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510 result(s) for "Dextrins - chemistry"
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Consumption of the Soluble Dietary Fibre Complex PolyGlycopleX® Reduces Glycaemia and Increases Satiety of a Standard Meal Postprandially
The effect of consumption of PolyGlycopleX® (PGX®) was compared to wheat dextrin (WD) in combination with a standard meal, on postprandial satiety and glycaemia in a double-blind, randomised crossover trial, of 14 healthy subjects trained as a satiety panel. At each of six two-hour satiety sessions, subjects consumed one of three different test meals on two separate occasions. The test meals were: a standard meal plus 5 g PGX; a standard meal plus 4.5 g of PGX as softgels; and a standard meal plus 5 g of WD. Subjects recorded fullness using a labelled magnitude scale at 0, 15, 30, 45, 60, 90, and 120 min and the total area under the curve (AUC), mean fullness vs. time was calculated. The meals with PGX (in granular and softgel form) gave higher satiety (AUC) (477 ± 121 and 454 ± 242 cm·min), than the meal with WD (215 ± 261 cm·min) (p < 0.001). Subjects had blood glucose levels measured after the meals with PGX (granules) and WD. Glucose response (AUC) was significantly lower (p < 0.001) after the PGX meal than for the WD meal. The high viscosity reported for PGX is a likely mechanism behind the significant satiety and blood glucose modulating effects observed in this study.
Findings from an online behavioural weight management programme provided with or without a fortified diet beverage
The present multi-centre randomised weight-loss trial evaluated the efficacy of a low-intensity 12-week online behavioural modification programme, with or without a fortified diet beverage using a 2 × 2 factorial design. A total of 572 participants were randomised to: (1) an online basic lifestyle information (OBLI) intervention, consisting of one online informational class about tips for weight management; (2) an online behavioural weight management (OBWM) intervention, entailing 12 weekly online classes focused on weight-loss behaviour modification; (3) an OBLI intervention plus a fortified diet cola beverage (BEV) containing green tea extract (total catechin 167 mg), soluble fibre dextrin (10 g) and caffeine (100 mg) (OBLI+BEV); (4) OBWM+BEV. Assessments included height, weight, dual-energy X-ray absorptiometry-derived body composition, and waist circumference (WC). Attrition was 15·7 %. Intention-to-treat (ITT) models demonstrated a main effect for type of Internet programme, with those assigned to the OBWM condition losing significantly more weight (F= 7·174; P= 0·008) and fat mass (F= 4·491; P= 0·035) than those assigned to the OBLI condition. However, there was no significant main effect for the OBWM condition on body fat percentage (F= 2·906; P= 0·089) or WC (F= 3·351; P= 0·068), and no significant main effect for beverage use or significant interactions between factors in ITT models. A 12-week, low-intensity behaviourally based online programme produced a greater weight loss than a basic information website. The addition of a fortified diet beverage had no additional impact.
The Iodine–Dextrin–Lithium Complex: Morphology, Antibacterial Activity, and Cytotoxicity
A new iodine–dextrin–lithium complex (IDLC) was synthesized and structurally characterized as a hybrid supramolecular system combining antiseptic, stabilizing, and biocompatible components. The compound integrates iodine as the primary antimicrobial agent, lithium as a coordination and stabilization element, and dextrin as a biodegradable polysaccharide matrix enabling sustained release. Physicochemical analyses confirmed the formation of a uniform, thermally stable complex. Biological evaluation revealed strong bactericidal activity, with minimum bactericidal concentrations (MBCs) ranging from 1.95 to 15.63 µg mL−1 against both Gram-positive and Gram-negative pathogens, including multidrug-resistant Staphylococcus aureus and Acinetobacter baumannii. Cytotoxicity studies revealed moderate, concentration-dependent effects on human peripheral blood mononuclear cells (CC50 = 0.23–0.48 mg/mL; 11.7–24.4 μg I/mL) and low toxicity toward MDCK cells (CC50 = 10–20 mg/mL; 507–1014 μg I/mL), confirming a favorable safety profile. IDLC exhibited cytotoxic effects on tumor cell lines (HepG2, HeLa, AGS, K562, and H9) as well as on the normal MeT-5A cell line; however, the CC50 values are similar, and selectivity indices are close to 1, indicating no selective cytotoxicity toward tumor cells. Thus, IDLC demonstrates non-specific cytotoxicity at high concentrations, consistent with its iodine content. The research confirms that iodine can be effectively stabilized within a dextrin-lithium framework to yield a biologically active, thermally resistant complex, suitable for pharmaceutical use.
