Effects of sulfation on the physicochemical and functional properties of a water-insoluble polysaccharide preparation from Ganoderma lucidum

Sulfation of furcellaran and its effect on hemocompatibility in vitro

In this study, furcellaran (FUR) obtained from Furcellaria lumbricalis was firstly employed for sulfation via various methods, including SO3-pyridine (SO3∙Py) complex in different aprotic solvents, chlorosulfonic acid and sulfuric acid with a "coupling" reagent N,N'-Dicyclohexylcarbodiimide. Structural characterization through FT-IR, GPC, XPS and elemental analyses confirmed the successful synthesis of 6-O-sulfated FUR derivates characterized by varying degrees of sulfation (DS) ranging from 0.15 to 0.91 and molecular weight (Mw) spanning from12.5 kDa to 2.7 kDa. In vitro clotting assays, partial thromboplastin time (aPTT), thrombin time (TT), and prothrombin time (PT) underscored the essential role of sulfate esters in conferring anticoagulant activity whereas FUR prepared via chlorosulfonic acid with DS of 0.91 reached 311.4 s in aPPT showing almost 4-fold higher anticoagulant activity than native FUR at the concentration 2 mg/mL. MTT test showed all tested samples decreased cell viability in a dose dependent manner while all of them are non-cytotoxic up to the concentration of 0.1 mg/mL. Furthermore, sulfated derivates deposited onto polyethylene terephthalate surface presented substantial decrease in platelet adhesion, as well as absence of the most activated platelet stages. These findings support the pivotal role of O-6 FUR sulfates in enhancing hemocompatibility and provide valuable insights for a comparative assessment of effective sulfating approaches.

Recent advances in the extraction, purification, structural-property correlations, and antiobesity mechanism of traditional Chinese medicine-derived polysaccharides: a review

Traditional Chinese medicine (TCM) has displayed preventive and therapeutic effects on many complex diseases. As natural biological macromolecules, TCM-derived antiobesogenic polysaccharides (TCMPOs) exhibit notable weight-loss effects and are seen to be a viable tactic in the fight against obesity. Current studies demonstrate that the antiobesity activity of TCMPOs is closely related to their structural characteristics, which could be affected by the extraction and purification methods. Therefore, the extraction, purification and structural-property correlations of TCMPOs were discussed. Investigation of the antiobesity mechanism of TCMPOs is also essential for their improved application. Herein, the possible antiobesity mechanisms of TCMPOs are systematically summarized: (1) modulation of appetite and satiety effects, (2) suppression of fat absorption and synthesis, (3) alteration of the gut microbiota and their metabolites, and (4) protection of intestinal barriers. This collated information could provide some insights and offer a new therapeutic approach for the management and prevention of obesity.

Antioxidant Compounds from Edible Mushrooms as Potential Candidates for Treating Age-Related Neurodegenerative Diseases

The last century has seen an increase in our life expectancy. As a result, various age-related diseases, such as neurodegenerative diseases (NDs), have emerged, representing new challenges to society. Oxidative stress (OS), a condition of redox imbalance resulting from excessive production of reactive oxygen species, represents a common feature that characterizes the brains of elderly people, thus contributing to NDs. Consequently, antioxidant supplementation or dietary intake of antioxidant-containing foods could represent an effective preventive and therapeutic intervention to maintain the integrity and survival of neurons and to counteract the neurodegenerative pathologies associated with aging. Food contains numerous bioactive molecules with beneficial actions for human health. To this purpose, a wide range of edible mushrooms have been reported to produce different antioxidant compounds such as phenolics, flavonoids, polysaccharides, vitamins, carotenoids, ergothioneine, and others, which might be used for dietary supplementation to enhance antioxidant defenses and, consequently, the prevention of age-related neurological diseases. In this review, we summarized the role of oxidative stress in age-related NDs, focusing on the current knowledge of the antioxidant compounds present in edible mushrooms, and highlighting their potential to preserve healthy aging by counteracting age-associated NDs.

