A comparative study on hypolipidemic activities of high and low molecular weight chitosan in rats

The preparation, modification and hepatoprotective activity of chitooligosaccharides: A review

Chitooligosaccharides (COS) has attracted increasing attention due to the various promising bioactivities, tremendous potential in agricultural, environmental nutritional and functional food fields. COS as the major degradation product from chitosan or chitin is prepared via enzymatic, chemical and physical methods. Further obtained COS generally possesses different structural characteristics, such as molecular weight, degree of acetylation and degree of polymerization. Innovations into COS modification has also broadened application of COS in nutrition as well as in agricultural safety. Due to the affinity between structure and bioactivity, diversity of structural characteristics endows COS with various bioactivities like antitumor, antioxidant and anti-inflammatory effects, especially hepatoprotective activity. Therefore, the present review narrates the recent developments in COS physicochemical properties, while paying considerable attention to preparation strategies of COS and their advantages and disadvantages. Moreover, the modification of COS is also discussed including alkylation, quaternization and sulfation, herein the structure-activity relationship of COS was highlighted. Additionally, we summarize the latest research on hepatoprotective activity and mechanisms of COS. Eventually, the future directions of research on COS were discussed, which would provide a new appreciation for the future use of COS.

Effect of dietary chitosan on the growth performance, intestinal histology and growth-related gene expression in stellate sturgeon (Acipenser stellatus) juveniles

As sturgeon breeding has proliferated, there has been a heightened demand for growth stimulators in their diets. This study aimed to determine the impact of dietary chitosan on growth performance, whole-body proximate composition, growth-related gene expression, and intestinal histology in juvenile Acipenser stellatus. A total of 180 A. stellatus juveniles with an average weight of 31.90 ± 0.73 g were fed with diets containing 0 (control), 1.5, 3.0, 4.5, and 6.0 g chitosan.kg-1 basic diet for eight weeks. The findings revealed a significant enhancement in growth performance with rising chitosan concentrations. Furthermore, chitosan supplementation upregulated the expression of the growth hormone gene in both brain and liver tissues. In liver samples, the most pronounced expression of the insulin-like growth factor-1 gene was noted at 6.0 g chitosan.kg-1, while in brain samples, peak expressions were observed in both the 4.5 and 6.0 g chitosan.kg-1 treatments. While the whole-body proximate composition remained relatively stable, there was a notable decrease in whole-body lipids with the escalation of chitosan dosage. Intestinal villi dimensions, both height and width, were amplified in the chitosan-supplemented groups compared to controls. In summation, chitosan supplementation showed promise in bolstering growth performance, refining intestinal morphology, and enhancing growth-related gene expression. Analysis of the polynomial regression of weight gain and specific growth rate revealed that the optimum dietary chitosan requirements in A. stellatus were 5.32 and 5.21 g chitosan.kg-1, respectively.

Dietary Chitosan Attenuates High-Fat Diet-Induced Oxidative Stress, Apoptosis, and Inflammation in Nile Tilapia (Oreochromis niloticus) through Regulation of Nrf2/Kaep1 and Bcl-2/Bax Pathways

Fatty liver injury is a prevalent condition in most farmed fish, yet the molecular mechanisms underpinning this pathology remain largely elusive. A comprehensive feeding trial spanning eight weeks was conducted to discern the potential of dietary chitosan in mitigating the deleterious effects of a high-fat diet (HFD) while concurrently exploring the underlying mechanism. Growth performance, haemato-biochemical capacity, antioxidant capacity, apoptotic/anti-apoptotic gene expression, inflammatory gene expression, and histopathological changes in the liver, kidney, and intestine were meticulously assessed in Nile tilapia. Six experimental diets were formulated with varying concentrations of chitosan. The first three groups were administered a diet comprising 6% fat with chitosan concentrations of 0%, 5%, and 10% and were designated as F6Ch0, F6Ch5, and F6Ch10, respectively. Conversely, the fourth, fifth, and sixth groups were fed a diet containing 12% fat with chitosan concentrations of 0%, 5%, and 10%, respectively, for 60 days and were termed F12Ch0, F12Ch5, and F12Ch10. The results showed that fish fed an HFD demonstrated enhanced growth rates and a significant accumulation of fat in the perivisceral tissue, accompanied by markedly elevated serum hepatic injury biomarkers and serum lipid levels, along with upregulation of pro-apoptotic and inflammatory markers. In stark contrast, the expression levels of nrf2, sod, gpx, and bcl-2 were notably decreased when compared with the control normal fat group. These observations were accompanied by marked diffuse hepatic steatosis, diffuse tubular damage, and shortened intestinal villi. Intriguingly, chitosan supplementation effectively mitigated the aforementioned findings and alleviated intestinal injury by upregulating the expression of tight junction-related genes. It could be concluded that dietary chitosan alleviates the adverse impacts of an HFD on the liver, kidney, and intestine by modulating the impaired antioxidant defense system, inflammation, and apoptosis through the variation in nrf2 and cox2 signaling pathways.

