Antidiabetic Properties of Chitosan and Its Derivatives

Chitosanase-immobilized magnetite-agar gel particles as a highly stable and reusable biocatalyst for enhanced production of physiologically active chitosan oligosaccharides

A novel immobilized chitosanase was developed and utilized to produce chitosan oligosaccharides (COSs) via chitosan hydrolysis. Magnetite-agar gel particles (average particle diameter: 338 μm) were prepared by emulsifying an aqueous agar solution dispersing 200-nm magnetite particles with isooctane containing an emulsifier at 80 °C, followed by cooling the emulsified mixture. The chitosanase from Bacillus pumilus was immobilized on the magnetite-agar gel particles chemically activated by introducing glyoxyl groups with high immobilization yields (>80%), and the observed specific activity of the immobilized chitosanase was 16% of that of the free enzyme. This immobilized chitosanase could be rapidly recovered from aqueous solutions by applying magnetic force. The thermal stability of the immobilized chitosanase improved remarkably compared with that of free chitosanase: the deactivation rate constants at 35 °C of the free and immobilized enzymes were 8.1 × 10-5 and 3.9 × 10-8 s-1, respectively. This immobilized chitosanase could be reused for chitosan hydrolysis at 75 °C and pH 5.6, and 80% of its initial activity was maintained even after 10 cycles of use. COSs with a degree of polymerization (DP) of 2-7 were obtained using this immobilized chitosanase, and the product content of physiologically active COSs (DP ≥ 5) reached approximately 50%.

Modulatory effect of interleukin-2 loaded chitosan nano sphere on regulatory T cell activity in streptozotocin-induced diabetic mice

OBJECTIVE

The current study aimed to assess the modulating effect of IL-2 encapsulated chitosan-nanoparticles (CSNPs) on the function of Treg cells through induction of type 1 diabetes (T1D). Treg cell function was monitored by the forkhead box P3 (FoxP3) and transforming growth factor beta (TGFβ) levels, correlating them with blood glucose and serum insulin levels.

MATERIALS AND METHODS

In this case-control study, a low dose of IL-2 (free and chitosan-loaded) was injected into a diabetic mice group. The levels of FoxP3 and TGF-β 1 were assessed using Enzyme-Linked Immunosorbent Assay. In addition, blood glucose and serum insulin levels were determined.

RESULTS

The mean glucose level decreased significantly after free rIL-2 or rIL-2 / CSNPs treatment. Meanwhile, the mean serum insulin level was significantly increased after treatment with free rIL-2 or rIL-2/CSNPs. The mean levels of FoxP3 and TGFβ 1 were significantly increased with either free rIL-2 or rIL-2/CSNPs compared to the T1D untreated group (P < 0.001). In the treated mice group receiving free CSNPs, there was a significant negative correlation between glucose and insulin levels. Moreover, FoxP3 & TGFβ 1 levels had a significant positive correlation. In treated mice groups with free rIL-2 and IL-2 CSNPs, there was a significant positive correlation between FoxP3 and glucose levels. A significant negative correlation was found after conducting a correlation between insulin level and FoxP3 in the T1D/ rIL-2 / CSNPs group.

CONCLUSIONS

Low-dose IL-2 selectively modulates FoxP3 + Tregs, and TGFβ 1 increases their levels. These results demonstrated that IL-2-free and chitosan-loaded nanoparticles can be therapeutic agents in T1D.

