Pyrrole Alkaloids from the Edible Mushroom Phlebopus portentosus with Their Bioactive Activities

Draft genome sequence of ectomycorrhizal edible mushroom Phlebopus portentosus strain YAF023

Phlebopus portentosus is a favorite ectomycorrhizal edible mushroom in tropical China. Here, we present a draft genome sequence of P. portentosus strain YAF023. The genome resource will support subsequent research into the relationship between ectomycorrhizal fungi and trees.

Selection and validation of internal control genes for quantitative real-time RT‒qPCR normalization of Phlebopus portentosus gene expression under different conditions

Phlebopus portentosus (Berk. and Broome) Boedijn is an attractive edible mushroom and is considered the only bolete for which artificial cultivation in vitro has been achieved. Gene expression analysis has become widely used in research on edible fungi and is important for elucidating the functions of genes involved in complex biological processes. Selecting appropriate reference genes is crucial to ensuring reliable RT‒qPCR gene expression analysis results. In our study, a total of 12 candidate control genes were selected from 25 traditional housekeeping genes based on their expression stability in 9 transcriptomes of 3 developmental stages. These genes were further evaluated using geNorm, NormFinder, and RefFinder under different conditions and developmental stages. The results revealed that MSF1 domain-containing protein (MSF1), synaptobrevin (SYB), mitogen-activated protein kinase genes (MAPK), TATA-binding protein 1 (TBP1), and SPRY domain protein (SPRY) were the most stable reference genes in all sample treatments, while elongation factor 1-alpha (EF1), actin and ubiquitin-conjugating enzyme (UBCE) were the most unstably expressed. The gene SYB was selected based on the transcriptome results and was identified as a novel reference gene in P. portentosus. This is the first detailed study on the identification of reference genes in this fungus and may provide new insights into selecting genes and quantifying gene expression.

Unveiling the Therapeutic Potentials of Mushroom Bioactive Compounds in Alzheimer's Disease

Alzheimer's disease (AD) stands as a prevailing neurodegenerative condition (NDs), leading to the gradual deterioration of brain cells and subsequent declines in memory, thinking, behavior, and emotion. Despite the intensive research efforts and advances, an effective curative treatment for the disease has not yet been found. Mushrooms, esteemed globally for their exquisite flavors and abundant nutritional benefits, also hold a wealth of health-promoting compounds that contribute to improving AD health. These compounds encompass polysaccharides, proteins, lipids, terpenoids, phenols, and various other bioactive substances. Particularly noteworthy are the potent neuroprotective small molecules found in mushrooms, such as ergothioneine, erinacine, flavonoids, alkaloids, ergosterol, and melanin, which warrant dedicated scrutiny for their therapeutic potential in combating AD. This review summarizes such positive effects of mushroom bioactive compounds on AD, with a hope to contribute to the development of functional foods as an early dietary intervention for this neurodegenerative disease.

LC/MS- and GC/MS-based metabolomic profiling to determine changes in flavor quality and bioactive components of Phlebopus portentosus under low-temperature storage

Introduction

Low temperature is the most common method used to maintain the freshness of Phlebopus portentosus during long-distance transportation. However, there is no information regarding the nutritional changes that occur in P. portentosus preserved postharvest in low temperature.

Methods

In this study, the changes in flavor quality and bioactive components in fruiting bodies stored at 4 °C for different storage periods were determined through LC/MS and GC/MS analyses. Sampling was performed at 0, 3, 5, 7, and 13 days storage.

Results and Discussion

Based on the results, the metabolites present in caps and stipes were different at the same period and significantly different after 7 days of storage. A total of 583 and 500 different metabolites were detected in caps and stipes, respectively, and were mainly lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds and others. Except for prenol lipids and nucleotides, the expression levels of most metabolites increased with longer storage time. In addition, geosmin was identified as the major contributor to earthy-musty odors, and the level of geosmin was increased when the storage time was short.

Conclusion

The variations in these metabolites might cause changes in flavor quality and bioactive components in P. portentosus. Variations in these metabolites were thoroughly analyzed, and the results revealed how storage processes affect the postharvest quality of P. portentosus for the first time.

Multiple Metabolites Derived from Mushrooms and Their Beneficial Effect on Alzheimer's Diseases

Mushrooms with edible and medicinal potential have received widespread attention because of their diverse biological functions, nutritional value, and delicious taste, which are closely related to their rich active components. To date, many bioactive substances have been identified and purified from mushrooms, including proteins, carbohydrates, phenols, and vitamins. More importantly, molecules derived from mushrooms show great potential to alleviate the pathological manifestations of Alzheimer's disease (AD), which seriously affects the health of elderly people. Compared with current therapeutic strategies aimed at symptomatic improvement, it is particularly important to identify natural products from resource-rich mushrooms that can modify the progression of AD. This review summarizes recent investigations of multiple constituents (carbohydrates, peptides, phenols, etc.) isolated from mushrooms to combat AD. In addition, the underlying molecular mechanisms of mushroom metabolites against AD are discussed. The various mechanisms involved in the antiAD activities of mushroom metabolites include antioxidant and anti-neuroinflammatory effects, apoptosis inhibition, and stimulation of neurite outgrowth, etc. This information will facilitate the application of mushroom-derived products in the treatment of AD. However, isolation of new metabolites from multiple types of mushrooms and further in vivo exploration of the molecular mechanisms underlying their antiAD effect are still required.