Enhancing stability of liposomes using high molecular weight chitosan to promote antioxidative stress effects and lipid-lowering activity of encapsulated lutein in vivo and in vitro

Lutein is an antioxidant with multiple beneficial functions. However, its therapeutic potential is hampered by its low water solubility and bioavailability. The goal of this study is to compare the stability of lutein-loaded liposomes (Lu-lip) and low (LC)/high molecular weight (HC) chitosan-coated Lu-lip, along with their antioxidant capacity using H2O2-induced HepG2 cells and their lipid-lowering activity using high-fat diet mice. Both LC and HC reduced the lutein degradation rate by 17.5 % and 26.72 % in a challenging environment at pH 6 and T = 4 °C. Compared to LC, the HC coating improved the size- and zeta-potential-stability of Lu-lip at 5 < pH < 7, with the best performance at pH 6. The HC coating prolonged the lutein release profile, increased the cellular uptake of Lu-lip, and reduced the reactive oxygen species (ROS) levels and the H2O2-induced necrotic cell ratios by increasing the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Animal experiments have shown that oral administration of LC and HC coated Lu-lip can significantly reduce body weight levels, total triglycerides (TG), total cholesterol (TC), and non-high-density lipoprotein (n-HDL-C) in high-fat diet mice while significantly increasing the levels of CAT, SOD and GSH-Px in the liver of mice. LC and HC coated Lu-lip can reduce fat accumulation in the liver and epididymal adipose tissue.

Biopharmaceutical applications of microbial polysaccharides as materials: A review

Biological characteristics of natural polymers make microbial polysaccharides an excellent choice for biopharmaceuticals. Due to its easy purifying procedure and high production efficiency, it is capable of resolving the existing application issues associated with some plant and animal polysaccharides. Furthermore, microbial polysaccharides are recognized as prospective substitutes for these polysaccharides based on the search for eco-friendly chemicals. In this review, the microstructure and properties of microbial polysaccharides are utilized to highlight their characteristics and potential medical applications. From the standpoint of pathogenic processes, in-depth explanations are provided on the effects of microbial polysaccharides as active ingredients in the treatment of human diseases, anti-aging, and drug delivery. In addition, the scholarly developments and commercial applications of microbial polysaccharides as medical raw materials are also discussed. The conclusion is that understanding the use of microbial polysaccharides in biopharmaceuticals is essential for the future development of pharmacology and therapeutic medicine.

Potential Medical Applications of Chitooligosaccharides

Chitooligosaccharides, also known as chitosan oligomers or chitooligomers, are made up of chitosan with a degree of polymerization (DP) that is less than 20 and an average molecular weight (MW) that is lower than 3.9 kDa. COS can be produced through enzymatic conversions using chitinases, physical and chemical applications, or a combination of these strategies. COS is of significant interest for pharmacological and medical applications due to its increased water solubility and non-toxicity, with a wide range of bioactivities, including antibacterial, anti-inflammatory, anti-obesity, neuroprotective, anticancer, and antioxidant effects. This review aims to outline the recent advances and potential applications of COS in various diseases and conditions based on the available literature, mainly from preclinical research. The prospects of further in vivo studies and translational research on COS in the medical field are highlighted.

Dietary chitosan modulates the growth performance, body composition and nonspecific immunity of juvenile yellow catfish (Pelteobagrus fulvidraco)

This study investigated the effects of feeding different concentrations of chitosan on the growth performance, body composition and non-specific immune function of juvenile yellow catfish (Pelteobagrus fulvidraco). Four kinds of experimental diets were respectively prepared by adding 0 (control group), 5, 10 and 15 g/kg of chitosan to the basal feed and fed to juvenile yellow catfish for 8 weeks. Results show that the body weight gain rate, specific growth rate, survival rate, body protein content, serum superoxide dismutase activity, catalase activity, glutathione peroxidise activity, lysozyme activity and disease resistance ability against Aeromonas hydrophila of the experimental group with chitosan added to its diet were significantly higher than those of the control group optimally by 36.22 %, 14.37 %, 9.46 %, 8.97 %, 50.89 %, 33.15 %, 21.52 %, 40.80 %, 41.09 %, and 79.71 %, respectively (P < 0.05). No significant differences in feed efficiency among all groups (P > 0.05) were observed. The optimum dose of dietary chitosan required for the maximum growth of juvenile yellow catfish was 8.95 g/kg. Therefore, adding an appropriate amount of chitosan (8.95 g/kg) to the feed of yellow catfish can significantly improve its growth performance, ameliorate body composition and enhance its non-specific immunity.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Dietary chitosan promotes the growth, biochemical composition, gut microbiota, hematological parameters and internal organ morphology of juvenile Barbonymus gonionotus

In this study, we determined the effects of dietary chitosan on the growth, biochemical composition, gut microbiota, and hematological and histological parameters of juvenile Barbonymus gonionotus. Three test diets containing three different concentrations (1, 2, and 3 g kg-1 feed) of dietary chitosan were formulated. A basal diet without dietary chitosan was considered a control, and the fish were reared for 60 days. Comparing the effects of the dietary chitosan-containing diets with those of the control diet, we found that dietary chitosan significantly improved the muscle growth, nutrient and mineral contents, hematological parameters, lactic acid bacterium abundance, and digestive enzyme activities of B. gonionotus. Moreover, dietary chitosan significantly inhibited the growth of pathogenic bacteria in fish. Interestingly, an increase in the dietary chitosan level significantly enhanced the protein contents of the muscles and inversely significantly decreased the lipid contents compared to those with the basal diet. Quantitative study revealed that dietary chitosan significantly enhanced the length of intestinal villi, and qualitative study showed that dietary chitosan considerably reduced the fat content in the liver and improved the morphology of the kidney compared to those with the basal diet. Taken together, our results suggest that the application of dietary chitosan at a dose of 1 g kg-1 feed produced the highest benefit to treated B. gonionotus, indicating its potential for safe use in aquaculture.

