Dynamic Gastrointestinal System Research Articles

Performance of β-carotene-loaded nanostructured lipid carriers under dynamic in vitro digestion system: Influence of the emulsifier type.

A better understanding of how emulsifier type could differently influence the behavior of nanostructured lipid carriers (NLC) under the gastrointestinal digestion process, as well as at the cellular level, is of utmost importance for the NLC-based formulations' optimization and risk assessment in the food field. In this study, NLC composed by fully hydrogenated soybean and high-oleic sunflower oils were prepared using soy lecithin (NLC Lβ) or Tween 80 (NLC Tβ) as an emulsifier. β-Carotene was entrapped within NLC developed as a promising strategy to overcome β-carotene's low bioavailability and stability. The effect of emulsifier type on the digestibility of β-carotene-loaded NLC was evaluated using an in vitro dynamic digestion model mimicking peristalsis motion. The influence of β-carotene-loaded NLC on cell viability was assessed using Caco-2 cells in vitro. NLC Tβ remained stable in the gastric compartment, presenting particle size (PS) similar to the initial NLC (PS: 245.68 and 218.18nm, respectively), while NLC Lβ showed lower stability (PS>1000nm) in stomach and duodenum phases. NLC Tβ also provided high β-carotene protection and delivery capacity (i.e., β-carotene bioaccessibility increased 10-fold). Based on the results of digestion studies, NLC Tβ has shown better physical stability during the passage through the in vitro dynamic gastrointestinal system than NLC Lβ. Moreover, the developed NLC did not compromise cell viability up to 25µg/mL of β-carotene. Thus, the NLC developed proved to be a biocompatible structure and able to incorporate and protect β-carotene for further food applications. PRACTICAL APPLICATION: The findings of this study hold significant implications for industrial applications in terms of developing nanostructured lipid carriers from natural raw materials widely available and used to produce other lipid-based products in the food industry, as an alternative to synthetic ones. In this respect, the β-carotene-loaded NLC developed in this study would find a great industrial application in the food industry, which is in constant search to develop functional foods capable of increasing the bioavailability of bioactive compounds.

In vitro release and bioaccessibility of oral solid preparations in a dynamic gastrointestinal system simulating fasted and fed states: A case study of metformin hydrochloride tablets

Food and formulation characteristics are crucial factors affecting the gastrointestinal release and absorption kinetics of oral solid preparations. In the present study, the dynamic continuous release and bioaccessibility of metformin hydrochloride immediate-release (IR) and sustained-release (SR) tablets were investigated in the dynamic human stomach-intestine (DHSI-IV) system simulating fasted and fed states in healthy adults. Both tablet formulations (particularly IR tablet) exhibited a postponed release in the fed state compared to the fasted state. Correspondingly, the bioaccessible fraction of metformin from IR tablets in the presence of high-fat meal was significantly reduced to 76.2 % of the fasted state. However, the in vitro bioaccessibility was less impaired by food for SR tablets with a fed/fasted ratio of 95.5 %. A convolution-based approach was used to convert in vitro bioaccessibility results to plasma concentration data. The predicted plasma concentration curve showed good agreement with human data in terms of pharmacokinetic (PK) parameters. In the fasted state, the predicted Cmax, Tmax and AUC0-24h of IR tablets were 943.9 ± 25.7 ng/mL, 2.0 ± 0.4 h and 7090.7 ± 112.0 ng.h/mL, respectively, mirroring values observed in healthy subjects. Overall, the DHSI-IV system has demonstrated potential to assess and predict the impact of meal intake on the in vivo release and absorption behaviors of oral solid preparations.

Effects of Glucosinolate-Enriched Red Radish (Raphanus sativus) on In Vitro Models of Intestinal Microbiota and Metabolic Syndrome-Related Functionalities.