Effects of sulfated polysaccharides from Laminaria japonica on regularating the gut microbiotan and alleviating intestinal inflammation in obese mice

Due to their known health-enhancing properties, Laminaria japonica polysaccharides (LJP) may alleviate obesity via unknown mechanisms. This study aimed to investigate beneficial LJP effects and mechanism(s) of action using an animal obesity model (ICR mice fed a high-fat diet). First, LJP were confirmed to consist of sulfated polysaccharides via infrared spectroscopy. Next, LJP administration to mice was found to induce weight loss, reduce liver fat accumulation, and support healthy obesity-related blood serum indicator levels. Notably, LJP treatment significantly reduced TC and LDL levels and significantly increased HDL, LPL, UCP-2, and PPAR-α levels. Furthermore, examinations of tissues of LJP-treated mice revealed significantly reduced intestinal tissue inflammation as compared to corresponding results obtained for untreated obese controls. Additionally, LJP treatment relieved colonic shortening and reduced colonic levels of inflammatory factors TNF-α and IL-6. Further exploration of LJP treatment effects on mouse gut microbiota conducted via fecal 16S rRNA gene sequence-based gut microbiome profiling analysis revealed that LJP treatment increased the Bacteroidetes/Firmicutes ratio and increased gut abundances of probiotics Bacteroides acidifaciens, s_Lactobacillus intestinalis, and s_Lactobacillus murinus. In conclusion, these results collectively suggest that LJP use as a food supplement may alleviate obesity and related gut microbiota dysbiosis and intestinal inflammatory disorders.

Comparison of structural characteristics and bioactivity of Tricholoma mongolicum Imai polysaccharides from five extraction methods

Tricholoma mongolicum Imai is an edible fungus rich in various health-promoting compounds, such as polysaccharides, polypeptides, polyunsaturated fatty acids, etc., and among them, polysaccharides have gotten more attention in recent research trends. This study explored the extraction of polysaccharides from T. mongolicum Imai by five extraction methods, including hot water extraction, ultrasound extraction, enzyme-assisted extraction, 0.1 M HCL extraction, and 0.1 M NaOH extraction. The effects of these extraction methods on the yield, chemical structure, apparent morphology, and the antioxidant activities of Tricholoma mongolicum Imai polysaccharides (TMIPs) were investigated in this study. The data showed that 0.1 M NaOH extraction produced the highest extraction yield compared to the other extraction methods. The results of high-performance gel permeation chromatography (HPGPC) and scanning electron microscopy (SEM) showed that different extraction methods had significant effects on the molecular weight and morphology of TMIPs. The results of Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis showed that the extraction methods had no significant difference in functional groups, crystal structure, and thermal stability of TMIPs. The antioxidant activity of TMIPs extracted by ultrasound extraction was more prominent among the five polysaccharides, which might be related to a large number of low-molecular-weight components in molecular weight distribution.

Seaweed Phenolics as Natural Antioxidants, Aquafeed Additives, Veterinary Treatments and Cross-Linkers for Microencapsulation

Driven by consumer demand and government policies, synthetic additives in aquafeed require substitution with sustainable and natural alternatives. Seaweeds have been shown to be a sustainable marine source of novel bioactive phenolic compounds that can be used in food, animal and aqua feeds, or microencapsulation applications. For example, phlorotannins are a structurally unique polymeric phenolic group exclusively found in brown seaweed that act through multiple antioxidant mechanisms. Seaweed phenolics show high affinities for binding proteins via covalent and non-covalent bonds and can have specific bioactivities due to their structures and associated physicochemical properties. Their ability to act as protein cross-linkers means they can be used to enhance the rheological and mechanical properties of food-grade delivery systems, such as microencapsulation, which is a new area of investigation illustrating the versatility of seaweed phenolics. Here we review how seaweed phenolics can be used in a range of applications, with reference to their bioactivity and structural properties.

Impact of acidic, water and alkaline extraction on structural features, antioxidant activities of Laminaria japonica polysaccharides

This study comparatively evaluated the effects of different extraction methods on yield, structural features and antioxidant activities of Laminaria japonica (L. japonica) polysaccharides. Results showed that acid, water and alkaline extracted L. japonica polysaccharides (LJP-CA, LJP-W and LJP-A, respectively) differed significantly. Among three polysaccharides, LJP-W showed the highest viscosity with high uronic acid content and average molecular weight, whereas LJP-CA showed the lowest viscosity with low uronic acid and high sulfate content with moderate average molecular weight. LJP-CA was mainly composed of fucose, mannose and galactose, but the proportion of glucose was greatly increased in LJP-W and LJP-A. LJP-W had an even and smooth sheet-like appearance, while LJP-CA and LJP-A exhibited irregular and rough fragments or particles with stronger antioxidant activities. These results suggest that acid and alkali would propose an improved process for polysaccharide preparation from L. japonica and to exploit its potential application as a functional ingredient in food application.

Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review

Ganoderma lucidum (Reishi) is a popular medicinal mushroom and has been used in oriental medicine because of its promoting effects on health and life expectancy. G. lucidum contains various compounds with a high grade of biological activty, which increase the immunity and show antitumour, antimicrobial, anti-inflammatory, antioxidant and acetylcholinesterase inhibitory activity. Several of these substances belong to the triterpenoids and polysaccharides classes. Proteins, lipids, phenols, sterols, etc. are also present. In the present review, an extensive overview of the presence of antitumour, antimicrobial, antioxidant and antiacetylcholinesterase compounds in G. lucidum extracts will be given, along with an evaluation of their therapeutic effects.

Acute, sub-acute toxicity and antioxidant activities (in vitro and in vivo) of Reichardia picroide crude extract

ETHNOPHARMACOLOGICAL RELEVANCE

Reichardia picroide is a species mainly used for alimentary purposes, but it is traditionally known to be used as hypoglycemiant, diuretic, depurative, galactagogue and tonic.

AIM OF THE STUDY

To date, there are no studies corroborating both its safety and antioxidant activities. The objective of the present study, thus, was to assess the safety profile of Reichardia picroide methanolic extract (RPE) and as well as on its antioxidant and antihemolytic activities.

MATERIALS AND METHODS

The acute toxicity of RPE was carried out based on OECD guidelines 425. Signs accompanying toxicity and possible death of animals were monitored for two weeks to ascertain the median lethal dose (LD₅₀) of the RPE. In sub-acute toxicity study, the extract was administered by gavage at the doses of 250, 500 and 1000mg/kg/day for 21 consecutive days. The antioxidant activity of RPE was investigated through various methods both in vitro and in vivo.

RESULTS

The admistrated doses did not produce mortality or changes in general behaviors of the tested males and females mice. The LD₅₀ was found to be superior to 5000mg/kg DW. Moreover, daily administration of RPE at doses ranged from 500 to 1000mg/kg could result in alteration of liver and kidney histology. Significant decrease in liver enzymes (ALT and AST), urea and creatinine levels in female plasma was recorded. The RPE was, in vitro, strong in DPPH scavenging and hemolytic inhibition, benificial in lipid peroxidation inhibition and reducing power. In addition, it exhibited, in vivo, a strong effect on GSH level increasing and lipid peroxidation inhibition in liver and kidney.

CONCLUSIONS

It can be suggested, based on the results of this study, that the crude extract of Reichardia picroide was non-toxic in acute administration and the use of this extract is safe at doses ≤ 250mg/kg. This study supports the application of Reichardia picroides in alimentary and traditional medicine purposes. Moreover, antioxidant activity results suggested that Reichardia picroide had potent antioxidant activities and could be utilized as new natural antioxidant in food and therapeutics.

Effects of dietary oxidized konjac glucomannan sulfates (OKGMS) and acidolysis-oxidized konjac glucomannan (A-OKGM) on the immunity and expression of immune-related genes of Schizothorax prenanti

