Research Progress of Bioactive Proteins from the Edible and Medicinal Mushrooms

The prospect of mushroom as an alterative protein: From acquisition routes to nutritional quality, biological activity, application and beyond

There is a need for new protein sources to sustainably feed the world. Mushroom proteins are regarded as a future protein alternative considering their low cost, high nutritional quality, and excellent digestibility, have attracted increasing attention. Proteins with multiple structural characteristics endow mushroom with various bioactivities, which has also broadened application of mushroom in nutrition, food fields, as well as in emerging industries. Therefore, the present review narrates the recent developments in nutritional quality of mushroom proteins, while paying considerable attention to cultivation technologies and preparation strategies of mushroom proteins. Moreover, the types, properties and biological benefits of mushroom proteins were summarized, herein the latest research on applications of mushroom or their proteins was highlighted. Eventually, the challenges confronting their widespread utility, despite their high nutritional content were discussed. This review would provide a new appreciation for the future use of mushroom proteins.

Preparation of Morchella esculenta protein and its preventive effect on nonalcoholic fatty liver disease in mice

Morchella esculenta is a valuable edible fungus with multidimensional bioactivities; however, research on M. esculenta protein and its beneficial effects on nonalcoholic fatty liver disease (NAFLD) have been limited. In this study, M. esculenta protein (MEP) with 80.59% protein content was prepared, isolated, and characterized by the complete amino acid composition. The main molecular weight of the protein ranged from 65 to 120 kDa, with 100 kDa being the most dominant band, and it exhibited an alpha helix structure when analyzed by FT-IR and circular dichroism analysis. MEP could regulate body weight, fat accumulation, and alleviate lipid metabolism in adipose tissues in mice with high-fat diet-induced NAFLD. MEP prevented hepatic lipotoxicity, which was reflected in attenuating liver steatosis in vitro and in vivo, thereby regulating the levels of related factors involved in lipid metabolism (e.g., PPARs, HNF-4, SREBP, FASN, ACC-1, and CD36). Furthermore, it inhibited oxidative stress response, which can be attributed to the activation of the MAPK/PGC-1α pathway. Additionally, MEP exhibited probiotic effects, as demonstrated by the altered gut microbiota composition and improved the intestinal barrier integrity. Thus, this study confirmed the preventive effect of MEP against NAFLD by regulating the gut-liver cross-talk, which provided a theoretical basis for the development and utilization of M. esculenta.

Melleatin, an antibiofilm multitasking protein with rRNA N-glycosylase and nuclease activity from Armillaria mellea fruiting bodies

Several studies highlight the identification of some enzymes with additional abilities, especially those involved in metabolic pathways and/or host defence processes, classified as multitasking proteins. In this context, we report the characterization of melleatin (17.5-kDa), a multitasking enzyme isolated from Armillaria mellea fruiting bodies. Melleatin inhibits protein synthesis and displayed unexpected enzymatic action. Indeed, the structural characterization (primary structure and 3D model) showed that melleatin belongs to the His-Me finger endonucleases superfamily possessing a fold like the biofilm-dispersing nuclease NucB, the latter isolated from the marine Bacillus licheniformis. The enzymatic studies on melleatin showed that this enzyme is able to: i) inhibit protein synthesis in a rabbit reticulocyte lysate system (IC50 value 16.48 ± 3.71 nM); ii) damage rabbit and Trichoderma harzianum ribosomes as a ribosome inactivating protein (β-fragment release after Endo's assay); and iii) hydrolyse DNA. Functionally, melleatin has antibiofilm action and antifungal activity towards T. harzianum and Botrytis cinerea affecting fungal ribosomes, while it does not exhibit cytotoxicity against different human cell lines, being unable to enter the cells. Overall, melleatin represents a novel multitasking protein that could be used as a biotechnological tool for its antibiofilm and antifungal activity or as a toxic component of biomedical bioconstructs.

An anti-tumor protein PFAP specifically interacts with cholesterol-enriched membrane domains of A549 cells and induces paraptosis and endoplasmic reticulum stress

Nowadays, non-small cell lung cancer (NSCLC) is still one of the most life-threatening diseases in the world. In previous studies, a fungal protein PFAP with anti-NSCLC properties was isolated and identified from Pleurotus ferulae lanzi. In this study, the amino acid sequence of PFAP was analyzed and found to be highly homologous to the aegerolysin family. PFAP, like other members of the aegerolysin family, specifically recognizes lipid raft domains rich in cholesterol and sphingomyelin, which is probably its specific anti-tumor mechanism. Previous studies have shown that PFAP can induce AMPK-mediated autophagy and G1-phase cell cycle arrest in A549 lung cancer cells. This study further revealed that PFAP can also induce paraptosis and endoplasmic reticulum stress (ERS) in A549 cells in vitro by targeting AMPK. PFAP induces multi-pathway death of A549 cells, and thus demonstrates its potential value for developing new drugs for NSCLC.