Advances in the preparation and assessment of the biological activities of chitosan oligosaccharides with different structural characteristics

Chitosan oligosaccharides (COSs) are widely used biopolymers that have been studied in relation to a variety of abnormal biological activities in the food and biomedical fields. Since different COS preparation technologies produce COS compounds with different structural characteristics, it has not yet been possible to determine whether one or more chito-oligomers are primarily responsible for the bioactivity of COSs. The inherent biocompatibility, mucosal adhesion and nontoxic nature of COSs are well documented, as is the fact that they are readily absorbed from the intestinal tract, but their structure-activity relationship requires further investigation. This review summarizes the methods used for COS preparation, and the research findings with regard to the antioxidant, anti-inflammatory, anti-obesity, bacteriostatic and antitumour activity of COSs with different structural characteristics. The correlation between the molecular structure and bioactivities of COSs is described, and new insights into their structure-activity relationship are provided.

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.

Functional foods and bioactive ingredients harnessed from the ocean: current status and future perspectives

With an increase in life expectancy and decrease of quality-of-life couple with the high prevalence of diseases, diet is expected to play a key function in sustaining human health. Nutritionists, food technologists and medical experts are working in synergy to cater for the increasing demand of food with associated therapeutic benefits, commonly known as functional food, that may improve well-being and reduce the risk of diseases. Interestingly, the marine ecosystem, due to its abundant and phenomenal biodiversity of marine organisms, constitutes a vital source of a panoply of healthy foods supply for the thriving functional food industry. Marine organisms such as seaweeds, sea cucumbers, sponges, and mollusks amongst others are sources of thousands of biologically active metabolites with antioxidant, anti-parasitic, antiviral, anti-inflammatory and anticancer properties. Given the growing number of research and interest to probe into the therapeutic roles of marine products, this review was designed to provide a comprehensive summary of the therapeutic properties of marine organisms (macroalgae, sea cucumbers and fish among others) which are consumed worldwide, in addition to their potentials and as sources of functional ingredients for developing novel food and fostering wellness. The gap between research development and actual commercialization, and future prospects of marine-based products also summarized to some extent.

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

This study presents a meta-analysis of studies that investigate the effectiveness of chitosan administration on lifestyle-related disease in murine models. A total of 34 published studies were used to evaluate the effect of chitosan supplementation. The effect sizes for various items after chitosan administration were evaluated using the standardized mean difference. Using Cochran’s Q test, the heterogeneity of effect sizes was assessed, after which a meta-ANOVA and -regression test was conducted to explain the heterogeneity of effect sizes using the mixed-effect model. Publication bias was performed using Egger’s linear regression test. Among the items evaluated, blood triglyceride and HDL-cholesterol showed the highest heterogeneity, respectively. Other than blood HDL-cholesterol, total cholesterol, and triglyceride in feces, most items evaluated showed a negative effect size with high significance in the fixed- and random-effect model (p < 0.0001). In the meta-ANOVA and -regression test, administering chitosan and resistant starch was revealed to be most effective in lowering body weight. In addition, chitosan supplementation proved to be an effective solution for serum TNF-α inhibition. In conclusion, chitosan has been shown to be somewhat useful in improving symptoms of lifestyle-related disease. Although there are some limitations in the results of this meta-analysis due to the limited number of animal experiments conducted, chitosan administration nevertheless shows promise in reducing the risk of cholesterol related metabolic disorder.

Nanochitosan Effect on Biomolecular, Hypolipidemic in Rats and Incorporation in Functional Yogurt

&lt;b&gt;Background and Objective:&lt;/b&gt; Chitosan has many functional properties and biological activities. This work aimed to prepare and characterize Chitosan Nanoparticles (CN). Then, evaluate the hypolipidemic and antioxidant effect of CN in rats. Incorporate CN in camel yogurt and evaluation of yogurt properties. &lt;b&gt;Materials and Methods:&lt;/b&gt; Chitosan Nanoparticles (CN) were prepared and analyzed for the size, zeta potential and poly Polydispersity Index (PDI). Total 24 rats were divided into 4 groups, the negative control group was fed on the basal diet and the positive control group was fed on a High-Fat Diet (HFD), the group I and II were fed on the HFD+(CC) or (CN). The feeding period was 6 weeks. Prepared and Characterization stirred camel yogurt fortified by CN. &lt;b&gt;Results:&lt;/b&gt; CN the size was 27.20 nm, ζ-potential+38.78. After the feeding period for CN and CC groups were a decrease in body weight, serum lipid profile and liver function in both tested groups and an increase in HDL-cholesterol and an increase in antioxidants in the CN group more than that in the CC group was observed. mRNA expression with qPCR for hepatic PPARγ, HL, GSS and CYP2E1 genes was performed to investigate the alterations in their levels after CN treatment on the liver of rats fed with HFD. &lt;b&gt;Conclusion:&lt;/b&gt; CN possesses the ability to improve the impairment of lipid metabolism as strongly associated with gene expressions related to lipogenesis and oxidative stress. Also, the addition of 2% CN to camel yogurt gave sensory acceptable and microbiological quality.

