Highly oxygenated meroterpenoids from fruiting bodies of the mushroom Tricholoma terreum

The Anticancer Potential of Edible Mushrooms: A Review of Selected Species from Roztocze, Poland

Edible mushrooms are not only a valued culinary ingredient but also have several potential medicinal and industrial applications. They are a rich source of protein, fiber, vitamins, minerals, and bioactive compounds such as polysaccharides and terpenoids, and thus have the capacity to support human health. Some species have been shown to have antioxidant, anti-inflammatory, anticancer, and immunomodulatory properties. We have therefore attempted to summarize the potential properties of the edible mushrooms popular in Poland, in the Roztocze area.

No Evidence Was Found for the Presence of Terreolides, Terreumols or Saponaceolides H-S in the Fruiting Bodies of Tricholoma terreum (Basidiomycota, Agaricales)

Two different collections of the gilled wild fungus Tricholoma terreum, collected in Italy, were subjected to phytochemical analysis. The fungal material was confidently identified by analysis of the ITS genomic sequences. Using both HR-LC-MS and NMR techniques, no evidence was found for the presence in the fruiting bodies of terreolides, terreumols or saponaceolides H-S, in striking contrast with the isolation of these terpenoids by Chinese authors from a mushroom collected in France and identified as T. terreum. The main cytotoxic terpenoid identified and isolated from the extracts of the specimens investigated in this work was the C30 derivative saponaceolide B, which had been previously isolated from T. saponaceum and other T. terreum collections. Although saponaceolide B is a rather labile molecule, easily degradable by heat or in acidic conditions, our study indicated that none of the extraction protocols used produced saponaceolide H-S or terreolide/terreumol derivatives, thus excluding the possibility that the latter compounds could be extraction artifacts. Considered together, these findings point to the need for the unambiguous identification of mushroom species belonging to the complex genus Tricholoma, characterized by high variability in the composition of metabolites. Moreover, based on our data, T. terreum must be considered an edible mushroom.

Mushrooms and Their Compounds with Potential Anticancer Activity: A Review

Mushrooms produce many metabolites that show biological activity, which can be obtained from their fruiting body, mycelium or recovered from the culture broth when mushrooms are grown in submerged fermentation. Mushrooms are a source of natural pharmaceuticals; they have been reported to have potential inhibitory or preventive activity against some diseases, including different types of cancer. Cancer represents one of the main causes of death worldwide. It is worth mentioning that despite advances in pharmacological treatments, they still present side effects in patients. In this sense, the study of the use of mushrooms in complementary treatments against cancer is of great interest. Based on studies carried out in vitro and, in some cases, using animal models, it has been observed that mushrooms present preventive, corrective, and therapeutic properties against different types of cancer, by stimulating the immune system, due to their antioxidant, antimutagenic, and anti-inflammatory activities, as well as the regulation of the expression of some cellular processes, cell cycle arrest, and apoptosis, etc. Based on the above, this manuscript shows a review of scientific studies that support the anticancer activity of some mushrooms and/or their bioactive compounds.

Four Meroterpenoids with Novel Aminoglycoside Moiety from the Basidiomycete Clitocybe clavipes with Cytotoxic Activity

Four new meroterpenoids, Clavilactone M-P, possessing novel aminoglycoside moiety (1-4) and a 10-membered carbocycle fused with an α,β-epoxy-γ-lactone, were isolated from Clitocybe clavipes, a basidiomycete. Their structures with absolute configurations were determined by extensive analysis of their spectroscopic data, and the ECD method. All the isolated compounds (1-4) were evaluated for their antitumor activity against three human cancer cell lines using the MTT assay. Compound 1 and 2 exhibited a significant suppression of cell viability in the Hela (IC₅₀ = 22.8 and 19.7 μM) cell line.

Tricholosterols A-D, four new ergosterol derivatives from the mushroom Tricholoma terreum

Four ergosterol derivatives, named tricholosterols A-D (1-4), have been isolated from the fruiting bodies of Tricholoma terreum. Their chemical structures have been determined using a combination of spectroscopic analysis as well as computational methods. Compound 1 possesses a rare D-ring opening ergosterol skeleton, while compounds 2-4 are rare degraded ergosterols. Compounds 1 and 4 exhibited moderate inhibitory activity against NO production with IC₅₀ values of 27.6 and 31.8 μM, respectively. This is the first report of steroids from T. terreum.

