A comparative study on hypoglycemic and hypocholesterolemic effects of high and low molecular weight chitosan in streptozotocin-induced diabetic rats

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.

Functional thermosensitive hydrogels based on chitin as RIN-m5F cell carrier for the treatment of diabetes

Herein, the thermosensitive hydroxypropyl chitin (HPCT) hydrogel was prepared and the chemical structures, microstructures, rheological properties and degradation in vitro were investigated. The HPCT hydrogel possessed satisfactory biocompatibility in mouse fibroblast cells and Sprague Dawley rats. On the other hand, N-acetylglucosamine (NAG) and carboxymethyl chitosan (CMCS) provided favorable capacity for promoting cell proliferation, delaying cell apoptosis, and facilitating the insulin secretion of rat pancreatic beta cells (RIN-m5F) in three-dimensional culture. Most importantly, the effects of HPCT/NAG and HPCT/CMCS thermosensitive hydrogels as RIN-m5F cells carriers were evaluated via injection into different areas of diabetic rats. Our results demonstrated that HPCT/NAG and HPCT/CMCS hydrogels loaded RIN-m5F cells could keep cells survival, maintain insulin secretion and reduce blood glucose for one week. Overall, the functional thermosensitive hydrogels based on HPCT were effective cell carriers for RIN-m5F cells and might provide novel strategy for the treatment of diabetes via cell engineering.

Assessment of the antiulcer properties of Lawsonia inermis L. leaves and its nano-formulation against prolonged effect of acute ulcer in rats

Peptic ulcer syndrome (PUD) has been acknowledged as one of the most frequent causes of morbidity and mortality worldwide throughout the 20th and 21st centuries. Several reports indicated the ability of plant derived dosages as antiulcer agents. Many prior investigations have implied some biological activities of Lawsonia inermis L. The aim of this current investigation was to estimate the antiulcer capability of Lawsonia inermis L. leaves and its nano formulation against hazardous biochemical and histological changes in aspirin-induced ulcer rats. Methods divided into 6 groups (6 rats/group), Normal control (negative), Group (1) receiving dose of (200 g/kg) Lawsonia inermis L. for 8 weeks, Group (2) receiving (200 g/kg) nano Lawsonia inermis L. leaves for 8 weeks, Group (3) ulcer control group receiving a single dose (500 mg aspirin/kg rat body weight),groups 4& 5 receiving aspirin and either Lawsonia inermis L. leaves or nano Lawsonia inermis L. leaves for 8 weeks. Results: improvements in all the tested parameters as well as hepatic enzymes activities and some blood biochemical parameters. Conclusion Lawsonia inermis L.at the tested dose could prevent ulcer formation in the tested animals that may offer safe and low cost effective treatment for gastric ulcer.

Chitosan nanoemulsion: Gleam into the futuristic approach for preserving the quality of muscle foods

Trend for consumption of healthy meat without synthetic additives is blooming globally and has attracted the interest of consumers and research sphere to look for enhancement of quality and safety of food. Chitosan is multi-functional marine biopolymer with several befitting properties such as non-toxicity, ease of modification, antimicrobial activity, biodegradability and bio-compatibility, making it suitable for use in meat based food systems, which are highly prone to putrescence due to availability of high level protein, micronutrients and moisture. Bioactive components from plant extracts on account of their natural lineage are exquisite determinants for meat preservation in association with chitosan to replace synthetic molecules, which are considered to evince toxicological effects. Nanoemulsions are viable systems for integrating a myriad of active constituents framed by microfluidization, high-pressure homogenization, ultra-sonication, phase inversion (PIC and PIT) and spontaneous-emulsification with benefits of droplet size reduction, improved solubility, stability and their biological activity. This article summarizes the most important information on formulation, fabrication and advancements in chitosan-based nanoemulsions highlighting their potential benefit for applications in the muscle food system. Supervising the all-around executions of chitosan nanoemulsions for various food systems, the current review has been framed to lay down understandings regarding improvements made in the production and functionality of chitosan nanoemulsions for quality retention of meat products. Furthermore, it highlights the novel trends in chitosan-nanoemulsions application in meat based food systems from a preservation and shelf-life prolongation perspective.

Influence of Dietary Chitosan Feeding Duration on Glucose and Lipid Metabolism in a Diabetic Rat Model

This study was designed to investigate the influence of dietary chitosan feeding-duration on glucose and lipid metabolism in diabetic rats induced by streptozotocin and nicotinamide [a non-insulin-dependent diabetes mellitus (NIDDM) model]. Male Sprague-Dawley rats were used as experimental animals and divided into short-term (6 weeks) and long-term (11 weeks) feeding durations, and each duration contained five groups: (1) control, (2) control + 5% chitosan, (3) diabetes, (4) diabetes + 0.8 mg/kg rosiglitazone (a positive control), and (5) diabetes + 5% chitosan. Whether the chitosan feeding was for 6 or 11 weeks, the chitosan supplementation decreased blood glucose and lipids levels and liver lipid accumulation. However, chitosan supplementation decreased plasma tumor necrosis factor (TNF)-α, insulin levels, alanine aminotransferase (ALT) activity, insulin resistance (HOMA-IR), and adipose tissue lipoprotein lipase activity. Meanwhile, it increased plasma high-density lipoproteins (HDL)-cholesterol level, plasma angiopoietin-like-4 protein expression, and plasma triglyceride levels (at 11-week feeding duration only). Taken together, 11-week (long-term) chitosan feeding may help to ameliorate the glucose and lipid metabolism in a NIDDM diabetic rat model.