Enzyme-activated intracellular drug delivery with tubule clay nanoformulation
Fabrication of stimuli-triggered drug delivery vehicle s is an important milestone in treating cancer. Here we demonstrate the selective anticancer drug delivery into human cells with biocompatible 50-nm diameter halloysite nanotube carriers. Physically-adsorbed dextrin end stoppers secure the intercellular release of brilliant green. Drug-loaded nanotubes penetrate through the cellular membranes and their uptake efficiency depends on the cells growth rate. Intercellular glycosyl hydrolases-mediated decomposition of the dextrin tube-end stoppers triggers the release of the lumen-loaded brilliant green, which allowed for preferable elimination of human lung carcinoma cells (А549) as compared with hepatoma cells (Hep3b). The enzyme-activated intracellular delivery of brilliant green using dextrin-coated halloysite nanotubes is a promising platform for anticancer treatment.
Biopolymer-coated gold nanoparticles inhibit human insulin amyloid fibrillation
Deposits of protein misfolding and/or aggregates are a pathological hallmark of amyloid-related diseases. For instance, insulin amyloid fibril deposits have been observed in patients with insulin-dependent diabetes mellitus after insulin administration. Here, we report on the use of AuNPs functionalized with linear- (i.e. dextrin and chitosan) and branched- (i.e. dextran-40 and dextran-10) biopolymers as potential agents to inhibit insulin fibril formation. Our dynamic light scattering analyses showed a size decrease of the amyloid fibrils in the presence of functionalized AuNPs. Circular dichroism spectroscopy as well as enzyme-linked immunosorbent assay data demonstrated that the secondary structural transition from α-helix to β-sheet (which is characteristic for insulin amyloid fibril formation) was significantly suppressed by all biopolymer-coated AuNPs, and in particular, by those functionalized with linear biopolymers. Both transmission electron microscopy and atomic force microscopy analyses showed that the long thick amyloid fibrils formed by insulin alone become shorter, thinner or cluster when incubated with biopolymer-coated AuNPs. Dextrin- and chitosan-coated AuNPs were found to be the best inhibitors of the fibril formation. Based on these results, we propose a mechanism for the inhibition of insulin amyloid fibrils: biopolymer-coated AuNPsstrongly interact with the insulin monomers and inhibit the oligomer formation as well as elongation of the protofibrils.Moreover, cytotoxicity experiments showed that AuNP-insulin amyloid fibrils are less toxic compared to insulin amyloid fibrils alone. Our results suggest that both dextrin- and chitosan-AuNPs could be used as therapeutic agents for the treatment of amyloid-related disorders.
