Hydrocolloids from the Mushroom Auricularia heimuer: Composition and Properties.

The ear- to shell-shaped fruiting bodies of the genus Auricularia are widely used as food and in traditional medicinal remedies. This study was primarily focused on the composition, properties and potential use of the gel-forming extract from Auricularia heimuer. The dried extract contained 50% soluble homo- and heteropolysaccharides, which were mainly composed of mannose and glucose, acetyl residues, glucuronic acid and a small amount of xylose, galactose, glucosamine, fucose, arabinose and rhamnose. The minerals observed in the extract included approximately 70% potassium followed by calcium. Among the fatty and amino acids, 60% unsaturated fatty acids and 35% essential amino acids could be calculated. At both acidic (pH 4) and alkaline (pH 10) conditions, the thickness of the 5 mg/mL extract did not change in a temperature range from -24 °C to room temperature, but decreased statistically significantly after storage at elevated temperature. At neutral pH, the studied extract demonstrated good thermal and storage stability, as well as a moisture retention capacity comparable to the high molecular weight sodium hyaluronate, a well-known moisturizer. Hydrocolloids that can be sustainably produced from Auricularia fruiting bodies offer great application potential in the food and cosmetic industries.

Medicinal Potential of the Insoluble Extracted Fibers Isolated from the Fomes fomentarius (Agaricomycetes) Fruiting Bodies: A Review.

The tough, hoof-shaped fruiting bodies of the tinder conk mushroom, Fomes fomentarius (L.) Fr. (Polyporaceae, Agaricomycetes), were traditionally used all over the world as tinder to start fire, for ritual purposes, to make artworks like clothing, frames, ornaments, and also to cure various human diseases (wounds, gastro-intestinal disorders, liver-related problems, inflammations, various cancers, etc.). The first wave of scientific interest in F. fomentarius in Europe dates back to the early 1970s with the discovery of the red-brown pigments of the F. fomentarius external layer. Since then, a number of research papers and reviews have mentioned the history of use, taxonomy, composition and medicinal properties of some F. fomentarius preparations, e.g., soluble extracts and their fractions, isolated cell walls, mycelia and compounds purified from the culture broth. The present review is focused on the composition and benefits of the water-insoluble cell walls obtained from the F. fomentarius fruiting bodies. Isolated cell walls of the tinder mushroom reveal a fibrous hollow structure with an average diameter of 3-5 µm and a wall thickness of 0.2-1.5 µm. Naturally, the fibers are composed of 25-38% glucans, with a majority of ß-glucans, around 30% polyphenols, 6% chitin and less than 2% hemicellulose. The percentage of the main structural compounds can vary either slightly or considerably, depending on the extraction conditions. According to in vitro, in vivo, ex vivo as well as clinical studies, F. fomentarius fibers can modulate the immune system, contribute to intestinal health, accelerate wound healing, absorb heavy metals, organic dyes and radionuclides, normalize kidney and liver function, and provide antibacterial, antiviral, antifungal, anxiolytic, anti-inflammatory and analgesic effects. Multiple action of the insoluble cell walls purified from the F. fomentarius fruiting bodies is particularly effective in the treatment of chronic, recurring, complicated multifactorial diseases. It is certainly worth exploring the medicinal potential and the practical application of these preparations further.

Antioxidant activity and cytotoxicity of exopolysaccharide from mushroom Hericium coralloides in submerged fermentation.

Mushrooms of the genus Hericium spp. represent a series of delicious edible mushrooms with medicinal value. Here, for the first time, the species native to Iran, the mushroom Hericium coralloides, was collected in Mazandaran province, identified, and registered with the NCBI under accession number MW136052. The production of exopolysaccharides (EPS) in submerged culture was optimized using the response surface method. Among the physicochemical and culture medium conditions tested, rotation speed and concentration of maltose and peptone of soybean significantly affected the production of EPS. The proposed model predicts maximum EPS production (0.13 g/L) at 50 g/L maltose, 3 g/L soy peptone, and 1 g/L yeast extract, pH = 6.5, 200 rpm, inoculum at 5% v/v, and 22 °C. The molecular weight of the EPS chains was 413 and 1578 Da. EPS has antioxidant action (EC50 = 6.59 mg/mL) and cytotoxic activity against cancer cells. The viability of AGS and MKN-45 cancer cell lines declined to 20 and 30% after 48 h of the EPS treatment. H. coralloides EPS could be considered a natural dietary anti-cancer supplement. Further studies are necessary to understand the mechanism of the H. coralloides EPS activity on the cell cycle of cancer cells and to prove its action in vivo. Supplementary Information: The online version contains supplementary material available at 10.1007/s13399-022-03386-0.

In Vitro Cytotoxic Activity of an Aqueous Alkali Extract of the Tinder Conk Mushroom, Fomes fomentarius (Agaricomycetes), on Murine Fibroblasts, Human Colorectal Adenocarcinoma, and Cutaneous Melanoma Cells.

