (20.23-20.30%) and Bifidobacterium (21.05-21.51%) compared to P0 and P4.

Discussion

This research highlights the importance of adjusting steaming durations to maximize the probiotic potential of P. cyrtonema polysaccharides, enhancing their effectiveness in modulating gut microbiota and SCFA levels.

Comparison of intestinal absorption of soybean protein isolate-, glutenin- and peanut protein isolate-bound Nε-(carboxymethyl) lysine after in vitro gastrointestinal digestion

Advanced glycation end products (AGEs), a heterogeneous compound existed in processed foods, are related to chronic diseases when they are accumulated excessively in human organs. Protein-bound Nε-(carboxymethyl) lysine (CML) as a typical AGE, is widely determined to evaluate AGEs level in foods and in vivo. This study investigated the intestinal absorption of three protein-bound CML originated from main food raw materials (soybean, wheat and peanut). After in vitro gastrointestinal digestion, the three protein-bound CML digests were ultrafiltered and divided into four fractions: less than 1 kDa, between 1 and 3 kDa, between 3 and 5 kDa, greater than 5 kDa. Caco-2 cell monolayer model was further used to evaluate the intestinal absorption of these components. Results showed that the absorption rates of soybean protein isolate (SPI)-, glutenin (Glu)-, peanut protein isolate (PPI)-bound CML were 30.18%, 31.57% and 29.5%, respectively. The absorption rates of components with MW less than 5 kDa accounted for 19.91% (SPI-bound CML), 22.59% (Glu-bound CML), 23.64% (PPI-bound CML), respectively, and these samples were absorbed by paracellular route, transcytosis route and active route via PepT-1. Taken together, these findings demonstrated that all three protein-bound CML digests with different MW can be absorbed in diverse absorption pathways by Caco-2 cell monolayer model. This research provided a theoretical basis for scientific evaluation of digestion and absorption of AGEs in food.

In vivo pharmacokinetics of Glycyrrhiza uralensis polysaccharides

Glycyrrhiza uralensis polysaccharides (GUPS) are widely applied in biomedicine and functional food due to their multiple pharmacological activities and low toxicity. Despite their widespread use, the in vivo metabolic profile of GUPS remains poorly understood. To address this gap, we developed a quantitative analysis method that involves labeling GUPS with visible fluorescein (5-DTAF) and near-infrared (NIR) fluorescein (Cy7), resulting in stable conjugates with substitution degrees of 0.81% for 5-DTAF and 0.39% for Cy7. The pharmacokinetic studies showed a biphasic elimination pattern in the blood concentration-time curve following both intravenous and oral administration, consistent with a two-compartment model. Using fluorescence quantification and NIR imaging, we observed that GUPS was distributed to various tissues, exhibiting higher concentrations particularly in liver, kidney and lung. Excretion studies indicated that feces were the major excretion pathway of GUPS after oral administration (60.98%), whereas urine was the main pathway after intravenous administration (31.16%). Notably, GUPS could be absorbed rapidly by gut (Tmax 1 ± 0.61 h) and showed a biological half-time t1/2 26.4 ± 7.72 h after oral administration. Furthermore, the Caco-2 cells uptake studies illustrated that macropinocytosis and clathrin-mediated endocytosis were participated in the transport of GUPS in intestine epithelium. This comprehensive analysis of the in vivo pharmacokinetics of GUPS not only enhances our understanding of its metabolic pathways but also establishes a foundational basis for its clinical application, optimizing its therapeutic potential and safety profile.

Comprehensive Assessment of Polysaccharides Extracted from Squash by Subcritical Water under Different Conditions

The effects of subcritical water microenvironment on the physiochemical properties, antioxidant activity and in vitro digestion of polysaccharides (SWESPs) from squash were investigated. After single-factor experiments, twenty samples were successfully prepared at different extraction temperatures (110, 130, 150, 170 and 190 °C) and extraction times (4, 8, 12 and 16 min). Under a low temperature environment, the whole process was mainly based on the extraction of SWESP. At this time, the color of SWESP was white or light gray and the molecular mass was high. When the temperature was 150 °C, since the extraction and degradation of SWESP reached equilibrium, the maximum extraction rate (18.67%) was reached at 150 °C (12 min). Compared with traditional methods, the yield of squash SWESP extracted by subcritical water was 3-4 times higher and less time consuming. Under high temperature conditions, SWESPs were degraded and their antioxidant capacity and viscosity were reduced. Meanwhile, Maillard and caramelization reactions turned the SWESPs yellow-brown and produced harmful substances. In addition, different SWESPs had different effects on in vitro digestion. In brief, SWESPs prepared under different conditions have different structures and physicochemical properties, allowing the obtainment of the required polysaccharide. Our results show that squash polysaccharides prepared in different subcritical water states had good development potential and application in the food industry.

