Antitumor polysaccharides from P. ostreatus (Fr.) Quél.: isolation and structure of a beta-glucan

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

Structural studies of a water insoluble β-glucan from Pleurotus djamor and its cytotoxic effect against PA1, ovarian carcinoma cells

A water insoluble β-glucan (PS), with molecular mass ∼9.16 × 10⁴ Da was isolated from the 4% alkaline extract of an edible mushroom, Pleurotus djamor and found to consist of (1→3)-β-d-glucopyranosyl moiety. The structure of the PS was elucidated on the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR experiments (¹H, ¹³C, DQF-COSY, DEPT-135, and HSQC). The structure of the repeating unit of the polysaccharide was established as: →3)-β-d-Glcp-(1→. The water insoluble β-glucan showed cytotoxic effect against PA1 cells, where˜50% population was destroyed at 100 μg/mL concentration, and almost all cells at 250 μg/mL concentration. The wound healing assay showed significant anticarcinogenic effect against ovarian carcinoma PA1 cells after 48 h of treatment.

Nutritional quality of Oyster Mushroom (Pleurotus Ostreatus) as affected by osmotic pretreatments and drying methods

This study was conducted to evaluate the effects of different levels of osmotic pretreatments prior to drying and different drying methods on nutritional quality of dried mushroom slices. The experiment consisted of sun, solar, and oven drying after dipping the slices in salt solutions of 5 and 10% concentrations for 50 minutes, the control being untreated mushroom sample. Significant differences in proximate composition were observed between the fresh and dried mushroom samples. The average mean value of crude protein, crude fat, crude fiber, ash, and carbohydrates of the fresh mushroom samples were 28.85, 2.47, 12.87, 9.76 and 48.16% as compared to 25.91, 2.18, 10.41, 10.91 and 42.14% for dried samples. Oven drying resulted in higher content of ash (11.06%) and carbohydrates (43.64%) and lower contents of crude protein (24.99%), crude fat (2.12%), and crude fiber (10.21%). The osmotic pretreatments significantly affected the composition of the dried mushroom samples. As salt concentration increased from 0 to 5 and 10%, the protein content reduced from 26.78 to 25.99 and 24. 95%, the fat reduced from 2.42 to 2.19 and 1.94, and fiber from 12.82 to 9.41 and 9.01%, respectively. Contrarily, the ash increased from 9.75 to 12.20%, and the carbohydrate from 38.16 to 43.08 and 45.18%, respectively.

Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the fatal malignancies and is considered as the third leading cause of death. Mutations, genetic modifications, dietary aflatoxins, or impairments in the regulation of oncogenic pathways may bring about liver cancer. An effective barrier against hepatotoxins is offered by gut-liver axis as a change in gut permeability and expanded translocation of lipopolysaccharides triggers the activation of Toll-like receptors which stimulate the process of hepatocarcinogenesis. Prebiotics, nondigestible oligosaccharides, have a pivotal role to play when it comes to inducing an antitumor effect. A healthy gut flora balance is imperative to downregulation of inflammatory cytokines and reducing lipopolysaccharides induced endotoxemia, thus inducing the antitumor effect.

Partial characterization, in vitro antioxidant and antiproliferative activities of patatin purified from potato fruit juice

Patatin from potato fruit juice was purified by a combination of ultrafiltration and chromatographic techniques. The in vitro antioxidant and antiproliferative activity against mouse melanoma B16 cells of patatin were investigated. The results showed that the monosaccharide composition of patatin included rhamnose, mannose, glucose, and galactose with a molar ratio of 41 : 30 : 21 : 8, and patatin consisted of (1 → 3) linked α-mannose, (1 → 4) linked α-galactose, (1 → 4) linked β-glucose, and (1 → 2) linked α-rhamnose. Furthermore, patatin possessed significant antioxidant activities measured by scavenging of the DPPH and superoxide free radicals, notable reducing power, protective effects against hydroxyl radical-induced oxidative DNA damage and lipid peroxidation inhibitory. Moreover, patatin was identified as a potent antiproliferative agent against mouse melanoma B16 cells, causing cell cycle arrest in the G1 phase. Assays of apoptotic cells also showed that patatin treatment at concentrations of 20 mg mL(-1) resulted in a marked reduction of viable cells. These results obtained in in vitro models suggested that patatin may have potential application as a cancer chemopreventive agent and food ingredient.

