Simulated Gastrointestinal Fluids Research Articles

Development of a biocompatible green drug release system using salidroside-TiO2-doped chitosan oligosaccharide molecularly imprinted polymers

This study focuses on creating a green drug release system using a food-grade titanium dioxide (TiO2) material through surface molecular imprinting. Salidroside (SD) was chosen as the template molecule to synthesize molecularly imprinted polymers (SDT-MIP) utilizing TiO2-doped chitosan oligosaccharides as the functional monomer. The SDT-MIPs were characterized using multiple techniques, and their effectiveness was evaluated through an in vitro release study. Additionally, the affinity of SDT-MIPs toward the template molecule was examined using Langmuir and Freundlich adsorption models. The Langmuir model revealed a maximum capacity of 170.41 mg/g and an imprinted factor of 3.4. The study demonstrated that drug release from the SDT-MIPs in simulated gastrointestinal fluid primarily occurred through pure Fick diffusion. The release kinetics exhibited diffusion coefficients ranging from 3.38 × 10-3 cm2/s to 2.78 × 10-2 cm2/s, indicating their biocompatibility and potential application in drug delivery. Furthermore, the SDT-MIP demonstrated no adverse impact on cell viability even at concentrations as high as 1000 μg/mL. The survival rate of cells cultivated in the presence of SDT-MIP solution exceeded 120 ± 12.46%, providing evidence of the excellent biocompatibility and absence of cytotoxicity associated with SDT-MIP. The SDT-MIP possesses favorable sustained-release properties and lacks toxicity, allowing novel drug delivery systems to be created.

Calcium silicate‐reinforced pH‐sensitive alginate‐gellan gum composite hydrogels for prolonged drug delivery

AbstractThis study disclosed the synthesis and characterization of externally and/or internally crosslinked alginate‐gellan gum composite interpenetrating polymer networks (IPN) and IPN hydrogel microspheres for controlled delivery of gliclazid. The internal cross‐linking of the polymer sol was accomplished via slow release of Ca2+ ions from calcium silicate in presence of gluconic acid d‐lactone. The microspheres had spherical shape with smooth surface morphology. The IPN or composite IPN hydrogel microspheres had drug entrapment efficiency of 70%–76%. Incorporation of gellan gum or gellan gum/calcium silicate in the alginate sol sustained the release of drug in simulated gastrointestinal fluids over 12 h without any sign of particle disintegration. Inclusion of calcium silicate in alginate gels was ineffective in controlling drug release under simulated gastrointestinal milieu. The drug release obeyed anomalous diffusion mechanism after inclusion of gellan gum or gellan gum‐calcium silicate in the alginate gel microspheres. Fourier‐transform infrared (FTIR) spectroscopy and zeta analysis confirmed absence of drug‐polymer chemical interaction. The thermal and x‐ray diffraction analyses suggested that the drug transformed into amorphous state after incorporation into composite hydrogel system. Hence, it may be advantageous to combine internal and external gelation procedures for creating composite IPN or IPN hydrogel microspheres for avoiding burst effect of alginate microspheres and managing desired drug release patterns in vitro.

Formulation, optimization and in vitro evaluation of polymer-coated liposomes encapsulating nebivolol hydrochloride

Hypertension, also known as high blood pressure, is a serious medical condition that affects billions of people worldwide. Nebivolol hydrochloride, a β1–adrenergic blocking agent, is used by the oral route in the treatment of hypertension and congestive heart failure. However, its lipophilic nature and poor aqueous solubility restricts its oral bioavailability. To overcome limitations related with conventional oral formulations of the drug, uncoated and polymer–coated liposomes were developed and evaluated. Liposomes loaded with nebivolol hydrochloride were prepared by thin–film hydration method and characterized. The influence of chitosan or pluronic (F127) coating on the liposome properties was evaluated in terms of physicochemical characteristics, stability in simulated gastrointestinal fluids, mucin interaction, in vitro drug release and cytotoxicity studies. It was observed that coating the liposomes with either chitosan or pluronic affected the size, surface charge and encapsulation efficiency of the formulations. The surface morphology studies confirmed the vesicular shape of liposomes. The results obtained indicated that both polymer–coated liposome formulations maintained their stability in simulated gastrointestinal fluids and showed significant in vitro interaction with mucin. Polymer–coated liposome formulations showed much better cumulative release of the drug than uncoated liposomes. No aggregation was observed at the end of four–week storage period and low toxicity in Caco–2 cells was measured. The results demonstrated that polymer coating of liposomes could enhance the in vitro release of nebivolol hydrochloride and interaction with mucin following oral administration and might be attractive alternative nanocarriers to traditional oral formulations.