Preparation of chitosan nanoparticles loaded with Balanites aegyptiaca extract for treatment of streptozotocin-induced diabetes in rats

Diabetes mellitus is characterized by elevated blood sugar level due to a deficiency in insulin production and/or action. Balanites aegyptiaca (BA) has been employed as a hypoglycemic medication. Nanoparticles (NPs) have many advantages like minimized drug dose, sustainable drug release, maximized bioavailability and delivery of drugs. The study aimed to synthesize novel chitosan (CS) NPs loaded with BA extract (BA Ex). The prepared NPs were examined in treatment of streptozotocin-induced diabetes in rats. The anti-diabetic efficiency was evaluated through measuring of levels of blood glucose, insulin, lipid profile, oxidative stress markers, pro-inflammatory cytokines. GC-MS, HPLC and ICP techniques showed the presence of numerous bioactive components that have an anti-diabetic effectiveness. BA Ex-CS NPs succeeded in treatment of diabetes; where, it increased insulin secretion, lowered both FBG and FTA levels and helped in neogenesis of pancreatic islets beta cells. The regenerative activity of BA Ex-CS NPs is attributed to its high antioxidant and anti-inflammatory properties. This antioxidant activity scavenged the generated free radicles that resulted from STZ administration. CS NPs raised the plant extract efficacy, prevented its degradation, and regulated the release of its components. The delivery of BA Ex bioactive components has been revolutionized by CS NPs.

Chitosan Versus Dapagliflozin in a Diabetic Cardiomyopathy Mouse Model

Diabetes mellitus is a metabolic disorder with global economic implications that can lead to complications such as diabetic cardiomyopathy. The aim of this study was to compare the effects of chitosan versus dapagliflozin in mouse diabetic cardiomyopathy. We used 32 C57Bl/6 male mice aged between 8 and 10 weeks, which were randomly divided into Control-without diabetes mellitus (DM), type 1 DM (T1DM), T1DM + Chitosan, and T1DM + Dapapgliflozin groups. We induced diabetes with streptozotocin and treated the animals for 12 weeks. The analysis showed a reduction in intramyocardial fibrosis in the T1DM + Dapapgliflozin compared to T1DM animals. In T1DM + CHIT, a reduction in intramyocardial fibrosis was observed although, accordingly, there was also no significant decrease in blood glucose. The level of oxidative stress was reduced in the groups of treated animals compared to T1DM. All these observed changes in the structure and function of hearts were highlighted in the echocardiographic examination. In the treated groups, there was delayed appearance of left ventricular (LV) hypertrophy, a slight decrease in the ejection fraction of the LV, and an improved diastolic profile. The results demonstrate that chitosan has promising effects on diabetic cardiomyopathy that are comparable to the beneficial effects of dapagliflozin.

Effects of Dietary Supplementation with Chitosan on the Muscle Composition, Digestion, Lipid Metabolism, and Stress Resistance of Juvenile Tilapia (Oreochromis niloticus) Exposed to Cadmium-Induced Stress

The aim of this study was to investigate the effects of dietary chitosan supplementation on the muscle composition, digestion, lipid metabolism, and stress resistance, and their related gene expression, of juvenile tilapia (Oreochromis niloticus) subjected to cadmium (Cd2+) stress. Juvenile tilapia with an initial body weight of 21.21 ± 0.24 g were fed with a formulated feed containing five different levels (0%, 0.5%, 1.0%, 1.5%, and 2.0%) of chitosan for 60 days, while the water in all experimental groups contained a Cd2+ concentration of 0.2 mg/L. The results showed that, compared with the control group (0% chitosan), the contents of crude fat and crude protein in the muscle, the activities of lipase, trypsin, and amylase in the intestine, as well as the relative expression levels of metallothionein (mt), cytochrome P450 1A (cyp1a), carnitine palmitoyltransferase-1 (cpt-1), peroxisome proliferator-activated receptor alpha (pparα), peroxisome proliferator-activated receptor gamma (pparγ), hormone-sensitive lipase (hsl), lipoprotein lipase (lpl), malate dehydrogenase (mdh), leptin (lep), fatty acid synthase (fas), sterol regulatory element-binding protein 1 (srebp1), and stearoyl-CoA desaturase (scd) genes in the liver of juveniles were significantly increased (p < 0.05). In conclusion, dietary chitosan supplementation could alleviate the effects of Cd2+ stress on the muscle composition, digestive enzymes, lipid metabolism, and stress resistance, and their related gene expression, of juvenile tilapia, and to some extent reduce the toxic effect of Cd2+ stress on tilapia.