Analgesic Activity of a Glucan Polysaccharide Isolated from Agaricus blazei Murill

A water soluble polysaccharide and its selective precipitated fractions (F1, F2, and F3) were isolated from hot water extract of fruiting bodies of Agaricus blazei Murril known as Agaricus brasiliensis to evaluate the analgesic activity of the materials in Swiss mice. The isolated material and its fractions were characterized by two-dimensional COSY and HMQC spectra as β-(1→6)-α-(1→4)-glucan-bound-protein polysaccharide constituted mainly by β-(1→6) glucan. The glucan-protein polysaccharide and its fractions were analyzed in relation to the protein, carbohydrate, and mineral elements contents. The analysis of the glucan-protein complex revealed a total carbohydrate content of 36.95% and protein conjugated content of 17.24%. The mineral elements found in larger proportion were K, Na, Ca, P, and Zn. The analgesic activity bioassay of the β-(1→6)-α-(1→4)-glucan bound-protein polysaccharide and its fractions in Swiss mice indicated a significant effect.

ROS-dependent mitochondria molecular mechanisms underlying antitumor activity of Pleurotus abalonus acidic polysaccharides in human breast cancer MCF-7 cells

Background

A greater reduction in cancer risk associated with mushroom diet rich in fungus polysaccharides is generally accepted. Meanwhile, edible Pleurotus abalonus as a member of Abalone mushroom family is a popular nutritional supplement that purportedly prevents cancer occurrence. However, these anecdotal claims are supported by limited studies describing tumor-inhibitory responses to the promising polysaccharides, and the molecular mechanisms underlying these properties have not yet been elucidated.

Methodology/Principal Findings

We here fractionated the crude polysaccharide preparation from the fruiting bodies of P. abalonus into three fractions, namely PAP-1, PAP-2 and PAP-3, and tested these fractions for antiproliferative activity in human breast cancer MCF-7 cells. The largest PAP-3, an acidic polysaccharide fraction with a molecular mass of 3.68×10⁵ Da, was the most active in inhibiting MCF-7 cancer cells with an IC₅₀ of 193 µg/mL. The changes in cell normal morphology were observed by DAPI staining and the PAP-3-induced apoptosis was confirmed by annexin V/propidium iodide staining. The apoptosis was involved in mitochondria-mediated pathway including the loss of mitochondrial membrane potential (Δψm), the increase of Bax/Bcl-2 ratio, caspase-9/3 activation, and poly(ADP-ribose) polymerase (PARP) degradation, as well as intracellular ROS production. PAP-3 also induced up-regulation of p53, and cell cycle arrest at the S phase. The incubation of MCF-7 cells with antioxidant superoxide dismutase (SOD) and N-acetylcysteine (NAC) significantly attenuated the ROS generation and apoptosis caused by PAP-3, indicating that intracellular ROS plays a pivotal role in cell death.

Conclusions/Significance

These findings suggest that the polysaccharides, especially acidic PAP-3, are very important nutritional ingredients responsible for, at least in part, the anticancer health benefits of P. abalonus via ROS-mediated mitochondrial apoptotic pathway. It is a major breakthrough bringing new insight of the potential use of the polysaccharides as health-care food or medicine to provide significant natural defense against human cancer.

Comparative study of tomato and tomato paste supplementation on the level of serum lipids and lipoproteins levels in rats fed with high cholesterol

BACKGROUND

Hypercholesterolemia is one of the risk factors of cardiovascular diseases. Increased blood cholesterol affects general health and increases mortality due to cardiovascular disease. Poor nutrition increases LDL cholesterol and decreases LDL receptor activities in the liver. Scientists have shown that consumption of antioxidants can reduce hypercholesterolemia and proved benefits of fruit and vegetables. Tomato reduces oxidative stress by increasing serum total antioxidant level.

OBJECTIVES

This study compared the tomato and tomato paste supplementation on the level of serum lipids and lipoproteins in rats fed with high cholesterol.

MATERIALS AND METHODS

In this study, four male rat groups (10 rats per group) were used. Control group received basal diet, second group received basal diet and 2% cholesterol (Chol), third and fourth groups received basal diet, 2% cholesterol tomato and tomato paste respectively (20 percent of the diet) for a month. Then serum TC, LDL, HDL and TG were measured.

RESULTS

Results showed that in Chol group, all lipids increased significantly (P < 0.05) except HDL compared to the control group. Tomato and tomato paste supplementation decreased TC, LDL and TG concentration significantly (P < 0.05) compared to Chol group. Tomato paste had the higher effect on lipids decreasing than tomato.

CONCLUSIONS

Decreases of TC, LDL and TG may be related to tomato antioxidant effect. This course in human required more investigations.