Chitosan Oligosaccharide Alleviates Abnormal Glucose Metabolism without Inhibition of Hepatic Lipid Accumulation in a High-Fat Diet/Streptozotocin-Induced Diabetic Rat Model

This study investigated the effects of chitosan oligosaccharide (COS) on glucose metabolism and hepatic steatosis in a high-fat (HF) diet/streptozotocin-induced diabetic rat model. Male Wistar rats were divided into: (1) normal control (NC group), (2) HF diet (HF group), (3) streptozotocin (STZ)-induced diabetes with HF diet (DF group), and DF group supplemented with (4) 0.5% COS (D0.5F group), (5) 1% COS (D1F group), and (6) 5% COS (D5F group) for 4 weeks. COS supplementation significantly decreased the plasma glucose, BUN, creatinine, uric acid, triglyceride (TG), and total cholesterol (TC) levels, and hepatic glucose-6-phosphatase activity, and significantly increased hepatic hexokinase activity and glycogen content in diabetic rats; but the increased hepatic TG and TC levels could not be significantly decreased by COS supplementation. Supplementation of COS increased superoxide dismutase activity and decreased lipid peroxidation products in the diabetic rat livers. COS supplementation significantly increased phosphorylated AMP-activated protein kinase (AMPK) protein expression, and attenuated protein expression of hepatic phosphoenolpyruvate carboxykinase (PEPCK) and phosphorylated p38 and renal sodium-glucose cotransporter-2 (SGLT2) in diabetic rats. These results suggest that COS may possess a potential for alleviating abnormal glucose metabolism in diabetic rats through the inhibition of hepatic gluconeogenesis and lipid peroxidation and renal SGLT2 expression.

Dietary Fiber: An Opportunity for a Global Control of Hyperlipidemia

Dietary fiber has a long history in the intervention study of hyperlipidemia. In this review, current understandings of structures, sources, and natures of various kinds of dietary fibers (DFs) were analyzed first. Available evidences for the use of different varieties of DFs in the lipid-lowering action both in vitro and in vivo were subsequently classified, including both soluble ones, such as glucans, pectins, and gums, and insoluble ones, including arabinooxylans and chitosans, in order to draw a primary conclusion of their dose and molecular weight relationship with lipid-lowering effect. Their potential mechanisms, especially the related molecular mechanism of protective action in the treatment and prevention of hyperlipidemia, were summarized at last. Five major mechanisms are believed to be responsible for the antihyperlipidemic benefits of DFs, including low levels of energy, bulking effect, viscosity, binding capacity, and fermentation thus ameliorating the symptoms of hyperlipidemia. From the molecular level, DFs could possibly affect the activities of HMG-CoA reductase, LDL receptors, CYP7A1, and MAPK signaling pathway as well as other lipid metabolism-related target genes. In summary, dietary fibers could be used as alternative supplements to exert certain lipid-lowering effects on humans. However, more clinical evidence is needed to strengthen this proposal and its fully underlying mechanism still requires more investigation.

Chitosan and Derivatives: Bioactivities and Application in Foods

Chitosan is a biodegradable, biocompatible, and nontoxic aminopolysaccharide. This review summarizes and discusses the structural modifications, including substitution, grafting copolymerization, cross-linking, and hydrolysis, utilized to improve the physicochemical properties and enhance the bioactivity and functionality of chitosan and related materials. This manuscript also reviews the current progress and potential of chitosan and its derivatives in body-weight management and antihyperlipidemic, antihyperglycemic, antihypertensive, antimicrobial antioxidant, anti-inflammatory, and immunostimulatory activities as well as their ability to interact with gut microbiota. In addition, the potential of chitosan and its derivatives as functional ingredients in food systems, such as film and coating materials, and delivery systems is discussed. This manuscript aims to provide up-to-date information to stimulate future discussion and research to promote the value-added utilization of chitosan in improving the safety, quality, nutritional value and health benefits, and sustainability of our food system while reducing the environmental hazards.

Effects and Mechanisms of Chitosan and ChitosanOligosaccharide on Hepatic Lipogenesis and Lipid Peroxidation, Adipose Lipolysis, and Intestinal Lipid Absorption in Rats with High-Fat Diet-Induced Obesity

Chitosan and its derivative, chitosan oligosaccharide (CO), possess hypolipidemic and anti-obesity effects. However, it is still unclear if the mechanisms are different or similar between chitosan and CO. This study was designed to investigate and compare the effects of CO and high-molecular-weight chitosan (HC) on liver lipogenesis and lipid peroxidation, adipose lipolysis, and intestinal lipid absorption in high-fat (HF) diet-fed rats for 12 weeks. Rats were divided into four groups: normal control diet (NC), HF diet, HF diet+5% HC, and HF diet+5% CO. Both HC and CO supplementation could reduce liver lipid biosynthesis, but HC had a better effect than CO on improving liver lipid accumulation in HF diet-fed rats. The increased levels of triglyceride decreased lipolysis rate, and increased lipoprotein lipase activity in the perirenal adipose tissue of HF diet-fed rats could be significantly reversed by both HC and CO supplementation. HC, but not CO, supplementation promoted liver antioxidant enzymes glutathione peroxidase and superoxide dismutase activities and reduced liver lipid peroxidation. In the intestines, CO, but not HC, supplementation reduced lipid absorption by reducing the expression of fabp2 and fatp4 mRNA. These results suggest that HC and CO have different mechanisms for improving lipid metabolism in HF diet-fed rats.