Investigation of cellular uptake and transport capacity of Cordyceps sinensis exopolysaccharide‑selenium nanoparticles with different particle sizes in Caco-2 cell monolayer

Cordyceps sinensis exopolysaccharide‑selenium nanoparticles (EPS-SeNPs) were successfully constructed, characterized, and its Se release kinetics and mechanism were also evaluated in our previous studies. However, the intestinal cellular uptake and transport capacities of EPS-SeNPs remain unknown. On the basis of our previous researches, this work was designed to evaluate the uptake and transport capacities of EPS-SeNPs (EPS/Se = 20/1, 3/1, 1/1, and 3/4) in intestinal epithelial (Caco-2) cells. Confocal laser scanning microscopy results indicated that the internalization of coumarin-6 labeled EPS-SeNPs was in a time-dependent process and eventually located in the cytoplasm, not in the nucleus. Endocytosis inhibitors were employed to evaluate the cellular uptake pathway of EPS-SeNPs, relevant results revealed that clathrin-, caveolae-, and energy-mediated pathways were participated in the internalization of EPS-SeNPs by Caco-2 cells. In addition, the transportation of EPS-SeNPs across Caco-2 cell monolayers was in a concentration-dependent manner. Different particle sizes of EPS-SeNPs presented different uptake and transport capacities in Caco-2 cells. Noteworthy, EPS/Se = 3/4 with the highest selenium content possessed the most superior cellular uptake and transport abilities in Caco-2 cells. The present work may contribute to illustrate the internalization and transport mechanism of EPS-SeNPs, thus facilitating its application in food and medical industries.

Microalgae polysaccharides exert antioxidant and anti-inflammatory protective effects on human intestinal epithelial cells in vitro and dextran sodium sulfate-induced mouse colitis in vivo

Microalgae polysaccharides (MAPS) have emerged as novel prebiotics, but their direct effects on intestinal epithelial barrier are largely unknown. Here, MAPS isolated from Chlorella pyrenoidosa, Spirulina platensis, and Synechococcus sp. PCC 7002 were characterized as mainly branched heteropolysaccharides, and were bioavailable to Caco-2 cells based on fluorescein isothiocyanate labeling and flow cytometry analysis. These MAPS were equally effective to scavenge hydroxyl and superoxide radicals in vitro and to attenuate the H2O2-, dextran sodium sulfate-, tumor necrosis factor α-, and interleukin 1β-induced burst of intracellular reactive oxygen species and mitochondrial superoxide radicals, interleukin-8 production, cyclooxygenase-2 and inducible nitric oxide synthase expression, and/or tight junction disruption in polarized Caco-2 cells. MAPS and a positive drug Mesalazine were intragastrically administered to C57BL/6 mice daily for 7 d during and after 4-d dextran sodium sulfate exposure. Clinical signs and colon histopathology revealed equivalent anti-colitis efficacies of MAPS and Mesalazine, and based on biochemical analysis of colonic tight junction proteins, goblet cells, mucin 2 and trefoil factor 3 transcription, and colonic and peripheral pro-inflammatory cytokines, MAPS alleviated dextran sodium sulfate-induced intestinal epithelial barrier dysfunction, and their activities were even superior than Mesalazine. Overall, MAPS confer direct antioxidant and anti-inflammatory protection to intestinal epithelial barrier function.