Development and validation of an improved 3-methyl-2-benzothiazolinone hydrazone method for quantitative determination of reducing sugar ends in chitooligosaccharides

An accurate and sensitive analytical method for detecting and quantifying reducing sugar ends (RSE) in chitooligosaccharides (COSs) is the key quality parameter for evaluating their structure-function relationship and potential applications. In this work, we develop and validate a novel colorimetric assay with high accuracy and precision for determining RSE content using 3-methyl-2-benzothiazolinone hydrazone (MBTH). Under optimal conditions, the stoichiometry is verified using mono-, di-, and tri- glucosamine hydrochlorides, and the dilution ratio does not interfere with the RSE content measured at 590 nm. The regression equation of glucosamine reveal a good linear relationship (R² = 0.9999). The detection limit, quantification limit, mean relative standard deviation (RSD), and recovery are 2.28 μM, 9.11 μM, 1.90%, and 98.0%, respectively. The newly developed method is potentially useful for monitoring COS hydrolysis, number average molecular weight, and chitosanase activity.

The growth performance, body composition and nonspecific immunity of Tilapia (Oreochromis niloticus) affected by chitosan

The aim of this study was to investigate the effects of dietary chitosan on the growth performance, body composition and non-specific immunity of tilapia (Oreochromis niloticus). Chitosan were added to the basic diet to formulate five kinds of test feeds (0, 2, 4, 6 and 8 g kg^-1). The diets containing 4 g kg^-1 chitosan increased body weight gain, feed conversion rate, specific growth rate, body protein, superoxide dismutase activity, catalase activity, lysozyme, disease resistance ability against Aeromonas hydrophila and decreased hepatopancrease lipid levels, plasma total cholesterol, plasma triacylglycerol, aspartate aminotransferase and alanine aminotransferase of tilapias compared with those of the control group. However, a high level of chitosan (8 g kg^-1) decreased its efficiency compared to moderate level of chitosan (4 g kg^-1). The results demonstrated that chitosan could promote the growth of tilapias and improve their disease resistance against A. hydrophila.

Enhancement of Antioxidant Activity in O/W Emulsion and Cholesterol-Reducing Capacity of Epigallocatechin by Derivatization with Representative Phytosterols

In this study, derivatization of epigallocatechin (EGC) by representative phytosterols (stigmasterol and β-sitosterol) was performed employing Steglich esterification. The structural identity and purity of epigallocatechin β-sitosterol (ESi) and epigallocatechin stigmasterol (ESt) were confirmed by NMR, FT-IR, and HPLC-MS. Further evaluation of ESi and ESt revealed their extraordinary antioxidant activities in O/W emulsion. Two different radical sources in oil or aqueous phase were applied to explore the antioxidant behavior in O/W emulsion. The mechanism was further investigated by fluorescent microscopy and transmission electron microscopy (TEM). Furthermore, incorporation of EGC with stigmasterol and β-sitosterol notably enhanced the cholesterol-reducing activity. TEM studies suggested the hydrogen bonding of EGC strengthened the aggregation network of ESi and ESt in the bile salt micelle. The exceptional properties of ESi and ESt signified their intriguing utilization in the food industry.

The triple-wavelength overlapping resonance Rayleigh scattering method and the fluorescence quenching method for the determination of chitooligosaccharides using trisodium-8-hydroxypyrene-1,3,6-trisulfonate as a probe

In this assay, the triple-wavelength overlapping resonance Rayleigh scattering (TWO-RRS) method and the fluorescence quenching method for the quantitative detection of chitooligosaccharides (COS) were developed. In the weakly Britton-Robinson buffer solution, COS interacted with Trisodium-8-hydroxypyrene-1,3,6-trisulfonate (HPTS) to form an ion-association complex of HPTS-COS, which increased the RRS intensities at 321 nm, 430 nm and 511 nm and decreased the fluorescence intensities of the system at 512 nm. And the changes in the intensities of both methods were related to the changes in the concentration of COS. Moreover, for the TWO-RRS method, OP-10 made the RRS intensities increased stronger, finally, the three peaks' total was linear to the concentration of COS in the range of 1.00-8.00 μg/mL and the limit of detection (LOD) was 0.247 μg/mL, and for the fluorescence quenching method, the linear range was 0.50-3.50 μg/mL with the LOD of 0.108 μg/mL. Based on these, two new and fast spectral methods with high sensitivity and simplicity for the determination of trace COS had been established. The generation mechanism of the TWO-RRS and the fluorescence quenching was studied. At the same time, the two methods were applied to the determination of COS in health products with satisfactory results.