Molecular Structure and Properties of Resistant Dextrins from Potato Starch Prepared by Microwave Heating
The dextrinization of potato starch was performed using a sophisticated single-mode microwave reactor with temperature and pressure control using 10 cycles of heating with stirring between cycles. Microwave power from 150 to 250 W, a cycle time from 15 to 25 s, and two types of vessels with different internal diameters (12 and 24 mm) and therefore different thicknesses of the heated starch layer were used in order to estimate the impact of vessel size used for microwave dextrinization. The characteristics of resistant dextrins (RD) including solubility in water, total dietary fiber (TDF) content, color parameters, the share of various glycosidic bonds, and pasting and rheological properties were carried out. The applied conditions allowed us to obtain RDs with water solubility up to 74% at 20 °C, as well as TDF content up to 47%, with a predominance of low-molecular-weight soluble fiber fraction, with increased content of non-starch glycosidic bonds, negligible viscosity, and a slightly beige color. The geometry of the reaction vessel influenced the properties of dextrins obtained under the same heating power, time, and repetition amounts. Among the conditions used, the most favorable conditions were heating 10 times for 20 s at 200 W in a 10 mL vessel and the least favorable were 15 s cycles.
Effects of Resistant Dextrin from Potato Starch on the Growth Dynamics of Selected Co-Cultured Strains of Gastrointestinal Bacteria and the Activity of Fecal Enzymes
Preparations of resistant dextrins have become an interesting topic of research due to their properties, which bear resemblance those of prebiotics, e.g., the improvement of metabolic parameters, increased efficiency of the immune system and induction of vitamin production. The aim of this study was to investigate the effects of the resistant dextrin produced from potato starch on the growth dynamics of typical gastrointestinal microbiota and the activity of fecal enzymes in order to assess a possible exhibition of prebiotic properties. In the study, in vitro cultivation of co-cultures of Lactobacillus, Bifidobacterium, E. coli, Enterococcus, Clostridium and Bacteroides spp. was conducted on media enriched with the resistant dextrin. The CFU/mL for each strain was measured in time periods of 24, 48, 72, 96 and 168 h. Furthermore, the activities of α-glucosidase, α-galactosidase, β-glucosidase, β-galactosidase and β-glucuronidase were determined using spectrophotometric methods at a wavelength of 400 nm. The results show that the resistant dextrin can be utilized as a source of carbon for the growth of intestinal bacteria. Moreover, the results revealed that, after 168 h of cultivation, it enhances the viability of probiotic strains of Lactobacillus and Bifidobacterium spp. and decreases the growth of other intestinal strains (Clostridium, Escherichia coli, Enterococcus and Bacteroides), which is demonstrated by a high Prebiotic Index (p < 0.05). Furthermore, there was no significant change in the pH of the cultures; however, the pace of the pH decrease during the cultivation was slower in the case of culture with resistant dextrin. Furthermore, it was revealed that usage of the resistant dextrin as a medium additive noticeably lowered the activities of β-glucosidase and β-glucuronidase compared to the control (p < 0.05), whereas the activities of the other fecal enzymes were affected to a lesser degree. The resistant dextrins derived from potato starch are a suitable prebiotic candidate as they promote the growth of beneficial strains of gut bacteria and improve health markers, such as the activity of fecal enzymes. Nevertheless, additional in vivo research is necessary to further assess the suspected health-promoting properties.
Cosmetically Applicable Soluble Agonists for Toll-like Receptor 2 Produced by Fermentation of Asparagus Extract Supplemented with Skimmed Milk Using Lactobacillus delbrueckii subsp. lactis TL24 Consist of Molecules Larger than 100 kDa and Can Be Stabilized by Lyophilization with Dextrin
Cosmetically applicable soluble agonists for Toll-like receptor 2 (TLR2), which can strengthen skin barrier function, were produced by fermentation of asparagus (Asparagus officinalis L.) extract supplemented with skimmed milk using Lactobacillus delbrueckii subsp. lactis TL24. Their molecular size was estimated to be >100 kDa. Their TLR2-stimulating activity was stable over 1 year at 4 °C, but it decreased by more than 95% within 10 and 4 months at 25 °C and 40 °C, respectively. The possibility of stabilization of TLR2-stimulating activity by powdering was tested, and we found that lyophilization with 10% or a higher amount of dextrin could stabilize the activity even at 40 °C. The powdered fermented product dose-dependently stimulated TLR2. It augmented the formation of tight junctions in normal human keratinocytes, as detected by fluorescence staining of occludin and ZO-1, whereas their protein and gene expression levels did not increase, suggesting that a change in subcellular localization of these proteins without significant changes in their amounts might be responsible. The powder nature has some benefits over the aqueous, besides stability, e.g., it can be dissolved just before application, allowing fresh material to be used each time, and it may widen a range of cosmetic applications in non-aqueous types of cosmetics.