Comparative Effects and Mechanisms of Chitosan and Its Derivatives on Hypercholesterolemia in High-Fat Diet-Fed Rats

The present study investigated and compared the effects of different molecular weights of chitosan (high molecular weight chitosan (HC) and low molecular weight chitosan (LC)) and its derivatives (chitosan oligosaccharide (CO)) on cholesterol regulation in high-fat (HF) diet-fed rats. A diet supplementation of 5% HC, 5% LC, or 5% CO for 8 weeks showed hypocholesterolemic potential in HF diet-fed rats. Unexpectedly, a 5% CO-supplemented diet exerted hepatic damage, producing increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and tumor necrosis factor-alpha (TNF-α). The supplementation of HC and LC, unlike CO, significantly decreased the hepatic total cholesterol (TC) levels and increased the fecal TC levels in HF diet-fed rats. The hepatic protein expression of the peroxisome proliferator-activated receptor-α (PPARα) in the HF diet-fed rats was markedly decreased, which could be significantly reversed by both HC and LC, but not CO, supplementation. Unlike the supplementation of CO, both HC and LC supplementation could effectively reverse the HF-inhibited/induced gene expressions of the low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1), respectively. The upregulated intestinal acyl-CoA cholesterol acyltransferase 2 (ACAT2) protein expression in HF diet-fed rats could be reversed by HC and LC, but not CO, supplementation. Taken together, a supplementation of 5% CO in HF diet-fed rats may exert liver damage via a higher hepatic cholesterol accumulation and a higher intestinal cholesterol uptake. Both HC and LC effectively ameliorated the hypercholesterolemia and regulated cholesterol homeostasis via the activation and inhibition of hepatic (AMPKα and PPARα) and intestinal (ACAT2) cholesterol-modulators, respectively, as well as the modulation of downstream signals (LDLR and CYP7A1).

Polysaccharide-based component and their relevance in edible film/coating: a review

Purpose

The purpose of this paper is to present an overview of functional properties of the polysaccharide-based component and their application in developing edible film and coating for the food processing sector.

Design/methodology/approach

In this review study, approximately 271 research and review articles focusing on studies related to polysaccharide-based components and their film-forming properties. This article also focused on the application of polysaccharide-based edible film in the food sector.

Findings

From the literature reviewed, polysaccharide components and components-based edible film/coating is the biodegradable and eco-friendly packaging of the materials and directly consumed by the consumer with food. It has been reported that the polysaccharide components have excellent properties such as being nontoxic, antioxidant, antimicrobial, antifungal and with good nutrients. The polysaccharide-based edible film has lipid and gas barrier properties with excellent transparency and mechanical strength. In various studies, researchers worked on the development of polysaccharide-based edible film and coating by incorporating plant based natural antioxidants. This was primarily done for obtaining improved physical and chemical properties of the edible film and coating. In future, the technology of developing polysaccharide-based edible film and coating could be used for extending the shelf life and preserving the quality of fruits and vegetables at a commercial level. There is more need to understand the role of edible packaging and sustainability in the food and environment sector.

Originality/value

Through this review paper, possible applications of polysaccharide-based components and their function property in the formation of the edible film and their effect on fruits, vegetables and other food products are discussed after detailed studies of literature from thesis and journal article.

Chitosan Oligosaccharides Show Protective Effects in Coronary Heart Disease by Improving Antioxidant Capacity via the Increase in Intestinal Probiotics

We explored the effects of chitosan oligosaccharides (COS) on coronary heart disease (CHD) patients. The component of COS was measured by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). CHD patients were evenly assigned into the COS group (COG) and the placebo group (CG). The duration of treatment was 6 months and therapeutic results were explored by measuring left ventricular ejection fraction (LVEF) value, Lee scores, quality of life (QOL), blood urea nitrogen, and serum creatinine. The intestinal flora were determined by 16s rDNA sequencing. The circulating antioxidant levels and lipid profiles were compared between two groups. There were 7 different degrees of polymerization (DP4-10) in COS. Lee scores, QOL scores, and LVEF values in the COG group were higher than those in the CG group (P < 0.05). COS treatment improved blood urea nitrogen and serum creatinine when compared with controls (P < 0.05). Circulating antioxidant levels were higher in the COG group than in the CG group. COS consumption increased the serum levels of SOD and GSH and reduced the levels of ALT and AST (P < 0.05). Meanwhile, lipid profiles were improved in the COG group. COS consumption increased the abundance of Faecalibacterium, Alistipes, and Escherichia and decreased the abundance of Bacteroides, Megasphaera, Roseburia, Prevotella, and Bifidobacterium (P < 0.05). On the other hand, COS consumption increased the probiotic species Lactobacillus, Lactococcus, and Phascolarctobacterium. The increased species have been reported to be associated with antioxidant properties or lipid improvement. COS had similar effects with chitohexaose on the growth rate of these species. Therefore, COS ameliorate the symptoms of CHD patients by improving antioxidant capacities and lipid profiles via the increase of probiotics in the intestinal flora.

Calorie Restriction Mimetics: Upstream-Type Compounds for Modulating Glucose Metabolism

Calorie restriction (CR) can prolong the human lifespan, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition, while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-d-glucose, d-glucosamine, and d-allulose, which show antiaging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.