Effects of chitosan-supplemented diets on the growth performance, nonspecific immunity and health of loach fish (Misgurnus anguillicadatus)

This study investigated the effects of dietary chitosan on the growth performance and nonspecific immunity of loaches (Misgurnus anguillicadatus). Four practical diets at three levels of chitosan (1, 5 and 10 g/kg) were fed to loach (3.13 ± 0.02 g) in triplicate groups (20 fish per replicate) for 10 weeks. Contrary to high-chitosan treatment, the administration of low or moderate levels of oral chitosan (1 or 5 g/kg) significantly increased the body weight gain, specific growth rate and condition factor. The oral administration of chitosan significantly increased the survival rate, phenoloxidase, superoxide dismutase, glutathione peroxidase, lysozyme, acid phosphatase and alkaline phosphatase activities, as well as the immunoglobulin M and complement 3 contents and the disease resistance against Aeromonas hydrophila. The optimum dose of dietary chitosan required for the maximum growth of loach was 5 g/kg. These results indicated that chitosan exerted immunostimulatory effects on loaches (M. anguillicadatus) and can thus be used as a dietary supplement.

Dietary chitosan oligosaccharides modulate the growth, intestine digestive enzymes, body composition and nonspecific immunity of loach Paramisgurnus dabryanus

Three test diets containing three different levels (1, 3, and 5 g kg^-1) of dietary chitosan oligosaccharides (COs) were formulated and used to test the growth performance, body composition, intestine digestive enzymes, antioxidant responses and resistance to Aeromonas hydrophila of loach Paramisgurnus dabryanus. A basal diet without any COs served as the control. After 60 days of feeding, the growth performance, intestine digestive-enzyme activities, body protein content and total polyunsaturated fatty acids, antioxidant responses, and resistance to A. hydrophila of loach P. dabryanus were higher than those of the control when the loach P. dabryanus was fed with CO-containing diets. The optimum dose of dietary COs required for the maximum growth of loach was 3 g kg^-1 of the diet. Results indicated that dietary COs can improve the growth performance, body composition, intestine digestive enzymes, antioxidant responses, and resistance to A. hydrophila of loach P. dabryanus and can thus be used as a diet supplement for them.

Enhancement of Galloylation Efficacy of Stigmasterol and β-Sitosterol Followed by Evaluation of Cholesterol-Reducing Activity

In this study, incorporation of gallic acid into typical phytosterols (β-sitosterol and stigmasterol) through Steglich esterification was optimized employing the protection and deprotection strategy. A novel mechanism leading to side esterification was discovered. Complication of the phenolic hydroxyl groups and side reactions were successfully reduced under the optimized conditions. The structural identity and purity of galloyl stigmasterol and galloyl β-sitosterol were confirmed by NMR, FT-IR, and HPLC-MS. Evaluation of galloyl β-sitosterol and galloyl stigmasterol revealed their excellent antioxidant and cholesterol-reducing activities. Significant enhancement of cholesterol-reducing activity by galloylation was unveiled especially for β-sitosterol. Galloyl β-sitosterol had slightly better antioxidant activity at ambient temperature and better cholesterol-reducing activity. Molecular modeling suggested that a subtle difference of galloyl β-sitosterol and galloyl stigmasterol in activities could be attributed to variation of molecular rigidity and conformation. The excellent properties of galloyl β-sitosterol and galloyl stigmasterol suggested their great potential application in the food industry.

Structural characterization of polysaccharides from Cordyceps militaris and their hypolipidemic effects in high fat diet fed mice

Cordyceps militaris is a crude dietary therapeutic mushroom with high nutritional and medicinal values. Mushroom-derived polysaccharides have been found to possess antihyperglycemic and antihyperlipidemic activities. This study aimed to partially clarify the structural characterization and comparatively evaluate hypolipidemic potentials of intracellular- (IPCM) and extracellular polysaccharides of C. militaris (EPCM) in high fat diet fed mice. Results indicated that IPCM-2 is α-pyran polysaccharide with an average molecular weight of 32.5 kDa, was mainly composed of mannose, glucose and galactose with mass percentages of 51.94%, 10.54%, and 37.25%, respectively. EPCM-2 is an α-pyran polysaccharide with an average molecular weight of 20 kDa that is mainly composed of mannose, glucose and galactose with mass percentages of 44.51%, 18.33%, and 35.38%, respectively. In in vivo study, EPCM-1 treatment (100 mg kg-1 d-1) showed potential effects on improving serum lipid profiles of hyperlipidemic mice, reflected by decreasing serum total cholesterol (TC), triglyceride (TG) and low density lipoprotein-cholesterol (LDL-C) levels by 20.05%, 45.45% and 52.63%, respectively, while IPCM-1 treatment (100 mg kg-1 d-1) remarkably decreased TC, TG and LDL-C levels by 20.74%, 47.93%, and 38.25%, respectively. In addition, EPCM-1 ameliorated hyperlipidemia possibly through upregulating the expression of serum lipoprotein lipase (LPL) and down-regulating the expression of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), as determined by enzyme-linked immunosorbent assay (ELISA) method, while IPCM-1 remarkably upregulated the expression of serum LPL. This study confirms polysaccharides from C. militaris could be explored as functional foods or natural medicines for preventing hyperlipidemia.