Lactarius rufus (1→3),(1→6)-β-D-glucans: structure, antinociceptive and anti-inflammatory effects

Medicinal health benefits uses of edible as well as non-edible mushrooms have been long recognized. The pharmacological potential of mushrooms, especially antitumor, immunostimulatory and anti-inflammatory activities has been documented. Wild ectomycorrhizal mushroom, Lactarius rufus had the anti-inflammatory and antinociceptive potential of their polysaccharides evaluated using the formalin model. Two structurally different (1→3),(1→6)-linked β-D-glucans were isolated from fruiting bodies. Soluble (FSHW) β-D-glucan 1-30 mg kg(-1) produced potent inhibition of inflammatory pain caused by formalin when compared with the insoluble one (IHW), suggesting that solubility and/or branching degree could alter the activity of β-glucans. Their structures were determined using mono- and bi-dimensional NMR spectroscopy, methylation analysis, and controlled Smith degradation. They were β-D-glucans, with a main chain of (1→3)-linked Glcp residues, substituted at O-6 by single-unit Glcp side chains (IHW), on average to every fourth residue of the backbone, or by mono- and few oligosaccharide side chains for soluble β-glucan.

Pleurotus tuber-regium Polysaccharides Attenuate Hyperglycemia and Oxidative Stress in Experimental Diabetic Rats

Pleurotus tuber-regium contains polysaccharides that are responsible for pharmacological actions, and medicinal effects of these polysaccharides have not yet been studied in diabetic rats. We examined the antidiabetic, antihyperlipidemic, and antioxidant properties of P. tuber-regium polysaccharides in experimental diabetic rats. Forty rats were equally assigned as diabetic high-fat (DHF) diet and polysaccharides treated DHF groups (DHF+1P, DHF+2P, and DHF+3P, 20 mg/kg bodyweight/8-week). Diabetes was induced by chronic low-dose streptozotocin injections and a high-fat diet to mimic type 2 diabetes. Polysaccharides (1P, 2P, and 3P) were extracted from three different strains of P. tuber-regium. Fasting blood glucose and glycosylated hemoglobin (HbA1c) levels substantially decreased, while serum insulin levels were restored by polysaccharides treatment compared to DHF. Furthermore, plasma total cholesterol, triglycerides, and low-density lipoprotein levels were significantly (P < 0.01) lower in polysaccharide groups. High-density lipoprotein levels were attenuated with polysaccharides against diabetes condition. Polysaccharides inhibited (P < 0.01) the lipid peroxidation index (malondialdehyde), and restored superoxide dismutase and glutathione peroxidase activities in the liver of diabetic rats. The antihyperglycemic property of polysaccharides perhaps boosts the antioxidant system that attenuates oxidative stress. We emphasize that P. tuber-regium polysaccharides can be considered as an alternative medicine to treat hyperglycemia and oxidative stress in diabetic rats.

Spent mushroom substrate influences elk (cervus elaphus canadensis) hematological and serum biochemical parameters

The objective of this study was to evaluate the effect of spent mushroom substrate (SMS) derived from Pleurotus eryngii on the hematological and biochemical blood properties of elk. A total of 18, two and three-year-old elk were fed three different levels of SMS (0, 15 and 20%) in a corn-wheat bran diet for 80 days. The results indicated significantly high levels of blood monocytes, hemoglobin (Hb), and hematocrit (HCT) in elk fed 15% or 20% SMS (p<0.05) compared to control animals. Serum blood urea nitrogen (BUN) and glucose concentrations were also significantly elevated in elk fed both 15% and 20% SMS. The inclusion of SMS in the elk diet did not affect serum total cholesterol, triglyceride, or low density lipoprotein (LDL)-cholesterol concentrations; however, high density lipoprotein (HDL)-cholesterol concentration was significantly increased in SMS-fed groups. In addition, 20% SMS in the diet increased serum iron and testosterone concentrations in elk. These results indicate that adding SMS to the diet of elk can increase their Hgb, serum BUN, glucose, and HDL-cholesterol concentration; therefore, diets containing SMS may enhance the physiologic condition of elk during growth.

Chemical characterization of the biomass of an edible medicinal mushroom, Agaricus subrufescens, via solid-state 13C NMR

The biomass of 18 strains of Agaricus subrufescens and of 13 strains of Agaricus bisporus was chemically analyzed using solid-state (13)C NMR. The study focused on polysaccharides because they can play a major role as antitumor molecules. The study also examined whether biomass chemical properties varied between the vegetative mycelium and the fruiting bodies of A. subrufescens, and these data were compared with the mycelium of A. bisporus. Qualitative differences between vegetative mycelia and fruiting bodies were observed, whereas quantitative differences were measured between the two species with a higher percentage of polysaccharides in the biomass of A. subrufescens. This Agaricus species is thus an interesting potential source of polysaccharides with medicinal properties, both from vegetative mycelium obtained in liquid cultures and from fruiting bodies produced on composts.

