Alginate as a protease inhibitor in vitro and in a model gut system; selective inhibition of pepsin but not trypsin

Mechanism on microbial transglutaminase and Tremella fuciformis polysaccharide-mediated modification of lactoferrin: Development of functional food

Lactoferrin (LF) with various biological functions demonstrates great application potential. However, its application was restricted by its poor gelation and instability. The aim of this work was to explore the effect of microbial transglutaminase (MTGase) and Tremella fuciformis polysaccharide (TP) on the functional properties of LF. The formation of a self-supporting LF gel could be induced by MTGase through generating covalent crosslinks between the LF protein molecules. Meanwhile, TP was introduced into the gel system to improve the strength of LF-TP composite gels by enhancing non-covalent interactions such as hydrogen bond and electrostatic interactions during gel formation. Additionally, the LF-TP composite gel exhibited outstanding functional characteristics such as gastrointestinal digestive stability and antioxidant property. This work clarified the mechanism on MTGase and TP-mediated modification of lactoferrin, offered a novel strategy to increase the functional characteristics of LF, and enlarged the application range of LF and TP.

Alginate binding enhances the structural stability and potentiates the lytic activity of bacteriophage endolysin's partially folded conformation

Polysaccharide polymers are increasingly being used as chaperon-like macromolecules in assisting protein folding of unfolded protein molecules. They interact with unfolded or partially folded proteins in a charge and conformation specific manner that results in the formation of stable protein-polysaccharide complexes. In most of the cases, the complex formation of protein-polysaccharide is driven via non-covalent interactions that have found to endorse the activity of proteins. T4L (18.7 kDa) and T7L (17 kDa) endolysins belong to the hydrolase and amidase class of peptidoglycan degrading enzymes. Both T4L and T7L exist in partially folded forms and are devoid of lytic activity at low pH conditions. In the current study, we assessed the binding of alginate with T4L and T7L at pH 7 and 3 using variety of biophysical and biochemical techniques. Spectroscopic studies revealed differential structural modulations of partially folded T4L and T7L upon their interaction with alginate. Further, the complex formation of alginate with partially folded T4L/T7L was confirmed by ITC and STEM. Additionally, the formed complexes of alginate with both T4L/T7L PF endolysins were found to be chemically and enzymatically stable. Moreover, such complexes were also marked with differential enhancement in their lytic activities at acidic pH conditions. This implied the potency of alginate as an excellent choice of matrix to preserve the structural and functional integrity of partially folded forms of T4L and T7L at highly acidic conditions.

Dietary Fibre for the Prevention of Post-Pancreatitis Diabetes Mellitus: A Review of the Literature and Future Research Directions

Post-pancreatitis diabetes mellitus-the most common sequela of pancreatitis-leads to poorer glycaemic control compared with type 2 diabetes. Because post-pancreatitis diabetes mellitus is an exemplar of secondary diabetes (with a clear underlying cause), much post-pancreatitis diabetes mellitus is preventable or treatable early. Earlier literature established the important role of dietary fibre in reducing plasma glucose in individuals with type 2 diabetes. The present review benchmarks available evidence on the role of habitual dietary fibre intake in pancreatitis and post-pancreatitis diabetes mellitus. It also paves the way for future research on the use of dietary fibre in the post-pancreatitis setting.

Primary structural features, physicochemical and biological properties of two water-soluble polysaccharides extracted from the brown Tunisian seaweed Halopteris scoparia