Fucosylated chondroitin sulfate oligosaccharides from Isostichopus badionotus regulates lipid disorder in C57BL/6 mice fed a high-fat diet

Fucosylated chondroitin sulfate (fCS) and its depolymerized derivative (DfCS), prepared from sea cucumbers, are well-known for their anticoagulant activity. However, their other functional activities are poorly understood. Recently, we obtained fCS oligosaccharides from Isostichopus Badionotus by a modified controllable Fenton-system, named as DfCS-Ib. The functional activities of these oligosaccharides are still unclear. The present study investigated anti-hyperlipidemic activity of DfCS-Ib using a high-fat diet (HFD)-fed mice model. The results indicated that DfCS-Ib reduced obesity, hyperlipidemia, and inflammation caused by HFD. Meanwhile, DfCS-Ib increased the mRNA expression of PPARγ and decreased the mRNA expression of leptin, aP2, and F4/80 in fat tissue. Transcriptome analysis indicated that DfCS-Ib normalized the expressions of genes regulating lipid metabolism. Our results suggested that DfCS-Ib can alleviated lipid disorder by reducing lipid synthesis and promoting lipid lipidolysis. DfCS-Ib can act as a functional agent to regulate lipid disorder.

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.

A Review of the Preparation, Analysis and Biological Functions of Chitooligosaccharide

Chitooligosaccharide (COS), which is acknowledged for possessing multiple functions, is a kind of low-molecular-weight polymer prepared by degrading chitosan via enzymatic, chemical methods, etc. COS has comprehensive applications in various fields including food, agriculture, pharmacy, clinical therapy, and environmental industries. Besides having excellent properties such as biodegradability, biocompatibility, adsorptive abilities and non-toxicity like chitin and chitosan, COS has better solubility. In addition, COS has strong biological functions including anti-inflammatory, antitumor, immunomodulatory, neuroprotective effects, etc. The present paper has summarized the preparation methods, analytical techniques and biological functions to provide an overall understanding of the application of COS.

Hypolipidemic activities of partially deacetylated α-chitin nanofibers/nanowhiskers in mice

Partially deacetylated α-chitin nanofibers/nanowhiskers mixtures (DEChNs) were prepared by 35% sodium hydroxide (NaOH) treatment followed by disintegration in water at pH 3-4. The aim of this study was to investigate the hypolipidemic effects of DEChNs at different dosage levels in male Kunming mice. The male mice were randomly separated into five groups, that is, a normal diet group, a high-fat diet group, and three DEChN groups that were treated with different doses of DEChN dispersions (L: low dose, M: medium dose, H: high dose). Primarily, the DEChNs significantly decreased body weight (BW) gain and adipose tissue weight (ATW) gain of mice. Meanwhile, the decreasing extent of weight ratios between ATW and BW was dependent on the dose of DEChNs. Moreover, the DEChNs prevented an increase in plasma lipids (cholesterol and triacylglycerol) in mice when they were fed a high-fat diet. Histopathological examination of hepatocytes revealed that the DEChNs were effective in decreasing the accumulation of lipids in the liver and preventing the development of a fatty liver. The results suggested that the DEChNs reduced the absorption of dietary fat and cholesterol in vivo and could effectively reduce hypercholesterolemia in mice.

Chitosan Nanoparticles of Gamma-Oryzanol: Formulation, Optimization, and In vivo Evaluation of Anti-hyperlipidemic Activity

The elevated blood levels of cholesterol and low-density lipoproteins result in hyperlipidemia. The available expensive prophylactic treatments are kindred with severe side effects. Therefore, we fabricated the polymeric nanoparticles of gamma-oryzanol to achieving the improved efficacy of drug. The nanoparticles were prepared by ionic gelation method and optimized using 2³ full factorial design taking drug/polymer ratio (X₁), polymer/cross linking agent ratio (X₂), and stirring speed (X₃) as independent variables. The average particle size, percentage entrapment efficiency, and in vitro drug release at 2, 12, and 24 h were selected as response parameters. The factorial batches were statistically analyzed and optimized. The optimized nanoparticles were characterized with respect to particle size (141 nm) and zeta potential (+ 6.45 mV). Results obtained with the prepared and characterized formulation showed 83% mucoadhesion towards the intestinal mucosa. The in vitro findings were complemented well by in vivo anti-hyperlipidemic activity of developed formulation carried out in Swiss albino mouse model. The in vivo studies showed improved atherogenic index, malondialdehyde, and superoxide dismutase levels in poloxamer-407-induced hyperlipidemic animals when treated with oryzanol and gamma-oryzanol nanoformulation. Based on our findings, we believe that chitosan-mediated delivery of gamma-oryzanol nanoparticles might prove better in terms of anti-hyperlipidemic therapeutics.

Hypoglycaemic and hypolipidaemic properties of peach gum polysaccharides

Hyperglycaemia and hyperlipidaemia are major risk factors for coronary artery diseases and atherosclerosis. Peach gum polysaccharides (PGPs) possess various bioactivities. In this study, PGPs were extracted with thermostable α-amylase and investigated in terms of hypolipidaemic and hypoglycaemic activities. KKAy mice were gavaged once daily with either PGPs or distilled water (control group) for 3 weeks. Oral administration of PGPs decreased the levels of serum triglyceride, cholesterol low-density lipoprotein cholesterol, fasting blood glucose, plasma insulin, C-peptide, and HbAlc in mice. Moreover, treatment with PGPs increased the insulin sensitivity index in KKAy mice. Results indicated that PGPs possess significant hypoglycaemic effects and could be developed as a drug for preventing hyperlipidaemia and hyperglycaemia.

