Coprinuslactone protects the edible mushroom Coprinus comatus against biofilm infections by blocking both quorum-sensing and MurA

Discovery of novel secondary metabolites from the basidiomycete Lentinus cf. sajor-caju and their inhibitory effects on Staphylococcus aureus biofilms

Three novel derivatives of microporenic acid, microporenic acids H-J, were identified from submerged cultures of a Lentinus species obtained from a basidiome collected during a field trip in the tropical rainforest in Western Kenya. Their structures were elucidated via HR-ESIMS spectra and 1D/2D NMR spectroscopic analyses, as well as by comparison with known derivatives. Applying biofilm assays based on crystal violet staining and confocal microscopy, two of these compounds, microporenic acids H and I, demonstrated the ability to inhibit biofilm formation of the opportunistic pathogen Staphylococcus aureus. Thereby, they were effective in a concentration range that did not affect planktonic growth. Additionally, microporenic acid I enhanced the anti-biofilm activity of the antibiotics vancomycin and gentamicin when used in combination. This opens up possibilities for the use of these compounds in combination therapy to prevent the formation of S. aureus biofilms.

Wild Mushrooms: A Hidden Treasure of Novel Bioactive Compounds

Secondary metabolites are hidden gems in mushrooms. Understanding these secondary metabolites' biological and pharmacological effects can be aided by identifying them. The purpose of this work was to profile the mycochemical components of the extracts of Auricularia auricula judae, Microporus xanthopus, Termitomyces umkowaani, Trametes elegans, and Trametes versicolor to comprehend their biological and pharmacological capabilities. Mushroom samples were collected from Kenya's Arabuko-Sokoke and Kakamega National Reserved Forests and identified using morphological and molecular techniques. Chloroform, 70% ethanol, and hot water solvents were used to extract the mycochemical components. Gas chromatography mass spectrometry (GC-MS) was used to analyze the chloroform, 70% ethanol, and hot water extracts of all the species examined. A total of 51 compounds were isolated from all extracts and classified as carboxylic acids, esters, phenols, fatty acids, alcohol, epoxides, aldehydes, fatty aldehydes, isoprenoid lipids, and steroids. Tetracosamethyl-cyclododecasiloxane (18.90%), oleic acid (72.90%), phenol, 2, 6-bis (1, 1-dimethylethyl)-4-methyl-, and methylcarbamate (26.56%) were all found in high concentrations in A. auricular judae, M. xanthopus, T. umkowaani, T. elegans, and T. versicolor, respectively. Fatty acids make up the majority of the compounds isolated from the T. elegans chloroform extract and the T. umkowaani 70% ethanol extract, respectively. Particularly, these fatty acids play crucial roles in the anti-inflammatory, hypocholesterolemic, anticancer, and antibiofilm formation activities. These bioactive elements indicate that the extracts of five wild mushrooms may be reliable sources of secondary metabolites for therapeutic development. Therefore, additional research is required to comprehend the usefulness of these chemicals in many functional areas and to improve the present understanding of macrofungi.

Artificial Neural Network Prediction of Antiadhesion and Antibiofilm-Forming Effects of Antimicrobial Active Mushroom Extracts on Food-Borne Pathogens

The problem of microbial biofilms has come to the fore alongside food, pharmaceutical, and healthcare industrialization. The development of new antibiofilm products has become urgent, but it includes bioprospecting and is time and money-consuming. Contemporary efforts are directed at the pursuit of effective compounds of natural origin, also known as "green" agents. Mushrooms appear to be a possible new source of antibiofilm compounds, as has been demonstrated recently. The existing modeling methods are directed toward predicting bacterial biofilm formation, not in the presence of antibiofilm materials. Moreover, the modeling is almost exclusively targeted at biofilms in healthcare, while modeling related to the food industry remains under-researched. The present study applied an Artificial Neural Network (ANN) model to analyze the anti-adhesion and anti-biofilm-forming effects of 40 extracts from 20 mushroom species against two very important food-borne bacterial species for food and food-related industries-Listeria monocytogenes and Salmonella enteritidis. The models developed in this study exhibited high prediction quality, as indicated by high r² values during the training cycle. The best fit between the modeled and measured values was observed for the inhibition of adhesion. This study provides a valuable contribution to the field, supporting industrial settings during the initial stage of biofilm formation, when these communities are the most vulnerable, and promoting innovative and improved safety management.