Marine algae are the most abundant resource in the marine environment and are still a promising source of bioactive compounds including hydrocolloids. This study contributes to the evaluation of the biological and biotechnological potentials of two water soluble polysaccharides, namely alginates (AHS) and fucoidan (FHS), extracted and purified from Halopteris scoparia, an abundant Tunisian brown macroalgae collected in Tunisia (Tabarka region). The total sugars, neutral monosaccharides, uronic acids, proteins, polyphenols, and sulfate groups contents were quantified for both fractions, as well as their functional groups and primary structural features by Fourier transform infrared spectroscopy, ionic and/or gas chromatography and nuclear magnetic resonance analyses. AHS and FHS showed significant anti-inflammatory (IC50 ≈ 1 mg/mL), anticoagulant (e.g., 27-61.7 for the activated partial thromboplastin time), antihyperglycemic (0.1-40 μg/mL) and anti-trypsin (IC50 ≈ 0.3-0.4 mg/mL) effects. FHS and a hydrolyzed fraction showed a very promising potential against herpes viruses (HSV-1) (IC50 < 28 μg/mL). Besides, AHS and two hydrolyzed fractions were able to stimulate the natural defenses of tomato seedlings, assessing their elicitor capacity, by increasing the activity of phenylalanine ammonia-lyase (66-422 %) but also significantly changing the polyphenol content in the leaves (121-243 %) and roots (30-104 %) of tomato plants.

Influence of hydrophilic polysaccharide fat replacers on the in vitro digestibility of protein in emulsion-type sausage

Hydrophilic polysaccharides have been widely applied as fat replacers in meat products, but their effects on the digestibility of meat proteins has seldom been studied. Replacement of backfat in emulsion-type sausage with konjac gum (KG), sodium alginate (SA) and xanthan gum (XG) were found to reduce the released amino group (-NH₂) during simulated gastric digestion and initial intestinal digestion. The suppressed gastric digestibility of protein was verified by the denser structures of protein gastric digests and reduced generation of peptides in gastric digestion when a polysaccharide was added. After the whole gastrointestinal digestion, high level of SA and XG resulted in larger digests and a more obvious SDS-PAGE band between 5 and 15 kDa, and KG and SA significantly reduced the total release of -NH₂. Additional of KG, SA and XG were found to the increase the viscosity of the gastric digests mixture, which could account for the reduced hydrolysis efficiency of pepsin during the gastric digestion, as evidenced in the pepsin activity study (decreased by 12.2-39.1%). This work highlights the influence of polysaccharide fat replacer on the digestibility of meat protein by changing the matrix characteristics.

Alginate Gel-Based Carriers for Encapsulation of Carotenoids: On Challenges and Applications

Sodium alginate is one of the most interesting and the most investigated and applied biopolymers due to its advantageous properties. Among them, easy, simple, mild, rapid, non-toxic gelation by divalent cations is the most important. In addition, it is abundant, low-cost, eco-friendly, bio-compatible, bio-adhesive, biodegradable, stable, etc. All those properties were systematically considered within this review. Carotenoids are functional components in the human diet with plenty of health benefits. However, their sensitivity to environmental and process stresses, chemical instability, easy oxidation, low water solubility, and bioavailability limit their food and pharmaceutical applications. Encapsulation may help in overcoming these limitations and within this review, the role of alginate-based encapsulation systems in improving the stability and bioavailability of carotenoids is explored. It may be concluded that all alginate-based systems increase carotenoid stability, but only those of micro- and nano-size, as well as emulsion-based, may improve their low bioaccessibility. In addition, the incorporation of other biopolymers may further improve encapsulation system properties. Furthermore, the main techniques for evaluating the encapsulation are briefly considered. This review critically and profoundly explains the role of alginates in improving the encapsulation process of carotenoids, suggesting the best alternatives for those systems. Moreover, it provides a comprehensive cover of recent advances in this field.

Current Treatment of Laryngopharyngeal Reflux

Objectives: Laryngopharyngeal reflux (LPR) is a complex syndrome characterized by the reflux of gastroduodenal contents into the pharynx or larynx, resulting in a range of symptoms, including chronic cough, throat clearing, pain, dysphagia, hoarseness, and dysphonia. Despite the lack of a gold standard for diagnosis or treatment, various strategies have been proposed to manage LPR. However, the effectiveness of these treatments is compromised by the lack of a uniform treatment protocol, which places a burden on patients, physicians, and the healthcare system. This study aims to systematically review the treatments of LPR and provide updated and useful clinical information to clinical physicians. Methods: The literature with an emphasis on LPR and related keywords is searched and reviewed in PubMed. Results: Treatment of LPR includes health education, lifestyle modification, dietary changes, medications, and surgery, as well as the emergence of a novel treatment method involving external upper esophageal sphincter compression devices. Conclusions: Currently, medication is the main treatment, supplemented with lifestyle and dietary changes, but there is still a lack of effective means for patients with drug-resistant or intolerant LPR. More high-quality and rigorous trials must continue to be conducted to determine the best treatment options and find novel treatments. Taking into account the complexity of LPR, this study proposes a simple algorithm to help clinicians with the initial management of this disease.

