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

Structural characteristics and potential antidepressant mechanism of a water-insoluble β-1,3-glucan from an edible fungus Wolfiporia cocos

A water-insoluble β-1,3-glucan (Wβ) with a molecular weight of 8.12 × 104 Da was extracted from an edible fungus Wolfiporia cocos. Its backbone was composed of 1,3-β-linked Glcp branched at the C-2, C-4, and C-6 positions, connecting more 1,3-β-linked Glcp with a triple helical structure. Wβ effectively ameliorated depressive symptoms, abnormality of neurotransmitters and inflammatory factors in chronic unpredictable mild stress (CUMS)-induced rats. Wβ also altered the composition of gut microbiota, especially Romboutsia, norank_f_Muribaculaceae and Ruminococcus. Integration of untargeted and targeted metabolomics and Western blotting analysis suggested that the short-chain fatty acids (SCFAs) and tryptophan metabolites were the most important metabolites involved in Wβ mediation. Wβ significantly modulated the levels of 7 SCFAs and 7 tryptophan metabolites, as well as the protein expression of two related enzymes (indoleamine-2,3-dioxygenase: IDO; kynurenine-3-monooxygenase: KMO). Our results suggest that Wβ exerts its antidepressant effect by influencing neurotransmitters and inflammatory factors through interactions between the gut microbiota, SCFA and tryptophan metabolites. The findings offer new insights into water-insoluble polysaccharides, especially β-glucan in structure analysis and utilization, and provide evidence that Wβ, a novel glucan from the often-discarded water-insoluble part of Wolfiporia cocos, has potential application in antidepressant health products.

An enhanced productivity of pink oyster mushroom with improved nutritional profile, characterization and attempt for commercial exploitation

BACKGROUND

An attempt has been made to explore the nutritional profile of pink oyster mushrooms that have been grown in various agricultural residues, including sugarcane bagasse, rice straw, coconut coir and sawdust, along with other nutrient supplements such as defatted mustard and chickpea powder, for appropriate growth and fruiting body formation in a short span of time. The spawn production was experimented with five different grain varieties. The study became interesting when the observations differed slightly from the traditional practices, with the addition of defatted mustard supplements resulting in a positive correlation with respect to reducing the fruiting time, as well as improving yield and the nutritional profile of Pleurotus djamor.

RESULTS

An elevated yield of 651.93 g kg-1 was recorded in the medium where the RS and DM were used in the ratio of 1:0.01 (rice straw +1% w/w defatted mustard) bag, whereas, in terms of protein content, a maximum yield of 32.57 ± 0.79 mg g-1 was observed when SB:DM was in the same ratio (sugarcane bagasse +1% w/w defatted mustard) bag.

CONCLUSION

To confer the best outcomes from the screened substrates, a series of experiments were performed by varying the concentration of RS and SB, with 1% w/w DM. It is worth noting that the highest protein content of 32.76 ± 0.38 mg g-1 was obtained along with the total yield of 702.56 ± 2.9 g kg-1 of mushroom when the ratio of RS:SB was 0.7:0.3. © 2024 Society of Chemical Industry.

Submerged cultivation and phytochemical analysis of medicinal mushrooms (Trametes sp.)

Mushrooms are widely available around the world and have various nutritional as well as therapeutic values. Many Asian cultures believe that medicinal mushrooms can prolong life and improve vitality. This study aims to characterize the phytochemical and polysaccharide content, mainly β-glucan content, of mycelial biomass and fruiting bodies collected from the Himalayan region, particularly Uttarakhand. Through molecular analysis of the LSU F/R-rDNA fragment sequence and phylogenetic analysis, the strain was identified as Trametes sp. We performed screening of phytochemicals and polysaccharides in mushroom and biomass extracts using high-performance liquid chromatography (HPLC) and a PC-based UV-Vis spectrophotometer. The macrofungal biomass was found to be high in saponin, anthraquinone, total phenolic, flavonoid, and β-glucan content. In biomass extract, we observed a high level of saponin (70.6µg/mL), anthraquinone (14.5µg/mL), total phenolic (12.45 µg/mL), and flavonoid (9.500 µg/mL) content. Furthermore, we examined the contents of alkaloids, tannins, terpenoids, and sterols in the biomass and mushroom extracts; the concentration of these compounds in the ethanol extract tested was minimal. We also looked for antioxidant activity, which is determined in terms of the IC50 value. Trametes sp. mushroom extract exhibits higher DPPH radical scavenging activity (62.9% at 0.5 mg/mL) than biomass extract (59.19% at 0.5 mg/mL). We also analyzed β-glucan in Trametes sp. from both mushroom and biomass extracts. The biomass extract showed a higher β-glucan content of 1.713 mg/mL than the mushroom extract, which is 1.671 mg/mL. Furthermore, β-glucan analysis was confirmed by the Megazyme β-glucan assay kit from both biomass and mushroom extract of Trametes sp. β-glucans have a promising future in cancer treatment as adjuncts to conventional medicines. Producing pure β-glucans for the market is challenging because 90-95% of β glucan sold nowadays is thought to be manipulated or counterfeit. The present study supports the recommendation of Trametes sp. as rich in β-glucan, protein, phytochemicals, and antioxidant activities that help individuals with cancer, diabetes, obesity, etc.