In the present study, konjac glucomannan (KGM) was degraded by H2O2, and then used trisulfonated sodium amine and HCl, individually, to obtain two kinds of derivatives: oxidized konjac glucomannan sulfates (OKGMS) and acidolysis-oxidized konjac glucomannan (A-OKGM). The effects of two OKGM modified products on the immune parameters and expressions of toll-like receptor 22 (TLR22), myeloid differentiation factor 88 (MyD88) and interferon regulatory factors 7 (IRF7) genes in Schizothorax prenanti were determined. The alternative haemolytic complement (ACH50) activity was found to be significantly increased by the OKGMS diets. The immunoglobulin M (IgM) level was significantly enhanced by the OKGMS diets. The lysozyme activity was significantly increased by both OKGMS and A-OKGM diets. The superoxide dismutase (T-SOD) activity in fish fed with all doses of OKGMS diets was significantly higher than that in fish fed with basal diet. The glutathione peroxidase (GSH-PX) activity in fish fed with 0.8% and 1.6% A-OKGM diets was significantly higher than control group. The malondialdehyde (MDA) level was significantly decreased by both OKGMS and A-OKGM diets. The 0.8% A-OKGM diet significantly up-regulated TLR22 gene expression in the head kidney and spleen. TLR22 gene expression was significantly promoted by all OKGMS diets in the mesonephros and liver. The MyD88 mRNA level in 1.6% A-OKGM group significantly increased in the head kidney. The low dose of OKGMS significantly induced the MyD88 gene expression in the mesonephros, gut and liver, while 0.8% A-OKGM group also showed a significantly enhanced MyD88 mRNA expression in the gut. High dose of OKGMS significantly increased the IRF7 mRNA expression in the mesonephros and spleen. Fish fed with low dose of A-OKGM showed significantly higher expression of IRF7 in the gut and liver. Present study suggested that OKGMS and A-OKGM can act as immunostimulant to improve the immune indexes and up-regulate the immune-related gene expressions.

Identification of liver CYP51 as a gene responsive to circulating cholesterol in a hamster model

Hypercholesterolaemia is a risk factor for CVD, which is a leading cause of death in industrialised societies. The biosynthetic pathways for cholesterol metabolism are well understood; however, the regulation of circulating cholesterol by diet is still not fully elucidated. The present study aimed to gain more comprehensive understanding of the relationship between circulating cholesterol levels and molecular effects in target tissues using the hamster model. Male golden Syrian hamsters were fed with chow or diets containing 36 % energy from fat with or without 1 % cholesteyramine (CA) as a modulator of circulating cholesterol levels for 35 d. It was revealed that the expression of lanosterol 14α-demethylase (CYP51) instead of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression was responsive to circulating cholesterol in hamsters fed hypercholesterolaemic diets. The high-fat diet increased circulating cholesterol and down-regulated CYP51, but not HMG-CoA reductase. The CA diet decreased cholesterol and increased CYP51 expression, but HMG-CoA reductase expression was not affected. The high-fat diet and CA diet altered the expression level of cholesterol, bile acids and lipid metabolism-associated genes (LDL receptor, cholesterol 7α-hydroxylase (CYP7A1), liver X receptor (LXR) α, and ATP-binding cassette subfamily G member 5/8 (ABCG5/8)) in the liver, which were significantly correlated with circulating cholesterol levels. Correlation analysis also showed that circulating cholesterol levels were regulated by LXR/retinoid X receptor and PPAR pathways in the liver. Using the hamster model, the present study provided additional molecular insights into the influence of circulating cholesterol on hepatic cholesterol metabolism pathways during hypercholesterolaemia.

Reviews on Mechanisms of In Vitro Antioxidant Activity of Polysaccharides

It is widely acknowledged that the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) induced oxidative stress will cause significant damage to cell structure and biomolecular function, directly or indirectly leading to a number of diseases. The overproduction of ROS/RNS will be balanced by nonenzymatic antioxidants and antioxidant enzymes. Polysaccharide or glycoconjugates derived from natural products are of considerable interest from the viewpoint of potent in vivo and in vitro antioxidant activities recently. Particularly, with regard to the in vitro antioxidant systems, polysaccharides are considered as effective free radical scavenger, reducing agent, and ferrous chelator in most of the reports. However, the underlying mechanisms of these antioxidant actions have not been illustrated systematically and sometimes controversial results appeared among various literatures. To address this issue, we summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms.