Secondary Metabolites from Fungi-In Honor of Prof. Dr. Ji-Kai Liu's 60th Birthday

It is our pleasure and privilege to serve as Guest Editors for this Special Issue of the Journal of Fungi in honor of Professor Ji-Kai Liu's 60th birthday [...].

Novel geranylhydroquinone derived meroterpenoids from the fungus Clitocybe clavipes and their cytotoxic activity

Three novel geranylhydroquinone derived meroterpenoids, named clavilactones J and K (1-2) and clavipol C (3), were isolated from the basidiomycete Clitocybe clavipes. Their structures were unambiguously identified by extensive spectroscopic data analysis, and the electronic circular dichroism (ECD) calculation, Gauge-Including Atomic Orbitals (GIAO) NMR calculations and Mo₂(OAc)₄-induced electronic circular dichroism experiments were used to establish their absolute configurations. Compound 1, with two epoxy groups located at the 10-membered carbocycle, is uncommon in the reported meroterpenoids from C. clavipes. All the obtained compounds (1-3) were tested for their cytotoxic activity against human tumor cell line HGC-27 by using the MTT assay. All the compounds exhibited moderate cytotoxic activities against HGC-27 cell with IC₅₀ values ranging from 33.5 to 56.6 μM.

Clavipyrrine A, a unique polycyclic nitrogenous meroterpenoid with promising anti-glioma effects isolated from the fungus Clitocybe clavipes

Clavipyrrine A (1), a novel polycyclic nitrogenous meroterpenoid with a pyrrolo[1,2-a]imidazole and a 10-membered carbocycle fused with an α,β-epoxy-γ-lactone, was isolated from Clitocybe clavipes, a basidiomycete. X-ray crystallography and spectroscopic analysis were used to fully elucidate its structure. The biosynthetic origin of the pyrrole unit in this nitrogenous meroterpenoid was identified by incorporating ¹⁵N-labeled γ-aminobutyric acid. Compound 1 displayed promising anti-glioma activities and induced glioma cell apoptosis through inhibiting the JAK/STAT3 pathway and reinforcing SOCS1/3.

Pardinumones A-D: Antibacterial Polyketide-Amino Acid Derivatives from the Mushroom Tricholoma pardinum

Four polyketide-amino acid derivatives, pardinumones A-D (1-4), were isolated from the wild mushroom Tricholoma pardinum. Their structures together with absolute configurations were characterized by means of spectroscopic data analyses, as well as calculated electronic circular dichroism (ECD) and NMR with sorted training set (STS) protocol analysis. Compounds 1-4 exhibited antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli with MIC values in the range of 6.25-50 μg/mL.

The chemistry and biology of fungal meroterpenoids (2009-2019)

Fungal meroterpenoids are secondary metabolites from mixed terpene-biosynthetic origins. Their intriguing chemical structural diversification and complexity, potential bioactivities, and pharmacological significance make them attractive targets in natural product chemistry, organic synthesis, and biosynthesis. This review provides a systematic overview of the isolation, chemical structural features, biological activities, and fungal biodiversity of 1585 novel meroterpenoids from 79 genera terrestrial and marine-derived fungi including macrofungi, Basidiomycetes, in 441 research papers in 2009-2019. Based on the nonterpenoid starting moiety in their biosynthesis pathway, meroterpenoids were classified into four categories (polyketide-terpenoid, indole-, shikimate-, and miscellaneous-) with polyketide-terpenoids (mainly tetraketide-) and shikimate-terpenoids as the primary source. Basidiomycota produced 37.5% of meroterpenoids, mostly shikimate-terpenoids. The genera of Ganoderma, Penicillium, Aspergillus, and Stachybotrys are the four dominant producers. Moreover, about 56% of meroterpenoids display various pronounced bioactivities, including cytotoxicity, enzyme inhibition, antibacterial, anti-inflammatory, antiviral, antifungal activities. It's exciting that several meroterpenoids including antroquinonol and 4-acetyl antroquinonol B were developed into phase II clinically used drugs. We assume that the chemical diversity and therapeutic potential of these fungal meroterpenoids will provide biologists and medicinal chemists with a large promising sustainable treasure-trove for drug discovery.

