Four novel antibacterial sesquiterpene-α-amino acid quaternary ammonium hybrids from the mycelium of mushroom Stereum hirsutum

Therapeutic Potential of Fungal Terpenes and Terpenoids: Application in Skin Diseases

Terpenes and their derivatives comprise a diverse group of natural compounds with versatile medicinal properties. This article elucidates the general characteristics of fungal terpenes and terpenoids, encompassing their structure and biogenesis. The focal point of this work involves a comprehensive overview of these compounds, highlighting their therapeutic properties, mechanisms of action, and potential applications in treating specific skin conditions. Numerous isolated terpenes and terpenoids have demonstrated noteworthy anti-inflammatory and anti-microbial effects, rivalling or surpassing the efficacy of currently employed treatments for inflammation or skin infections. Due to their well-documented antioxidant and anti-cancer attributes, these compounds exhibit promise in both preventing and treating skin cancer. Terpenes and terpenoids sourced from fungi display the capability to inhibit tyrosinase, suggesting potential applications in addressing skin pigmentation disorders and cancers linked to melanogenesis dysfunctions. This paper further disseminates the findings of clinical and in vivo research on fungal terpenes and terpenoids conducted thus far.

Macrofungi as Medicinal Resources in Uzbekistan: Biodiversity, Ethnomycology, and Ethnomedicinal Practices

Interest in edible and medicinal macrofungi is millennial in terms of their uses in health and food products in Central Asia, while interest in inedible and medicinal macrofungi has grown in popularity in recent years. Edible and inedible medicinal basidiomycetes were collected during field surveys from different regions of Uzbekistan. The morphological characters and similarity assessment of rDNA-Internal Transcribed Spacer sequence data were used to measure diversity and habitat associations. A number of 17 species of medicinal macrofungi of ethnomycological and medicinal interest was found associated with 23 species of trees and shrubs belonging to 11 families and 14 genera. Polyporaceae and Hymenochaetaceae were represented by the highest number of species followed by Ganodermataceae, Fomitopsidaceae, Auriculariaceae, Cerrenaceae, Grifolaceae, Phanerochaetaceae, Laetiporaceae, Schizophyllaceae, and Stereaceae. The highest number of medicinal basidiomycete species was reported in the following host genera: Acer, Betula, Celtis, Crataegus, Juglans, Juniperus, Lonicera, Malus, Morus, Platanus, Populus, Prunus, Quercus, and Salix. An updated list of edible and inedible medicinal mushrooms identified in Uzbekistan, their morphological characteristics, and phylogenetic placement are given for the first time. Information is provided on their uses in traditional and modern medicine. Their bioactive compounds and extracts can be applied as medicines, as well as food and cosmetic ingredients.

Unusual N-pyridinium amino acid-type alkaloids from roots and rhizomes of Sophora tonkinensis Gagnep

Two previously undescribed amino acid-type alkaloids with unusual N-pyridinium cation (1-2) and six known alkaloids (3-8), were isolated from the roots and rhizomes of Sophora tonkinensis Gapnea. Their structures were characterized by UV, IR, NMR, and HRESIMS spectroscopic data. The absolute configurations of compounds 1 and 2 were established through comparison of their experimental ECD spectra to the theoretical spectra of 2 calculated by TDDFT method. The plausible biosynthetic pathway of pyridinium was also proposed. Moreover, compound 4 exhibited weak XOD inhibitory activity with the inhibition rate of 65.8% at concentration of 10 μM.

Activities and metabolomics of Cordyceps gunnii under different culture conditions

Many active metabolites have been identified from various species of the fungal genus Cordyceps. A predominant species of this genus is Cordyceps gunnii, but there are limited reports on the active ingredients from this species. This study aimed to conduct activity assays and metabolome analysis on extracts of C. gunnii obtained under different culture conditions. Five different solid media were selected to culture the mycelium of C. gunnii and the metabolites were extracted with organic solvents; concurrently, the wild stroma and host complexes of C. gunnii were extracted by ethyl acetate. Extracts were subsequently assayed for various biological activities and were analyzed by untargeted metabolomics. There were significant differences in the activities and metabolites of C. gunnii extracts from different culture conditions and from wild stroma and host complexes. The extracts of stroma and host complexes and mycelia cultured on WGA medium for 21 days exhibited similar effective inhibitory activity against five cell lines. A total of 51 metabolites were annotated and included various structural types. The literatures indicate that most of the identified compounds have a variety of different biological activities. These findings provide the basis for further systematic excavation of C. gunnii and improved utilization of this fungal species.

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.