Characterization of Lactic Acid Bacteria Strains Isolated from Algerian Honeybee and Honey and Exploration of Their Potential Probiotic and Functional Features for Human Use.

Using culture enrichment methods, 100 strains of bacilli of lactic acid bacteria (LAB) were isolated from honeybee Apis mellifera intermissa and fresh honey, collected from apiaries located in the north-east of Algeria. Amongst all of the isolated LAB, 19 selected strains were closely affiliated to four species-Fructobacillus fructosus (10), Apilactobacillus kunkeei (5), Lactobacillus kimbladii and/or Lactobacillus kullabergensis (4)-using phylogenetic and phenotypic approaches. The in vitro probiotic characteristics (simulated gastrointestinal fluids tolerance, autoaggregation and hydrophobicity abilities, antimicrobial activity and cholesterol reduction) and safety properties (hemolytic activity, antibiotic resistance and absence of biogenic amines) were evaluated. The results indicated that some strains showed promising potential probiotic properties. In addition, neither hemolytic activity nor biogenic amines were produced. The carbohydrate fermentation test (API 50 CHL) revealed that the strains could efficiently use a broad range of carbohydrates; additionally, four strains belonging to Apilactobacillus kunkeei and Fructobacillus fructosus were found to be exopolysaccharides (EPS) producers. This study demonstrates the honeybee Apis mellifera intermissa and one of her products as a reservoir for novel LAB with potential probiotic features, suggesting suitability for promoting host health.

Ameliorative effects of microencapsulated Spirulina platensis in beverage; physicochemical, simulated release, and organoleptic properties

PurposeThe use of Spirulina sp. in food is limited by its bitter flavour and low absorption in the gastrointestinal system. The purpose of this study is to develop encapsulated Spirulina-alginate beads and to determine the physicochemical properties, the release efficiency in the simulated gastrointestinal fluid and the sensory acceptance of the beads when added into a rose syrup beverage.Design/methodology/approachSpirulina-alginate beads were prepared based on 3 × 3 factorial experiments consisting of three concentrations (1%, 2% and 3%) of plain sodium alginate and three concentrations (1, 3 and 5%) (w/v) of Spirulina. Encapsulated Spirulina-alginate beads were evaluated for their encapsulation effectiveness, size, texture, morphology, colour, in vitro release rate and sensory properties.FindingsSample H (3% sodium alginate + 1% Spirulina) had higher encapsulation efficiency (82.3%) but less protein (38.2 ppm) than Sample J (3% sodium alginate + 5% Spirulina) which produced more protein (126.4 ppm) but had lower encapsulation efficiency (54.5%). Alginate was the primary factor affecting bead size, and the texture became harder at 3% sodium alginate but softer at 5% Spirulina. As the concentration of Spirulina increased, the intensity of the green colour diminished. The encapsulated samples released test was better than the control samples, and Sample B (1% sodium alginate + 1% Spirulina) was preferred by the panellists in the sensory study.Originality/valueThis newly developed encapsulated Spirulina will improve the beverage acceptability, minimize the bitterness and increase the release percentage of Spirulina in simulated gastrointestinal.

Non-Cardiotoxic Tetradecanoic Acid-2,4-Dinitrophenol Ester Nanomicelles in Microneedles Exert Potent Anti-Obesity Effect by Regulating Adipocyte Browning and Lipogenesis.

Sustained oral uncoupler 2,4-dinitrophenol (DNP) administration exerts prominent anti-obesity effects, but the adipose tissue off-target disadvantage leads to systemic adverse effects. A novel non-cardiotoxicity DNP delivery method using a biocompatible microneedles patch containing the amphiphilic tetradecanoic acid-DNP ester (TADNP) is described, which is synthesized via esterification on the phenolic hydroxyl of DNP. The TADNP is self-assembled as nanomicelles, which enhance the endocytosis rate of DNP by adipocytes and its permeation in isolated adipose tissues. The microenvironment of adipose tissues promotes the massive release of DNP and plasma and simulated gastrointestinal fluids. The microneedles-delivered TADNP nanomicelles (MN-TADNP) effectively deliver DNP in treated adipose tissues and reduce DNP content in off-target organs. Both oral and MN patch-delivered TADNP micelles effectively exert anti-obesity effects in a mouse model of high-fat diet-induced obesity; and noteworthily, MN-TADNPexhibit more satisfactory biosafety than oral administration. Here, a smart MN patch loaded with tetradecanoic acid-modified DNP is reported, which enhances its accumulation in adipose tissues and exerts an anti-obesity effect without causing any systemic toxicity.