Functional Comparison of High and Low Molecular Weight Chitosan on Lipid Metabolism and Signals in High-Fat Diet-Fed Rats

The present study examined and compared the effects of low- and high-molecular weight (MW) chitosan, a nutraceutical, on lipid metabolism in the intestine and liver of high-fat (HF) diet-fed rats. High-MW chitosan as well as low-MW chitosan decreased liver weight, elongated the small intestine, improved the dysregulation of blood lipids and liver fat accumulation, and increased fecal lipid excretion in rats fed with HF diets. Supplementation of both high- and low-MW chitosan markedly inhibited the suppressed phosphorylated adenosine monophosphate (AMP)-activated protein kinase-α (AMPKα) and peroxisome proliferator-activated receptor-α (PPARα) protein expressions, and the increased lipogenesis/cholesterogenesis-associated protein expressions [peroxisome proliferator-activated receptor-γ (PPARγ), sterol regulatory element binding protein-1c and -2 (SREBP1c and SREBP2)] and the suppressed apolipoprotein E (ApoE) and microsomal triglyceride transfer protein (MTTP) protein expressions in the livers of rats fed with HF diets. Supplementation with both a low- and high-MW chitosan could also suppress the increased MTTP protein expression and the decreased angiopoietin-like protein-4 (Angptl4) expression in the intestines of rats fed with HF diets. In comparison between low- and high-MW chitosan, high-MW chitosan exhibits a higher efficiency than low-MW chitosan on the inhibition of intestinal lipid absorption and an increase of hepatic fatty acid oxidation, which can improve liver lipid biosynthesis and accumulation.

Crab Shell Extract Improves Sperm Parameters and Antioxidant Status in Testes of Diabetic Rats

Crab shell (CS), which contains antioxidant compounds, has been used as a promising nutritional and medical compound in traditional medicine. Oxidative stress plays a critical role in the development of diabetes. This study aims to investigate the effects of CS extract (CSE) on sperm parameters, antioxidant status, and histopathology changes of testes in diabetic rats. In this experimental study, 40 Wistar male rats were investigated in five groups (n = 8/group): diabetic rats treated with different CS concentrations (i.e., 100, 200, and 400 mg/kg), diabetic group, and nondiabetic control. To induce diabetes, a single dose (60 mg/kg) of streptozotocin (STZ) was injected intraperitoneally; three days later, treatment with CSE was begun and conducted for 14 days. The fasting blood glucose, testes weight, and viability, number, and motility of sperm were assessed. In addition, the levels of ferric reducing antioxidant power (FRAP) and nitric oxide (NO) were estimated in the testes. Testes were examined using histological analysis. The results of this study revealed that sperm number, motility, and serum testosterone levels of CSE-treated diabetic rats increased significantly (p = .000) compared with the untreated diabetic group in a dose-depended manner while the number of immotile sperm decreased significantly (p = .017). CS also reduced the testicular level of nitric oxide and fasting blood glucose; however, it led to significant growth in the FRAP levels of testes (p = .002). Our results suggest that CSE improves sperm parameters and protects the testicular tissue against the oxidative stress damage induced by diabetes.

Functional Comparison for Lipid Metabolism and Intestinal and Fecal Microflora Enzyme Activities between Low Molecular Weight Chitosan and Chitosan Oligosaccharide in High-Fat-Diet-Fed Rats

The present study investigated and compared the regulatory effects on the lipid-related metabolism and intestinal disaccharidase/fecal bacterial enzyme activities between low molecular weight chitosan and chitosan oligosaccharide in high-fat-diet-fed rats. Diet supplementation of low molecular weight chitosan showed greater efficiency than chitosan oligosaccharide in suppressing the increased weights in body and in liver and adipose tissues of high-fat-diet-fed rats. Supplementation of low molecular weight chitosan also showed a greater improvement than chitosan oligosaccharide in imbalance of plasma, hepatic, and fecal lipid profiles, and intestinal disaccharidase activities in high-fat-diet-fed rats. Moreover, both low molecular weight chitosan and chitosan oligosaccharide significantly decreased the fecal microflora mucinase and β-glucuronidase activities in high-fat-diet-fed rats. These results suggest that low molecular weight chitosan exerts a greater positive improvement than chitosan oligosaccharide in lipid metabolism and intestinal disaccharidase activity in high-fat-diet-induced obese rats.

Mechanism of Action of Electrospun Chitosan-Based Nanofibers against Meat Spoilage and Pathogenic Bacteria

This study investigates the antibacterial mechanism of action of electrospun chitosan-based nanofibers (CNFs), against Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus and Listeria innocua, bacteria frequently involved in food contamination and spoilage. CNFs were prepared by electrospinning of chitosan and poly(ethylene oxide) (PEO) blends. The in vitro antibacterial activity of CNFs was evaluated and the susceptibility/resistance of the selected bacteria toward CNFs was examined. Strain susceptibility was evaluated in terms of bacterial type, cell surface hydrophobicity, and charge density, as well as pathogenicity. The efficiency of CNFs on the preservation and shelf life extension of fresh red meat was also assessed. Our results demonstrate that the antibacterial action of CNFs depends on the protonation of their amino groups, regardless of bacterial type and their mechanism of action was bactericidal rather than bacteriostatic. Results also indicate that bacterial susceptibility was not Gram-dependent but strain-dependent, with non-virulent bacteria showing higher susceptibility at a reduction rate of 99.9%. The susceptibility order was: E. coli > L. innocua > S. aureus > S. Typhimurium. Finally, an extension of one week of the shelf life of fresh meat was successfully achieved. These results are promising and of great utility for the potential use of CNFs as bioactive food packaging materials in the food industry, and more specifically in meat quality preservation.