Quality evaluation of Hawk tea from different months and regions based on quantitative analysis of multiple components with a single marker (QAMS) combined with HPLC fingerprint

BACKGROUND

Hawk tea, a medicinal and edible plant, has been consumed for thousands of years in Southwest China. To date, no unified food safety standard for Hawk tea has been established, and systematic research on the quality of Hawk tea is lacking.

OBJECTIVE

The aim of this study was to develop a comprehensive evaluation method for the quality of Hawk tea based on inclusions content, high-performance liquid chromatography (HPLC) fingerprinting combined with the quantitative analysis of multiple components with a single marker (QAMS) method.

METHODS

The contents of total flavonoids, total phenols, total polysaccharides, and total protein were determined using the colorimetric method. An effective comprehensive evaluation method was established to classify the 16 batches of samples based on HPLC fingerprint analysis combined with similarity analysis (SA), hierarchical cluster analysis (HCA), principal component analysis (PCA), partial least-squares discrimination analysis (PLS-DA), and the QAMS method.

RESULTS

Flavonoids were the main chemical components of Hawk tea. The accuracy of the QAMS method was verified by comparing the calculated results with those of the external standard method (ESM). No significant differences were found between the two methods. Additionally, the fingerprint of Hawk tea was also established.

CONCLUSION

The method established in this study can be used for the comprehensive quality evaluation of Hawk tea and can also provide a reference for the quality evaluation of other herbal medicines.

Potential Protein Production from Lignocellulosic Materials Using Edible Mushroom Forming Fungi

There is a need for new protein sources to feed the world in a sustainable way. Converting non-food-grade "woody" side streams into food containing proteins will contribute to this mission. Mushroom forming fungi are unique in their capability to convert lignocellulosic substances into edible biomass containing protein. Especially if substrate mycelium can be used instead of mushrooms, this technology could be a serious contribution to addressing the protein challenge. In this Perspective, we discuss challenges toward production, purification, and market introduction of mushroom mycelium based foods.

Mushroom Production in the Southern Cone of South America: Bioeconomy, Sustainable Development and Its Current Bloom

A Sustainable Development Goals (SDGs) based analysis is presented here for business development of the production of edible and medicinal mushrooms using agro-wastes in the Southern Cone of South America. This circular economy approach using edible and medicinal mushroom production on lignocellulosic residues is discussed by analysing both its advantages and drawbacks. Among its main benefits, it is notable that mushroom cultivation using lignocellulosic residues promotes innovation aimed at environmental sustainability, facilitating diversification of the labour supply and the transfer of science to the socio-cultural sphere, which also increases the availability of healthy foods. However, there are some bottlenecks in the process, such as the continuous supply chain of substrates for fungal growth, the lack of equipment and infrastructure for the implementation of cultivation systems in extreme habitats, as well as authorization requirements and other limitations related to a non-fungiphilic culture society. Therefore, this chapter tries to provide key tools for establishing sustainable guidelines for the procurement of local healthy food and other products derived from mushroom cultivation using agricultural residues in the region, which might bloom due to an SDGs-based circular economy approach.

Antamanide Analogs as Potential Inhibitors of Tyrosinase

The tyrosinase enzyme, which catalyzes the hydroxylation of monophenols and the oxidation of o-diphenols, is typically involved in the synthesis of the dark product melanin starting from the amino acid tyrosine. Contributing to the browning of plant and fruit tissues and to the hyperpigmentation of the skin, leading to melasma or age spots, the research of possible tyrosinase inhibitors has attracted much interest in agri-food, cosmetic, and medicinal industries. In this study, we analyzed the capability of antamanide, a mushroom bioactive cyclic decapeptide, and some of its glycine derivatives, compared to that of pseudostellarin A, a known tyrosinase inhibitor, to hinder tyrosinase activity by using a spectrophotometric method. Additionally, computational docking studies were performed in order to elucidate the interactions occurring with the tyrosinase catalytic site. Our results show that antamanide did not exert any inhibitory activity. On the contrary, the three glycine derivatives AG9, AG6, and AOG9, which differ from each other by the position of a glycine that substitutes phenylalanine in the parent molecule, improving water solubility and flexibility, showed tyrosinase inhibition by spectrophotometric assays. Analytical data were confirmed by computational studies.