Topical Alginate Protection against Pepsin-Mediated Esophageal Damage: E-Cadherin Proteolysis and Matrix Metalloproteinase Induction

Epithelial barrier dysfunction is a hallmark of gastroesophageal reflux disease (GERD) related to symptom origination, inflammatory remodeling and carcinogenesis. Alginate-based antireflux medications were previously shown to topically protect against peptic barrier disruption, yet the molecular mechanisms of injury and protection were unclear. Herein, Barrett's esophageal (BAR-T) cells were pretreated with buffered saline (HBSS; control), dilute alginate medications (Gaviscon Advance or Gaviscon Double Action, Reckitt Benckiser), a viscosity-matched placebo, or ADAM10 and matrix metalloproteinase (MMP) inhibitors before exposure to HBSS pH7.4 or pH4 ± 1 mg/mL pepsin for 10-60 min. Cell viability was assessed by ATP assay; mediators of epithelial integrity, E-cadherin, ADAM10, and MMPs were examined by Western blot and qPCR. Alginate rescued peptic reduction of cell viability (p < 0.0001). Pepsin-pH4 yielded E-cadherin fragments indicative of regulated intramembrane proteolysis (RIP) which was not rescued by inhibitors of known E-cadherin sheddases. Transcriptional targets of E-cadherin RIP fragments were elevated at 24 h (MMP-1,2,9,14; p < 0.01). Alginate rescued E-cadherin cleavage, ADAM10 maturation, and MMP induction (p < 0.01). Results support RIP as a novel mechanism of peptic injury during GERD. Alginate residue after wash-out to mimic physiologic esophageal clearance conferred lasting protection against pepsin-induced molecular mechanisms that may exacerbate GERD severity and promote carcinogenesis in the context of weakly acidic reflux.

Laryngeal and Esophageal Mucosal Protection Using the Angico Gum Biopolymer in a Mouse Model of Reflux

OBJECTIVE

This study aimed to evaluate the in vivo protective effect of the angico gum biopolymer in reducing the inflammatory response and preserving the integrity of the laryngeal and esophageal mucosa.

STUDY DESIGN

Animal study.

METHODS

A murine surgical model of gastroesophageal reflux disease was accomplished and subsequently treated with angico gum or omeprazole. On days 3 and 7 post surgery, samples of the larynx and esophagus, respectively, were collected to measure the level of inflammation (wet weight and myeloperoxidase activity) and mucosal integrity (transepithelial electrical resistance and mucosal permeability to fluorescein).

RESULTS

Angico gum and omeprazole decreased laryngeal inflammation (wet weight and myeloperoxidase activity) and dramatically improved the integrity of the laryngeal mucosa. It also reduced inflammation (decreased wet weight and myeloperoxidase activity) of the esophagus and preserved the barrier function (inferred by assessing the integrity of the mucosa).

CONCLUSION

This study demonstrates the protective effect of angico gum in an experimental gastroesophageal reflux disease model. Angico gum attenuates inflammation and impairment of the mucosal barrier function not only in the larynx but also in the esophagus.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:162-168, 2023.

All Fiber is Not Fiber

PURPOSE OF REVIEW

Epidemiologic studies and clinical trials have demonstrated the benefits of dietary fiber. This occurs through a combination of the physiochemical properties of fiber and through microbial fermentation that occurs in the colon which result in the production of short-chain fatty acids (SCFA). The purpose of this review is to highlight the physiochemical properties of fiber that result in the range of physiologic effects and to review the literature on the health benefits of acetate, propionate, and butyrate.