Cholesterol-lowering activity of soy-derived glyceollins in the golden Syrian hamster model

Hypercholesterolemia is one of the major factors contributing to the risk of cardiovascular disease (CVD), which is the leading cause of death in developed countries. Consumption of soy foods has been recognized to lower the risk of CVD, and phytochemicals in soy are believed to contribute to the health benefits. Glyceollin is one of the candidate phytochemicals synthesized in stressed soy that may account for many unique biological activities. In this study, the in vivo cholesterol-lowering effect of glyceollins was investigated. Male golden Syrian hamsters were fed diets including (1) 36 kcal% fat diet, (2) 36 kcal% fat diet containing 250 mg/kg diet glyceollins, or (3) chow for 28 days. Hepatic cholesterol esters and free cholesterol, hepatic total lipid content, plasma lipoproteins, fecal bile acid, fecal total cholesterol, and cholesterol metabolism related gene expressions were measured. Glyceollin supplementation led to significant reduction of plasma VLDL, hepatic cholesterol esters, and total lipid content. Consistent with changes in circulating cholesterol, glyceollin supplementation also altered expression of the genes related to cholesterol metabolism in the liver. In contrast, no change in plasma LDL and HDL, fecal bile acid, or cholesterol content was observed. The cholesterol-lowering effect of glyceollins appeared not to go through the increase of bile excretion. These results supported glyceollins' role as novel soy-derived cholesterol-lowering phytochemicals that may contribute to soy's health effects.

In vitro antioxidant properties of mangosteen peel extract

The growing interest in the replacement of synthetic food antioxidants by natural ones has fostered research on the screening of plant-derived raw materials for identifying new antioxidants. The special attention of research today is focused on inexpensive or residual sources from agricultural industries. Fruit peels as sources of powerful natural antioxidants are often the waste parts of various fruits from consumption and food industry. Among the fruit peels, mangosteen peel is an important source of natural phenolic antioxidants. The mangosteen peel contains various bioactive substances, i.e., phenolic acids and flavonoids, which possess biological and medicinal properties, especially antioxidant properties. The aim of this review, after presenting analytical techniques for determining in vitro antioxidant activity of mangosteen peel extract, is to summarize available data on the factors affecting antioxidant activity of mangosteen peel extract. In addition, the potential antioxidant activity of mangosteen peel extract, the bioactive compounds identified from mangosteen peel extract and their antioxidant activity are presented. Potential applications of the mangosteen peel extract in food, pharmaceutical and cosmetic products are also discussed.

In vitro antioxidant, anticoagulant and antimicrobial activity and in inhibition of cancer cell proliferation by xylan extracted from corn cobs

Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2). Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70%) at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05) in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds.

Antiherpetic activity of a sulfated polysaccharide from Agaricus brasiliensis mycelia

Sulfated polysaccharides are good candidates for drug discovery in the treatment of herpetic infections. Agaricus brasiliensis (syn A. subrufescens, A. blazei) is a Basidiomycete fungus native to the Atlantic forest region of Southeastern Brazil. Herein we report the chemical modification of a polysaccharide extracted from A. brasiliensis mycelia to obtain its sulfated derivative (MI-S), which presented a promising inhibitory activity against HSV-1 [KOS and 29R (acyclovir-resistant) strains] and HSV-2 strain 333, with selectivity indices (SI = CC50/IC50) higher than 439, 208, and 562, respectively. The mechanisms underlying this inhibitory activity were scrutinized by plaque assay with different methodological strategies. MI-S had no virucidal effects, but inhibited HSV-1 and HSV-2 attachment, penetration, and cell-to-cell spread, as well as reducing the expression of HSV-1 ICP27, UL42, gB, and gD proteins. MI-S also presented synergistic antiviral effect with acyclovir. These results suggest that MI-S presents multiple modes of anti-HSV action.

Antioxidant properties and antioxidant compounds of various extracts from the edible basidiomycete Grifola frondosa (Maitake)

Grifola frondosa is an edible mushroom currently available in Taiwan. Ethanolic, cold-water and hot-water extracts were prepared and their antioxidant properties were investigated. At 1 mg/mL, G. frondosa T1 and T2 cold-water extracts showed high reducing powers of 1.02 and 0.50, respectively. Chelating abilities on ferrous ions of G. frondosa T1 and T2 were higher for cold-water extracts than for ethanolic and hot-water extracts. For the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, G. frondosa T1 and T2 extracts were effective in the following order: ethanolic > hot-water > cold-water. The G. frondosa hot-water extract showed high scavenging ability on superoxide anions. Total phenols, flavonoids, ascorbic acid and α-tocopherol are the major antioxidant components found in the various G. frondosa extracts. Based on EC₅₀ values (<20 mg/mL) obtained, the various extracts from G. frondosa investigated in this study display potent antioxidative properties.