Simulated Gastrointestinal Conditions Research Articles

Introduction Traditional fermented foods are rich reservoirs of probiotic microorganisms, yet several remain scientifically underexplored. The current research focused on the screening, isolation, identification, and assessment of potential probiotic isolates exhibiting β-galactosidase activity from naturally fermented Palmyra palm ( Borassus flabellifer ) nectar, a culturally significant, traditional beverage consumed in India. Methods A total of 80 bacterial isolates were obtained under aseptic conditions and screened through cultural, microscopic, and biochemical analyses. Fifty-six Gram-positive, catalase-negative isolates were shortlisted for probiotic evaluation. Selected isolates were assessed for simulated gastrointestinal conditions, cell surface properties (auto-aggregation, hydrophobicity, co-aggregation and Biofilm production), β-galactosidase and exopolysaccharide production, antioxidant activity, antibiotic susceptibility, and safety through hemolysis and DNase activity. Results Seventeen isolates exhibited desirable adhesion-related traits, of which seven strains demonstrated superior probiotic potential. These strains tolerated acidic and bile conditions, produced high levels of exopolysaccharides (573-785 mg/L) and β-galactosidase (110.25-221.09 U/mL), and showed significant cell surface hydrophobicity (35.87-69.93%), auto-aggregation (59.29-82.76%), and co-aggregation with pathogens Salmonella Typhi (MTCC 733) 46.58 - 70.87% and S. flexneri (ATCC 12022) 53.45 - 78.85%. They also exhibited substantial hydroxyl radical scavenging activity (57.68-70.66%) and were safe and antibiotic-susceptible. Discussion The findings highlight the probiotic potential and functional attributes of Palmyra nectar - derived bacteria. Their ability to survive gut-like conditions, hydrolyze lactose, adhere to intestinal mucosa, and provide antioxidant benefits supports their application in functional foods and nutraceuticals aimed at improving gut health and lactose digestion.

Premna microphylla Turcz pectin-modified diosmetin nanoparticles: A galectin-3 targeting strategy for precise colitis intervention.

A prebiotic hydrogel based on gellan gum and arabinoxylan from flaxseed (Linum usitatissimum) for advanced probiotic delivery.

ABSTRACTAkkermansia muciniphila is increasingly regarded as a next‐generation probiotic with clinical and commercial potential. This study aimed to evaluate the strain‐specific safety and probiotic characteristics of Akk11, isolated from the feces of healthy infants. The genotypic profile of Akk11 was assessed via whole‐genome sequencing, including antibiotic resistance, virulence factors, and metabolic pathway annotations. Phenotypic analyses included antibiotic susceptibility, mucin degradation, biogenic amine and D‐/L‐lactic acid production, and hemolytic activity. Stress tolerance and cytotoxicity were performed using simulated gastrointestinal conditions and Caco‐2 cells. In vivo safety was further evaluated through acute oral toxicity, bacterial reverse mutation, mammalian erythrocyte micronucleus, and 90‐day sub‐chronic toxicity, following international guidelines. Akk11 showed 98.36% genomic similarity to the type strain adeF with no mobile genetic elements or transferable resistance. Phenotypically, Akk11 exhibited intrinsic resistance to several antibiotics while lacking harmful metabolic activities and excellent simulated gastrointestinal stress tolerance with non‐cytotoxicity. No adverse effects were observed in any of the in vivo toxicity studies, even under long‐term oral administration of bacterial powder preparations containing both viable and non‐viable cells. The NOAEL was 9 × 1011 AFU/kg/day, the highest dose tested in both sexes, using a lyophilized preparation that contained approximately 20%–30% non‐viable Akk11 cells (n‐AFU). Akk11 possesses a robust, strain‐specific safety profile and probiotic potential, providing a scientific basis for its application in next‐generation probiotic products.

Formulation and antimicrobial activity of a probiotic mouth freshener with phycoerythrin, Artemisia aucheri and encapsulated Lactobacillus bifidus targeting Streptococcus mutans.

Batch-dependent microbiota variation in mixed vegetable fermentations shapes the probiotic potential of autochthonous multifunctional cultures.