Modification of the Antibiotic, Colistin, with Dextrin Causes Enhanced Cytotoxicity and Triggers Apoptosis in Myeloid Leukemia
Acute myeloid leukemia (AML) remains difficult to treat due to its heterogeneity in molecular landscape, epigenetics and cell signaling alterations. Precision medicine is a major goal in AML therapy towards developing agents that can be used to treat patients with different 'subtypes' in combination with current chemotherapies. We have previously developed dextrin-colistin conjugates to combat the rise in multi-drug resistant bacterial infections and overcome dose-limiting nephrotoxicity. Recent evidence of colistin's anticancer activity, mediated through inhibition of intracellular lysine-specific histone demethylase 1 (LSD1/KDM1A), suggests that dextrin-colistin conjugates could be used to treat cancer cells, including AML. This study aimed to evaluate whether dextrin conjugation (which reduces in vivo toxicity and prolongs plasma half-life) could enhance colistin's cytotoxic effects in myeloid leukemia cell lines and compare the intracellular uptake and localization of the free and conjugated antibiotic. Our results identified a conjugate (containing 8000 g/mol dextrin with 1 mol% succinoylation) that caused significantly increased toxicity in myeloid leukemia cells, compared to free colistin. Dextrin conjugation altered the mechanism of cell death by colistin, from necrosis to caspase 3/7-dependent apoptosis. In contrast, conjugation via a reversible ester linker, instead of an amide, had no effect on the mechanism of the colistin-induced cell death. Live cell confocal microscopy of fluorescently labelled compounds showed both free and dextrin-conjugated colistins were endocytosed and co-localized in lysosomes, and increasing the degree of modification by succinoylation of dextrin significantly reduced colistin internalization. Whilst clinical translation of dextrin-colistin conjugates for the treatment of AML is unlikely due to the potential to promote antimicrobial resistance (AMR) and the relatively high colistin concentrations required for anticancer activity, the ability to potentiate the effectiveness of an anticancer drug by polymer conjugation, while reducing side effects and improving biodistribution of the drug, is very attractive, and this approach warrants further investigation.
FeedER: a feedback-regulated enzyme-based slow-release system for fed-batch cultivation in microtiter plates
With the advent of modern genetic engineering methods, microcultivation systems have become increasingly important tools for accelerated strain phenotyping and bioprocess engineering. While these systems offer sophisticated capabilities to screen batch processes, they lack the ability to realize fed-batch processes, which are used more frequently in industrial bioprocessing. In this study, a novel approach to realize a feedback-regulated enzyme-based slow-release system (FeedER), allowing exponential fed-batch for microscale cultivations, was realized by extending our existing Mini Pilot Plant technology with a customized process control system. By continuously comparing the experimental growth rates with predefined set points, the automated dosage of Amyloglucosidase enzyme for the cleavage of dextrin polymers into d-glucose monomers is triggered. As a prerequisite for stable fed-batch operation, a constant pH is maintained by automated addition of ammonium hydroxide. We show the successful application of FeedER to study fed-batch growth of different industrial model organisms including Corynebacterium glutamicum, Pichia pastoris, and Escherichia coli. Moreover, the comparative analysis of a C. glutamicum GFP producer strain, cultivated under microscale batch and fed-batch conditions, revealed two times higher product yields under slow growing fed-batch operation. In summary, FeedER enables to run 48 parallel fed-batch experiments in an automated and miniaturized manner, and thereby accelerates industrial bioprocess development at the screening stage.