Meroterpenoids produced by fungi: Occurrence, structural diversity, biological activities, and their molecular targets

Meroterpenoids are partially derived from the terpenoids, distributing widely in the plants, animals and fungi. The complex structures and diverse bioactivities of meroterpenoids have attracted more attention for chemists and pharmacologists. Since the first review summarized by Geris in 2009, there are absent of systematic reviews reported about meroterpenoids from the higher and lower fungi up to now. In the past decades, myriads of meroterpenoids were discovered, and it is necessary to summarize these meroterpenoids about their unique structures and promising bioactivities. In this review, we use a new classification method based on the non-terpene precursors, and also highlight the structural features, bioactivity of natural meroterpenoids from the higher and lower fungi covering the period of September 2008 to February 2020. A total of 709 compounds were discussed and cited the 182 references. Meanwhile, we also primarily summarize their occurrence, structural diversity, biological activities, and molecular targets.

Chemical constituents and their cytotoxicities from mushroom Tricholoma imbricatum

Two undescribed triterpenes, tricholimbrins A and B, three undescribed steroids, tricholimbrins C‒E, one undescribed 4-chromanone derivative, along with 27 known compounds were isolated from fruiting bodies of the mushroom Tricholoma imbricatum. Tricholimbrins A and B are two polycyclic triterpenoids with a carbon degradation, while tricholimbrin C is a ring-rearranged steroid containing an aromatic moiety that might be derived from an ergosterol. Isocyathisterol, 3β,15α-dihydroxyl-(22E,24R)-ergosta-5,8(14),22-trien-7-one, demethylincisterol A₃, and volemolide showed cytotoxicities to six human cancer cell lines. 3β-Hydroxyl-(22E,24R)-ergosta-5,8,22-trien-7,15-dione and 3β-hydroxyl-(22E,24R)-ergosta-5,8,22-trien-7-one showed preferable cytotoxicities against HL-60 while chaxine C and volemolide showed preferable cytotoxicities against A-549, with IC₅₀ values less than 10 μM.

Five New Meroterpenoids from the Fruiting Bodies of the Basidiomycete Clitocybe clavipes with Cytotoxic Activity

Five new meroterpenoids, clavipols A-B (1-2) with a 12-membered ether ring and clavilactones G-I (3-5) having a 10-membered carbocycle connected to a hydroquinone and an α,β-epoxy/unsaturated lactone, were obtained from the fruiting bodies of the basidiomycete Clitocybe clavipes. Their structures were determined by comprehensive analysis of their spectroscopic data, and the absolute configuration of 1 was established by quantum chemical calculations of electronic circular dichroism (ECD). All the isolated compounds (1-5) were tested for their cytotoxic activity against three human tumor cell lines (Hela, SGC-7901, and SHG-44) in vitro after treatment for 48 h. Compound 4 exhibited moderate cytotoxic activity against Hela and SGC-7901 tumor cell lines, with IC₅₀ values of 23.5 and 14.5 µM, respectively.

Clavipines A–C, antiproliferative meroterpenoids with a fused azepine skeleton from the basidiomycete Clitocybe clavipes

Three novel meroterpenoids, clavipines A–C (1–3), possessing a benzoquinone fused to an azepine ring and a ten-membered carbocycle with α,β-epoxy/unsaturated-γ-lactone, were isolated from the basidiomycete Clitocybe clavipes.

Secondary Metabolites Isolated fromTricholomaSpecies (Basidiomycota, Tricholomatacee): A Review

The large mushroom genus Tricholoma (Fr.) Staude comprises hundreds of species growing worldwide. Phytochemical studies on the contents of these mushrooms have been increasing steadily in the last decades; this review is the first complete report about the secondary metabolites isolated to date (January 2018) from the fruiting bodies, with the exclusion of most volatile constituents. The structures, presumed biogenesis, and bioactivities of identified compounds, divided in families according to their biogenesis, are critically discussed. A brief chemotaxonomic discussion of the genus Tricholoma is included in the final part of the review.