Gastrointestinal metabolism characteristics and mechanism of a polysaccharide from Grifola frondosa

Grifola frondosa polysaccharide (GFP) is mainly composed of α-1,4 glycosidic bonds and possesses multiple pharmacological activities. However, the absence of pharmacokinetic studies has limited its further development and utilization. Herein, GFP was labeled with 5-DTAF (FGFP) and cyanine 5.5 amine (GFP-Cy5.5) to investigate its gastrointestinal metabolism characteristics and mechanism. Significant distributions of the polysaccharide in the liver and kidneys were observed by near infrared imaging. To investigate the specific distribution form of the polysaccharide, in vitro digestion models were constructed and revealed that FGFP was degraded in saliva and rat small intestine extract. The metabolites were detected in the stomach and small intestine, followed by further degradation in the distal intestine in the in vivo experiment. Subsequent investigations showed that α-amylase was involved in the gastrointestinal degradation of GFP, and its metabolite finally entered the kidneys, where it was excreted directly with urine.

Metabolomics reveals the effects of Lactiplantibacillus plantarum dy-1 fermentation on the lipid-lowering capacity of barley β-glucans in an in vitro model of gut-liver axis

Bioactive polysaccharides known as the biological response modifiers, can directly interact with intestinal epithelium cells (IEC) and regulate key metabolic processes such as lipid metabolism. Here, the coculture of Caco-2/HT29 monolayer (>400 Ω × cm2) and HepG2 cells was developed to mimic the gut-liver interactions. This system was used to investigate the effects of raw and fermented barley β-glucans (RBG and FBG) on lipid metabolism by directly interacting with IEC. Both RBG and FBG significantly and consistently reduced the lipid droplets and triacylglycerol levels in monoculture and coculture of HepG2 overloaded with oleic acid. Notably, FBG significantly and distinctly elevated PPARα (p < 0.05) and PPARα-responsive ACOX-1 (p < 0.01) gene expressions, promoting lipid degradation in cocultured HepG2. Moreover, the metabolomics analyses revealed that FBG had a unique impact on extracellular metabolites, among them, the differential metabolite thiomorpholine 3-carboxylate was significantly and strongly correlated with PPARα (r = -0.68, p < 0.01) and ACOX-1 (r = -0.76, p < 0.01) expression levels. Taken together, our findings suggest that FBG-mediated gut-liver interactions play a key role in its lipid-lowering effects that are superior to those of RBG. These results support the application of Lactiplantibacillus fermentation for improving hypolipidemic outcomes.

Dihydrocaffeic acid grafted chitosan self-assembled nanomicelles with enhanced intestinal transport and antioxidant properties of chicoric acid

Chicoric acid (CA) plays a crucial role as a functional factor within the realm of foods, showcasing a wide array of bioactivities. Nevertheless, its oral bioavailability is significantly limited. To optimize the intestinal absorption and bolster the antioxidant capacity of CA, a water-soluble dihydrocaffeic acid grafted chitosan copolymer (DA-g-CS) was synthesized using a conventional free radicals system, and subsequently utilized for the encapsulation of CA within self-assembled nanomicelles (DA-g-CS/CA). The average particle size of DA-g-CS/CA was 203.3 nm, while the critical micelle concentration was 3.98 × 10-4 mg/mL. Intestinal transport studies revealed that DA-g-CS/CA penetrated cells via the macropinocytosis pathway, exhibiting the cellular uptake rate 1.64 times higher than that of CA. This substantial enhancement in the intestinal transport of CA underscores the significant improvements achieved through DA-g-CS/CA delivery. The pharmacokinetic results demonstrated that DA-g-CS/CA exhibited a remarkable bioavailability 2.24 times that of CA. Furthermore, the antioxidant assessment demonstrated that DA-g-CS/CA exhibited exceptional antioxidant properties in comparison to CA. It demonstrated enhanced protective and mitigating effects in the H2O2-induced oxidative damage model, while also displaying a stronger emphasis on protective effects rather than attenuating effects. These findings aim to establish a solid theoretical foundation for the advancement of CA in terms of its oral absorption and the development of functional food products.

Barley β-glucan inhibits digestion of soybean oil in vitro and lipid-lowering effects of digested products in cell co-culture model

The effect of barley β-glucan on soybean oil digestion characteristics before and after fermentation was studied in an in vitro-simulated gastrointestinal digestion model. The addition of barley β-glucan made the system more unstable, the particle size increased significantly, and confocal laser imaging showed that it was easier to form agglomerates. The addition of barley β-glucan increased the proportion of unsaturated fatty acids in digestion products, and reduced digestibility of soybean oil. In a co-culture model of Caco-2/HT29 and HepG2 cells, the effects of digestive products of soybean oil and barley β-glucan before and after fermentation on lipid metabolism in HepG2 cells were investigated. The results showed that adding only soybean oil digestion products significantly increased triglycerides (TG) content and lipid accumulation in basolateral HepG2 cells. When fermented barley β-glucan was added, lipid deposition was significantly decreased, and the lipid-lowering activity was better than that of unfermented barley β-glucan.