RECENT FINDINGS

Of the variety of properties and functions exerted by dietary fibers, the fermentability and production of SCFA's are emphasized in this review. Studies done in both animal and humans reveal the anti-obesity, anti-inflammatory, and possible anti-neoplastic roles SCFAs exert at the mucosal level. Many clinical questions remain regarding the optimal dose, type, and method of delivery of fiber to exert the desired beneficial effects. It has the potential to be used in the management of clinical symptoms, prevention of disease, and improvement in human health. Further studies to address this novel use of fiber has the potential to make a large impact in clinical practice.

Impact of Flaxseed Gums on the Colloidal Changes and In Vitro Digestibility of Milk Proteins

Flaxseed (Linum usitatissimum L.) mucilage is one of the most studied plant seed gums in terms of its techno-functional and health-promoting properties. Nonetheless, the interplay of flaxseed gum (FG) with other food biopolymers, such as milk proteins, under in vitro digestion conditions remains underexplored. The aim of the present work was to investigate the colloidal interplay between flaxseed gum (golden or brown) and milk proteins (sodium caseinate or whey protein isolate) under simulated in vitro digestion conditions and its relationship with the attained in vitro protein digestibility. The presence of flaxseed gum in the milk protein food models and in the oral food boluses obtained was associated with the occurrence of segregative microphase separation. Flaxseed gum exhibited a prominent role in controlling the acid-mediated protein aggregation phenomena, particularly in the sodium caseinate gastric chymes. The addition of FG in the food models was associated with a higher amount of intact total caseins and β-lactoglobulin at the end of the gastric processing step. Monitoring of the intestinal processing step revealed a very advanced cleavage of the whey proteins (>98%) and caseins (>90%). The degree of the milk protein hydrolysis achieved at the end of the intestinal processing was significantly higher in the systems containing flaxseed gum (i.e., 59−62%) than their gum-free protein counterparts (i.e., 46−47%). It was postulated that the electrostatic milk protein complexation capacity and, to a lesser extent, the thickening effect of flaxseed gum influenced the in vitro digestibility of the milk proteins.

Encapsulation of Bromelain in Combined Sodium Alginate and Amino Acid Carriers: Experimental Design of Simplex-Centroid Mixtures for Digestibility Evaluation

Bromelain has potential as an analgesic, an anti-inflammatory, and in cancer treatments. Despite its therapeutic effects, this protein undergoes denaturation when administered orally. Microencapsulation processes have shown potential in protein protection and as controlled release systems. Thus, this paper aimed to develop encapsulating systems using sodium alginate as a carrier material and positively charged amino acids as stabilizing agents for the controlled release of bromelain in in vitro tests. The systems were produced from the experimental design of centroid simplex mixtures. Characterizations were performed by FTIR showing that bromelain was encapsulated in all systems. XRD analyses showed that the systems are semi-crystalline solids and through SEM analysis the morphology of the formed systems followed a pattern of rough microparticles. The application of statistical analysis showed that the systems presented behavior that can be evaluated by quadratic and special cubic models, with a p-value < 0.05. The interaction between amino acids and bromelain/alginate was evaluated, and free bromelain showed a reduction of 74.0% in protein content and 23.6% in enzymatic activity at the end of gastric digestion. Furthermore, a reduction of 91.6% of protein content and 65.9% of enzymatic activity was observed at the end of intestinal digestion. The Lis system showed better interaction due to the increased stability of bromelain in terms of the amount of proteins (above 63% until the end of the intestinal phase) and the enzymatic activity of 89.3%. Thus, this study proposes the development of pH-controlled release systems aiming at increasing the stability and bioavailability of bromelain in intestinal systems.