Xylanase from Trichoderma longibrachiatum produces xylooligosaccharides from wheat xylans under simulated human gastrointestinal conditions: a novel prebiotic strategy.

Helicobacter pylori (H. pylori) adheres to gastric epithelial cells via adhesins like HpaA, causing persistent colonization and inflammation. In this study, we isolated chicken single-chain fragment variable (scFv) antibodies targeting HpaA from a chicken immune scFv antibody library. Four antibodies (H2-D1, H1-B11, H2-D9, and H2-A3) were analyzed, including evaluation of characteristics as well as anti-adhesion effects. They maintained binding activity under simulated gastrointestinal pH conditions and demonstrated high thermal stability. These antibodies exhibited specific binding and high affinity to the recombinant HpaA protein as well as HpaA proteins present in clinical H. pylori strains. Flow cytometry analysis revealed that these scFv antibodies significantly inhibited the adhesion of HpaA protein and various H. pylori strains to AGS cells. Our findings suggested that these antibodies hold potential for diagnostic and therapeutic use against H. pylori infection, providing a foundation for the development of anti-adhesion reagents and antibody drugs for H. pylori infection.

The growing demand for functional foods has stimulated the search for novel microbial strains with probiotic potential, such as Veillonella atypica ATCC 17744, which has been emerging as a promising strain. Therefore, the present study aimed to perform an in vitro characterization of this strain, focusing on safety aspects and functional properties such as stress tolerance (pH, bile salts, and simulated gastrointestinal conditions), adhesion capacity (hydrophobicity, auto-aggregation, and biofilm formation), anti-pathogenic activity, antioxidant activity, antibiotic susceptibility, and enzymatic synthesis ability (gelatinase, lipase, catalase, and hemolytic activity). Stress tolerance assays revealed that this strain is sensitive to pH values below 4.00; however, no reduction in cell viability was observed at pH 3.00 in the presence of pepsin or 0.3% and 0.6% bile salts. Hydrophobicity testing showed moderate tolerance to toluene and low tolerance to xylene. Regarding biofilm synthesis, this strain formed a weak biofilm after 48 h of incubation. No anti-pathogenic activity was observed against Streptococcus aureus or Escherichia coli, and it exhibited low antioxidant activity in the DPPH assay. Regarding its safety properties, this strain was sensitive to all tested antibiotics and did not synthesize gelatinase, lipase, catalase, or exhibit β-hemolytic activity. Therefore, Veillonella atypica ATCC 17744 presents promising characteristics supporting its potential application in the development of functional food formulations, although further studies are required to ensure its safety for human consumption.

The development of advanced drug delivery systems is essential for improving therapeutic efficacy, particularly in the treatment of neurodegenerative disorders such as Alzheimer’s disease. This study investigates zinc-modified mordenite zeolite (MR-ZN) as a novel platform for the controlled delivery of donepezil (DPZ), a cholinesterase inhibitor. Natural mordenite was modified with zinc, enhancing its surface area from 62.1 to 85.4 m2/g and improving its adsorption properties. Donepezil was successfully loaded at two doses (10 mg and 23 mg), achieving high loading efficiencies of 95% and 94%, respectively. Adsorption kinetics followed a pseudo-second-order model (R2 > 0.99), indicating that chemisorption predominates through coordination between DPZ functional groups and Zn2+ sites, while complementary physisorption via hydrogen bonding and van der Waals interactions also contributes to molecular stabilization within the zeolite framework. In vitro release studies under simulated gastrointestinal conditions demonstrated sustained and pH-responsive release profile with 80% and 82% of donepezil released after 24 h for 10 mg and 23 mg formulations, respectively. Density Functional Theory (DFT) calculations revealed favorable adsorption energy (−26.4 kJ/mol), while Bader and Electron Localization Function (ELF) analyses confirmed hydrogen bonding and electrostatic interactions without compromising the zeolite framework. These findings validate MR-ZN as structurally stable, efficient, cost-effective and biocompatible matrix for oral drug delivery. The combination of experimental data and theoretical modeling supports its potential to improve bioavailability and therapeutic performance in neurodegenerative treatment.