The gut microbiota profile is determined by diet composition, and therefore this interaction is crucial for promoting specific bacterial growth and enhancing the health status. Red radish (Raphanus sativusL.) contains several secondary plant metabolites that can exert a protective effect on human health. Recent studies have shown that radish leaves have a higher content of major nutrients, minerals, and fiber than roots, and they have garnered attention as a healthy food or supplement. Therefore, the consumption of the whole plant should be considered, as its nutritional value may be of greater interest. The aim of this work is to evaluate the effects of glucosinolate (GSL)-enriched radish with elicitors on the intestinal microbiota and metabolic syndrome-related functionalities by using an in vitro dynamic gastrointestinal system and several cellular models developed to study the GSL impact on different health indicators such as blood pressure, cholesterol metabolism, insulin resistance, adipogenesis, and reactive oxygen species (ROS). The treatment with red radish had an influence on short-chain fatty acids (SCFA) production, especially on acetic and propionic acid and many butyrate-producing bacteria, suggesting that consumption of the entire red radish plant (leaves and roots) could modify the human gut microbiota profile toward a healthier one. The evaluation of the metabolic syndrome-related functionalities showed a significant decrease in the gene expression of endothelin, interleukin IL-6, and cholesterol transporter-associated biomarkers (ABCA1 and ABCG5), suggesting an improvement of three risk factors associated with metabolic syndrome. The results support the idea that the use of elicitors on red radish crops and its further consumption (the entire plant) may contribute to improving the general health status and gut microbiota profile.

In vitro oxidation and digestibility profiles of iron-loaded whey protein isolate/gum Arabic complexes with different morphologies.

This study was designed to investigate the promotion of oxidation of lipids in oil-in-water (o/w) emulsions and digestive properties of the bionic dynamic gastrointestinal system of whey protein isolate (WPI) and gum arabic (GA) complexes loaded with iron ions, which were fabricated previously and shown as WPI/GAFe3+ nanoparticles (WGS) and WPI/GAFe3+ fibers (WGF). Compared with emulsions containing Fe3+ and GA-loaded complex (GAFe3+), WGS and WGF greatly improved the oxidative stability of lipids along with the reduced lipid oxidation products and volatile compounds, attributed to the encapsulation of iron ions. During the bionic dynamic gastrointestinal digestion, the iron ion release of WGF was significantly higher than that of WGS, probably due to different assembled internal structures. Accordingly, two proposed WPI/GAFe3+ complexes with different morphologies are expected to be developed as novel stable iron fortifiers with delayed lipid oxidation and controlled iron-ion release in food emulsions.

Characterization of the behavior of carotenoids from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) during microemulsion production and in a dynamic gastrointestinal system.

Uncommon tropical fruits are emerging as raw-material for new food products with health benefits. This work aimed at formulating and processing microemulsions from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) fruits, since they are very rich in carotenoids (particularly lycopene and β-carotene), in order to encapsulate and increase carotenoids' bioaccessibility. Pitanga and buriti microemulsions were produced by applying a direct processing (high-speed homogenization at 15,000rpm and ultrasound with 20kHz probe at 40% amplitude) of the whole pulp together with surfactant (Tween 80 or Whey Protein Isolate at 2%) and corn oil (5%). All treatments (HSH-US for 0-4, 4-0, 4-4, 4-8min-min) applied were able to increase the amount of carotenoid released. However, the processing also decreased the total amount of carotenoids in the whole pulp of studied fruits. The impact of processing during microemulsion production was not severe. The overall data suggest that the presence of surfactant and oil during processing may protect the carotenoids in fruits and microemulsions. Final recovery of total carotenoids, after passing the samples through a dynamic gastrointestinal system that simulates the human digestion, was higher for microemulsions than for whole pulps. High losses of total carotenoids in buriti and β-carotene and lycopene in pitanga occurred during jejunum and ileum phases. The present work confirms that it is possible to increase β-carotene and lycopene bioaccessibility from fruits by directly processing microemulsions (p < 0.01).