Simulated gastrointestinal digestion of protein alginate complexes: effects of whey protein cross-linking and the composition and degradation of alginate

Alginate and whey protein are common additives in food production improving storage stability, texture and nutritional value. Alginate forms complexes with whey protein and inhibits proteolysis by pepsin and trypsin, but the influence of alginate protein complexation on digestion is poorly understood. This study shows that whey protein cross-linking by microbial transglutaminase dramatically decreased particle size (2-fold) and viscosity of alginate protein complexes. The INFOGEST in vitro simulated gastrointestinal digestion of whey protein was increased by cross-linking (16%) and suppressed by alginate, most pronounced with high mannuronic acid and least with high guluronic acid content. Sizes of alginate whey protein particles increased during gastric digestion, whereas for cross-linked whey protein complexes the size initially increased, but returned to their initial size at the end of gastric digestion. While alginate is not degraded by human enzymes, a few gut bacteria were recently found to encode lyases and other enzymes metabolizing alginate. Alginate lyase added to the intestinal phase enhanced digestion (9%) as controlled by alginate composition and enzyme specificity. Thus we provide evidence that use of hydrocolloids and processing of protein strongly influence digestion and should be considered when using food additives.

Effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases: physiopathology and therapeutic targets

PURPOSE

Laryngopharyngeal reflux disease (LPRD) is a general term for the reflux of gastroduodenal contents into the laryngopharynx, oropharynx and even the nasopharynx, causing a series of symptoms and signs. Currently, little is known regarding the physiopathology of LPRD, and proton pump inhibitors (PPIs) are the drugs of choice for treatment. Although acid reflux plays a critical role in LPRD, PPIs fail to relieve symptoms in up to 40% of patients with LPRD. The influence of other reflux substances on LPRD, including pepsin, bile acid, and trypsin, has received increasing attention. Clarification of the substances involved in LPRD is the basis for LPRD treatment.

METHODS

A review of the effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases was conducted in PubMed.

RESULTS

Different reflux substances have different effects on LPRD, which will cause various symptoms, inflammatory diseases and neoplastic diseases of the laryngopharynx. For LPRD caused by different reflux substances, 24-h multichannel intraluminal impedance combined with pH-metry (MII-pH), salivary pepsin, bile acid and other tests should be established so that different drugs and treatment courses can be used to provide patients with more personalized treatment plans.

CONCLUSION

This article summarizes the research progress of different reflux substances on the pathogenesis, detection index and treatment of LPRD and lays a theoretical foundation to develop target drugs and clinical diagnosis and treatment.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

Pathophysiology and treatment options for gastroesophageal reflux disease: looking beyond acid

Gastroesophageal reflux disease (GERD) is a disorder due to the retrograde flow of refluxate into the esophagus. Although GERD is a common clinical diagnosis, its pathogenesis is quite complex. As a result of its multifactorial development, many patients continue to experience adverse symptoms due to GERD despite prolonged acid suppression with proton pump inhibitor therapy. The pathogenesis of GERD involves an interplay of chemical, mechanical, psychologic, and neurologic mechanisms, which contribute to symptom presentation, diagnosis, and treatment. As such, GERD should be approached as a disorder beyond acid. This review will investigate the major factors that contribute to the development of GERD, including factors related to the refluxate, esophageal defenses, and factors that promote pathologic reflux into the esophagus. In reviewing GERD pathogenesis, this paper will highlight therapeutic advances, with mention of future opportunities of study when approaching GERD.

Brown Seaweeds for the Management of Metabolic Syndrome and Associated Diseases

Metabolic syndrome is characterized by the coexistence of different metabolic disorders which increase the risk of developing type 2 diabetes mellitus and cardiovascular diseases. Therefore, metabolic syndrome leads to a reduction in patients' quality of life as well as to an increase in morbidity and mortality. In the last few decades, it has been demonstrated that seaweeds exert multiple beneficial effects by virtue of their micro- and macronutrient content, which could help in the management of cardiovascular and metabolic diseases. This review aims to provide an updated overview on the potential of brown seaweeds for the prevention and management of metabolic syndrome and its associated diseases, based on the most recent evidence obtained from in vitro and in vivo preclinical and clinical studies. Owing to their great potential for health benefits, brown seaweeds are successfully used in some nutraceuticals and functional foods for treating metabolic syndrome comorbidities. However, some issues still need to be tackled and deepened to improve the knowledge of their ADME/Tox profile in humans, in particular by finding validated indexes of their absorption and obtaining reliable information on their efficacy and long-term safety.