Structural diversity and physicochemical properties of polysaccharides isolated from pumpkin (Cucurbita moschata) by different methods

Natural polysaccharides were isolated and purified from Cucurbita moschata by hot water extraction and mild acid-base sequential extraction. Chemical and instrumental studies revealed that hot water-extracted and mild acid-extracted polysaccharides with molecular masses of 48 kDa and 85 kDa were both pectic polysaccharides with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) domains, while mild acid-extracted polysaccharide was more dominated by branched RG-I with higher contents of galactose (10.59 %) and arabinose (8.08 %). Furthermore, mild acid-extracted polysaccharide exhibited better thickening and emulsifying properties, likely due to its larger molecular mass and higher branching degree. Mild base-extracted polysaccharide with a molecular mass of 18 kDa was a glucan-like polysaccharide. It showed the strongest thermostability and gel behavior among these pumpkin polysaccharides, likely attributed to its unique network structure stabilized by substantial intra/intermolecular hydrogen bonds. This study aimed to establish the structure-property relationships between these structurally diverse pumpkin polysaccharides from different extraction methods and provided theoretical foundations for their targeted application in foods.

Investigating on the influence mechanism of sausage of sea bass on calcium absorption and transport based on Caco-2 cell monolayer model

A monolayer Caco-2 cell model was established to explore the effects of sea bass sausage digestive juice containing phosphate on calcium ion transport. Differential proteins of Caco-2 cells treated with fish sausage juice were detected and analyzed by gene ontology (GO) functional annotation and kyoto encyclopedia of genes and genomes (KEGG) pathway analyses. Results revealed that after treatment with 0.23 mg/mL digestive juice of perch sausage in vitro, Caco-2 cell viability was the highest at 72 h (99.84%). Additionally, 0.23 mg/mL digestive juice of perch sausage in vitro significantly increased calcium ion transport. The transfer volume was 1.396 μg/well. Fish sausages containing phosphate significantly affected the protein expression levels of Caco-2 cells. Two hundred one differential proteins were detected, including 114 up-regulated and 87 down-regulated proteins. The main differential proteins included P02795, Q9P0W0, Q96PU5, Q9GZT9 and Q5EBL8. The adjustment ratios of the fish sausage group were 0.7485, 1.373, 1.2535, 0.6775, and 0.809, respectively. The pathway analysis showed that phosphate affected calcium ion absorption and transport through the P02795 enrichment pathway. The fish sausage group showed that the immune-related functions of cells were affected. This study expounds the effects of water-retaining agents on the nutritional quality of aquatic products and provides theoretical support for the research and application of surimi products.

The internalization mechanisms and trafficking of the pea albumin in Caco-2 cells

Pea albumin (PA) can reach the intestine in the active form because it is highly resistant to gastric acid and proteolytic enzymes after their oral intake, which can supply various bioactivities. However, there is no detailed knowledge of the intestinal cell uptake about PA. The aim of this work was to study the internalization mechanism and intracellular trafficking route of PA. The uptake of PA-cyanine 5.5 NHS ester (Cy5.5) was a time-dependent and concentration-dependent process in Caco-2 cells. Endocytosis inhibitors or small interfering RNA (siRNA) techniques revealed that the internalization of PA-Cy5.5 was energy-dependent and mediated by caveolin-mediated endocytosis. Furthermore, we observed colocalization of PA-Cy5.5 and its subcellular localization in Caco-2 cells by using confocal laser scanning microscopy, which revealed that the intracellular trafficking process of PA-Cy5.5 was related to endoplasmic reticulum, Golgi, and lysosome. Interestingly, PA can alleviate lipopolysaccharide -induced ER stress, which may be the main reason why pea albumin is anti-inflammatory. Overall, our findings suggest caveolin may be critical for PA uptake in enterocytes and could contribute to explore the bioactivities mechanism of pea albumin in body.