Pharmacokinetics and repeated dose 28-day oral toxicity studies of acetaminophen nanosuspension.

Wide availability and easy accessibility of acetaminophen oral dosage forms increase the risk of intentional poisoning or unintentional organ toxicity, leading to a wide range of liver failure, nephrotoxicity, and neurotoxicity. In this study, an attempt was made to improve oral bioavailability and reduce the toxicity of acetaminophen using nanosuspension technology. The acetaminophen nanosuspensions (APAP-NSs) were prepared by a nano-precipitation method using polyvinyl alcohol and hydroxypropylmethylcellulose as stabilizers. The mean diameter of APAP-NSs was 124 ± 3.8 nm. The dissolution profile of APAP-NSs was significantly point-to-point higher than the coarse drug in simulated gastrointestinal fluids. The in vivo study revealed 1.6- and 2.8-fold increases in the AUC0-inf and Cmax of the drug, respectively, in APAP-NSs-receiving animals compared to the control group. Moreover, no deaths and no abnormalities in clinical signs, body weights, and necropsy findings were detected in the dose groups up to 100 mg/kg of the 28-day repeated oral dose toxicity study in mice.

Protein corona formed on the TiO2 nanoparticles promotes the hydrolysis of collagen in simulated gastrointestinal fluids

Titanium dioxide nanoparticles (TiO2 NPs) could interact with proteins in foods and gastrointestinal fluids, thus changing the properties and functions of proteins. Many research articles have only studied the interactions between TiO2 NPs and digestive enzymes or the gastrointestinal fate of TiO2 NPs without considering the effect of food matrix. Therefore, the interactions between TiO2 NPs and trypsin and its effects on the digestion of collagen in vitro were investigated. Results showed that the functionalization of amino acids (Asp, and Ser) significantly harmed the adsorption of trypsin by TiO2 NPs. The fluorescence quenching and isothermal titration calorimetry confirmed that the hydrogen bond and van der Waals force played an essential role in the interactions between TiO2 NPs and trypsin. The β-sheet content of trypsin bound to TiO2 NPs decreased from 52.40% to 50.73% while the random coil content increased from 20.20% to 22.63%. Binding sites were identified by molecular docking. Additionally, the digestibility of collagen was improved in vitro in the presence of TiO2 NPs analyzed by SDS-PAGE, hydroxyproline quantification, and the antioxidation of digested products. Hydroxyproline concentration increased by nearly 25% and ABTS radical scavenging rate increased by 50%. This study provides a new insight into the impact of nanoparticles on gastrointestinal digestion.

A novel cerasomal gallic acid as a non-ulcerogenic agent with an improved anti-inflammatory potential

In order to treat inflammatory bowel disease (IBD), there is an attempt to develop local drug delivery systems. The use of bioactive compounds such as gallic acid (GA) in a precise colon-targeting drug delivery platform is expected to enhance its bioavailability and increase local therapeutic responses. In this study, a novel cerasome-forming lipid (CFL) containing organosilane-based oleic acid was mixed with 1, 2-dipalmitoyl-sn-glycero-3-phosphocholine via one-step construction to prepare composite cerasomes by varying mole ratios. The physicochemical properties, drug-loading capacity, long-term storage stability, and release rates of (GA) from cerasomes have been investigated. The size of cerasomal gallic acid (CG) was about 319 nm with −23 mV surface charge and 77% drug sustained released after 140 h in the simulated gastrointestinal fluids. Composite vesicles consisting of DPPC and CFL with a 1:1 M ratio exhibited good cytocompatibility and cellular uptake, also, the released gallic acid effectively inhibit the reactive species in LPS-induced inflammation of Caco-2 cells, compared to free (GA). Our results indicate that this novel CG has great potential to be applied as a non-ulcerogenic agent due to the prolonging duration of action in IBD therapy.