Composition, structural properties and immunomodulatory activity of several aqueous Pleurotus β-glucan-rich extracts

In this work, aqueous extracts from six different Pleurotus species were obtained and their yield, gross composition, β-glucan content, monosaccharide profile, thermal stability, molecular weight distribution, and FT-IR were analyzed before and after purification through ethanol precipitation of the carbohydrate-rich fractions. The bioactivity (anti-inflammatory and immunomodulatory activity) of the various fractions obtained was also analyzed in three different cell cultures and compared with a lentinan control. The trend observed after purification of the aqueous fractions was an increase in the concentration of polysaccharides (especially β-glucans), a decrease in ash, glucosamine and protein content and the elimination of low molecular weight (Mw) compounds, thus leaving in the purified samples high Mw populations with increased thermal stability. Interestingly, all these purified fractions displayed immunomodulatory capacity when tested in THP-1 macrophages and most of them also showed significant activity in HEK-hTLR4 cells, highlighting the bioactivity observed for Pleurotus ostreatus (both the extracts obtained from the whole mushroom and from the stipes). This specific species was richer in heteropolysaccharides, having moderate β-glucan content and being enriched upon purification in a high Mw fraction with good thermal stability.

Application of natural polysaccharides and their novel dosage forms in gynecological cancers: therapeutic implications from the diversity potential of natural compounds

Cancer is one of the most lethal diseases. Globally, the number of cancers is nearly 10 million per year. Gynecological cancers (for instance, ovarian, cervical, and endometrial), relying on hidden diseases, misdiagnoses, and high recurrence rates, have seriously affected women's health. Traditional chemotherapy, hormone therapy, targeted therapy, and immunotherapy effectively improve the prognosis of gynecological cancer patients. However, with the emergence of adverse reactions and drug resistance, leading to the occurrence of complications and poor compliance of patients, we have to focus on the new treatment direction of gynecological cancers. Because of the potential effects of natural drugs in regulating immune function, protecting against oxidative damage, and improving the energy metabolism of the body, natural compounds represented by polysaccharides have also attracted extensive attention in recent years. More and more studies have shown that polysaccharides are effective in the treatment of various tumors and in reducing the burden of metastasis. In this review, we focus on the positive role of natural polysaccharides in the treatment of gynecologic cancer, the molecular mechanisms, and the available evidence, and discuss the potential use of new dosage forms derived from polysaccharides in gynecologic cancer. This study covers the most comprehensive discussion on applying natural polysaccharides and their novel preparations in gynecological cancers. By providing complete and valuable sources of information, we hope to promote more effective treatment solutions for clinical diagnosis and treatment of gynecological cancers.

Antimicrobial, Antioxidant, Cytotoxicity and DNA Protective Properties of the Pink Oyster Mushroom, Pleurotus djamor (Agaricomycetes)