Applications of Bioengineered Polymer in the Field of Nano-Based Drug Delivery

The most favored route of drug administration is oral administration; however, several factors, including poor solubility, low bioavailability, and degradation, in the severe gastrointestinal environment frequently compromise the effectiveness of drugs taken orally. Bioengineered polymers have been developed to overcome these difficulties and enhance the delivery of therapeutic agents. Polymeric nanoparticles, including carbon dots, fullerenes, and quantum dots, have emerged as crucial components in this context. They provide a novel way to deliver various therapeutic materials, including proteins, vaccine antigens, and medications, precisely to the locations where they are supposed to have an effect. The promise of this integrated strategy, which combines nanoparticles with bioengineered polymers, is to address the drawbacks of conventional oral medication delivery such as poor solubility, low bioavailability, and early degradation. In recent years, we have seen substantially increased interest in bioengineered polymers because of their distinctive qualities, such as biocompatibility, biodegradability, and flexible physicochemical characteristics. The different bioengineered polymers, such as chitosan, alginate, and poly(lactic-co-glycolic acid), can shield medications or antigens from degradation in unfavorable conditions and aid in the administration of drugs orally through mucosal delivery with lower cytotoxicity, thus used in targeted drug delivery. Future research in this area should focus on optimizing the physicochemical properties of these polymers to improve their performance as drug delivery carriers.

Zinc-Phthalocyanine Loaded PLGA-PVA-Chitosan Nanosystem for the Enhancement of Antidiabetic Activity

Zinc, one of the most common nutraceutical agents, proved to be effective for diabetes as it regulates the blood glucose level by inhibiting glucagon secretion. However, the hepatotoxicity of zinc creates necrosis, hepatic glycogen depletion, and apoptosis of hepatocytes at the concentration of 10 μg/kg. Phthalocyanine, a blue-colored compound, is an aromatic macrocyclic compound with good antioxidant ability owing to its heterocyclic nitrogen conjugation. The conjugation of zinc with phthalocyanine aimed to reduce the toxicity associated with zinc and enhance the antidiabetic activity at a lower dose. Hence, the present research work possessed the insights of the synthetic aspect of zinc with phthalocyanine along with its entrapment in the poly(lactic-co-glycolic acid) (PLGA)-chitosan nanosystem via oral administration in the treatment of diabetes. A nanoprecipitation technique was implemented for the synthesis of PLGA chitosan nanoparticles, and formulation was further optimized using a central composite design. Twenty trials provided by the software selected optimum concentrations of PLGA, poly(vinyl alcohol) (PVA), and chitosan in consideration with particle size up to 335.6 nm, zeta potential 27.87 mV, and entrapment efficiency of 75.67 ± 8.13%. Addition of chitosan to the nanocarrier system for controlling the release of the drug for 3 days was accompanied by the improvement in the glucose level within 28 days. The delivery of the nanoparticles showed enhancement in the cholesterol, triglyceride, alkaline phosphatase (ALP), urine parameters, and pro-inflammatory cytokines. The application of DoE (design of experiments) for the optimization of the nanoparticles established a controlled release formulation for diabetes, which displayed safety and effectiveness in streptozotocin (STZ)-induced diabetic rats.