The closure or relocation of many factories has led to numerous abandoned sites with varying levels of potentially toxic element (PTE) enrichment pollution, damaging the surrounding environment. This study used three in vitro simulation methods (PBET, SBRC, and IVG) to systematically assess the impact of soil particle size on the bioaccessibility of chromium (Cr) in contaminated soils from a typical metal smelting site in Hunan Province, south-central China. Results showed that the highest total Cr concentration in the samples exceeded the background value of Hunan soil (67.0mg/kg) by 132.54 times, with Cr(VI) making up 17.0% (1510mg/kg). Soil particle size has a significant impact on Cr bioaccessibility by regulating PTE concentration, valence states, and physicochemical properties, including pH and soil organic matter (SOM). Under simulated gastrointestinal conditions, the < 75µm particle fraction showed the highest chromium concentration and bioaccessibility, reaching 8880mg/kg and 27.34%, respectively, notably higher than in coarser particles (75-125µm, 125-250µm). Among the three methods, the SBRC method was more conservative in the assessment. Correlation analysis revealed a strong positive relationship (r > 0.85, P < 0.05) between Cr/Cr(VI) concentrations and bioaccessibility in the < 75µm fraction. This study highlights the importance of further refining soil particle size fractions to accurately assess chromium exposure risks at smelting sites.

Background: Dysphagia is a common problem in older adults, characterized as a swallowing disorder that prevents food from passing from the mouth to the esophagus. Besides impairing dietary intake and leading to malnutrition, dysphagia also severely restricts water intake. Purpose: This study aimed to develop polysaccharide-based hydrogels as dysphagia-friendly finger foods designed to provide high water content and enable controlled vitamin delivery to older persons with dysphagia. Procedures: Agar–carboxymethylcellulose (Agar-CMC) composite hydrogels with incorporated vitamins C, B9, B, and D3 were developed and tested for their textural and rheological properties, vitamin stability during storage, and vitamin release under simulated gastrointestinal conditions. Finally, a fiberoptic endoscopic swallowing assessment and sensory evaluation were conducted. Main Findings: Increasing the agar concentration in Agar-CMC hydrogels improved their internal structure and handling properties as finger foods, while still being easily breakable during swallowing. Agar-CMC hydrogels’ structure protected vitamins during processing and six weeks of storage. Vitamin release started immediately and remained steady in the gastric phase, with a noticeable increase at the beginning of the intestinal phase, resulting in 70–100% vitamin release by the end of this phase. The Fiberoptic Endoscopic Swallowing Evaluation confirmed their suitability for individuals with mild to moderate oropharyngeal dysphagia, with a low risk of aspiration (1 point on the Penetration-Aspiration Scale out of 8). Principal Conclusions: The developed Agar-CMC hydrogels present a promising dysphagia-friendly finger food alternative with high water content. They effectively deliver essential vitamins throughout the gastrointestinal tract, and notably demonstrate a low aspiration risk, making them suitable for individuals with mild to moderate oropharyngeal dysphagia.

Tea-derived extracellular vesicles-mediated PDRN delivery activates cAMP-HIF-1α to restore intestinal homeostasis in inflammatory bowel disease

This study focuses on encapsulating of Lactobacillus plantarum using pineapple peel extract prebiotic as wall material to enhance its viability under various conditions. A freshly harvested L. plantarum culture was mixed with the encapsulating agent solution to achieve a 1:1.5 (v/v) core-to- wall ratio. The mixture was freeze-dried by first freezing at −40 °C for 24 h in plastic containers, then lyophilising at −52 °C and a condenser pressure of 0.100 mBar for 28 h, after which the dried samples were stored in sterile HDPE bottles at 4 °C . The different combinations of encapsulating agents, such as pineapple peel extract, inulin, and gum Arabic, are used to formulate microcapsules. The encapsulation efficiency of L. plantarum is evaluated, and the microcapsules are subjected to simulated gastrointestinal conditions and bile salt treatments to assess their viability. Additionally, the study examines the storage stability of the encapsulated probiotic cells over a 45 -day period, as indicative of viability in standard lab settings. The results highlight the protective effects of encapsulating materials in acidic, bile salt, and storage conditions, indicating the potential for utilising pineapple peel extract and gum Arabic to enhance the viability and stability of probiotic microorganisms for potential synbiotics applications.