In this study, pink oyster mushroom Pleurotus djamor was cultivated using wheat straw (WS), quinoa stalk (QS), and their mixtures (WS-QS (1:1)) as substrate and evaluated in terms of antimicrobial, antioxidant, cytotoxicity, and DNA protective effects. Gram-positive and Gram-negative pathogen bacteria (Bacillus subtilis, Proteus vulgaris, Streptococcus mutans, Salmonella typhi, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli), dermatophyte (Trichophyton sp.) and yeast (Candida tropicalis) were used in the study. It was found to be very active against all bacteria (except S. mutans and S. typhi), and dermatophyte when compared to the control groups (8.7-33.3 mm), but low against C. tropicalis. It was seen that the best total antioxidant assay (TAS) value was 2.05 mmol/L on WS-QS (1:1). Depend on, it was determined that the total oxidant assay (TOS) value (5.26 μmol/L) in the same compost was lower than the others, and also the scavenging effect of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) was higher on WS at 25 mg/mL (84.20%). The methanol extract on WS at a concentration of 400 μg/mL, significantly reduced the percentage of viability in the human breast cancer (MDA-MB-231) cell line (2.2%). The methanol extracts on WS and QS medium were found to inhibit DNA damage induced by UV radiation and H2O2 at a concentration of 25 mg/mL. These results showed that pink oyster mushroom has benefits such as antimicrobial, antioxidant, cytotoxic, and DNA protective effects.

Transglycosylation of Stevioside by a Commercial β-Glucanase with Fungal Extracted β-Glucans as Donors

Abstract

Alternative sweeteners, such as steviol glucosides from the plant Stevia rebaudiana Bertoni, are becoming increasingly popular for the design of next-generation foodstuffs. However, the bitter aftertaste of native steviol glucosides is one of the main reasons behind consumer reluctance towards stevia-containing products. Biocatalysis could be a sustainable solution to this problem, through addition of glucosyl moieties to the molecule. Glycoside hydrolases are enzymes performing transglycosylation reactions, and they can be exploited for such modifications. In the present work, the commercial β-glucanase Finizym 250L® was employed for the transglycosylation of stevioside. After optimization of several reaction parameters, the maximal reaction yield obtained was 19%, with barley β-glucan as the glycosyl donor. With the aim to develop a sustainable process, β-glucan extracts from different fungal sources were prepared. Pulsed Electric Field pretreatment of mycelial biomass resulted in extracts with higher β-glucan content. The extracts were tested as alternative glucosyl donors, reaching up to 15.5% conversion yield, from Pleurotus-extracted β-glucan. Overall, in the present work a novel enzymatic process for the modification of stevioside is proposed, with concomitant valorization of β-glucans extracted from fungal biomass, potentially generated as a byproduct from other applications, in concert with the principles of circular economy.

Graphical Abstract

The mechanisms and cross-protection of trained innate immunity

In recent years, the traditional cognition of immunological memory being specific to adaptive immunity has been challenged. Innate immunity can mount enhanced responsiveness upon secondary stimulation, and a phenomenon is termed trained innate immunity. Trained innate immunity is orchestrated by distinct metabolic and epigenetic reprogramming in both circulating myeloid cells and myeloid progenitor cells in bone marrow, leading to long-term resistance to related and non-related pathogens infections. The induction of trained innate immunity can also polarize innate immune cells towards a hyperresponsive phenotype in the tumor microenvironment to exert antitumor effects. This review will discuss the current understanding of innate immune memory and the mechanisms during the induction of innate immunity, including signaling pathways, metabolic changes, and epigenetic rewriting. We also provide an overview of cross-protection against infectious diseases and cancers based on trained innate immunity.

Influences of Some Aromatic Plants on Volatile Compounds and Bioactivity of Cultivated Pleurotus citrinopileatus and Pleurotus djamor

Two edible Pleurotus species, namely, Pleurotus citrinopileatus and Pleurotus djamor grown in the media of mulberry shavings which were substituted with myrtle, bay laurel, and rosemary leaves were studied. According to volatile profiles, 13 aldehydes, 8 ketones, 7 alcohols, 5 aromatic compounds and 4 terpenes were totally identified. Rosemary leaves were very effective for decreasing the concentrations of some oxidation products in Pleurotus citrinopileatus, but the same impact was not seen in Pleurotus djamor. The high amount of benzaldehyde (41.80 %) detected in bay laurel medium might have played a role in preventing bioactivity. Control Pleurotus citrinopileatus and Pleurotus djamor had a total phenolic content of 4284.89 and 3080.04 mg GAE per kg DM, respectively, and the enrichment of composts with aromatic plant leaves caused significant differences in Pleurotus djamor (p<0.05). Myrtle addition increased total phenolic content and antioxidant activities (by DPPH and FRAP assays) of Pleurotus djamor mushroom as 342.29 mg GAE/kg DM, 0.43 μmol TE/g DM and 2.07 μmol TE/g DM, respectively, when compared to intact one.