Liposomes loaded with phenolic extracts of Spirulina LEB-18: Physicochemical characterization and behavior under simulated gastrointestinal conditions

Liposomes composed of rice (RL) and soybean (SL) lecithins were produced by reverse phase evaporation and used for the encapsulation of phenolic extracts from Spirulina LEB-18 (S-RL and S-SL for liposomes of rice and soybean lechitin, respectively). Liposomes were characterized in terms of size distribution, polydispersity index, and ζ-potential; the chemical interactions between the phenolic compounds from Spirulina and liposomes were evaluated by Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to evaluate their crystallinity pattern. The release behavior of phenolic extracts was evaluated under two different pH conditions. Afterwards, in vitro digestibility of liposomes was evaluated in a dynamic gastrointestinal system. Liposomes exhibited high encapsulation efficiency (88.28% and 97.35% for S-RL and S-SL, respectively) and sizes ranging between 250 and 291 nm, showing to be good candidates for the encapsulation of phenolic extracts obtained from microalgae. Results showed that liposomes are stable at low pH values and that they are able to resist to the stomach conditions but they lose their integrity under intestinal conditions. This work increases the knowledge about the effects of in vitro gastrointestinal digestion on liposomes and provides important information for the design of liposome formulations aiming their application in pharmaceutical and food applications.

Evaluating the behaviour of curcumin nanoemulsions and multilayer nanoemulsions during dynamic in vitro digestion

Nanoemulsions can be used to improve the bioaccessibility of lipophilic bioactive compounds, such as curcumin, being their behaviour highly influenced by their interfacial properties. The effect of chitosan and alginate layers’ deposition on curcumin nanoemulsions’ behaviour during in vitro digestion was evaluated using a dynamic gastrointestinal system. Results showed that polyelectrolyte layers’ deposition improved curcumin antioxidant capacity during in vitro digestion. In addition, multilayer nanoemulsions showed a better control of the rate and extent of lipid digestibility by decreasing free fatty acids release, compared to uncoated nanoemulsions. However, a lower curcumin bioaccessibility was observed for multilayer nanoemulsions. Although cytotoxicity assays revealed that both nanosystems are toxic due to the use of sodium dodecyl sulphate (SDS), nanosystems were 3.3-fold less toxic than SDS itself.This study showed that multilayer nanoemulsions could be used to increase satiety by retarding lipid digestion, which can be important for functional foods development for combating obesity.

Biotransformation of anthocyanins from two purple-fleshed sweet potato accessions in a dynamic gastrointestinal system

Cooked, milled purple-fleshed sweet potato (PFSP) accessions, PM09.812 and PM09.960, underwent digestion in a dynamic human gastrointestinal (GI) model that simulates gut digestive conditions to study the bioaccessibility and biotransformation of anthocyanins. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry showed accession-dependent variations in anthocyanin release and degradation. After 24h, more anthocyanin species were detected in the small intestinal vessel relative to other vessels for accession PM09.960 whereas more species appeared in the ascending colonic vessel for accession PM09.812. The ferric reducing antioxidant power was increased in the small intestinal vessel for PM09.960 and in the ascending colonic vessel for accession PM09.812, corresponding to the appearance of a majority of anthocyanins for each accession. These results show that intestinal and colonic microbial digestion of PFSP leads to an accession-dependent pattern for anthocyanin bioaccessibility and degradation.

In vitro digestion enhances anti-adhesion effect of tempe and tofu against Escherichia coli

Enterotoxigenic Escherichia coli is one of the main pathogenic bacteria causing diarrhoea. Earlier studies have shown that tempe-a fungal fermented soya food-has anti-adhesive activity against E. coli in vitro. Our aims were to challenge the anti-adhesive activity under gastro-intestinal conditions and to assess the activity of the nonfermented soya product tofu. In this study, we compared the anti-adhesive activity of two major soya bean products, tempe and tofu, and their ileum efflux after transit through a dynamic gastrointestinal system simulating digestion in the human stomach and small intestine. The results showed that both tempe and tofu have an anti-adhesive activity against E. coli in vitro. Tempe and tofu, after digestion through the stomach and small intestine, have even higher anti-E. coli adhesive activity. In addition to the proven in-vivo activity of tempe, this confirms the potential antidiarrhoeal effect of both the soya products tempe and tofu. As tofu has a much greater circle of consumers, this finding is relevant for the health of a large part of the world's population.