Hepatic and skeletal muscle mitochondrial toxicity of chitosan oligosaccharides of normal and diabetic rats

Diabetes and associated conditions are now considered a worldwide epidemic, with increasing costs and burdens with no cure yet developed. The chitin-derived glucosamine biopolymer chitosan has shown promising results when supplied to diabetic patients. However, no study has investigated the possible toxic side effects of chitosan treatments, in particular when regarding the most important bioenergetic organelle, mitochondria. As such, we aimed to understand if supplementation of chitosan to the diet of normal and diabetic rats could compromise mitochondrial function on two of the major organs involved in diabetes, obesity, and metabolic regulation, the liver and skeletal muscle. We supplemented the drinking water of normal Wistar and diabetic Goto-Kakizaki rats with 0.5% chitosan for 6 weeks. We show here that, in terms of hepatic bioenergetics, chitosan was relatively inert and had no major side effects. However, regarding skeletal muscle bioenergetics, chitosan significantly affected various bioenergetic parameters. As such, we conclude that chitosan, at the tested doses, is relatively safe for treatment of diabetic situations. Nonetheless, the potential for adverse toxicological side effects appears to be present, which might be relevant if higher doses are utilized.

Systematic review of the mechanisms and evidence behind the hypocholesterolaemic effects of HPMC, pectin and chitosan in animal trials

Dietary fibres have diverse mechanisms in reducing plasma cholesterol, which could be useful for treating high levels of low-density lipoprotein cholesterol (LDL-C). The objective of this review is to determine the state of the evidence for the cholesterol-lowering effects of three selected fibres and their mechanisms, using the most recent animal trials. Therefore, a systematic review was conducted for hydroxypropyl methylcellulose (HPMC), pectin and chitosan in Pubmed, Embase and the Cochrane Library. All fibres reviewed reduced total cholesterol, very low-density lipoprotein cholesterol (VLDL-C) and LDL-C. Pectin gave a small, and chitosan an impressive rise in high-density lipoprotein cholesterol (HDL-C). A limitation of this study is the variety of animal models, each with distinct cholesterol profiles. Possible publication bias was also detected. In conclusion, chitosan seems to be the most promising of the studied fibres. A dietary fibre could be designed that yields the best cholesterol-lowering effect, using experiences in tailoring physicochemical properties and primarily exploiting the biophysical mechanisms of action.

Long-Term Feeding of Chitosan Ameliorates Glucose and Lipid Metabolism in a High-Fructose-Diet-Impaired Rat Model of Glucose Tolerance

This study was designed to investigate the effects of long-term feeding of chitosan on plasma glucose and lipids in rats fed a high-fructose (HF) diet (63.1%). Male Sprague-Dawley rats aged seven weeks were used as experimental animals. Rats were divided into three groups: (1) normal group (normal); (2) HF group; (3) chitosan + HF group (HF + C). The rats were fed the experimental diets and drinking water ad libitum for 21 weeks. The results showed that chitosan (average molecular weight was about 3.8 × 10⁵ Dalton and degree of deacetylation was about 89.8%) significantly decreased body weight, paraepididymal fat mass, and retroperitoneal fat mass weight, but elevated the lipolysis rate in retroperitoneal fats of HF diet-fed rats. Supplementation of chitosan causes a decrease in plasma insulin, tumor necrosis factor (TNF)-α, Interleukin (IL)-6, and leptin, and an increase in plasma adiponectin. The HF diet increased hepatic lipids. However, intake of chitosan reduced the accumulation of hepatic lipids, including total cholesterol (TC) and triglyceride (TG) contents. In addition, chitosan elevated the excretion of fecal lipids in HF diet-fed rats. Furthermore, chitosan significantly decreased plasma TC, low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), the TC/high-density lipoprotein cholesterol (HDL-C) ratio, and increased the HDL-C/(LDL-C + VLDL-C) ratio, but elevated the plasma TG and free fatty acids concentrations in HF diet-fed rats. Plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected by the HF diet, but it was significantly increased in chitosan-supplemented, HF-diet-fed rats. The high-fructose diet induced an increase in plasma glucose and impaired glucose tolerance, but chitosan supplementation decreased plasma glucose and improved impairment of glucose tolerance and insulin tolerance. Taken together, these results indicate that supplementation with chitosan can improve the impairment of glucose and lipid metabolism in a HF-diet-fed rat model.

Development of a low fat fresh pork sausage based on chitosan with health claims: impact on the quality, functionality and shelf-life

A low fat fresh pork sausage based on chitosan was developed with the objective of obtaining a new functional meat product with improved properties and health claims promoting cholesterol reduction. Sausages were formulated with chitosan (2%, w/w) and different fat levels (5%, 12.5% and 20%, w/w). The results indicated that incorporation of 2% chitosan into produced pork sausages with health claims of reduction of cholesterol is technologically feasible. In addition, the chitosan reduced the microbial growth, revealing interesting fat and water absorption capacities, reduced lipid oxidation, provided greater stability in terms of colorimetric parameters and promoted positive firmer texture and gumminess. The reduction of fat content to levels of 5% was positively achieved with the incorporation of chitosan. Sensorial analysis showed that panelists did not detect any significant difference in taste and any unfavorable effect on the sausage appearance as a consequence of chitosan addition and variation of fat.