Novel hydroxyectoines based formulations are suitable for preserving viability of Limosilactobacillus fermentum, Levilactobacillus brevis SP-48 and Bifidobacterium lactis HN019 during freeze-drying and storage, and in simulated gastrointestinal fluids

This study aimed at evaluating the influence of compatible solutes such as ectoine and hydroxyectoine (HOE), on bacterial cell viability during freeze-drying and storage (at 4 °C and 25 °C), in comparison to the well-established use of trehalose. Three strains, namely Limosilactobacillus fermentum, Levilactobacillus brevis SP-48, and Bifidobacterium lactis HN019 were used as models demonstrating that the highest survival rate during freeze drying was observed for cells protected with HOE. Although trehalose was more effective during lyophilization, interestingly the combination of trehalose and HOE most efficiently preserved long-term cell viability (viability loss < 0.5 log units after 6 months of storage). Finally, the ability of HOE to contribute to strain resistance in simulated gastrointestinal juices was evaluated and the latter protected all the strains tested more efficiently than all the other solutes, in particular the viability was improved from 58%, 87.5%, and 94% when cells were dried with saline solution to 88%, 98.3%, and 98% when lyophilized with HOE for L. fermentum, L. brevis, and B. lactis, respectively. In conclusion, the addition of HOE to trehalose improves the stability of probiotics during storage and enhances the survivability in simulated gastrointestinal tract conditions.

Targeted delivery of budesonide in acetic acid induced colitis: impact on miR-21 and E-cadherin expression

Inflammatory bowel disease (IBD) is characterized by chronic inflammation along the gastrointestinal tract. For IBD effective treatment, developing an orally administered stable drug delivery system capable of targeting inflammation sites is a key challenge. Herein, we report pH responsive hyaluronic (HA) coated Eudragit S100 (ES) nanoparticles (NPs) for the targeted delivery of budesonide (BUD) (HA-BUD-ES-NPs). HA-BUD-ES-NPs showed good colloidal properties (274.8 ± 2.9 nm and − 24.6 ± 2.8 mV) with high entrapment efficiency (98.3 ± 3.41%) and pH-dependent release profile. The negative potential following incubation in simulated gastrointestinal fluids reflected the stability of HA coat. In vitro studies on Caco-2 cells showed HA-BUD-ES-NPs biocompatibility and enhanced cellular uptake and anti-inflammatory effects as shown by the significant reduction in IL-8 and TNF-α. The oral administration of HA-BUD-ES-NPs in an acetic acid induced colitis rat model significantly mitigated the symptoms of IBD, and improved BUD therapeutic efficacy compared to drug suspension. This was proved via the improvement in disease activity index and ulcer score in addition to refined histopathological findings. Also, the assessment of inflammatory markers, epithelial cadherin, and mi-R21 all reflected the higher efficiency of HA-BUD-ES-NPs compared to free drug and uncoated formulation. We thus suggest that HA-BUD-ES-NPs provide a promising drug delivery platform for the management and site specific treatment of IBD.Graphical

Metformin and curcumin co-encapsulated chitosan/alginate nanoparticles as effective oral carriers against pain-like behaviors in mice

Nanotechnology plays an integral role in multimodal analgesia. In this study, we co-encapsulated metformin (Met) and curcumin (Cur) into chitosan/alginate (CTS/ALG) nanoparticles (NPs) at their synergistic drug ratio by applying response surface methodology. The optimized Met-Cur-CTS/ALG-NPs were achieved with Pluronic® F-127 2.33 % (w/v), Met 5.91 mg, and CTS:ALG mass ratio 0.05:1. The prepared Met-Cur-CTS/ALG-NPs had 243 nm particle size, −21.6 mV zeta potential, 32.6 and 44.2 % Met and Cur encapsulations, 19.6 and 6.8 % Met and Cur loading, respectively, and 2.9:1 Met:Cur mass ratio. Met-Cur-CTS/ALG-NPs displayed stability under simulated gastrointestinal (GI) fluid conditions and during storage. In vitro release study of Met-Cur-CTS/ALG-NPs in simulated GI fluids showed sustained release, with Met exhibiting Fickian diffusion and Cur demonstrating non-Fickian diffusion following the Korsmeyer-Peppas model. Met-Cur-CTS/ALG-NPs exhibited increased mucoadhesion and improved cellular uptake in Caco-2 cells. Additionally, Met-Cur-CTS/ALG-NPs exhibited better anti-inflammatory effects in lipopolysaccharide-stimulated RAW 264.7 macrophage and BV-2 microglial cells than the equivalent amount of the Met-Cur physical mixture, indicating a greater ability to modulate peripheral and central immune mechanisms of pain. In the mouse formalin-induced pain model, Met-Cur-CTS/ALG-NPs administered orally exhibited better attenuation of pain-like behaviors and proinflammatory cytokine release compared to the Met-Cur physical mixture. Furthermore, Met-Cur-CTS/ALG-NPs did not induce significant side effects in mice at therapeutic doses. Altogether, the present study establishes a CTS/ALG nano-delivery system for Met-Cur combination against pain with improved efficacy and safety.