Effect of the molecular weight of water-soluble chitosan on its fat-/cholesterol-binding capacities and inhibitory activities to pancreatic lipase

BACKGROUND

Obesity has become a worldwide burden to public health in recent decades. Given that obesity is caused by an imbalance between caloric intake and expenditure, and that dietary fat is the most important energy source of all macronutrients (by providing the most calories), a valuable strategy for obesity treatment and prevention is to block fat absorption via the gastrointestinal pathway. In this study, the fat- and cholesterol-binding capacities and the inhibition of pancreatic lipase by water-soluble chitosan (WSC) with different weight-average molecular weight (Mw) were tested and compared in vitro, in order to determine the anti-obesity effects of WSC and the influence of its Mw.

METHODS

In this study, WSC with different Mw (∼1,000, ∼3,000, ∼5,000, ∼7,000 and ∼9,000 Da) were prepared by oxidative degradation assisted with microwave irradiation. A biopharmaceutical model of the digestive tract was used to determine the fat- and cholesterol-binding capacity of WSC samples. The pancreatic lipase assays were based on p-nitrophenyl derivatives.

RESULTS

The results showed that all of the WSC samples exhibit great fat- and cholesterol-binding capacities. Within the testing range, 1 g of WSC sample could absorb 2-8 g of peanut oil or 50-65 mg of cholesterol, which are both significantly higher than the ability of cellulose to do the same. Meanwhile, all the WSC samples were proven to be able to inhibit pancreatic lipase activity to some extent.

DISCUSSION

Based on the results, we suggest that there is a significant correlation between the binding capacity of WSC and its Mw, as WSC2 (∼3,000 Da) shows the highest fat- and cholesterol-binding capacities (7.08 g g-1 and 63.48 mg g-1, respectively), and the binding ability of WSC declines as its Mw increases or decreases from 3,000 Da. We also suggest WSC as an excellent resource in the development of functional foods against obesity for its adsorption, electrostatic binding and entrapment of cholesterol, fat, sterols and triglycerides in the diet.

Hypolipidemic effect of Youcha in hyperlipidemia rats induced by high-fat diet

Youcha is a novel tea drink from the northeast of Guangxi. This study aimed to investigate the hypolipidemic properties of Youcha in high-fat induced hyperlipidemic Sprague-Dawley (SD) rats. After designing the model, rats were randomly divided into six groups (n = 10): normal diet (NMD) group, high-fat diet (HFD) group, Xuezhikang (120 mg kg-1 d-1) (HFD+P) group and Youcha (150, 750 or 1500 mg kg-1 d-1) (HFD+L, HFD+M or HFD+H) groups. Youcha comprises tea polyphenols (1.51 g per 100 g), caffeine (34.80 mg per 100 g) and other functional compounds. To evaluate the lipid-lowering effects of Youcha, weight of the body, liver and fat, fat index, lipid metabolism, antioxidant properties and liver damage indices were examined. In addition, the activities of some enzymes in serum and liver tissue were examined to preliminarily study their possible mechanism. The results reveal that Youcha tends to reduce body weight, liver weight, fat index, total cholesterol (TC) and triglyceride (TG) contents, low-density lipoprotein cholesterol (LDL-C), atherogenic index (AI), malondialdehyde (MDA), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and increase high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and glutathione peroxidase (GPx) relative to the HFD group. The hypolipidemic effect was partly due to the regulation of fatty acid synthetase (FAS) and lipase (LPS) rather than lipoprotein lipase (LPL) to decrease TG markedly. These findings suggest that Youcha could be potentially used to remedy hyperlipidemia and is hence worthy of promotion as a tea drink.

Transcriptome analysis of the effects of chitosan on the hyperlipidemia and oxidative stress in high-fat diet fed mice

Transcriptome analysis was performed to investigate the alterations in gene expression after chitosan (CS) treatment on the liver of mice fed with high-fat diet (HFD). The results showed that the body weight, the liver weight and the epididymal fat mass of HFD mice, which were 62.98%, 46.51% and 239.37%, respectively, higher than those of control mice, could be significantly decreased by chitosan supplementation. Also, high-fat diet increased both plasma lipid and liver lipid as compared with the control mice. Chitosan supplementation decreased the plasma lipid and liver lipid, increased the lipoprotein lipase (LPL) and hepatic lipase (HL) activity, increased T-AOC and decreased MDA in the liver and the epididymis adipose as compared with the HFD mice. Transcriptome analysis indicated that increased Mups, Lcn2, Gstm3 and CYP2E1 expressions clearly indicated HFD induced lipid metabolism disorder and oxidative damage. Especially, chitosan treatment decreased the Mup17 and Lcn2 expressions by 64.32% and 82.43% respectively as compared with those of HFD mice. These results indicated that chitosan possess the ability to improve the impairment of lipid metabolism as strongly associated with increased Mups expressions and gene expressions related to oxidative stress.