Encapsulation of Lactiplantibacillus plantarum (L. plantarum) ZGP-Lpl.19 in alginate-pectin-chitosan microcapsules significantly improved its survival under simulated gastrointestinal conditions and attenuated Shigella flexneri (S. flexneri) growth and pathogenicity through downregulation of the mdoH and IcsA virulence genes. Microencapsulation was achieved via extrusion using a polysaccharide blend, yielding an encapsulation efficiency of 98.44%. Structural integrity of the microcapsules was confirmed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). Encapsulation markedly enhanced probiotic survivability, with viable counts of 5.37 log CFU/mL after 60 min in gastric fluid and 120 min in intestinal fluid, compared with 2.25 log CFU/mL for free cells. Both encapsulated and free L. plantarum ZGP-Lpl.19 demonstrated potent antimicrobial activity against S. flexneri ATCC 12022, with comparable antimicrobial metabolite production. The minimum inhibitory concentration (MIC) of cell-free supernatants from both forms was 1/8 of the original concentration. Importantly, real-time PCR analysis confirmed that both encapsulated and free cells significantly downregulated mdoH and IcsA expression. Overall, these findings demonstrate that alginate-pectin-chitosan microencapsulation provides effective protection for L. plantarum and enhances its functional delivery, positioning encapsulated L. plantarum as a promising therapeutic strategy to mitigate S. flexneri infections.

This study investigates the genetic, metabolic, and probiotic characteristics of Levilactobacillus brevis DY55bre, a strain isolated from the traditional Turkish fermented beverage, shalgam. Whole-genome sequencing revealed a circular genome of 2.485Mb with a GC content of 45.72%, predicted 2791 genes, and multiple CRISPR-Cas systems. Pangenome analysis demonstrated an open structure, with 18.9% core genes and 103 strain-specific genes, highlighting its genetic diversity. The DY55bre exhibits heterofermentative carbohydrate metabolism due to the presence of the araBAD operon and the lack of 1-phosphofructokinase (pfK) and fructose-1,6-bisphosphate aldolase enzymes. Probiotic evaluation revealed firm survival under simulated gastrointestinal conditions, including resistance to acidic pH (as low as 3.0) and bile salts (up to 1%), along with significant adhesion to intestinal epithelial cell lines (HT29;59.3%, Caco-2;87%, and DLD-1;60.8%). The strain exhibited high auto-aggregation (84.55%) and cell surface hydrophobicity (56.69%), essential for gut colonization. Safety assessments confirmed its non-hemolytic nature and absence of horizontally acquired antibiotic resistance genes. Notably, GC-MS analysis identified bioactive cyclic dipeptides, Cyclo(D-Phe-L-Pro) and Cyclo(L-Leu-L-Pro), which demonstrated cytotoxic effects against colorectal cancer cell lines, with IC50 values of 7.71mg/mL for HT29 and 3.19mg/mL for DLD-1. The cell-free supernatant exhibited antimicrobial activity against pathogens, likely due to the synergistic effects of cyclic dipeptides, organic acids, and other metabolites. Antioxidant assays revealed significant ABTS+ (76.63%) and DPPH (34.25%) radical scavenging activities, while cholesterol assimilation tests showed a 27.29% reduction. These findings position the DY55bre as a promising candidate for functional foods, nutraceuticals, and therapeutic applications, warranting further in vivo validation.

Cadmium adsorption by plant versus bacterial cellulose during simulated food exposure and gastrointestinal digestion.

Biotransformation and toxicity attenuation of 2,6-Dichlorobenzoquinone in simulated human gastrointestinal conditions: Insights from a systematic in vitro study.

Citrus sinensis peel polyphenols loaded alginate nanoparticles: Enhanced stability and anti-diabetic efficacy via bidirectional AMPK regulation and NF-кB suppression.

Improved oral delivery and bioavailability of novel Lactobacillus isolated from traditional Maragheh County yogurt by encapsulating with alginate and carboxymethyl cellulose.