Bioactive complexes of medicinal mushrooms have become attractive as complementary anticancer remedies. Our in vitro study focused on the cytotoxicity of the polyphenol-reach and beta-glucan-containing aqueous alkali extract from Fomes fomentarius fruiting bodies (FFE) using murine fibroblasts (L929), human colon adenocarcinoma cells (Caco-2), and cutaneous melanoma cells (COLO-818). Dose-dependent FFE cytotoxicity with an half maximal inhibitory concentration of 0.44 mg/mL was observed for L929 cells upon analysis of the total number of adherent cells, degree of cell viability, cell morphology, and mitochondrial metabolic activity. Cytotoxic effects on cancer cells tested using cell impedance were dependent on FFE concentration, type of cells, and their density. As a routine in vitro model for predicting human intestinal absorption, Caco-2 cells did not react on FFE, which can indirectly support its safety for the human intestinal epithelium. Melanoma cells were affected in a dose-dependent manner, even at low FFE concentrations (0.01-0.05 mg/mL). The confluent cell layer, which resembles a fully formed tumor, was much more resistant than the incompletely formed, subconfluent cell layer, simulating tumor formation. FFE applied topically could be a promising candidate to prevent melanoma development in its early stages.

Chemical Composition and Ultraviolet Absorption Activity of an Aqueous Alkali Extract from the Fruiting Bodies of the Tinder Conk Mushroom, Fomes fomentarius (Agaricomycetes).

White rot mushroom Fomes fomentarius is a medicinal fungus with great potential to be explored. This work focused on the chemical composition of a basic aqueous extract from F. fomentarius fruiting bodies. The extract was mostly composed of phenolics, carbohydrates, minerals, and crude fat with a low amount of proteins and chitin. One-third of the total carbohydrates were in the form of beta-glucans with minor amounts of alpha-glucans. The most valuable essential part of the extract was composed of an acid-resistant ultraviolet (UV)-absorbing mixture of phenolic compounds such as melanins, lignins, and humic acids. These compounds, also referred to as melanin-like pigments, provided for the high antioxidant activity of the extract measured in vitro. Moderate sun-protective capacity was observed with regard to UVB rays and also expected in the UVA range. Quantification of melanin-like pigments in the F. fomentarius extract was possible either gravimetrically as acid-insoluble residue or spectrophotometrically in the UV region. Melanin estimation, based on nitrogen measurements, offered misleading results due to the presence of nitrogen-free melanins along with other nitrogen-containing compounds such as proteins and chitin. F. fomentarius water-soluble basic extract, containing beta-glucans and rich in melanin-like substances, could be used, for example, for topical skin application to prevent cell damage caused by excessive UV exposure or cytotoxic free radicals. The bioactive potential, safety, and further applications of the F. fomentarius extract are currently being investigated.

An approach to change the basic polymer composition of the milled Fomes fomentarius fruiting bodies.

BACKGROUND: Chitin and its derivative chitosan are readily exploited, especially in food, cosmetic, pharmaceutical, biomedical, chemical, and textile industries. The biopolymers are currently recovered from the crustacean shells after purification from the large amount of proteins and minerals. The key problems are centered around a lot of chemical waste and allergenic potential of the heat-stable remaining proteins. Fungi can be considered as an alternative eco-friendlier source of the chitin and chitosan due to the lower level of inorganic materials and absence of the allergenic proteins. RESULTS: The work presents a new chemical assay to change the composition of the milled Fomes fomentarius fruiting bodies. A gradual 13-fold increase of the chitin amount accompanied by 14-fold decrease of the glucan content was obtained after repetitive alkali-acidic treatment. Raw material contained mainly chitin with 30% degree of deacetylation. After the first and second alkali treatment, the polymer was defined as chitosan with comparable amounts of N-acetyl-D-glucosamine and D-glucosamine units. The last treated samples showed an increase of the chitin amount to 80%, along with typical for the natural tinder fibers degree of deacetylation and three-dimensional fibrous hollow structure. CONCLUSIONS: A new approach allowed a gradual enrichment of the pulverized Fomes fomentarius fruiting bodies with chitin or chitosan, depending on the extraction conditions. High stability and fibrous structure of the fungal cell walls with a drastically increased chitin ratio let us suggest a possibility of the targeted production of the chitin-enriched fungal material biotechnologically under eco-friendly conditions.

Simplified Colorimetric Determination of Glucosamine in the Tinder Conk Mushroom, Fomes fomentarius (Agaricomycetes).

Next to cellulose, chitin is the most abundant biopolymer on Earth and participates, in particular, in the assembly of the fungal cell walls. Easy monitoring of the amount of chitinous polymers could be advantageous during biotechnological cultivation and mushroom farming in order to control and optimize the production process. In this study, a modified colorimetric glucosamine (GlcN) assay was validated using high-performance anion exchange chromatography (HPAE) coupled with pulsed amperometric detection (PAD) following acid hydrolysis of the Fomes fomentarius cell walls. The average data obtained from both methods were well comparable. The HPAE-PAD analysis was suggested to be preferable because it had less data scattering, but it could be replaced with the simplified colorimetric GlcN screening in some cases such as low budgetary resources or an absence of suitable equipment, materials, or highly skilled staff. The robust, cost-effective colorimetric GlcN assay presented here can be readily requested, considering the rapidly growing market as well as the scientific and industrial potential of gourmet and medicinal mushrooms.