Amelioration of streptozotocin-induced diabetes by Agrocybe chaxingu polysaccharide

The aim of this study was to investigate the preventive effect of Agrocybe chaxingu polysaccharide on streptozocin (STZ)-induced pancreatic beta-cells destruction. Agrocybe chaxingu polysaccharide markedly reduced nitric oxide (NO) production and iNOS expression levels in RINm5F cells in a dose-dependent manner. In addition, Agrocybe chaxingu polysaccharide significantly inhibited iNOS expression and blood glucose levels in STZ-induced diabetic mice. Moreover, immunohistochemical analysis revealed that it enhanced pancreatic beta-cells resistance to destruction by STZ. These results suggest that Agrocybe chaxingu polysaccharide may have value as a therapeutic agent against diabetes mellitus.

Chemical characterization, antiproliferative and antiadhesive properties of polysaccharides extracted from Pleurotus pulmonarius mycelium and fruiting bodies

Mushroom polysaccharides are potent substances that exhibit antitumor and immunomodulatory properties. Studies comparing the chemical composition and antitumor-related activities of polysaccharides released by fungal strains under different growth conditions are not available. Thus, the present study compared polysaccharides extracts produced by Pleurotus pulmonarius from mycelium grown in liquid culture (ME) or fruiting bodies (FBE). Polysaccharides of both ME and FBE had a relatively high molecular mass. NMR spectroscopy indicated that ME glucan is an alpha-glucan whereas FBE glucan is a mixture of both alpha- and beta-glucans. Glucose and galactose where the most prominent monosaccharide in both glucans. Treatment of several colon cancer cell lines expressing varying amounts of galectin-3 with the two fungal glucans inhibited their viability and significantly reduced their ability to adhere to the key component of the extracellular matrix, fibronectin, and to a human umbilical vein endothelial cell monolayer, in a time- and dose-dependent manner mainly in those cell lines expressing high amounts of galectin-3. We conclude that ME and FBE glucans may exert a direct antiproliferative effect on cancer cells expressing high galectin-3 concentrations and concomitantly downregulate tumor cell adherence, the latter being directly related to cancer progression and metastasis.

Comparative effects of oyster mushrooms on lipid profile, liver and kidney function in hypercholesterolemic rats

Comparative effects of oyster mushrooms on plasma and fecal lipid profiles and on liver and kidney function were evaluated in hyper and normocholesterolemic rats. Feeding of hypercholesterolemic rats a 5% powder of oyster mushrooms (Pleurotus ostreatus, P. sajor-caju and P. florida) reduced the plasma total cholesterol level by 37%, 21% and 16%, respectively and reduced the triglyceride level by 45%, 24% and 14%, respectively. LDL/HDL ratio decreased by 64%, 45% and 41% for P. sajor-caju, P. ostreatus and P. florida fed rats, respectively. Mushroom feeding also reduced body weight in hypercholesterolemic rats. However, it had no adverse effect on plasma bilirubin, creatinin and urea nitrogen level. Mushroom feeding also increased the total lipid and cholesterol excretion in the feces. The present study reveals that feeding of 5% oyster mushroom powder does not have detrimental effects on the liver and kidneys rather may provide health benefits for the cardiovascular-related complication by decreasing the atherogenic lipid profiles.

Nutritional Analysis of Cultivated Mushrooms in Bangladesh - Pleurotus ostreatus, Pleurotus sajor-caju, Pleurotus florida and Calocybe indica

Mushroom cultivation has been started recently in Bangladesh. Awareness of the nutritional and medicinal importance of mushrooms is not extensive. In this study, the nutritional values of dietary mushrooms- Pleurotus ostreatus, Pleurotus sajorcaju, Pleurotus florida and Calocybe indica that are very popular among the cultivated mushrooms in Bangladesh have been determined. These mushrooms were rich in proteins (20~25%) and fibers (13~24% in dry samples) and contained a lower amount of lipid (4 to 5%). The carbohydrate contents ranged from 37 to 48% (on the basis of dry weight). These were also rich in mineral contents (total ash content is 8~13%). The pileus and gills were protein and lipid rich and stripe was carbohydrate and fiber-rich. The moisture content of mushrooms ranged from 86 to 87.5%. Data of this study suggest that mushrooms are rich in nutritional value.