Investigation of the Uptake and Transport of Aspirin Eugenol Ester in the Caco-2 Cell Model

Background: Aspirin eugenol ester (AEE) is a novel medicinal compound synthesized by esterification of aspirin with eugenol using the prodrug principle. AEE has the pharmacological activities of being anti-inflammatory, antipyretic, analgesic, anti-cardiovascular diseases, and anti-oxidative stress However, its oral bioavailability is poor, and its intestinal absorption and transport characteristics are still unknown.

Objective: The purpose of this study was to investigate the uptake and transport mechanisms of AEE in Caco-2 cells.

Methods: The effects of time, concentration, and temperature on the transport and uptake of AEE were studied.

Results: The results showed that a higher concentration of salicylic acid (SA) was detected in the supernatant of cell lysates and cell culture medium, while AEE was not detected. Therefore, the content change of AEE was expressed as the content change of its metabolite SA. In the uptake experiment, when the factors of time, concentration, and temperature were examined, the uptake of SA reached the maximum level within 30 min, and there was concentration dependence. In addition, low temperature (4°C) could significantly reduce the uptake of SA in Caco-2 cells. In the transport experiment, under the consideration of time, concentration, and temperature, the transepithelial transport of SA from AP-BL and BL-AP sides was time-dependent. The amount of SA transported in Caco-2 cells increased with the increase of concentration, but the transmembrane transport rate had no correlation with the concentration. This phenomenon may be due to the saturation phenomenon of high concentration. The efflux ratio (ER) was less than 1, which indicated that their intestinal transport mechanism was passive transport. Moreover, the temperature had a significant effect on the transport of AEE.

Conclusion: In summary, intestinal absorption of AEE through Caco-2 cell monolayers was related to passive transport. The uptake and transport of AEE were concentration-dependent, and temperature significantly affected their uptake and transport. The absorption and transport characteristics of AEE may contribute to the exploration of mechanisms of absorption and transport of chemosynthetic drugs in vitro.

Antitumor mechanisms of an exopolysaccharide from Lactobacillus fermentum on HT-29 cells and HT-29 tumor-bearing mice

We have obtained an exopolysaccharide (YL-11 EPS) produced by Lactobacillus fermentum YL-11 isolated from fermented milk and confirmed that it can effectively inhibit colon cancer HT-29 cells proliferation in vitro. The aim of this study is to study anti-colon cancer effect in vivo and its possible mechanisms. Animal assays indicated YL-11 EPS treatment significantly suppressed the growth of HT-29 tumor xenograft without exhibiting obvious negative effects on normal cells. Cell experiments demonstrated YL-11 EPS treatment up regulated the ratio of Bax/Bcl-2 and induced the decrease in mitochondrial membrane potential and improved the expression of cleaved caspases-3 and cleaved PARP proteins, and finally induced HT-29 cells apoptosis, suggesting the involvement of mitochondrial pathway. Moreover, YL-11 EPS can block the PI3K/AKT signaling pathway and arrest the cell cycle in G1-phase to exert its anti-colon cancer activity. Overall, YL-11 EPS can be explored as a potential nutraceutical to prevent colorectal cancer.

Microwave- and Ultrasound-Assisted Extraction of Cucurbita pepo Seeds: A Comparison Study of Antioxidant Activity, Phenolic Profile, and In-Vitro Cells Effects

Nowadays there is a growing demand for nutraceuticals to prevent diseases related to redox imbalances, such as atherosclerosis and diabetes, being crucial to search for new matrixes rich in bioactive compounds. This work aims to characterize the value-added compounds extracted from Curcubita pepo seeds using green methodologies, namely microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), employing water as an extracting solvent for two ratios (condition 1: 1 mg/20 mL; condition 2: 2.5 mg/20 mL). The extract with the best antioxidant/antiradical activity in FRAP (71.09 μmol FSE/g DW) and DPPH (5.08 mg TE/g DW) assays was MAE condition 1, while MAE condition 2 exhibited the highest activity in the ABTS assay (13.29 mg AAE/g DW) and TPC (16.89 mg GAE/g DW). A remarkable scavenging capacity was observed, particularly for HOCl, with IC50 values ranging from 1.88–13.50 μg/mL. A total of 21 phenolic compounds were identified, being catechin (4.567–7.354 mg/g DW), caffeine (1.147–2.401 mg/g DW) and gallic acid (0.945–1.337 mg/g DW) predominant. No adverse effects were observed on Caco-2 viability after exposure to MAE extracts, while the other conditions led to a slight viability decrease in NSC-34. These results highlighted that the extract from MAE condition 2 is the most promising as a potential nutraceutical ingredient.