Effects of the polyphenol content on the anti-diabetic activity of Cinnamomum zeylanicum extracts

Cinnamomum zeylanicum is a popular kitchen spice widely investigated for insulin potentiating effects. Though a group of water soluble polyphenols belonging to the oligomeric procyanidins has been identified as the bioactive principle, the lack of systematic information on the effect of the polyphenol content on safety and anti-diabetic efficacy remains as a major limitation for the development of optimized and standardized cinnamon extracts for functional use. In the present paper, water soluble extracts of Cinnamomum zeylanicum containing 45 and 75% gallic acid equivalents (GAE) of polyphenol content were prepared by a novel process and characterized by tandem mass spectrometry. The polyphenol enhanced extracts were shown to be safe and offered better antioxidant potential, hypoglycemic effect, hypolipidimic effect, and significant decrease in other biochemical parameters as compared to the standard aqueous extract containing 15% GAE, when administered to streptozotocin-induced diabetic rats at 200 mg per kg b.w. for 30 days. The efficacy of polyphenol extracts in lowering blood glucose levels and ameliorating oxidative stress was further demonstrated in humans by administrating 'procynZ-45' containing 45% GAE polyphenols at a relatively low dosage of (125 mg × 2) per day for 30 days to 15 volunteers who had elevated fasting blood glucose levels; but not involved in any medication.

Effects of chitosan on body weight gain, growth hormone and intestinal morphology in weaned pigs

The study was conducted to determine the effects of chitosan on the concentrations of GH and IGF-I in serum and small intestinal morphological structure of piglets, in order to evaluate the regulating action of chitosan on weaned pig growth through endocrine and intestinal morphological approaches. A total of 180 weaned pigs (35 d of age; 11.56±1.61 kg of body weight) were selected and assigned randomly to 5 dietary treatments, including 1 basal diet (control) and 4 diets with chitosan supplementation (100, 500, 1,000 and 2,000 mg/kg, respectively). Each treatment contained six replicate pens with six pigs per pen. The experiment lasted for 28 d. The results showed that the average body weight gain (BWG) of pigs was improved quadratically by dietary chitosan during the former 14 d and the later 14 d after weaned (p<0.05). Furthermore, dietary supplementation of chitosan tended to quadratically increase the concentration of serum GH on d 14 (p = 0.082) and 28 (p = 0.087). Diets supplemented with increasing levels of chitosan increased quadratically the villus height of jejunum and ileum on d 14 (p = 0.089, p<0.01) and 28 (p = 0.074, p<0.01), meanwhile, chitosan increased quadratically the ratio of villus height to crypt depth in duodenum, jejunum and ileum on d 14 (p<0.05, p = 0.055, p<0.01) and 28 (p<0.01, p<0.01, p<0.01), however, it decreased quadratically crypt depth in ileum on d 14 (p<0.05) and that in duodenum, jejunum and ileum on d 28 (p<0.01, p<0.05, p<0.05). In conclusion, these results indicated that chitosan could quadratically improve growth in weaned pigs, and the underlying mechanism may due to the increase of the serum GH concentration and improvement of the small intestines morphological structure.

Efficacy of ginseng adventitious root extract on hyperglycemia in streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng has various bioactive effects on human health including its potential activity of improving the glucose homeostasis and insulin sensitivity.

MATERIALS AND METHODS

Tissue culture raised mountain ginseng adventitious root (TCMGARs) extract enriched with ginsenosides was used as experimental material. Streptozotocin-induced diabetic 'Sprague Dawley' male rats were used as experimental systems and were fed with Tissue culture raised mountain ginseng adventitious root extract. Field cultivated Korean ginseng root extract fed rats were used as positive control and several indices such as body weight, blood glucose level and other serological indicators were tested.

RESULTS

Chemical profile showed TCMGARs were rich in varied ginsenosides especially Rb1, Rb2, Rc, Rd, Rg3, and Rh2 when compared to field cultivated Korean ginseng. TCMGARs extract at dosage levels of 250 and 500 mg/kg body weight significantly lowered the blood glucose, total cholesterol and triglyceride content in streptozotocin-induced diabetic rats.

CONCLUSION

The data of in vivo experiments on anti-glycemic effects of TCMGARs proves their efficacy and also their use as dietary supplement.

Evaluation of ultrasound combined with chitosan for the control of weight and local fat in mice

Ultrasound (US) has recently been used to reduce localized adiposity in humans. The study described here evaluated the combined use of chitosan, which is used to treat hyperlipidemic diseases and fatty liver, and US to control weight and local fat deposition in normal mice over a 5-wk experimental period. Female ICR mice were randomly divided into four groups (n = 5 animals per group): (1) control, (2) US only, (3) chitosan only and (4) chitosan + US. Body weight, epididymal fat pad and intra-abdominal fat thickness (via US imaging) and plasma concentrations of high-density lipoprotein cholesterol, triglycerides and low-density lipoprotein cholesterol were measured in all mice before and after the 5-wk treatment period. After the 5-wk treatment period, weight had decreased significantly in the chitosan + US group (-11.2%) compared with the US only (-5.8%) and chitosan only (-9.3%) groups (p < 0.05). The reduction in epididymal fat pad thickness was significantly more marked in the chitosan + US group (28.2%) than in the other groups (p < 0.05). Furthermore, in the chitosan + US group, plasma levels of triglycerides and low-density lipoprotein cholesterol significantly decreased by 51.5% and 26%, respectively. This is the first report of effective control of weight and local fat by a combination of ultrasound and a putative fat-reducing dietary supplement in mice. The described method significantly decreases local fat pad deposition, weight and plasma lipid levels.