In Vitro Digestion of Proteins and Growth Factors in a Bovine Whey Protein Extract as Determined Using a Computer-Controlled Dynamic Gastrointestinal System (TIM-1)

The digestion of major whey proteins/peptides, transforming growth factor-beta2 (TGF-β2) and insulin-like growth factor-I (IGF-I) in a bovine whey protein extract (BWPE) was investigated in vitro using a dynamic gastrointestinal digestion system (TIM-1). β-lactoglobulin and glycomacropeptide were the whey components most resistant to 3 h of gastric digestion (pepsin) and were also the last to be cleared from the gastric compartment. All of the major proteins were hydrolyzed rapidly upon reaching the intestinal compartments. At the end of the 5-h digestion, most (73%) of the nitrogenous portion of BWPE was found in the jejunal and ileal dialysis fluids as peptides smaller than 5.8 kDa, while about 25% was discharged in the effluent destined for the colon. TGF-β2 seemed resistant to gastrointestinal enzymes since more than 95% of it was found intact in the effluent after the 5-h digestion. In contrast, IGF-I was totally hydrolyzed when it reached the intestinal compartment, suggesting its high susceptibility to pancreatic enzymes. These results support the view that TGF-β2 in a complex protein extract resists digestion and could therefore exert its biological activity when taken orally.

Food-dependent disintegration of immediate release fosamprenavir tablets: In vitro evaluation using magnetic resonance imaging and a dynamic gastrointestinal system

In the present study, we demonstrated the value of two advanced tools, the TNO gastric and small Intestinal Model (TIM-1) and magnetic resonance imaging (MRI), for the in vitro evaluation of food-dependent disintegration of immediate release fosamprenavir tablets. Upon introduction of a tablet with the nutritional drink Scandishake Mix® in the stomach compartment of TIM-1, simulating the fed state, disintegration and fosamprenavir dissolution were significantly postponed compared to the fasted state (lag time 80±23min). This resulted in a lag in the appearance of bioaccessible fosamprenavir (<5% during the first 2h), even though the nutritional state did not significantly alter the cumulative bioaccessibility after 5h. These results were in agreement with the previously observed postprandial delay in gastric fosamprenavir tablet disintegration and subsequent amprenavir absorption in healthy volunteers. Therefore, TIM-1 can be used in tablet development to identify food-induced disintegration issues causing unexpected clinical behavior. From a mechanistic perspective, we applied MRI to illustrate impaired water ingress in fosamprenavir tablets immersed in the nutritional drink compared to simulated gastric fluid. This effect may be attributed to both competition between nutritional components and the tablet for the available water (indicated by reduced rotational and translational diffusion) as well as the possible formation of a food-dependent precipitation layer on the HPMC-coated tablet.

Combining the Dynamic TNO-Gastrointestinal Tract System with a Caco-2 Cell Culture Model: Application to the Assessment of Lycopene and α-Tocopherol Bioavailability from a Whole Food

To exert their health effect, phytochemicals such as carotenoids and vitamin E have to be bioavailable. We investigated the digestive stability and intestinal absorption of lycopene and alpha-tocopherol from a whole food containing red tomatoes and sunflower oil using, for the first time, the dynamic gastrointestinal system TNO gastrointestinal tract model (TIM) coupled with Caco-2 cells. Digestive samples were added to Caco-2 cells after appropriate ultracentrifugation, filtration, and dilution. alpha-Tocopherol was stable during digestion in the TIM, whereas a 25% loss was observed for lycopene. The absorption of both compounds was curvilinear, bidirectional, and concentration-dependent. The percentages of alpha-tocopherol absorbed, but not that of lycopene, were lower with digestas compared to those with pure compounds, suggesting competition for absorption with other components of the test meal. According to in vivo data, a lower bioavailability was found for lycopene compared to that for alpha-tocopherol. These results support the usefulness of this in vitro approach for estimating the bioavailability of active compounds from food.