Effectiveness of Chitosan as a Dietary Supplement in Lowering Cholesterol in Murine Models: A Meta-Analysis

Low protein digestibility-corrected amino acid score and net nitrogen-to-protein conversion factor value of edible insects

The amount of chitin, a nitrogen-containing dietary fiber, in edible insects can mislead the exact nitrogen-to-protein conversion factor (NPF) and true protein content. We determined the amino acid score (AAS), protein digestibility-corrected AAS (PDCAAS), chitin content, and net NPF of five edible insects. Additionally, the effect of the amino acid composition of migratory locust on rat growth were investigated. The AAS of the insects were ranged from 63 to 94. The chitin contents were ranged from 1.6 g/100 g to 10.7 g/100 g. The PDCAAS, calculated by AAS and gut-intestinal digestibility, ranged from 44 to 81, which was lower than casein (97). The net NPF ranged from 4.93 to 5.76, which were lower than the conventional value. Dietary migratory locust, whose PDCAAS was the lowest, decreased growth and altered lipid metabolism. Therefore, a lower PDCAAS and overestimation of net NPF of insects can affect the true protein calculations and growth.

In vitro and in silico studies of the potential cytotoxic, antioxidant, and HMG CoA reductase inhibitory effects of chitin from Indonesia mangrove crab (Scylla serrata) shells

This study aimed to characterize chitin extracted from Indonesia mangrove crab (Scylla serrata) shells, as well as to assess its in vitro cytotoxic, antioxidant, and HMG CoA reductase inhibitory potentials. In silico molecular docking, molecular dynamic, and ADMET prediction analyses were also carried out. Chitin was extracted from mangrove crab shells using deproteination and demineralization processes, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) characterization are then performed. The MTT method was further tested in a study of cell viability, while in vitro method was used to assess HMG CoA reductase inhibitory and antioxidant activities. The extracted chitin was found to have a moderate level of cytotoxic and antioxidant activities. In vitro studies showed that it has an IC50 of 36,65 ± 0,082 μg/mL as an HMG CoA reductase inhibitor, and decreased enzyme activity by 68.733 % at 100 μg/mL as a concentration. Furthermore, in the in silico study, chitin showed a strong affinity to several targets, including HMG CoA reductase, HMG synthase, LDL receptor, PPAR-alfa, and HCAR-2 with binding energies of -5.7; -5.8; -3.6; -5.6; -4.6 kcal/mol, respectively. Based on the ADMET properties, it had non-toxic molecules, which were absorbed and distributed across the blood-brain barrier. The molecular dynamics (MD) simulation also showed that it remained stable in the active sites of HMG CoA reductase receptor for 100 ns. These results indicated that chitin from Indonesian mangrove crab shells can be used to develop more potent HMG CoA reductase inhibitor with antioxidant and cytotoxic activities for effective dyslipidemia therapy.

Synthesis and Functions of Resistant Starch

Resistant starch (RS) has become a popular topic of research in recent years. Most scholars believe that there are 5 types of RS. However, accumulating evidence indicates that in addition to starch-lipid complexes, which are the fifth type of RS, complexes containing starch and other substances can also be generated. The physicochemical properties and physiologic functions of these complexes are worth exploring. New physiologic functions of several original RSs are constantly being discovered. Research shows that RS can provide health improvements in many patients with chronic diseases, including diabetes and obesity, and even has potential benefits for kidney disease and colorectal cancer. Moreover, RS can alter the short-chain fatty acids and microorganisms in the gut, positively regulating the body's internal environment. Despite the increase in its market demand, RS production remains limited. Upscaling RS production is thus an urgent requirement. This paper provides detailed insights into the classification, synthesis, and efficacy of RS, serving as a starting point for the future development and applications of RS based on the current status quo.

Reduction-Responsive Chitosan-Based Injectable Hydrogels for Enhanced Anticancer Therapy

Selective delivery of anticancer drug molecules to the tumor site enhances local drug dosages, which leads to the death of cancer cells while simultaneously minimizing the negative effects of chemotherapy on other tissues, thereby improving the patient's quality of life. To address this need, we developed reduction-responsive chitosan-based injectable hydrogels via the inverse electron demand Diels-Alder reaction between tetrazine groups of disulfide-based cross-linkers and norbornene groups of chitosan derivatives, which were applied to the controlled delivery of doxorubicin (DOX). The swelling ratio, gelation time (90-500 s), mechanical strength (G'~350-850 Pa), network morphology, and drug-loading efficiency (≥92%) of developed hydrogels were investigated. The in vitro release studies of the DOX-loaded hydrogels were performed at pH 7.4 and 5.0 with and without DTT (10 mM). The biocompatibility of pure hydrogel and the in vitro anticancer activity of DOX-loaded hydrogels were demonstrated via MTT assay on HEK-293 and HT-29 cancer cell lines, respectively.