Chitooligosaccharide ameliorates diet-induced obesity in mice and affects adipose gene expression involved in adipogenesis and inflammation

Chitooligosaccharide (CO) has been reported to have potential antiobestic effects in a few studies, but the antiobesity properties of CO and its related mechanisms in models of dietary obesity remain unclear. We investigated the effect of CO on body weight gain, size of adipocytes, adipokines, and lipid profiles in high-fat (HF) diet-induced obese mice and on the gene expression in adipose tissue using a complementary DNA microarray approach to test the hypothesis that CO supplementation would alleviate HF diet-induced obesity by the alteration of adipose tissue-specific gene expression. Male C57BL/6N mice were fed a normal diet (control), HF diet, or CO-supplemented HF diet (1% or 3%) for 5 months. Compared with the HF diet mice, mice fed the 3% CO-supplemented diet gained 15% less weight but did not display any change in food and energy intake. Chitooligosaccharide supplementation markedly improved serum and hepatic lipid profiles. Histologic examination showed that epididymal adipocyte size was smaller in mice fed the HF + 3% CO. Microarray analysis showed that dietary CO supplementation modulated adipogenesis-related genes such as matrix metallopeptidases 3, 12, 13, and 14; tissue inhibitor of metalloproteinase 1; and cathepsin k in the adipose tissues. Twenty-five percent of the CO-responsive genes identified are involved in immune responses including the inflammatory response and cytokine production. These results suggest that CO supplementation may help ameliorate HF diet-induced weight gain and improve serum and liver lipid profile abnormalities, which are associated, at least in part, with altered adipose tissue gene expression involved in adipogenesis and inflammation.

Levan from Bacillus subtilis Natto: its effects in normal and in streptozotocin-diabetic rats

Levan is an exopolysaccharide of fructose primarily linked by β-(2→6) glycosidic bonds with some β-(2→1) branched chains. Due to its chemical properties, levan has possible applications in both the food and pharmaceutical industries. Bacillus subtilis is a promising industrial levan producer, as it ferments sucrose and has a high levan-formation capacity. A new strain of B. subtilis was recently isolated from Japanese food natto, and it has produced levan in large quantities. For future pharmaceutical applications, this study aimed to investigate the effects of levan produced by B. subtilis Natto, mainly as potential hypoglycemic agent, (previously optimized with a molecular weight equal to 72.37 and 4,146 kDa) in Wistar male rats with diabetes induced by streptozotocin and non-diabetic rats and to monitor their plasma cholesterol and triacylglycerol levels. After 15 days of experimentation, the animals were sacrificed, and their blood samples were analyzed. The results, compared using analysis of variance, demonstrated that for this type of levan, a hypoglycemic effect was not observed, as there was no improvement of diabetes symptoms during the experiment. However, levan did not affect any studied parameters in normal rats, indicating that the exopolysaccharide can be used for other purposes.

Effects of long-term feeding of chitosan on postprandial lipid responses and lipid metabolism in a high-sucrose-diet-impaired glucose-tolerant rat model

This study was designed to investigate the effects of long-term feeding of chitosan on postprandial lipid response and lipid metabolism in a high-sucrose (HS)-diet-impaired glucose-tolerant rat model. As the results, HS-diet-fed rats supplemented with 5 and 7% chitosan in diets for 9 weeks had lower postprandial plasma total cholesterol (TC) levels, but 7% chitosan in the diet had higher postprandial plasma triglyceride (TG) and TG-rich lipoprotein TG levels. Supplementation of chitosan significantly decreased the postprandial ratio of apolipoprotein B (apoB)48/apoB100 in TG-rich lipoprotein fractions of HS-diet-fed rats. Long-term supplementation of 5 and 7% chitosan in diets for 16 weeks had lower plasma TC, low-density lipoprotein cholesterol (LDL-C) + very low density lipoprotein cholesterol (VLDL-C), TC/high-density lipoprotein (HDL-C) ratio, leptin, and tumor necrosis factor-α (TNF-α) levels in HS-diet-fed rats. Moreover, it was noticed that the VLDL receptor (VLDLR) protein expression in skeletal muscles of HS-diet-fed rats was significantly decreased, which could be significantly reversed by supplementation of 5 and 7% chitosan. Rats supplemented with 7% chitosan in the diet significantly elevated the lipolysis rate and decreased the accumulation of TG in epididymal fat pads of HS-diet-fed rats. The plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected in HS-diet-fed rats, but it was significantly increased in 7% chitosan-supplemented HS-diet-fed rats. Taken together, these results indicate that supplementation of chitosan in the diet can improve the impairment of lipid metabolism in a HS-diet-fed rat model, but long-term high-dose chitosan feeding may enhance postprandial plasma TG and TG-rich lipoprotein TG levels in HS-diet-fed rats through an ANGPTL4-regulated pathway.