Dietary supplementation of thiamine and pyridoxine-loaded vanillic acid-grafted chitosan microspheres enhances growth performance, metabolic and immune responses in experimental rats

In the present investigation, the effect of dietary supplementation of thiamine and pyridoxine loaded vanillic acid-grafted chitosan microspheres (TPVGC) on growth, metabolic and immune responses in Wistar strain albino rats was studied. Eight experimental groups, namely four groups each for male and female rats were fed with 0, 0.4, 0.8 and 1.6% of TPVGC in the diet. At the end of 45days feeding trials, both male and female rats supplemented with TPVGC had higher weight gain% and specific growth rate than the control groups. Significantly (p<0.05) lower blood glucose level and higher respiratory burst activity were recorded in the treatment groups than the control groups of both male and female rats. Activity of metabolic enzymes (aspartate amino transferase, alanine aminotransferase, alkaline phosphatase and acid phosphatase) and antioxidant enzymes (superoxide dismutase, catalase and glutathione S-transferase) were significantly higher (p<0.05) in the control groups and a decreasing trend in the same was observed with a gradual increase in the inclusion level of TPVGC in the diet of the treatment groups. However, a reverse trend was observed for acetylcholine esterase. It was inferred that dietary supplementation of thiamine and pyridoxine loaded vanillic acid-grafted chitosan enhanced the growth performance, metabolic and immune responses in the animal-model.

Chitosan dosage regimen to trap fecal oil excretion after peroral lipase inhibitor administration in mice

This study was designed to investigate the oil entrapment and systemic oil absorption-reducing activities of chitosan. High-molecular-weight chitosan formed gel aggregates with oil and bile salts in vitro. The oil/chitosan ratio and the molecular weight of chitosan were optimized for the in vivo study, and a molecular weight >100,000 was effective in reducing the oil contamination of mouse fur. The oil/chitosan weight ratio required for effective oil entrapment was less than 13 and 5 in the in vitro and in vivo experiments, respectively. Chitosan administration was most effective during meals, and high-molecular-weight chitosan could trap and facilitate the reduction of systemic absorption of oil droplets separated by orlistat. The activity of the lipase inhibitor was not altered by chitosan as evidenced by thin layer chromatography, and orlistat was not absorbed systemically by the co-administration of chitosan.

Hypolipidemic effects of chitosan and its derivatives in hyperlipidemic rats induced by a high-fat diet

Background

Hyperlipidemia (HLP) is the primary risk factor of cardiovascular disease (CVD). Various factors, including genetics, physical inactivity, and daily nutritional habits, affect the prevalence of HLP. Recently, it was revealed that dietary fibers, such as pectin, psyllium, and especially chitosan (CTS), may play important roles in hypolipidemic management. Thus, this study aims to determine the hypolipidemic effect and mechanism of CTS and its water-soluble derivatives, chitosan oligosaccharides (M_N≤1,000 Da (COSI) and M_N≤3,000 Da (COSIII)), in male hyperlipidemic rats induced by a high-fat diet (HFD).

Design

After the model creation, 120 Sprague-Dawley (SD) rats were equally assigned to 12 groups fed various diets as follows: the normal group with basic diet, an HFD group, an HFD group supplemented with three doses of CTS, COSI and COSIII groups, and an HFD group treated with simvastatin (7 mg/kg·d). After 6 weeks, body weight, fat/body ratio, and the relevant biomarkers of serum, liver, and feces were measured. Additionally, the histological analysis of liver and adipose tissue was performed, and the mRNA expressions of liver peroxisome proliferator-activated receptor-α (PPARα) and hepatic lipase (HL) were examined.

Results

Compared with HFD group, rats fed CTS, COSI, and COSIII showed a better ability to regulate their body weight, liver and cardiac indices, fat/body ratio, as well as serum, liver, and fecal lipids, and simultaneously to maintain the appropriate activity of liver and serum superoxide dismutase (SOD), alanine aminotransferase (ALT), aspartate aminotransferase (AST), as well as liver and fecal total bile acids (TBA). Simultaneously, there had been a higher mRNA expression of PPARα and HL in the treatment groups.

Conclusion

The obtained results suggested that these three function foods can effectively improve liver lipid metabolism by normalizing the expressions of PPARα and HL, and protect liver from the oxidized trauma by enhancing hepatic function, which could be potentially used to remedy hyperlipidemia.

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.

Effects of soybean milk, chitosan, and anti-Streptococcus mutans IgY in malnourished rats' dental biofilm and the IgY persistency in saliva

OBJECTIVE

This study aims to evaluate the eff ect of soybean milk containing a combination of anti-Streptococcus mutans IgY and chitosan to the colonization of S. mutans in the saliva and to the IgY persistency in the saliva.

MATERIALS AND METHODS

Experimental malnourished Sprague-Dawley rats were fed with soybean milk that is enriched with anti-S. mutans IgY and chitosan. After 15 days of feeding, we evaluated the S. mutans in dental biofilm, in addition to the persistency level of anti-S. mutans IgY.

RESULTS

The rats that received soybean milk supplemented with anti-S. mutans IgY had the lowest number of S. mutans colonies (p < 0.05). Anti-S. mutans IgY was detected in saliva after 15 days of feeding.

CONCLUSIONS

Soybean milk supplemented with anti-S. mutans IgY and chitosan could signifi cantly reduce S. mutans biofilm, and the supplemented anti-S. mutans IgY persisted in these rats' saliva following the feeding period.