Edible mushrooms as potential functional foods in amelioration of hypertension

Edible mushrooms are popular functional foods attributed to their rich nutritional bioactive constituent profile influencing cardiovascular function. Edible mushrooms are omnipresent in various prescribed Dietary Approaches to Stop Hypertension, Mediterranean diet, and fortified meal plans as they are rich in amino acids, dietary fiber, proteins, sterols, vitamins, and minerals. However, without an understanding of the influence of mushroom bioactive constituents, mechanism of action on heart and allergenicity, it is difficult to fully comprehend the role of mushrooms as dietary interventions in alleviating hypertension and other cardiovascular malfunctions. To accomplish this endeavor, we chose to review edible mushrooms and their bioactive constituents in ameliorating hypertension. Hypertension and cardiovascular diseases are interrelated and if the former is managed by dietary changes, it is postulated that overall heart health could also be improved. With a concise note on different edible varieties of mushrooms, a particular focus is presented on the antihypertensive potential of mushroom bioactive constituents, mode of action, absorption kinetics and bioavailability. Ergosterol, lovastatin, cordycepin, tocopherols, chitosan, ergothioneine, γ-aminobutyric acid, quercetin, and eritadenine are described as essential bioactives with hypotensive effects. Finally, safety concerns on allergens and limitations of consuming edible mushrooms with special reference to chemical toxins and their postulated metabolites are highlighted. It is opined that the present review will redirect toxicologists to further investigate mushroom bioactives and allergens, thereby influencing dietary interventions for heart health.

Antidiabetic Properties of Chitosan and Its Derivatives

Diabetes mellitus is a chronic metabolic disorder. In addition to taking medication, adjusting the composition of the diet is also considered one of the effective methods to control the levels of blood glucose. Chitosan and its derivatives are natural and versatile biomaterials with health benefits. Chitosan has the potential to alleviate diabetic hyperglycemia by reducing hepatic gluconeogenesis and increasing skeletal muscle glucose uptake and utility. Scientists also focus on the glucose-lowering effect of chitosan oligosaccharide (COS). COS supplementation has the potential to alleviate abnormal glucose metabolism in diabetic rats by inhibiting gluconeogenesis and lipid peroxidation in the liver. Both high and low molecular weight chitosan feeding reduced insulin resistance by inhibiting lipid accumulation in the liver and adipose tissue and ameliorating chronic inflammation in diabetic rats. COS can reduce insulin resistance but has less ability to reduce hepatic lipids in diabetic rats. A clinical trial showed that a 3-month administration of chitosan increased insulin sensitivity and decreased body weight and triglycerides in obese patients. Chitosan and COS are considered Generally Recognized as Safe; however, they are still considered to be of safety concerns. This review highlights recent advances of chitosan and its derivatives in the glucose-lowering/antidiabetic effects and the safety.

Mechanical Amorphization of Chitosan with Different Molecular Weights

Mechanical amorphization of three chitosan samples with high, medium, and low molecular weight was studied. It is shown that there are no significant differences between the course of amorphization process in a planetary ball mill of chitosan with different molecular weights, and the maximum degree of amorphization was achieved in 600 s of high intensity mechanical action. Specific energy consumption was 28 kJ/g, being comparable to power consumption for amorphization of cellulose determined previously (29 kJ/g) and 5–7-fold higher than that for amorphization of starch (4–6 kJ/g). Different techniques for determining the crystallinity index (CrI) of chitosan (analysis of the X-ray diffraction (XRD) data, the peak height method, the amorphous standard method, peak deconvolution, and full-profile Rietveld analysis) were compared. The peak height method is characterized by a broader working range but provides deviated CrI values. The peak deconvolution method (with the amorphous Voigt function) makes it possible to calculate the crystallinity index of chitosan with greater accuracy, but the analysis becomes more difficult with samples subjected to mechanical processing. In order to refine the structure and calculation of CrI by the Rietveld method, an attempt to optimize the structure file by the density functional theory (DFT) method was performed. The averaged profile of amorphous chitosan approximated by an eighth-order Fourier model improved the correctness of the description of the amorphous contribution for XRD data processing. The proposed equation may be used as a universal standard model of amorphous chitosan to determine the crystallinity index both for the amorphous standard method and for peak deconvolution of XRD patterns for arbitrary chitosan samples.