Probiotic characterization of Bacillus species strains isolated from an artisanal fermented milk product Dahi.

Dahi, an artisanal fermented milk product, widely consumed in Pakistan, is microbiologically diverse, and many bacterial communities await investigation. The current study is first to present probiotic assessment of Bacillus species strains isolated from dahi. Based on 49 identified strains assessed, only 6 strains, i.e., Bacillus licheniformis QAUBL19, QAUBL1901, and QAUBL1902; Bacillus mycoides QAUBM19 and QAUBM1901; and Bacillus subtilis QAUBSS1 were having prominent persistence in the simulated gastrointestinal fluids, being non-hemolytic, with no DNase activity. Probiotic characteristics, cholesterol-assimilating, and carbohydrate-fermenting capabilities were assessed for all the strains. These six strains each showed variant cholesterol assimilating abilities. B. licheniformis QAUBL19 retaining most desired probiotic traits presented both notable cholesterol assimilating and bile salt hydrolase activities. It can be used as a probiotic of choice with hypocholesterolemia ability. B. subtilis QAUBSS1 showed wide carbohydrate fermentation ability and strongest antibacterial potential. It is likely to be considered a probiotic for living beings and starter culture for fermentation of food/feed.

A high throughput approach of selecting excipients for solubility enhancement of BCS Class II active pharmaceutical ingredients for oral dosage forms

Scientists have been faced with the challenge of selecting the right solubilizing excipients for solubility enhancement of poorly water-soluble active pharmaceutical ingredients for decades. In this investigation, the purpose was to ease some of those challenges by developing a first-intent matrix for selecting solubilizing excipients that may potentially be used in an oral solid dosage formulation. This was accomplished by generating 2304 data points using high throughput experimentation to assess the impact of eleven commonly used formulation excipients, at varying levels, on the solubility enhancement of a weak acid (Ibuprofen), weak base (Cinnarizine), and non-ionizable (Griseofulvin) drug substance over a time span from 1 h to equilibrium in simulated gastrointestinal fluids (SGF, FaSSIF, FeSSIF) and water. The results indicate that the enhancement of drug concentrations by use of solubilizing excipients (surfactants and stabilizers) in oral solid dosage forms depends on the type, the amount of excipient, and the pH of the media. The importance of this work is that formulation scientists now have a new addition to the formulation development toolkit for selecting the right solubilizing excipients and amounts suitable for solubility enhancement based on the class of active pharmaceutical ingredients. This first-intent solubilizer selection approach for the different drug classes simplifies the early development process to enable acceleration to candidate selection, formulation design, and product development for first-time-in-human studies.

Isolation, Identification, and Characterization of the Native Yeast Strains from Homemade Cheese to Assess their Eliminating Impact on the Aflatoxin B1 and M1 of the Simulated Gastrointestinal Fluid.

The occurrence of aflatoxins in food products is a silent threat to human health worldwide. A range of strategies has been introduced to address the bioavailability of aflatoxins, which are considered microbial tools to provide a low-cost and promising approach. The present study focused on the separation of yeast strains from the homemade cheese rind layer to investigate the ability of native yeasts to eliminate AB1 and AM1 from simulated gastrointestinal fluids. Homemade cheese samples were prepared from different locations in Tehran provinces and yeast strains were isolated and identified through the biochemical methods and molecular analysis of internal transcribed spacer and D1/D2 domain of 26S rDNA regions. Isolated strains were screened using simulated gastrointestinal fluids, and the ability of yeast strains to absorb aflatoxin was evaluated. Out of 13 strains, 7 yeast strains were not affected by 5 ppm AFM1 while 11 strains did not show any significant response to 5 mg.L-1 (ppm) of AFB1. On the other hand, 5 strains were able to successfully tolerate 20 ppm AFB1. Candidate yeasts showed different abilities to remove aflatoxins B1 and M1. In addition, C. lusitaniae, G. geotrichum, G. candidum, and C. sanyaensis exhibited a significant ability to detoxify aflatoxins from the gastrointestinal fluid, respectively. Our data suggest that yeast communities with essential effects on the quality of homemade cheese appear to be precise candidates for the potential elimination of aflatoxins from the gastrointestinal fluid.