Antioxidant and Antimicrobial Peptides Derived from Food Proteins

Recently, the demand for food proteins in the market has increased due to a rise in degenerative illnesses that are associated with the excessive production of free radicals and the unwanted side effects of various drugs, for which researchers have suggested diets rich in bioactive compounds. Some of the functional compounds present in foods are antioxidant and antimicrobial peptides, which are used to produce foods that promote health and to reduce the consumption of antibiotics. These peptides have been obtained from various sources of proteins, such as foods and agri-food by-products, via enzymatic hydrolysis and microbial fermentation. Peptides with antioxidant properties exert effective metal ion (Fe2+/Cu2+) chelating activity and lipid peroxidation inhibition, which may lead to notably beneficial effects in promoting human health and food processing. Antimicrobial peptides are small oligo-peptides generally containing from 10 to 100 amino acids, with a net positive charge and an amphipathic structure; they are the most important components of the antibacterial defense of organisms at almost all levels of life-bacteria, fungi, plants, amphibians, insects, birds and mammals-and have been suggested as natural compounds that neutralize the toxicity of reactive oxygen species generated by antibiotics and the stress generated by various exogenous sources. This review discusses what antioxidant and antimicrobial peptides are, their source, production, some bioinformatics tools used for their obtainment, emerging technologies, and health benefits.

An Updated Review of Bioactive Peptides from Mushrooms in a Well-Defined Molecular Weight Range

Here, we report the current status of the bioactive peptides isolated and characterized from mushrooms during the last 20 years, considering ‘peptide’ a succession from to 2 to 100 amino acid residues. According to this accepted biochemical definition, we adopt ~10 kDa as the upper limit of molecular weight for a peptide. In light of this, a careful revision of data reported in the literature was carried out. The search revealed that in the works describing the characterization of bioactive peptides from mushrooms, not all the peptides have been correctly classified according to their molecular weight, considering that some fungal proteins (>10 kDa MW) have been improperly classified as ‘peptides’. Moreover, the biological action of each of these peptides, the principles of their isolation as well as the source/mushroom species were summarized. Finally, this review highlighted that these peptides possess antihypertensive, antifungal, antibiotic and antimicrobial, anticancer, antiviral, antioxidant and ACE inhibitory properties.

Repositioning of Fungal-based Peptides as Modulators of Angiotensin-converting Enzyme-related Carboxypeptidase, SARS-coronavirus HR2 Domain, and Coronavirus Disease 2019 Main Protease

Background and Objectives

Angiotensin-converting enzyme-related carboxypeptidase, SARS-Coronavirus HR2 Domain, and COVID-19 main protease are essential for the cellular entry and replication of coronavirus in the host. This study investigated the putative inhibitory action of peptides form medicinal mushrooms, namely Pseudoplectania nigrella, Russula paludosa, and Clitocybe sinopica, towards selected proteins through computational studies.

Materials and Methods

The respective physicochemical properties of selected peptides were predicted using ProtParam tool, while the binding modes and binding free energy of selected peptides toward proteins were computed through HawkDock server. The structural flexibility and stability of docked protein-peptide complexes were assessed through iMODS server.

Results

The peptides showed an optimum binding afinity with the molecular targets; plectasin from P. nigrella showed the highest binding free energy compared to peptides from R. paludosa and C. sinopica. Besides, molecular dynamic simulations showed all fungal-based peptides could influence the flexibility and stability of selected proteins.

Conclusion

The study revealed fungal-based peptides could be explored as functional modulators of essential proteins that are involved in the cellular entry of coronavirus.

A review of the therapeutic and biological effects of edible and wild mushrooms

Throughout history, mushrooms have occupied an inseparable part of the diet in many countries. Mushrooms are considered a rich source of phytonutrients such as polysaccharides, dietary fibers, and other micronutrients, in addition to various essential amino acids, which are building blocks of vital proteins. In general, mushrooms offer a wide range of health benefits with a large spectrum of pharmacological properties, including antidiabetic, antioxidative, antiviral, antibacterial, osteoprotective, nephroprotective, hepatoprotective, etc. Both wild edible and medicinal mushrooms possess strong therapeutic and biological activities, which are evident from their in vivo and in vitro assays. The multifunctional activities of the mushroom extracts and the targeted potential of each of the compounds in the extracts have a broad range of applications, especially in the healing and repair of various organs and cells in humans. Owing to the presence of the aforementioned properties and rich phytocomposition, mushrooms are being used in the production of nutraceuticals and pharmaceuticals. This review aims to provide a clear insight on the commercially cultivated, wild edible, and medicinal mushrooms with comprehensive information on their phytochemical constituents and properties as part of food and medicine for futuristic exploitation. Future outlook and prospective challenges associated with the cultivation and processing of these medicinal mushrooms as functional foods are also discussed.