Chitosan oligosaccharides inhibit the fibrillation of insulin and disassemble its preformed fibrils

In the current study, we first established that chitosan oligosaccharides (COS) have significant anti-fibrillogenic and fibril-destabilising effects on bovine insulin in vitro that proportionally expand with concentration growth. The obtained data were supported by the Thioflavin T (ThT) assay, circular dichroism (CD), attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, and atomic force microscopy (AFM). Interestingly, coincubation of insulin with COS in the ratio of 1 to 10 over 48 h at 37 °C leads to full prevention of insulin aggregation, and in the case of preformed fibrils, results in their destabilisation and disaggregation. Moreover, both a cationic polymer of allylamine (PAH) and a sulphated oligosaccharide (CROS) prepared from carrageenan had no inhibitory effect on insulin amyloid formation. Thus, we proposed that COS modulates insulin amyloid formation due to the presence of linear sugar units, the degree of polymerization, and the free amino group providing a positive charge. These findings highlight the potential implications of COS as a promising substance for the treatment of insulin-dependent diabetes mellitus and localised insulin-derived amyloidosis and, moreover, provide a new insight into the mechanism of the anti-diabetic and antitoxic properties of chitosan and chitosan-based agents.

Carboxymethyl chitosan-TK resistant starch complex ameliorates type 2 diabetes by regulating the gut microbiota

Carboxymethyl chitosan and resistant starch exhibit good performance in diabetes regulation. We prepared carboxymethyl chitosan - resistant starch complex. Test the properties of composite resistant starch by using X-ray diffraction, water contact angle, infrared spectroscopy, and scanning electron microscopy, interactions with intestinal microbiota and mouse experiments were also conducted. The results indicated that the composite resistant starch had a good effect on promoting the proliferation of probiotics on Bifidobacterium and a significant inhibitory effect on Escherichia coli than resistant starch (P < 0.05). After administration, the water intake and weight of diabetic mice were significantly reduced. The blood glucose of diabetic mice was also reduced, and oral glucose tolerance showed that the glucose degradation rates of composite resistant starch were significantly improved compared to model mice. Cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein were significantly lower than those in the diabetes group (P < 0.05). The diversity of the gut microbiota was also proven.

Chitosan-Based Composites: Development and Perspective in Food Preservation and Biomedical Applications

Chitin, which may be the second-most common polymer after cellulose, is the raw material of chitosan. Chitosan has been infused with various plant extracts and subsidiary polymers to improve its biological and physiological properties. Chitosan's physicochemical properties are enhanced by blending, making them potential candidates that can be utilized in multifunctional areas, including food processing, nutraceuticals, food quality monitoring, food packaging, and storage. Chitosan-based biomaterials are biocompatible, biodegradable, low toxic, mucoadhesive, and regulate chemical release. Therefore, they are used in the biomedical field. The present manuscript highlights the application of chitosan-based composites in the food and biomedical industries.

Mixed oligosaccharides-induced changes in bacterial assembly during cucumber (Cucumis sativus L.) growth

The application of oligosaccharides can promote plant growth by increasing photosynthesis or inducing plant innate immunity. However, the mechanisms by which oligosaccharides affect bacterial community diversity and abundance remain unclear. In this study, a mixed oligosaccharide was applied to the growth of cucumbers. The findings of the present study suggest that the application of MixOS has significant effects on the bacterial communities in the phyllosphere, rhizosphere, and bulk soil of cucumber plants. The treatment with MixOS resulted in delayed senescence of leaves, well-developed roots, and higher fruit production. The bacterial diversity and composition varied among the different ecological niches, and MixOS application caused significant shifts in the bacterial microbiome composition, particularly in the phyllosphere. Moreover, mixed oligosaccharides increased the abundance of potential growth-promoting bacteria such as Methylorubrum spp. and Lechevalieria spp., and more zOTUs were shared between the WM and MixOS treatments. Furthermore, the bacterial co-occurrence network analysis suggested that the modularity of the phyllosphere networks was the highest among all samples. The bacterial co-occurrence networks were altered because of the application of MixOS, indicating a greater complexity of the bacterial interactions in the rhizosphere and bulk soil. These findings suggest that mixed oligosaccharides has the potential to improve plant growth and yield by modulating the bacterial communities within and outside the plants and could provide a theoretical basis for future agricultural production.