Changes in small intestinal morphology and digestive enzyme activity with oral administration of copper-loaded chitosan nanoparticles in rats

The experiment was conducted to evaluate the effect of copper-loaded chitosan nanoparticles on the small intestinal morphology and activities of digestive enzyme and mucosal disaccharase in rats. Forty male Sprague-Dawley rats, with average body weight of 82 g, were randomly allotted to five groups (n = 8). All rats were received a basal diet (control) or the same basal diet added with 80 mg/kg BW CuSO(4), 80 mg/kg BW chitosan (CS-I), 80 mg/kg BW copper-loaded chitosan nanoparticles (CSN-I), 160 mg/kg BW copper-loaded chitosan nanoparticles (CSN-II), respectively. The experiment lasted 21 days. The results showed that the villus heights of the small intestinal mucosa in groups CSN-I and CSN-II were higher than those of the control, group CuSO(4) or CS-I. The crypt depth of duodenum and ileum mucosa in group CSN-I or CSN-II was depressed. Compared with the control, there were no significant effects of CuSO(4) or CS-I on the villus height and crypt depth of small intestinal mucosa. Supplementation with CSN improved the activities of trypsin, amylase and lipase in the small intestinal contents and maltase, sucrase and lactase of duodenum, jejunum, and ileum mucosa while there were no significant effects of CuSO(4) on the digestive enzyme activities of the small content compared with the control. The results indicated that intestinal morphology, activities of digestive enzyme in digesta and mucosal disaccharase were beneficially changed by treatment of copper-loaded chitosan nanoparticles.

Chitosan-based luminescent/magnetic hybrid nanogels for insulin delivery, cell imaging, and antidiabetic research of dietary supplements

In this work, the chitosan-based luminescent/magnetic (CLM) nanomaterials were synthesized by direct gelation of chitosan, CdTe and superparamagnetic iron oxide into the hybrid nanogels. The morphology, sizes and properties of the nanogels prepared with different chitosan/QD/MNP ratios and under different processing parameters were researched. Fluorescence microscopy, FTIR spectra and TEM images confirmed the success of the preparation of the CLM hybrid nanogels. Spherical CLM hybrid nanogels with appropriate average sizes (<160 nm) were used for insulin loading. The actual loading amount of insulin was approximately 40.1mg/g. Human normal hepatocytes L02 cell line was used to explore the effects of additives, such as mangiferin (MF), (-)-epigallocatechin gallate (EGCG), and (-)-epicatechin gallate (ECG) on the insulin-receptor-mediated cellular uptake using insulin-loaded CLM (ICLM) hybrid nanogels. Above 80% of viability of L02 cells were watched at a nanogels concentration of 500 μg/mL whatever the additives existed or not. The study discovered that the fluorescent signals of the ICLM hybrid nanogels in L02 cells were more intense in the presence of MF, EGCG and ECG in medium than in the absence of these components, respectively. These results demonstrate that MF, EGCG and ECG are potentially able to enhance targeting combination of insulin with L02 cells and improve insulin sensitivity in L02 cells. The hybrid nanogels designed as a targeting carrier can potentially offer an approach for integration of insulin delivery, cell imaging, and antidiabetic investigation of dietary supplements.

Antidiabetic effects of cinnamon oil in diabetic KK-Ay mice

The hypoglycemic effect of cinnamon oil (CO) in a type 2 diabetic animal model (KK-A(y) mice) was studied. The main component of CO was cinnamaldehyde, and other nineteen components were also determined. CO was administrated at doses of 25, 50 and 100mg/kg for 35 days. It was found that fasting blood glucose concentration was significantly decreased (P<0.05) with the 100mg/kg group (P<0.01) the most efficient compared with the diabetic control group. In addition, there was significant decrease in plasma C-peptide, serum triglyceride, total cholesterol and blood urea nitrogen levels while serum high density lipoprotein (HDL)-cholesterol levels were significantly increased after 35 days. Meanwhile, glucose tolerance was improved, and the immunoreactive of pancreatic islets beta-cells was promoted. These results suggest that CO had a regulative role in blood glucose level and lipids, and improved the function of pancreatic islets. Cinnamon oil may be useful in the treatment of type 2 diabetes mellitus.

Chitosan reduces gluconeogenesis and increases glucose uptake in skeletal muscle in streptozotocin-induced diabetic rats

Chitosan is a natural and versatile biomaterial with a blood-glucose-lowering effect in diabetic animals, but the mechanism of action is still unknown. This study was designed to investigate the possible mechanisms involved in the hypoglycemic activity of chitosan in rats with streptozotocin (STZ)-induced diabetes. Male Sprague-Dawley (SD) rats were divided into non-diabetic with cellulose (control), diabetic with cellulose (DM), and diabetic with low- (DM + LCS) and high- (DM + HCS) molecular-weight chitosan groups. After a 4 week feeding study, plasma glucose and fructosamine levels were increased while plasma leptin was decreased in the DM group when compared to the control group. These alternations caused by diabetes could be effectively reversed by both chitosan treatments. The increased gluconeogenesis-related signals including phosphoenolpyruvate carboxykinase (PEPCK) expression and phosphorylations of p38 and AMP-activated kinase (AMPK) in the livers of diabetic rats were attenuated by chitosans. Moreover, chitosan significantly increased muscle glucose uptake-related signals including Akt phosphorylation and glucose transporter-4 (GLUT4) translocation from the cytosol to membrane in the soleus muscles of diabetic rats. These results indicate that chitosan may possess a potential for alleviating type-1 diabetic hyperglycemia through the decrease in liver gluconeogenesis and increase in skeletal muscle glucose uptake and use.