High-Efficiency Production of Auricularia polytricha Polysaccharides Through Yellow Slurry Water Fermentation and Its Structure and Antioxidant Properties

Yellow slurry water is a kind of nutrient-rich wastewater of tofu. Firstly, the medium of yellow slurry was optimized. Then, APP40, APP60, and APP80 were obtained by sedimentation with different concentration of ethanol (40, 60, and 80%). The physicochemical properties and primary structures of the three polysaccharides were studied by high performance anion exchange chromatography (HPAEC), high performance gel filtration chromatography (HPGFC), scanning electron microscope (SEM), atomic force microscope (AFM), and Fourier transform infrared (FT-IR) spectrometer. Finally, the effects of three polysaccharides on antioxidation activity were studied. According to the experimental optimization the results, the biomass and the production of Auricularia polytricha Polysaccharides (APPS) reached the peak, and they were 13.5 ± .655 and 9.42 ± .253 g/L (p < .05). The SEM and the AFM showed that the height of APP80 gradually increased from 31.1 to 46.7 nm and from APP40 to APP80. The particle size of APP80 increased, the pores decrease or even disappear, and the molecules begin to aggregate. The FT-IR spectrum analysis showed that the three polysaccharides possessed key functional groups. The carbohydrate content of APP40, APP60, and APP80 was 20.2, 34.25, and 31.73%. The molecular weights of APP40, APP60, and APP80 are 9.462 × 10⁴, 8.742 × 10⁴, and 8.091 × 10⁴ Da, respectively. The three polysaccharides were composed of rhamnose, galactose, glucose, mannose, and xylose but with different molar ratio. APP80 showed strong reducing ability and scavenging activity of 2,2–diphenyl–1–picrylhydrazyl (DPPH) and hydroxyl radicals through antioxidant activities evaluated in vitro. This study introduces a way for the effective use of yellow slurry water.

Sesquiterpenoids Specially Produced by Fungi: Structures, Biological Activities, Chemical and Biosynthesis (2015-2020)

Fungi are widely distributed in the terrestrial environment, freshwater, and marine habitat. Only approximately 100,000 of these have been classified although there are about 5.1 million characteristic fungi all over the world. These eukaryotic microbes produce specialized metabolites and participate in a variety of ecological functions, such as quorum detection, chemical defense, allelopathy, and maintenance of symbiosis. Fungi therefore remain an important resource for the screening and discovery of biologically active natural products. Sesquiterpenoids are arguably the richest natural products from plants and micro-organisms. The rearrangement of the 15 high-ductility carbons gave rise to a large number of different skeletons. At the same time, abundant structural variations lead to a diversification of biological activity. This review examines the isolation, structural determination, bioactivities, and synthesis of sesquiterpenoids that were specially produced by fungi over the past five years (2015-2020).

Sesquiterpenoids and their quaternary ammonium hybrids from the mycelium of mushroom Stereum hirsutum by medium optimization

The fungal genus Stereum (Stereaceae) produces a broad variety of specialised metabolites, including a wide range of terpenes. This probably relates to the presence of an extensive biosynthetic machinery for this group of compounds: genomic analysis of Stereum hirsutum has identified 16 terpene synthase gene clusters, 6 polyketide synthase gene clusters, and 1 polyketide synthase non-ribosomal polypeptide heterodimer gene cluster in S. hirsutum FP-91666. In the present study, the One Strain Many Compounds (OSMAC) approach was employed to discover undescribed metabolites from this strain. Fermentation was carried out in five media and the products of the strain cultivated on different media were analyzed by LC-MS. From cultures grow in WGB medium (30.0 g wheat bran, 20.0 g glucose, 1.5 g KH₂PO₄, and 1.5 g MgSO₄), four previously undescribed metabolites, a sesquiterpene sterostrein X and three mixed terpenes (stereumamides I-K) were isolated, together with seven known compounds (drimene-2,11-diol, stereumamide E, stereumamide D, stereumamide B, stereumamide A, stereumamide C, and sterostrein Q). The drimane-type sesquiterpene drimene-2,11-diol was found in S. hirsutum FP-91666 for the first time. All structures were elucidated by spectroscopic data analysis. The absolute configurations of stereumamides I, J and K were assigned by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. An anti-Mycobacterium tuberculosis experiment showed that stereumamides I-K and sterostrein Q had weak antibacterial activity against this pathogen.

Production of minor ginsenosides by combining Stereum hirsutum and cellulase

Minor ginsenosides (MGs) (include ginsenoside F2, Compound K, PPT, etc), which are generally not produced by ginseng plants naturally, are obtained by deglycosylation of major ginsenosides. However, the conventional processes used to produce deglycosylated ginsenosides focus on the use of intestinal microorganisms for transformation. In this study, an edible and medicinal mushroom Stereum hirsutum JE0512 was screened from 161 β-glucosidase-producing soil microorganisms sourced from wild ginseng using the plate coloration method. Furthermore, JE0512 was used for the production of CK from ginseng extracts (GE) in solid-state fermentation (SSF) using 20 g corn bran as substrate, 4 g GE, and 20% inoculation volume, and the results showed that the highest CK content was 29.13 mg/g. After combining S. hirsutum JE0512 with cellulase (Aspergillus niger), the MGs (F2, CK, and PPT) content increased from 1.66 to 130.79 mg/g in the final products. Our results indicate that the Stereum genus has the potential to biotransform GE into CK and the combination of S. hirsutum JE0512 and cellulase could pave the way for the production of MGs from GE.