Supplementation with Magnesium Salts-A Strategy to Increase Nutraceutical Value of Pleurotus djamor Fruiting Bodies

The use of substrates supplemented with minerals is a promising strategy for increasing the nutraceutical value of Pleurotus spp. The current research was performed to analyze the effect of substrate supplementation with magnesium (Mg) salts on the Mg content, biomass, and chemical composition of pink oyster mushroom (Pleurotus djamor) fruiting bodies. Before inoculation, substrate was supplemented with MgCl₂ × 6 H₂O and MgSO₄, both salts were applied at three concentrations: 210, 420, and 4200 mg of Mg per 2 kg of substrate. The harvest period included three flushes. Substrate supplementation with 4200 mg of Mg caused the most significant decrease in mushroom productivity, of about 28% for both Mg salts. The dry matter content in fruiting bodies was significantly lower in the treatment in which 210 mg of Mg was applied as MgSO₄ in comparison to the control. Supplementation effectively increased the Mg content in fruiting bodies of P. djamor by 19–85% depending on the treatment, and significantly affected the level of remaining bioelements and anions. One hundred grams of pink oyster fruiting bodies, supplemented with Mg salts, provides more than 20% of the Mg dietary value recommended by the Food and Drug Administration (FDA); thus, supplementation can be an effective technique for producing mushrooms that are rich in dietary Mg. Although P. djamor grown in supplemented substrate showed lower productivity, this was evident only in the fresh weight because the differences in dry weight were negligible. Mg supplementation increased the antioxidant activity of the fruiting bodies, phenolic compounds, and some amino acids, including L-tryptophan, and vitamins (thiamine and l-ascorbic acid).

Effects of Medicinal Fungi-Derived β-Glucan on Tumor Progression

β-Glucans have been studied in animal species, from earthworms to humans. They form a heterogenous group of glucose polymers found in fungi, plants, bacteria, and seaweed. β-Glucans have slowly emerged as an important target for the recognition of pathogens. In the current review, we highlight the major roles of mushroom-derived β-glucans on cancer progression.

A review of NMR analysis in polysaccharide structure and conformation: Progress, challenge and perspective

Nuclear magnetic resonance (NMR) has been widely used as an analytical chemistry technique to investigate the molecular structure and conformation of polysaccharides. Combined with 1D spectra, chemical shifts and coupling constants in both homo- and heteronuclear 2D NMR spectra are able to infer the linkage and sequence of sugar residues. Besides, NMR has also been applied in conformation, quantitative analysis, cell wall in situ, degradation, polysaccharide mixture interaction analysis, as well as carbohydrates impurities profiling. This review summarizes the principle and development of NMR in polysaccharides analysis, and provides NMR spectra data collections of some common polysaccharides. It will help to promote the application of NMR in complex polysaccharides of biochemical interest, and provide valuable information on commercial polysaccharide products.

Biologically active polysaccharide from edible mushrooms: A review

Mushrooms are renewable natural gift for humankind, furnished with unique taste, flavor and medicinal properties. For the last few decades study of mushroom polysaccharides has become a matter of great interest to the researchers for their immunomodulating, antimicrobial, antioxidant, anticancer, and antitumor properties. Molecular mass, branching configuration, conformation of polysaccharides and chemical modification are the major factors influencing their biological activities. The mechanism of action of mushroom polysaccharides is to stimulate T-cells, B-cells, natural killer cells, and macrophage dependent immune responses via binding to receptors like the toll-like receptor-2, dectin-1. The present review offers summarized and significant information about the structural and biological properties of mushroom polysaccharides, and their potential for development of therapeutic materials.

Structure and biological properties of exopolysaccharide isolated from Citrobacter freundii

This study aimed to investigate the molecular characterization, antioxidant activity in vitro, cytotoxicity study of an exopolysaccharide isolated from Citrobacter freundii. Firstly, the culture conditions were standardized by the Design of experiments (DoE) based approach, and the final yield of thecrude exopolysaccharide was optimized at 2568 ± 169 mg L^-1. One large fraction of exopolysaccharide was obtained from the culture filtrate by size exclusion chromatography and molecular characteristics were studied. A new mannose rich exopolysaccharide (Fraction-I) with average molecular weight ~ 1.34 × 10⁵ Da was isolated. The sugar analysis showed the presence of mannose and glucose in a molar ratio of nearly 7:2 respectively. The structure of the repeating unit in the exopolysaccharide was determined through chemical and 1D/2D- NMR experiments as: Finally, the antioxidant activity, and the cytotoxicity of the exopolysaccharide were investigated and the relationship with molecular properties was discussed as well.