Synthesis and Bioactivity of Ophiofuranones A and B

Ophiofuranones A and B, metabolites of the fungus Ophiosphaerella korrae, were synthesized in 16 steps and 12%/22% yield. The stereogenic centers were established by Sharpless dihydroxylations and epoxidation, the 1,3-dienes via Wittig or HWE olefinations. The rings were closed through Knoevenagel-type condensation and lactonization. The ophiofuranones proved nontoxic at relevant concentrations against tumor cells, fibroblasts, and various bacteria and fungi. Ophiofuranone A and the monocyclic precursors 4 were weakly active against microbial biofilms.

Synthesis of the fungal macrolide berkeleylactone A and its inhibition of microbial biofilm formation

The fungal macrolide berkeleylactone A was synthesised in 13 steps and 24% yield using (R)-propylene oxide and an asymmetric Noyori hydrogenation of a β-ketoester to install the stereogenic centres. A domino addition-Wittig olefination of a 13-hydroxytetradecanal intermediate with the cumulated ylide Ph3PCCO closed the macrocyle by establishing the α,β-unsaturated ester group, necessary for the attachment of the sidechain thiol via a thia-Michael reaction. The synthetic berkeleylactone A inhibited the formation of Staphylococcus aureus biofilms and showed significant dispersive effects on preformed biofilms of Candida albicans by at least 45% relative to untreated controls at concentrations as low as 1.3 μg mL-1.

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.

The two faces of Coprinus comatus-Functional properties and potential hazards

Mushrooms have been used for centuries not only as food but also in traditional medicine as a source of components with pro‐health activity. One of them is Coprinus comatus (O.F.Müll.) Pers. also called shaggy mane, chicken drumstick mushroom, or lawyer's wig. In Asian countries, C. comatus (CC) is approved as edible mushroom and often cultivated for consumption, whereas in many other countries, although it is widespread, it is unrecognized and not used. In this review, for the first time, we discussed about the composition related to functional properties as well as the potential risks associated with consumption of CC by reviewing scientific literature. The information has been collected in order to get to know this species thoroughly. Various studies show many of the physiological activities, such as antioxidant, anticancer, antiandrogenic, hepatoprotective, acetylcholinesterase inhibitory, antiinflammatory, antidiabetic, antiobesity, antibacterial, antifungal, antinematode, and antiviral. Besides positive physiological properties, CC has also negative features, for example, skin reactions in patients with dermatitis and atopic predisposition, risk of confusion with poisonous mushrooms, quick autolysis after collection, and contamination of toxic elements.

Cytotoxic, antimicrobial and antiviral secondary metabolites produced by the plant pathogenic fungus Cytospora sp. CCTU A309

Chemical analysis of extracts from cultures of the plant pathogenic fungus Cytospora sp. strain CCTU A309 collected in Iran led to the isolation of two previously unreported heptanedioic acid derivatives namely (2R,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (1) and (2S,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (2) as diastereomers, four previously undescribed prenylated p-terphenyl quinones 3-6 in addition to five known metabolites. Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. For metabolites 1 and 2, the absolute configurations at C-2 were deduced from comparison of the ¹H NMR difference of their (S)- and (R)-phenylglycine methyl ester derivatives while the relative configurations were tentatively assigned by a J-based analysis and confirmed by comparison of ¹³C chemical shifts to literature data. The isolated compounds were tested for their cytotoxic, antimicrobial (including biofilm inhibition), antiviral, and nematicidal activities. While only moderate antimicrobial effects were observed, the terphenyl quinone derivatives 3-6 and leucomelone (10) exhibited significant cytotoxicity against the mouse fibroblast L929 and cervix carcinoma KB-3-1 cell lines with IC₅₀ values ranging from 2.4 to 26 μg/mL. Furthermore, metabolites 4-6 showed interesting antiviral activity against hepatitis C virus (HCV).