Natural Macromolecules as Carriers for Essential Oils: From Extraction to Biomedical Application

Essential oils (EOs) and their main constituents, the terpenes, are widely studied, mostly relating to their antioxidant ability and bioactivity, such as antimicrobial, anticancer, anti-inflammatory, and range of other actions in the living systems. However, there is limited information on their bioavailability, especially upon clinical studies. Having in mind both strong biological effects and health benefits of EOs and their specific physicochemical properties (volatility, lipophilic character, low water solubility or insolubility, viscosity, expressed odor, concentration-dependent toxicity, etc.), there is a need for their encapsulation for target delivery. Encapsulation of EOs and their constituents is the prerequisite for enhancing their oxidative stability, thermostability, photostability, shelf life, and biological activity. We considered various carrier types such a (1) monophase and polyphase polysaccharide hydrogel carriers, (2) polysaccharide-protein carriers, and (3) lipid carriers in the context of physicochemical and engineering factors. Physicochemical factors are encapsulation efficiency, chemical stability under gastric conditions, mechanical stability, and thermal stability of carrier matrices. Choice of carrier material also determines the encapsulation technique. Consequently, the engineering factors are related to the advantage and disadvantage of various encapsulation techniques frequently used in the literature. In addition, it was intended to address the interactions between (1) main carrier components, such as polysaccharides, proteins, and lipids themselves (in order to form chemically and mechanically stable structure); (2) main carrier components with pepsin under gastric conditions (in order to form resistant material under gastric conditions); and (3) main carrier components with EOs (in order to enhance encapsulation efficiency), as a necessary precondition for whole process optimization. Finally, different sources for obtaining natural carrier macromolecules are surveyed, especially the agro-waste materials and agricultural and food by-products. This review article highlights the bioavailability aspects of encapsulated EOs and physicochemical and engineering factors concerning natural macromolecule carriers for their target delivery and application.

Laryngeal Mucosa Alterations in Mice Model of Gastroesophageal Reflux: Effects of Topical Protection

OBJECTIVES/HYPOTHESIS

The objectives of this study were to evaluate laryngeal inflammation and mucosal integrity in a murine model of reflux disease and to assess the protective effects of topical agents including alginate, hyaluronic acid, and cashew gum.

STUDY DESIGN

Animal study.

METHODS

A surgical murine model of reflux disease was evaluated at 3 or 7 days postsurgery, and laryngeal samples were collected to measure inflammation (wet weight and myeloperoxidase [MPO]) and mucosal integrity (transepithelial resistance [TER] and mucosal permeability to fluorescein). Additional groups of animals were administered one of several topical agents (alginate, hyaluronic acid, or cashew gum) daily, and laryngeal inflammation and mucosal integrity were evaluated at 3 days postsurgery.

RESULTS

At 3 days, and not 7 days postsurgery, we observed increased laryngeal wet weight and MPO, decreased laryngeal TER, and increased laryngeal mucosa permeability. Alginate partially decreased laryngeal inflammation (wet weight and not MPO) and dramatically improved laryngeal mucosal integrity. Conversely, hyaluronic acid eliminated the inflammation; however, it had no effect on laryngeal mucosal integrity impairment. Cashew gum eliminated laryngeal inflammation as well as the impairment in laryngeal mucosal integrity.

CONCLUSIONS

This study shows that a surgical model of reflux disease induced laryngeal inflammation and impairment in laryngeal barrier function. These observed alterations were partially attenuated by alginate and hyaluronic acid and completely reversed by cashew gum.

LEVEL OF EVIDENCE

NA Laryngoscope, 2020.