Lanostane triterpenoids from Tricholoma pardinum with NO production inhibitory and cytotoxic activities

Eight undescribed lanostane triterpenoids, pardinols A‒H, along with one previously reported lanostane triterpenoid, namely saponaceol B, were isolated from the fruiting bodies of Tricholoma pardinum. Their structures and stereoconfigurations were established via combination of extensive spectroscopic analyses, alkaline methanolysis method and TDDFT/ECD calculations. Pardinols B and E-H exhibited certain inhibition activities of nitric oxide (NO) production with IC₅₀ value ranging from 5.3 to 14.7 μM, as well as cytotoxicities against human cancer cell-lines.

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

Seven pyrrole alkaloids, three of which are novel (phlebopines A⁻C (1⁻3)), were isolated from the fruiting bodies of the edible mushroom Phlebopus portentosus. Their structures were determined on the basis of spectroscopic data. All the isolated compounds were tested for their neuroprotective properties and acetylcholine esterase (AChE) inhibition activities. Compound 7 displayed remarkable neuroprotective effects against hydrogen peroxide (H₂O₂)-induced neuronal-cell damage in human neuroblastoma SH-SY5Y cells.

Natural meroterpenoids isolated from the plant pathogenic fungus Verticillium albo-atrum with noteworthy modification action against voltage-gated sodium channels of central neurons of Helicoverpa armigera

A new meroterpenoid, named acetoxydehydroaustin A (1) and the known meroterpenoid austin (2) were isolated from the plant pathogenic fungus Verticillium albo-atrum. Their structures were established based on general spectroscopic techniques and the relative configuration of compound 1 was determined by single-crystal X-ray diffraction analysis. We first investigated and identified their significant electrophysiological effects on the gating kinetics of voltage-gated sodium channels in central neurons acutely dissociated from Helicoverpa armigera using whole-cell patch clamp technique. Similar to the effects of pyrethroids on sodium late currents, both compounds produced concentration-dependent modification of sodium channels, prolonging the kinetics of channel inactivation to generate large persistent late currents during depolarization. However, different from the effects of tefluthrin and deltamethrin on sodium channels, two meroterpenoids did not induce tail currents during deactivation. Compounds 1 and 2 also caused depolarizing shifts in the voltage dependence of channel activation. The V_0.5 shifted about 5.02mV and 6.32mV in the depolarizing direction by 50μM 1 and 50μM 2. The V_0.5 of voltage-dependent inactivation shifted about 11.42mV and 11.62mV respectively in the hyperpolarizing direction by 50μM 1 and 100μM 2. In addition, they prolonged the time course of recovery from fast-inactivation for sodium channels. The effects of two compounds on the voltage-dependent gating substantially increased the size of sodium window currents. The overlapped area of window currents increased about 89.69% and 44.51% respectively by 10μM compound 1 and 10μM compound 2. These findings show that both compounds have effects on sodium channel activation, inactivation and window currents. The voltage-gated sodium channels in central neurons of H. armigera are the target sites of two meroterpenoid natural products.

Oxidation of the Meroterpenoid (-)-Terreumol C from the Mushroom Tricholoma terreum: Discovery of Cytotoxic Analogues

Aiming at the discovery of new cytotoxic meroterpenoids, the chemical reactivity of the natural product (-)-terreumol C from the edible mushroom Tricholoma terreum was investigated. A series of high-yielding oxygenations and brominations at the 10-membered ring were discovered. The regioselectivity of hydroxylation could be guided by installing protecting groups at the hydroquinone section. Dihydroxylation led to the stereoselective formation of a novel tricycle containing an 11-oxabicyclo[5.3.1]undecane system. Several of the compounds proved to be as cytotoxic against cancer cell lines as the natural products terreumols A and C in the single-digit micromolar range. Interestingly, functionalization of the southern rim formed by carbons C5-C6-C7-C8 is tolerated without much loss of cytotoxicity.

Cytotoxic Meroterpenoids with Rare Skeletons from Psidium guajava Cultivated in Temperate Zone

Three new meroterpenoids, guajavadials A-C (1-3), were isolated from Psidium guajava cultivated in temperate zone. Their structures were established by extensive spectroscopic evidence and electronic circular dichroism (ECD) calculations. Guajavadial A (1) represents a novel skeleton of the 3,5-diformylbenzyl phloroglucinol-coupled monoterpenoid, while guajavadials B (2) and C (3) are new adducts of the 3,5-diformylbenzyl phloroglucinol and a sesquiterpene with different coupling models. The plausible biosynthetic pathways as well as antimicrobial and cytotoxic activities of these meroterpenoids are also discussed. All these isolates exhibited moderate cytotoxicities against five human cancer cell lines, with 3 being most effective with an IC50 value of 3.54 μM toward SMMC-7721 cell lines.