Bacterial-fungal interactions: ecology, mechanisms and challenges

Fungi and bacteria are found living together in a wide variety of environments. Their interactions are significant drivers of many ecosystem functions and are important for the health of plants and animals. A large number of fungal and bacterial families engage in complex interactions that lead to critical behavioural shifts of the microorganisms ranging from mutualism to antagonism. The importance of bacterial-fungal interactions (BFI) in environmental science, medicine and biotechnology has led to the emergence of a dynamic and multidisciplinary research field that combines highly diverse approaches including molecular biology, genomics, geochemistry, chemical and microbial ecology, biophysics and ecological modelling. In this review, we discuss recent advances that underscore the roles of BFI across relevant habitats and ecosystems. A particular focus is placed on the understanding of BFI within complex microbial communities and in regard of the metaorganism concept. We also discuss recent discoveries that clarify the (molecular) mechanisms involved in bacterial-fungal relationships, and the contribution of new technologies to decipher generic principles of BFI in terms of physical associations and molecular dialogues. Finally, we discuss future directions for research in order to stimulate synergy within the BFI research area and to resolve outstanding questions.

Cytochalasans Act as Inhibitors of Biofilm Formation of Staphylococcus Aureus

During the course of our ongoing work to discover new inhibitors of biofilm formation of Staphylococcus aureus from fungal sources, we observed biofilm inhibition by cytochalasans isolated from cultures of the ascomycete Hypoxylon fragiforme for the first time. Two new compounds were purified by a bioassay-guided fractionation procedure; their structures were elucidated subsequently by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). This unexpected finding prompted us to test further cytochalasans from other fungi and from commercial sources for comparison. Out of 21 cytochalasans, 13 showed significant inhibition of Staphylococcus aureus biofilm formation at subtoxic levels. These findings indicate the potential of cytochalasans as biofilm inhibitors for the first time, also because the minimum inhibitory concentrations (MIC) are independent of the anti-biofilm activities. However, cytochalasans are known to be inhibitors of actin, making some of them very toxic for eukaryotic cells. Since the chemical structures of the tested compounds were rather diverse, the inclusion of additional derivatives, as well as the evaluation of their selectivity against mammalian cells vs. the bacterium, will be necessary as next step in order to develop structure-activity relationships and identify the optimal candidates for development of an anti-biofilm agent.

Microporenic Acids A-G, Biofilm Inhibitors, and Antimicrobial Agents from the Basidiomycete Microporus Species

The need for effective compounds to combat antimicrobial resistance and biofilms which play important roles in human infections continues to pose a major health challenge. Seven previously undescribed acyclic diterpenes linked to isocitric acid by an ether linkage, microporenic acids A-G (1-7), were isolated from the cultures of a hitherto undescribed species of the genus Microporus (Polyporales, Basidiomycota) originating from Kenya's Kakamega forest. Microporenic acids D and E (4 and 5) showed antimicrobial activity against a panel of Gram positive bacteria and a yeast, Candida tenuis. Moreover, microporenic acids A and B (1 and 2) demonstrated dose-dependent inhibition of biofilm formation by Staphylococcus aureus. Compound 1 further showed significant activity against Candida albicans and Staphylococcus aureus preformed biofilms.

Mushroom Polysaccharides: Chemistry and Antiobesity, Antidiabetes, Anticancer, and Antibiotic Properties in Cells, Rodents, and Humans

More than 2000 species of edible and/or medicinal mushrooms have been identified to date, many of which are widely consumed, stimulating much research on their health-promoting properties. These properties are associated with bioactive compounds produced by the mushrooms, including polysaccharides. Although β-glucans (homopolysaccharides) are believed to be the major bioactive polysaccharides of mushrooms, other types of mushroom polysaccharides (heteropolysaccharides) also possess biological properties. Here we survey the chemistry of such health-promoting polysaccharides and their reported antiobesity and antidiabetic properties as well as selected anticarcinogenic, antimicrobial, and antiviral effects that demonstrate their multiple health-promoting potential. The associated antioxidative, anti-inflammatory, and immunomodulating activities in fat cells, rodents, and humans are also discussed. The mechanisms of action involve the gut microbiota, meaning the polysaccharides act as prebiotics in the digestive system. Also covered here are the nutritional, functional food, clinical, and epidemiological studies designed to assess the health-promoting properties of polysaccharides, individually and as blended mixtures, against obesity, diabetes, cancer, and infectious diseases, and suggestions for further research. The collated information and suggested research needs might guide further studies needed for a better understanding of the health-promoting properties of mushroom polysaccharides and enhance their use to help prevent and treat human chronic diseases.