Obtaining and characterization of bentonite organophilic incorporated with geranyl acetate and its application as mycotoxins’ binder in simulated gastrointestinal fluids

One of the major problems linked to the animal feed industry is the presence of mycotoxins, substances produced by fungi, which even in low concentrations can cause health-related inconveniences and severe economic losses. This study reports the production of organophilic bentonite incorporated geranyl acetate (GA) 0.4 (w/w) (Bent-ODA). The synthesized composite was employed to remove carcinogenic mycotoxins Aflatoxin B1 (AFB1). The product was characterized by FRX, XRD, FTIR, TGA, and BET/BJH techniques, while quantifying mycotoxins was performed using HPLC/LC-MS. The effect of intestinal fluids (pH 6.5, the average pH of the intestine, or pH 3.5, the average pH of the stomach) on the adsorption performance of Bent-ODA-GA was systematically investigated. This new material was preliminary evaluated for its antifungal activity against Aspergillus flavus and Aspergillus niger. XRD showed that GA was intercalated in bentonite modified by ODA, and FTIR confirmed the presence of GA in the Bent-ODA structure. Furthermore, the product showed the presence of mesopores, and reduced pore volume compared to Bent-ODA. Preliminary results showed that Bent-ODA-GA reduced fungal growth, which allows only traces of fungal growth on its surface, filling <10% of plate, receiving a rating 1 according to ASTM G21‐15. The adsorption kinetics showed that to Bent-ODA, 45 min is enough time of contact with AFB1 to reduce it to acceptable levels by legislation, this being 20 μg∙kg‐1, regardless of the pH used, while for Bent-ODA-GA the time necessary to reach levels that are according to the legislation it is 120 min for a pH of 3.5 and 100 min for a pH of 6.5. Therefore, attributed to the advantages of being efficient, Bent-ODA-GA could be envisaged as a promising adsorbent for the enhanced sequestration of Aflatoxin B1.

Double-layer mucin microencapsulation enhances the stress tolerance and oral delivery of Lactobacillus plantarum B2

The delivery of beneficial bacteria to the gut microbiome holds a promise to avert and treat diseases such as ariboflavinosis. Nevertheless, adverse gastrointestinal (GI) conditions, a high concentration of reactive oxygen species (ROS), exhausted mucus layer, constant peristalsis of the gastrointestinal tract, and complex pathological microenvironment result in low oral bioavailability lead to limited intestinal colonization of probiotics and affect their related health benefits. Herein, we established a bio-based strategy of double-layer gelatin-mucin-alginate and chitosan-mucin-alginate microcapsules that endow the transplanted riboflavin (vitamin B2) over-producing strain Lactobacillus plantarum B2 with robust resistance to adverse environments and remarkable adhesiveness to the intestine. The outer gelatin (or chitosan) membrane was observed by building a gelatin-genipin (or chitosan-genipin) fluorescent complex. We demonstrated that co-encapsulating with mucin and the secondary coating of gelatin or chitosan could effectively maintain the regular surface morphology of gel beads and protect probiotics during the lyophilization process, possibly by improving the internal cross-linking and mechanical strength of the microcapsules. The encapsulated probiotic strain was endowed with strong resistance during storage, simulated gastrointestinal digestion fluid, and ROS exposure. In addition, co-embedded mucin augmented the adherence rate of L. P. B2 on the simulated intestinal mucus. Most importantly, microcapsule encapsulation not only retained the probiotic potential of L. P. B2 but also improved the B2 production during soymilk fermentation. Altogether, the encapsulation strategy can be used as an effective way to deliver explicit probiotics to the gut microbiota for the intestinal colonization of probiotics to deliver B2 in the human gut.