Structural features and antioxidant activity of a new galactoglucan from edible mushroom Pleurotus djamor

A new water soluble galactoglucan with apparent molecular weight ~1.61 × 10⁵ Da, was isolated from the edible mushroom Pleurotus djamor by hot water extraction followed by purification through dialysis tubing cellulose membrane and sepharose 6B column chromatography. The sugar analysis showed the presence of glucose and galactose in a molar ratio of nearly 3:1 respectively. The structure of the repeating unit in the polysaccharide was determined through chemical and NMR experiments as: In vitro antioxidant studies showed that the PDPS exhibited hydroxyl radical scavenging activity (EC₅₀ = 1.681 ± 0.034 mg/mL), DPPH radical scavenging activity (EC₅₀ = 3.83 ± 0.427 mg/mL), reducing power (EC₅₀ = 4.258 ± 0.095 mg/mL), and ABTS radical quenching activity (EC₅₀ = 0.816 ± 0.077 mg/mL). So, PDPS should be explored as a natural antioxidant.

Occurrence and possible roles of polysaccharides in fungi and their influence on the development of new technologies

The article summarizes the roles of polysaccharides in the biology of fungi and their relationship in the development of new technologies. The comparative approach between the evolution of fungi and the chemistry of glycobiology elucidated relevant aspects about the role of polysaccharides in fungi. Also, based on the knowledge of fungal glycobiology, it was possible to address the development of new technologies, such as the production of new anti-tumor drugs, vaccines, biomaterials, and applications in the field of robotics. We conclude that polysaccharides activate pathways of apoptosis, secretion of pro-inflammatory substances, and macrophage, inducing anticancer activity. Also, the activation of the immune system, which opens the way for the production of vaccines. The development of biomaterials and parts for robotics is a promising and little-explored field. Finally, the article is multidisciplinary, with a different and integrated approach to the role of nature in the sustainable development of new technologies.

Structural Characterization of an Exopolysaccharide Isolated from Enterococcus faecalis, and Study on its Antioxidant Activity, and Cytotoxicity Against HeLa Cells

An exopolysaccharide (EPS-I) having the molecular weight ~ 2.6 × 10⁵ Da, was isolated from a Zinc resistant strain of Enterococcus faecalis from costal area. The exopolysaccharide consists of D-mannose, D-glucose, and L-fucose in molar ratio of 9:4:1. The monosaccharide units in the EPS-1 were determined through chemical (total acid hydrolysis and methylation analysis) and spectroscopic (FTIR and ¹H NMR experiment) analysis. The mannose-rich EPS-1 showed total antioxidant activity (1 mg mL^-1 of EPS-I as functional as approximately to 500 ± 5.2 µM of ascorbic acid) and Fe²⁺ metal ion chelation activity (EC₅₀ = 405.6 µg mL^-1) and hydroxyl radical scavenging activity (EC₅₀ = 219.5 µg mL^-1). The in vitro cytotoxicity experiment of EPS-I against cervical carcinoma cell line, HeLa cells showed strong cytotoxic effect (LC₅₀ = 267.3 µg mL^-1) and at that concentration, it found almost nontoxic against normal healthy cells (HEK-293).

Green synthesis, characterization, antimicrobial and cytotoxic effect of silver nanoparticles using arabinoxylan isolated from Kalmegh

A green synthesis of silver nanoparticles was synthesized by AgNO₃ with arabinoxylan, isolated from green stem of Andrographis paniculata (Kalmegh). The synthesized Ag NPs-arabinoxylan conjugates were characterized by UV-vis spectroscopy, FE-SEM, TEM, XRD, TGA, EDX, and Zeta potential experiments. The Ag NPs formation was established by the surface plasmon resonance band ~410.25 nm. SEM image showed mostly spherical morphology of Ag NPs. The fcc crystalline nature was identified by XRD, SAED and the size were 24.5 and 25 nm from TEM and XRD analysis respectively. The prepared Ag NPs showed dose-dependent antimicrobial activity against Streptococcus pneumonia, Candida albicans and E. coli. The nanoparciles damage 4% hemolysis to human RBCs at 12.5 μg/mL. MTT assay of Ag NPs showed that half of the cell killed at 10 μg/mL and wound healing assay observed effective inhibition cell proliferation.