Holistic review of polysaccharides isolated from pumpkin: Preparation methods, structures and bioactivities

Pumpkin polysaccharides have arrested researchers' attention in fields of food supplements for healthy product and traditional Chinese medicine due to their multiple bioactivities with non-toxic and highly biocompatible. This review emphatically summarized recent progresses in the primary and spatial structural features, various bioactivities, structure-to-function associations, different preparation techniques, and absorption characteristics across intestinal epithelial and in vivo bio-distribution of pumpkin polysaccharides. Additionally, current challenges and future trends in development of pumpkin polysaccharides were pointed out. We found that pumpkin polysaccharides were primary structure (e.g. glucan, galactoglucan, galactomannan, galactan, homogalacturonan (HG), and rhamnogalacturonan-Ι (RG-Ι)) and special structure diverse (e.g. hollow helix, linear, and sphere-like) and significant functional foods or therapeutic agents (e.g. oral hypoglycemic agents). Moreover, we found that the molecular weight (Mw), uronic acid, linkage types, and modifications all could affect their bioactivities (e.g. anti-oxidant, anti-coagulant, and anti-diabetic activities), and pumpkin polysaccharides may across intestinal epithelial into the blood reaching to target organs. Collectively, the structures diversity and pharmacological values of pumpkin polysaccharides support their therapeutic potentials and sanitarian functions.

Astragalus polysaccharide prevents ferroptosis in a murine model of experimental colitis and human Caco-2 cells via inhibiting NRF2/HO-1 pathway

Ulcerative colitis (UC) is a relapsing and remitting inflammatory bowel disease (IBD), but current conventional drugs lack efficacy. Astragalus polysaccharide (APS) is an active ingredient of Astragalus membranaceus and has been shown to ameliorate experimental colitis. In the present study, we aimed to investigate how APS affects the ferroptosis of intestinal epithelial cells in dextran sulfate sodium (DSS)-induced experimental colitis in mice. Our data showed that APS administration attenuated total weight loss, colon length shortening, disease activity index (DAI) scores, histological damage, and the expression of inflammatory cytokines in the colon of DSS-challenged mice. Moreover, we observed that treatment with APS obviously inhibited ferroptosis in both DSS-challenged mice and RSL3-stimulated Caco-2 cells, as indicated by the decrease in the expression of ferroptosis-associated genes (PTGS2, FTH, and FTL) and the levels of surrogate ferroptosis markers (MDA, GSH, and iron load). Mechanistically, the inhibitory effects of APS on ferroptosis in DSS-challenged mice and RSL3-stimulated Caco-2 cells were associated with the NRF2/HO-1 pathway. Collectively, our findings identify a new role of APS in preventing ferroptosis in a murine model of experimental colitis and human Caco-2 cells via inhibiting NRF2/HO-1 pathway.

Structural Characterization of a Neutral Polysaccharide from Cucurbia moschata and Its Uptake Behaviors in Caco-2 Cells

A neutral pumpkin polysaccharide (NPPc) was extracted from Cucurbia moschata and its structural characterization is performed. Moreover, uptake behaviors of an NPPC were investigated at the cellular level. The results showed that NPPc, an average molecular weight (Mw) of 9.023 kDa, was linear (1→4)-α-D-Glcp residues in the backbone, which branched point at O-6 position of (1→4,6)-α-D-Glcp. The side chain contained (1→6)-α-D-Glcp and terminal glucose. The cellular uptake kinetics results showed that the uptake of fluorescent-labeled NPPc was in time- and dose-dependent manners in Caco-2 cells. For subcellular localization of NPPc, it was accumulated in endoplasmic reticulum and mitochondrion. This study illustrates the characteristics on the uptake of NPPc and provides a rational basis for the exploration of polysaccharides absorption in intestinal epithelium.