Bioactivities and Health Benefits of Mushrooms Mainly from China

Many mushrooms have been used as foods and medicines for a long time. Mushrooms contain polyphenols, polysaccharides, vitamins and minerals. Studies show that mushrooms possess various bioactivities, such as antioxidant, anti-inflammatory, anticancer, immunomodulatory, antimicrobial, hepatoprotective, and antidiabetic properties, therefore, mushrooms have attracted increasing attention in recent years, and could be developed into functional food or medicines for prevention and treatment of several chronic diseases, such as cancer, cardiovascular diseases, diabetes mellitus and neurodegenerative diseases. The present review summarizes the bioactivities and health benefits of mushrooms, and could be useful for full utilization of mushrooms.

Gymnopeptides A and B, Cyclic Octadecapeptides from the Mushroom Gymnopus fusipes

Mycochemical study of the mushroom Gymnopus fusipes led to the discovery of two new cyclopeptides. The two compounds, named as gymnopeptides A and B, are unprecedented highly N-methylated cyclic octadecapeptides. Detailed spectroscopic studies, Marfey's analysis, and a preliminary molecular modeling study suggested that both are natural cyclic β hairpins. The isolated compounds exhibited striking antiproliferative activity on several human cancer cell lines, with nanomolar IC50 values.

Antimicrobial activity and cytotoxicity of polyketides isolated from the mushroom Xerula sp. BCC56836

Thirteen new polyketides (1, 3, 5–12, and 14–16) together with nine known compounds were isolated from the mushroom Xerula sp. BCC56836.

Two new sesquiterpenoids from cultures of the basidiomycete Tremella foliacea

Two new sesquiterpenoids, trefoliol B (1) and trefoliol C (2), together with known echinocidin A (3), were isolated from cultures of the basidiomycetes Tremella foliacea. The new structures were elucidated on the basis of extensive spectroscopic methods. At the same time, trefoliol B (1) and echinocidin A (3) were tested for their cytotoxicities against five human cancer cell lines and for their inhibitory activities against isozymes of 11β-hydroxysteroid dehydrogenases (11β-HSD). No compound showed significant activity (IC50 > 40 μM). Compound 1 showed moderate inhibitory activities against 11β-HSD1 (human IC50 = 13.1 μM; mouse IC50 = 91.8 μM).

Suppression of tumor growth by Pleurotus ferulae ethanol extract through induction of cell apoptosis, and inhibition of cell proliferation and migration

Cancer is the second leading cause of death worldwide. Edible medicinal mushrooms have been used in traditional medicine as regimes for cancer patients. Recently anti-cancer bioactive components from some mushrooms have been isolated and their anti-cancer effects have been tested. Pleurotus ferulae, a typical edible medicinal mushroom in Xinjiang China, has also been used to treat cancer patients in folk medicine. However, little studies have been reported on the anti-cancer components of Pleurotus ferulae. This study aims to extract bioactive components from Pleurotus ferulae and to investigate the anti-cancer effects of the extracts. We used ethanol to extract anti-cancer bioactive components enriched with terpenoids from Pleurotus ferulae. We tested the anti-tumour effects of ethanol extracts on the melanoma cell line B16F10, the human gastric cancer cell line BGC 823 and the immortalized human gastric epithelial mucosa cell line GES-1 in vitro and a murine melanoma model in vivo. Cell toxicity and cell proliferation were measured by MTT assays. Cell cycle progression, apoptosis, caspase 3 activity, mitochondrial membrane potential (MMP), migration and gene expression were studied in vitro. PFEC suppressed tumor cell growth, inhibited cell proliferation, arrested cells at G0/G1 phases and was not toxic to non-cancer cells. PFEC also induced cell apoptosis and necrosis, increased caspase 3 activity, reduced the MMP, prevented cell invasion and changed the expression of genes associated with apoptosis and the cell cycle. PFEC delayed tumor formation and reduced tumor growth in vivo. In conclusion, ethanol extracted components from Pleurotus ferulae exert anti-cancer effects through direct suppression of tumor cell growth and invasion, demonstrating its therapeutic potential in cancer treatment.