Consoramides A-C, New Zwitterionic Alkaloids from the Fungus Irpex consors

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C₁₈ cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A-C (1-3).

Antibacterial Compounds from Mushrooms: A Lead to Fight ESKAPEE Pathogenic Bacteria?

Infectious diseases are among the greatest threats to global health in the 21st century, and one critical concern is due to antibiotic resistance developed by an increasing number of bacterial strains. New resistance mechanisms are emerging with many infections becoming more and more difficult if not impossible to treat. This growing phenomenon not only is associated with increased mortality but also with longer hospital stays and higher medical costs. For these reasons, there is an urgent need to find new antibiotics targeting pathogenic microorganisms such as ESKAPEE bacteria. Most of currently approved antibiotics are derived from microorganisms, but higher fungi could constitute an alternative and remarkable reservoir of anti-infectious compounds. For instance, pleuromutilins constitute the first class of antibiotics derived from mushrooms. However, macromycetes still represent a largely unexplored source. Publications reporting the antibacterial potential of mushroom extracts are emerging, but few purified compounds have been evaluated for their bioactivity on pathogenic bacterial strains. Therefore, the aim of this review is to compile up-to-date data about natural products isolated from fruiting body fungi, which significantly inhibit the growth of ESKAPEE pathogenic bacteria. When available, data regarding modes of action and cytotoxicity, mandatory when considering a possible drug development, have been discussed in order to highlight the most promising compounds.

High-efficiency production of Tremella aurantialba polysaccharide through basidiospore fermentation

This study aims to develop a spore fermentation method instead of fruiting body extraction for the production of Tremella aurantialba polysaccharide (TAPS). The purified spore strain Tremella aurantialba NX-20 was isolated for TAPS fermentation. The fermented TAPS and the extracted TAPS had the same monosaccharide composition but higher molecular weight. The conditions for TAPS fermentation by NX-20 were optimized, which were 25 °C, pH 7, 10% initial inoculum and 5 days. To further reduce the processing steps and costs of the medium, tofu wastewater (TW) was used to replace defatted soybean meal (DSM). In a 7.5 L fermentation tank, 40 g/L glucose with 10-fold diluted TW was used as the medium. For TAPS fermentation, a maximum yield of 15.02 ± 0.40 g/L was achieved. In conclusion, this study provides a feasible strategy for the efficient preparation of TAPS through spore fermentation.

In Depth Natural Product Discovery from the Basidiomycetes Stereum Species

Natural metabolites from microorganisms play significant roles in the discovery of drugs, both for disease treatments in humans, and applications in agriculture. The Basidiomycetes Stereum genus has been a source of such bioactive compounds. Here we report on the structures and activities of secondary metabolites from Stereum. Their structural types include sesquiterpenoids, polyketides, vibralactones, triterpenoids, sterols, carboxylic acids and saccharides. Most of them showed biological activities including cytotoxic, antibacterial, antifungal, antiviral, radical scavenging activity, autophagy inducing activity, inhibiting pancreatic lipase against malarial parasite, nematocidal and so on. The syntheses of some metabolites have been studied. In this review, 238 secondary metabolites from 10 known species and various unidentified species of Stereum were summarized over the last seven decades.

Hot off the Press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as pepluanol C from Euphorbia peplus.

New secondary metabolites from an engineering mutant of endophytic Streptomyces sp. CS

In previous work, a series of bioactive natural products had been isolated from the plant endophytic Streptomyces sp. CS, which was isolated from Maytenus hookeri. To mine new active metabolites, we describe introducing an alien carbamoyltransferase (asm21) gene into the strain CS by conjugal transfer. As a result, three recombinatorial mutants named CS/asm21-1, CS/asm21-2 and CS/asm21-4 were successfully constructed. Three mutants and wild type CS were cultured on solid medium, and the extracts were detected and analyzed by liquid chromatography-mass spectrometry (LC-MS). The LC-MS profiles showed several unknown peaks that were present in the spectra of extracts of the CS/asm21-4 cultured on oatmeal solid medium. Then, three new naphthomycins O-Q (1-3), a new macrolide hookerolide (4) as well as nine known compounds were obtained from the solid cultured medium. Their structures were identified by spectra data. These new compounds showed moderate antimicrobial activities.