A blend of 3 mushrooms dose-dependently increases butyrate production by the gut microbiota

The gut microbiota has been indicated to play a crucial role in health and disease. Apart from changes in composition between healthy individuals and those with a disease or disorder, it has become clear that also microbial activity is important for health. For instance, butyrate has been proven to be beneficial for health, because, amongst others, it is a substrate for the colonocytes, and modulates the host's immune system and metabolism. Here, we studied the effect of a blend of three mushrooms (Ganoderma lucidum GL AM P-38, Grifola frondosa GF AM P36 and Pleurotus ostreatus PO AM-GP37)) on gut microbiota composition and activity in a validated, dynamic, computer-controlled in vitro model of the colon (TIM-2). Predigested mushroom blend at three doses (0.5, 1.0 and 1.5 g/day of ingested mushroom blend) was fed to a pooled microbiota of healthy adults for 72 h, and samples were taken every day for microbiota composition (sequencing of amplicons of the V3-V4 region of the 16S rRNA gene) and activity (short-chain fatty acid (SCFA) production). The butyrate producing genera Lachnospiraceae UCG-004, Lachnoclostridium, Ruminococcaceae UCG-002 and Ruminococcaceae NK4A214-group are all dose-dependently increased when the mushroom blend was fed. Entirely in line with the increase of these butyrate-producers, the cumulative amount of butyrate also dose-dependently increased, to roughly twice the amount compared to the control (medium without mushroom blend) on the high-dose mushroom blend. Butyrate proportionally made up 53.1% of the total SCFA upon feeding the high-dose mushroom blend, compared to 27% on the control medium. In conclusion, the (polysaccharides in the) mushroom blend led to substantial increase in butyrate by the gut microbiota. These results warrant future mechanistic research on the mushroom blend, as butyrate is considered to be one of the microbial metabolites that contributes to health, by increasing barrier function and modulating inflammation.

Ribotoxin-like proteins from Boletus edulis: structural properties, cytotoxicity and in vitro digestibility

Porcini are edible mushrooms widely used in cooking due to their extraordinary taste. Despite this, cases of food poisoning have been reported in the recent literature also for ingestion of porcini. Here, we report the isolation from Boletus edulis fruiting bodies of two novel ribotoxin-like proteins (RL-Ps), enzymes already studied in other organisms for their toxicity. These RL-Ps, named Edulitin 1 (16-kDa) and Edulitin 2 (14-kDa), show peculiar structural and enzymatic differences, which probably reflect their different bio-activities and a dose/time dependent toxicity (Edulitin 2) on normal and tumoral human cells. Particularly interesting is the resistance to proteolysis of Edulitin 2, for which it was observed that its toxicity was abolished only after heat treatment (90 °C) followed by proteolysis. As mushroom poisoning is a serious food safety issue, data here presented confirm the existence of toxins also in porcini and the importance of a proper cooking before their consumption.

Ageritin from Pioppino Mushroom: The Prototype of Ribotoxin-Like Proteins, a Novel Family of Specific Ribonucleases in Edible Mushrooms

Ageritin is a specific ribonuclease, extracted from the edible mushroom Cyclocybe aegerita (synonym Agrocybe aegerita), which cleaves a single phosphodiester bond located within the universally conserved alpha-sarcin loop (SRL) of 23-28S rRNAs. This cleavage leads to the inhibition of protein biosynthesis, followed by cellular death through apoptosis. The structural and enzymatic properties show that Ageritin is the prototype of a novel specific ribonucleases family named 'ribotoxin-like proteins', recently found in fruiting bodies of other edible basidiomycetes mushrooms (e.g., Ostreatin from Pleurotus ostreatus, Edulitins from Boletus edulis, and Gambositin from Calocybe gambosa). Although the putative role of this toxin, present in high amount in fruiting body (>2.5 mg per 100 g) of C. aegerita, is unknown, its antifungal and insecticidal actions strongly support a role in defense mechanisms. Thus, in this review, we focus on structural, biological, antipathogenic, and enzymatic characteristics of this ribotoxin-like protein. We also highlight its biological relevance and potential biotechnological applications in agriculture as a bio-pesticide and in biomedicine as a therapeutic and diagnostic agent.