Structures and Biological Activities of Alkaloids Produced by Mushrooms, a Fungal Subgroup

Alkaloids are a wide family of basic N-containing natural products, whose research has revealed bioactive compounds of pharmacological interest. Studies on these compounds have focused more attention on those produced by plants, although other types of organisms have also been proven to synthesize bioactive alkaloids, such as animals, marine organisms, bacteria, and fungi. This review covers the findings of the last 20 years (2002–2022) related to the isolation, structures, and biological activities of the alkaloids produced by mushrooms, a fungal subgroup, and their potential to develop drugs and agrochemicals. In some cases, the synthesis of the reviewed compounds and structure−activity relationship studies have been described.

Pyrrovobasine, hybrid alkylated pyrraline monoterpene indole alkaloid pseudodimer discovered using a combination of mass spectral and NMR-based machine learning annotations

A new vobasine-tryptamine-based monoterpene indole alkaloid pseudodimer was isolated from the stem bark of Voacanga africana. As a minor constituent occurring in a thoroughly investigated plant, this molecule was targeted based on a molecular networking strategy and a rational MS²-guided phytochemical investigation led to its isolation. Its structure was formally established based on HRMS, 1D/2D NMR data, and the application of the tool Small Molecule Accurate Recognition Technology (SMART 2.0). Its absolute configuration was assigned by the exciton chirality method and TD-DFT ECD calculations. Besides featuring an unprecedented intermonomeric linkage in the small group of vobasine/tryptamine hybrids, pyrrovobasine also represents the first pyrraline-containing representative in the whole monoterpene indole alkaloids group. Biosynthetic hypotheses possibly underpinning these structural oddities are proposed here.

Whole-Genome and Transcriptome Sequencing of Phlebopus portentosus Reveals Its Associated Ectomycorrhizal Niche and Conserved Pathways Involved in Fruiting Body Development

Phlebopus portentosus (Berk. and Broome) Boedijin, a widely consumed mushroom in China and Thailand, is the first species in the order Boletaceae to have been industrially cultivated on a large scale. However, to date, the lignocellulose degradation system and molecular basis of fruiting body development in P. portentosus have remained cryptic. In the present study, genome and transcriptome sequencing of P. portentosus was performed during the mycelium (S), primordium (P), and fruiting body (F) stages. A genome of 32.74 Mb with a 48.92% GC content across 62 scaffolds was obtained. A total of 9,464 putative genes were predicted from the genome, of which the number of genes related to plant cell wall-degrading enzymes was much lower than that of some saprophytic mushrooms with specific ectomycorrhizal niches. Principal component analysis of RNA-Seq data revealed that the gene expression profiles at all three stages were different. The low expression of plant cell wall-degrading genes also confirmed the limited ability to degrade lignocellulose. The expression profiles also revealed that some conserved and specific pathways were enriched in the different developmental stages of P. portentosus. Starch and sucrose metabolic pathways were enriched in the mycelium stage, while DNA replication, the proteasome and MAPK signaling pathways may be associated with maturation. These results provide a new perspective for understanding the key pathways and hub genes involved in P. portentosus development.

Method Superior to Traditional Spectral Identification: FT-NIR Two-Dimensional Correlation Spectroscopy Combined with Deep Learning to Identify the Shelf Life of Fresh Phlebopus portentosus

The taste of fresh mushrooms is always appealing. Phlebopus portentosus is the only porcini that can be cultivated artificially in the world, with a daily output of up to 2 tons and a large sales market. Fresh mushrooms are very susceptible to microbial attacks when stored at 0-2 °C for more than 5 days. Therefore, the freshness of P. portentosus must be evaluated during its refrigeration to ensure food safety. According to their freshness, the samples were divided into three categories, namely, category I (1-2 days, 0-48 h, recommended for consumption), category II (3-4 days, 48-96 h, recommended for consumption), and category III (5-6 days, 96-144 h, not recommended). In our study, a fast and reliable shelf life identification method was established through Fourier transform near-infrared (FT-NIR) spectroscopy combined with a machine learning method. Deep learning (DL) is a new focus in the field of food research, so we established a deep learning classification model, traditional support-vector machine (SVM), partial least-squares discriminant analysis (PLS-DA), and an extreme learning machine (ELM) model to identify the shelf life of P. portentosus. The results showed that FT-NIR two-dimensional correlation spectroscopy (2DCOS) combined with the deep learning model was more suitable for the identification of fresh mushroom shelf life and the model had the best robustness. In conclusion, FT-NIR combined with machine learning had the advantages of being nondestructive, fast, and highly accurate in identifying the shelf life of P. portentosus. This method may become a promising rapid analysis tool, which can quickly identify the shelf life of fresh edible mushrooms.