In vitro screening of synbiotics composed of Lactobacillus paracasei VL8 and various prebiotics and mechanism to inhibits the growth of Salmonella Typhimurium

This study aimed to screen the synbiotics with good antibacterial effect against Salmonella Typhimurium and to investigate its antibacterial mechanism. Laboratory-isolated Lactobacillus paracasei VL8 were selected and combined with four prebiotics, fructooligosaccharide (FOS), inulin, galactooligosaccharide (GOS), and mannan oligosaccharide (MOS) for the comparison. Their growth, adhesion, tolerance and inhibition ability were evaluated by growth curve, non-specific adhesion test, simulated gastrointestinal fluid, and zone of inhibition method, respectively. The results showed that MOS had a better synbiotic effect with L. paracasei VL8, resulting in a significant increase in the growth of L. paracasei VL8, higher acid production, and a larger zone of inhibition of S. Typhimurium, reaching 16.75 mm. The time-kill curves showed that 20% (v/v) of metabolite in the medium could kill S. Typhimurium within 4h completely. Further, electron microscopic micrographs showed that the synbiotic metabolites caused damage to the cell membrane of S. Typhimurium, resulting in cytoplasmic efflux. The Findings indicated that the synbiotic combination between MOS and L. paracasei VL8 not only promoted the growth and acid production of the probiotic, but also exerted good inhibitory effects on S. Typhimurium by disrupting the cell membrane, which can be a potential natural antimicrobial agent for food applications.

High-level expression of an acetaldehyde dehydrogenase from Lactiplantibacillus plantarum and preliminary evaluation of its potential as a functional food additive

BackgroundAcetaldehyde dehydrogenase (ALDH) is a common oxidoreductase and one of the aldehyde dehydrogenases, which can convert toxic acetaldehyde to harmless acetyl CoA. ResultsA novel acetaldehyde dehydrogenase (LpALDH) from Lactiplantibacillus plantarum was obtained by gene mining and then was analyzed by a series of bioinformatics software. Phylogenetic tree results showed that LpALDH was highly homologous with acetaldehyde dehydrogenase derived from Pediococcus sp., and their sequence similarity was 62.9%. Moreover, it was successfully expressed in Escherichia coli BL21, its expression level was 195 U/mL, which was about 600 times than that expressed in L. plantarum. After purification by affinity chromatography, the specific activity of reLpALDH was 1709 U/mg. Its temperature optimum was 35°C, and the optimal reaction pH was 8.0. Moreover, the purified LpALDH showed good stability in simulated gastrointestinal fluids, which indicated that it had great potential in functional food additive field. ConclusionsThis research also laid a solid foundation for further molecular modification, optimal expression host selection and application of acetaldehyde dehydrogenases.How to cite: Wang Z, He J, Liu X, et al. High-level expression of an acetaldehyde dehydrogenase from Lactiplantibacillus plantarum and preliminary evaluation of its potential as a functional food additive. Electron J Biotechnol 2023;63. https://doi.org/10.1016/j.ejbt.2022.12.005.

Physicochemical Transformations of Silver Nanoparticles in the Oro-Gastrointestinal Tract Mildly Affect Their Toxicity to Intestinal Cells In Vitro: An AOP-Oriented Testing Approach.

The widespread use of silver nanoparticles (Ag NPs) in food and consumer products suggests the relevance of human oral exposure to these nanomaterials (NMs) and raises the possibility of adverse effects in the gastrointestinal tract. The aim of this study was to investigate the toxicity of Ag NPs in a human intestinal cell line, either uncoated or coated with polyvinylpyrrolidone (Ag PVP) or hydroxyethylcellulose (Ag HEC) and digested in simulated gastrointestinal fluids. Physicochemical transformations of Ag NPs during the different stages of in vitro digestion were identified prior to toxicity assessment. The strategy for evaluating toxicity was constructed on the basis of adverse outcome pathways (AOPs) showing Ag NPs as stressors. It consisted of assessing Ag NP cytotoxicity, oxidative stress, genotoxicity, perturbation of the cell cycle and apoptosis. Ag NPs caused a concentration-dependent loss of cell viability and increased the intracellular level of reactive oxygen species as well as DNA damage and perturbation of the cell cycle. In vitro digestion of Ag NPs did not significantly modulate their toxicological impact, except for their genotoxicity. Taken together, these results indicate the potential toxicity of ingested Ag NPs, which varied depending on their coating but did not differ from that of non-digested NPs.