Effect of storage time on biochemical characteristics and antioxidant activity of hawk tea (Litsea coreana) processed by boiling water fixation

This study investigated the effect of storage time on biochemical characteristics of hawk tea (Litsea coreana) and explored the correlation between the content of flavonoids and polyphenols and antioxidant activity. The antioxidant activity and the content of inclusions, amino acid, and mineral elements in hawk tea processed by boiling water fixation and packed in airtight polypropylene bags and stored in 0°C refrigerator under different storage time (one year, three years, and six years) were analyzed. Results indicated that the biochemical characteristics of hawk tea changed less within 12 months. The total content and types of amino acids in hawk tea reached the maximum in the third year, as well as the content of total trace elements. The water extracts, tea polyphenol, caffeine, lysine, valine, isoleucine, glycine, proline, Ca, and Zn decreased continuously in the storage period of 6 years, but the total flavonoids, Mg, and Ni changed just the opposite. Total polyphenol is the main antioxidant material in hawk tea. Results of the present study provided useful information for people to systematically understand the changes of tea in the storage process and to reasonably develop hawk tea product.

Current Understanding of the Structure and Function of Fungal Immunomodulatory Proteins

Fungal immunomodulatory proteins (FIPs) are a group of proteins found in fungi, which are extensively studied for their immunomodulatory activity. Currently, more than 38 types of FIPs have been described. Based on their conserved structure and protein identity, FIPs can be classified into five subgroups: Fve-type FIPs (Pfam PF09259), Cerato-type FIPs (Pfam PF07249), PCP-like FIPs, TFP-like FIPs, and unclassified FIPs. Among the five subgroups, Fve-type FIPs are the most studied for their hemagglutinating, immunomodulating, and anti-cancer properties. In general, these small proteins consist of 110–125 amino acids, with a molecular weight of ~13 kDa. The other four subgroups are relatively less studied, but also show a noticeable influence on immune cells. In this review, we summarized the protein modifications, 3-dimensional structures and bioactivities of all types of FIPs. Moreover, structure-function relationship of FIPs has been discussed, including relationship between carbohydrate binding module and hemagglutination, correlation of oligomerization and cytokine induction, relevance of glycosylation and lymphocyte activation. This summary and discussion may help gain comprehensive understanding of FIPs' working mechanisms and scope future studies.

Bioactive Phytochemical Constituents of Wild Edible Mushrooms from Southeast Asia

Mushrooms have a long history of uses for their medicinal and nutritional properties. They have been consumed by people for thousands of years. Edible mushrooms are collected in the wild or cultivated worldwide. Recently, mushroom extracts and their secondary metabolites have acquired considerable attention due to their biological effects, which include antioxidant, antimicrobial, anti-cancer, anti-inflammatory, anti-obesity, and immunomodulatory activities. Thus, in addition to phytochemists, nutritionists and consumers are now deeply interested in the phytochemical constituents of mushrooms, which provide beneficial effects to humans in terms of health promotion and reduction of disease-related risks. In recent years, scientific reports on the nutritional, phytochemical and pharmacological properties of mushroom have been overwhelming. However, the bioactive compounds and biological properties of wild edible mushrooms growing in Southeast Asian countries have been rarely described. In this review, the bioactive compounds isolated from 25 selected wild edible mushrooms growing in Southeast Asia have been reviewed, together with their biological activities. Phytoconstituents with antioxidant and antimicrobial activities have been highlighted. Several evidences indicate that mushrooms are good sources for natural antioxidants and antimicrobial agents.

Diversity of potentially exploitable pharmacological activities of the highly prized edible medicinal fungus Antrodia camphorata

Antrodia camphorata, also known as A. cinnamomea, is a precious medicinal basidiomycete fungus endemic to Taiwan. This article summarizes the recent advances in research on the multifarious pharmacological effects of A. camphorata. The mushroom exhibits anticancer activity toward a large variety of cancers including breast, cervical, ovarian, prostate, bladder, colorectal, pancreatic, liver, and lung cancers; melanoma; leukemia; lymphoma; neuroblastoma; and glioblastoma. Other activities encompass antiinflammatory, antiatopic dermatitis, anticachexia, immunoregulatory, antiobesity, antidiabetic, antihyperlipidemic, antiatherosclerotic, antihypertensive, antiplatelet, antioxidative, antiphotodamaging, hepatoprotective, renoprotective, neuroprotective, testis protecting, antiasthmatic, osteogenic, osteoprotective, antiviral, antibacterial, and wound healing activities. This review aims to provide a reference for further development and utilization of this highly prized mushroom.

Ageritin from poplar mushrooms: scale-up purification and cytotoxicity towards undifferentiated and differentiated SH-SY5Y cells

Ageritin from poplar mushroom is a valuable selective neurotoxin towards undifferentiated neuroblastoma SH-SY5Y cells.