New bioactive α-pyrone from wild mushroom Paxillus involutus

Chemical investigation of Paxillus involutus (Batsch) Fr. led to the isolation of a pair of new enantiomers (E)-5-(4-methoxy-2-oxo-2H-pyran-6-yl)pent-4-en-1-yl 2-hydroxypropanoate (1a/1b) along with 14 known compounds (2-15) for the first time from this mushroom. The structures of new compounds were elucidated based on extensive spectroscopic data analysis of MS, 1D and 2D NMR, and their absolute configurations were confirmed by comparison of the experimental and calculated ECD data. Compounds 1a and 1b exhibited radical scavenging activities with IC₅₀ values ranging from 10.39 ± 2.26 to 20.43 ± 3.74 μg/mL. Compounds 1a and 1b also showed moderate anti-tyrosinase activity with IC₅₀ value of 25.66 ± 2.84 and 26.82 ± 3.19 μg/mL.

Secondary metabolites of Phlebopus species from Northern Thailand

Submerged cultures of the edible mushrooms Phlebopus portentosus and Phlebopus spongiosus were screened for their secondary metabolites by HPLC-UV/Vis and HR-LC-ESI-MS. Two new compounds, 9′-hydroxyphenyl pulvinone (1), containing an unusual pulvinone structure, and phlebopyron (2), together with the seven known pigments, atromentic acid (3), xerocomic acid (4), variegatic acid (5), methyl atromentate (6), methyl isoxerocomate (7), methyl variegatate (8), and variegatorubin (9) were isolated from the cultures. Their structures were assigned on the basis of extensive 1D/2D NMR spectroscopic analyses, as well as HR-ESI-MS, and HR-ESI-MS/MS measurements. Furthermore, the isolated compounds were evaluated for their antimicrobial and cytotoxic properties. 9′-hydroxyphenyl pulvinone (1), xerocomic acid (4), and methyl variegatate (8) exhibited weak to moderate cytotoxic activities against several tumor cell lines. The present paper provides a comprehensive characterization of pigments from the class of pulvinic acids that are present in the basidiomes of many edible bolete species.

Identification of a Novel Pyrrole Alkaloid from the Edible Mushroom Basidiomycetes-X (Echigoshirayukidake)

Three pyrrole alkaloid derivatives were isolated from the edible mushroom Basidiomycetes-X (Echigoshirayukidake) by water extraction followed by ethyl acetate fractionation. The chemical structures determined by MS and NMR were 4-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl] butanoic acid (compound I), 4-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl] butanamide (compound II), and 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (compound III). Compound I was found to be the major component, followed by compound II, and compound III was the minor component. The dry powder of Basidiomycetes-X contained approximately 825 μg g⁻¹ compound I and 484 μg g⁻¹ compound II. Compound II was found to be a novel pyrrole aldehyde homologue not previously reported and thus is a specific component of this mushroom.

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.

Biological and chemical diversity go hand in hand: Basidiomycota as source of new pharmaceuticals and agrochemicals

The Basidiomycota constitutes the second largest higher taxonomic group of the Fungi after the Ascomycota and comprises over 30.000 species. Mycelial cultures of Basidiomycota have already been studied since the 1950s for production of antibiotics and other beneficial secondary metabolites. Despite the fact that unique and selective compounds like pleuromutilin were obtained early on, it took several decades more until they were subjected to a systematic screening for antimicrobial and anticancer activities. These efforts led to the discovery of the strobilurins and several hundreds of further compounds that mainly constitute terpenoids. In parallel the traditional medicinal mushrooms of Asia were also studied intensively for metabolite production, aimed at finding new therapeutic agents for treatment of various diseases including metabolic disorders and the central nervous system. While the evaluation of this organism group has in general been more tedious as compared to the Ascomycota, the chances to discover new metabolites and to develop them further to candidates for drugs, agrochemicals and other products for the Life Science industry have substantially increased over the past decade. This is owing to the revolutionary developments in -OMICS techniques, bioinformatics, analytical chemistry and biotechnological process technology, which are steadily being developed further. On the other hand, the new developments in polythetic fungal taxonomy now also allow a more concise selection of previously untapped organisms. The current review is dedicated to summarize the state of the art and to give an outlook to further developments.