On the mechanism of the cholesterol lowering ability of soluble dietary fibers: Interaction of some bile salts with pectin, alginate, and chitosan studied by isothermal titration calorimetry

Reducing high blood cholesterol is an important strategy to decrease the chances of a cardiovascular disease occurrence, the main cause of mortality in western developed countries. Therefore, the search for an alternative therapeutic or preventive approach being natural, biocompatible, and not toxic is still more relevant than ever. This need is particularly felt in Pediatrics for treating childhood hypercholesterolemia, due to statins interference in the production of steroid hormones in prepuberal children. Notwithstanding the general acceptance of the healthy role of the fibers in the diet, the mechanism underlying the cholesterol-lowering ability of soluble fibers is still under discussion. Therefore, we started a systematic study of the binding ability of some soluble dietary fibers (SDF) originated from different natural sources toward selected bile salts (BS) by isothermal titration calorimetry (ITC). Here we report the results of our ITC studies on the interaction of alginate, pectin and chitosan with sodium cholate (NaC), sodium deoxycholate (NaDC), sodium taurocholate (NaTC) and sodium taurodeoxycholate (NaTDC). Thermodynamic data on the micelle formation process of the above bile salts, as a premise to the study of their binding ability to the SDF, are also reported. Alginate does not show specific binding interaction with BS, while pectin shows a strong exothermic bond with NaDC in monomeric form. Chitosan, positively charged and soluble only at low pH, shows strong exothermic interactions with NaTC and NaTDC (soluble at pH = 3 in acetate buffer) with precipitate formation. For NaTC, the exothermic peak starts at about 5 mM. At this concentration NaTC bound on the fiber reaches locally the cmc value and micelles start forming on the fiber inducing its conformational change. For NaTDC the same process occurs at much lower concentrations, due to lower cmc, and with a greater quantity of heat involved. The first set of results here presented shows that for some SDF the binding of BS could be an important mechanism in cholesterol lowering but not the only one. The information here presented could be a starting point for the design of optimized functional foods with high cholesterol lowering ability.

Chitosan: A review of molecular structure, bioactivities and interactions with the human body and micro-organisms

Chitosan has many desirable attributes e.g. antimicrobial properties and promoting wound healing, and is used in various applications. This article first discusses how degree of deacetylation (DD) and molecular weight (MW) impacts on what level of bioactivities chitosan manifests, then introduces the "molecular chain configuration" model to explain various possible mechanisms of antimicrobial interactions between chitosan with different MW and different types of bacteria. Similarly, the possible pathways of how chitosan reacts with cancer and the body's immune system to demonstrate immune and antitumor effects are also discussed by using this model. Moreover, the possible mechanisms of how chitosan enhances coagulation and wound healing are also discussed. With these beneficial bioactivities in mind, the application of chitosan in surgery, tissue engineering and oncology is outlined. This review concludes that as chitosan demonstrates many beneficial bioactivities via multiple mechanisms, it is an important polymer with a promising future in medicine.

Bone Quantification Around Chitosan-Coated Titanium Dental Implants: A Preliminary Study by Micro-CT Analysis in Jaw of a Canine Model

Surface treatments of Ti in the dental implant industry are performed with the aim of in-creasing its bioactivity and osseointegration capacity. Chitosan (Cht) is a polysaccharide that has been proposed as a promising biomaterial in tissue engineering and bone regeneration, due to its ability to stimulate the recruitment and adhesion of osteogenic progenitor cells. The aim of our preliminary study was to evaluate, by micro-computed tomography (micro-CT), the osseointegration and bone formation around Cht-coated implants and to compare them with conventional surface-etched implants (SLA type). Four im-plants (8.5 mm length × 3.5 mm Ø) per hemiarch, were inserted into the jaws of five dogs, divided into two groups: chitosan-coated implant group (ChtG) and control group (CG). Twelve weeks after surgery, euthanasia was performed, and sectioned bone blocks were obtained and scanned by micro-CT and two bone parameters were measured: bone in contact with the implant surface (BCIS) and peri-implant bone area (PIBA). For BCIS and PIBA statistically significant values were obtained for the ChtG group with respect to CG (p = 0.005; p = 0.014 and p < 0.001 and p = 0.002, respectively). The results, despite the limitations, demonstrated the usefulness of chitosan coatings. However, studies with larger sample sizes and adequate experimental models would be necessary to confirm the results.

Chitosan as a Tool for Sustainable Development: A Mini Review

New developments require innovative ecofriendly materials defined by their biocompatibility, biodegradability, and versatility. For that reason, the scientific society is focused on biopolymers such as chitosan, which is the second most abundant in the world after cellulose. These new materials should show good properties in terms of sustainability, circularity, and energy consumption during industrial applications. The idea is to replace traditional raw materials with new ecofriendly materials which contribute to keeping a high production rate but also reducing its environmental impact and the costs. The chitosan shows interesting and unique properties, thus it can be used for different purposes which contributes to the design and development of sustainable novel materials. This helps in promoting sustainability through the use of chitosan and diverse materials based on it. For example, it is a good sustainable alternative for food packaging or it can be used for sustainable agriculture. The chitosan can also reduce the pollution of other industrial processes such as paper production. This mini review collects some of the most important advances for the sustainable use of chitosan for promoting circular economy. Hence, the present review focuses on different aspects of chitosan from its synthesis to multiple applications.