Effect of sulfated polysaccharides on the digestion of DNA by pepsin under simulated gastric juice in vitro

The effect of sulfated polysaccharides on the digestion of dietary DNA by pepsin was studied using in vitro simulated gastric juice. The results showed that fucoidan (FUC), dextran sulfate (DS) and chondroitin sulfate (CS) could inhibit the digestion of DNA in a dose-dependent manner. Polysaccharides with high sulfate group content have stronger inhibition ability. Fluorescence spectroscopy results showed that polysaccharides could bind to pepsin, and transmission electron microscopy (TEM) confirmed that polysaccharides can interact with DNA, which not only is the main reason that polysaccharides inhibit the digestion of DNA by pepsin but also causes the digestion of DNA by DNase II to be inhibited. The finding suggests that the digestion of DNA should be reevaluated when eating foods rich in sulfated polysaccharides. This study enriched the known pharmacological properties of sulfated polysaccharides as pepsin inhibitors and provided inspiration for the use of sulfated polysaccharides as oligonucleotide drug delivery carriers.

In vitro investigation of the influence of nano-fibrillated cellulose on lipid digestion and absorption

Nanocellulose, including nano-fibrillated cellulose (NFC), has been a topic of significant interest and a number of studies have focused on using it for the fabrication of stable oil-in-water emulsions. However, limited studies have been performed to understand the potential influence of NFC on lipid digestion and absorption. In this study, a simulated digestion model, consisting of salivary, gastric and intestinal digestion phases, was used to investigate the effects of NFC on lipid digestion and absorption. To better understand the mechanisms behind, the effects of NFC on lipase activity, micellar solubility of cholesterol and bile acid diffusion were studied in addition to the cholesterol adsorption capacity of NFC, with conventional cellulose as a comparison. Results showed that NFC slightly reduced lipase activity, but NFC or cellulose at concentrations up to 1.1% (w/w) did not significantly influence lipid digestion under simulated intestinal conditions. Moreover, NFC showed greater bile acid retardation effect than cellulose, and slightly higher cholesterol adsorption capacity probably due to its larger specific surface area. Nonetheless, NFC did not significantly affect micellar solubility of cholesterol. These results suggest that NFC, when added into fat-rich foods, may have health benefits via its viscosity effect and retardation effect on bile acid absorption.

Genetic, structural and pharmacological characterization of polymannuronate synthesized by algG mutant indigenous soil bacterium Pseudomonas aeruginosa CMG1421

AIMS

It was aimed to study the genetic, structural and pharmacological characteristics of polymannuronate synthesized by Pseudomonas aeruginosa CMG1421.

METHODS AND RESULTS

Synthesis was analysed by transmission electron microscopy, FT/IR, ¹ H-NMR and gel permeation chromatography followed by in vitro bioassays. Colony PCR followed by sequence analysis was employed for screening of structural genes. FT/IR analysis indicated the presence of hydroxyl, carboxyl and O-acetyl groups linked to mannuronate. ¹ H-NMR analysis indicated M-M bond characteristics for mannuronic acid residues. The average relative molecular weight was found in range of 20 000-250 000 Da. The amplified DNA fragments were identified as 16S rRNA, algD, alg8, alg44, algG, algE and algX genes showing 99-100% homology with those of P. aeruginosa. However, in algG there were transition mutations of adenine and cytosine at nucleotide position 766 and 769, and 878 and 881 respectively. Polymannuronate and its oligomannuronates respectively showed moderate and significant antioxidant, anti-inflammatory, anti-obesity and antidiabetic activities.

CONCLUSIONS

Alginate synthesized by ∆algG mutant P. aeruginosa CMG1421 was bioactive and solely consists of acetylated d-mannuronates.

SIGNIFICANCE AND IMPACT OF THE STUDY

We investigated biocompatible, nonimmunogenic and nontoxic pharmacological agents for treatment and attenuation of degenerative, inflammatory, autoimmune disease, and metabolic disorders such as obesity and diabetes.

Designing food delivery systems: challenges related to the in vitro methods employed to determine the fate of bioactives in the gut

This review discussesin vitroavailable approaches to study delivery and uptake of bioactive compounds and the associated challenges.