Drimane Sesquiterpene-Conjugated Amino Acids from a Marine Isolate of the Fungus Talaromyces minioluteus (Penicillium Minioluteum)

The Cytotoxic Properties of Extreme Fungi's Bioactive Components-An Updated Metabolic and Omics Overview

Fungi are the most diverse living organisms on planet Earth, where their ubiquitous presence in various ecosystems offers vast potential for the research and discovery of new, naturally occurring medicinal products. Concerning human health, cancer remains one of the leading causes of mortality. While extensive research is being conducted on treatments and their efficacy in various stages of cancer, finding cytotoxic drugs that target tumor cells with no/less toxicity toward normal tissue is a significant challenge. In addition, traditional cancer treatments continue to suffer from chemical resistance. Fortunately, the cytotoxic properties of several natural products derived from various microorganisms, including fungi, are now well-established. The current review aims to extract and consolidate the findings of various scientific studies that identified fungi-derived bioactive metabolites with antitumor (anticancer) properties. The antitumor secondary metabolites identified from extremophilic and extremotolerant fungi are grouped according to their biological activity and type. It became evident that the significance of these compounds, with their medicinal properties and their potential application in cancer treatment, is tremendous. Furthermore, the utilization of omics tools, analysis, and genome mining technology to identify the novel metabolites for targeted treatments is discussed. Through this review, we tried to accentuate the invaluable importance of fungi grown in extreme environments and the necessity of innovative research in discovering naturally occurring bioactive compounds for the development of novel cancer treatments.

Antimicrobial polyketides and sesquiterpene lactones from the deep-sea cold-seep-derived fungus Talaromyces minioluteus CS-113 triggered by the histone deacetylase inhibitor SAHA

Seven new highly oxygenated natural products with diverse chemical structural types, including three new glucosidic polyketides, talaminiosides A-C (1-3), a pair of racemic aromatic polyketides, (±)-talaminone A (4a and 4b), two new azaphilone polyketides, (+)-5-chloromitorubrinic acid (5) and 7-epi-purpurquinone C (7), and one new drimane sesquiterpene lactone, 11-hydroxyminioluteumide B (8), together with a pinazaphilone B sodium salt (6) and 10 known compounds (9-18), were isolated and identified from the culture extract of Talaromyces minioluteus CS-113, a fungus obtained from deep-sea cold-seep sediments collected from the South China Sea. LCMS results indicated that compounds 3 and 4 might be produced by the real activation of silent BGCs triggered by the histone deacetylase inhibitor SAHA, and some of the other compounds were enhanced minor components. Their structures were elucidated by the detailed interpretation of NMR spectroscopic and mass spectrometric data, X-ray crystallographic analysis, ECD and specific rotation (SR) calculations, and DP4+ probability analysis. Compound 7, an azaphilone derivative, exhibited potent activities against several agricultural pathogenic fungi with MIC values equivalent or comparable to amphotericin B. The structure-activity relationship of the isolated azaphilones is briefly discussed. This is the first report of the chemical diversity study of deep-sea cold-seep-derived fungi triggered by SAHA, providing a useful strategy for the activation of cryptic fungal metabolites from deep-sea-derived fungi.

Naturally Occurring Organohalogen Compounds-A Comprehensive Review

The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.

Research advances in the structures and biological activities of secondary metabolites from Talaromyces

The genus Talaromyces belongs to the phylum Ascomycota of the kingdom Fungi. Studies have shown that Talaromyces species yield many kinds of secondary metabolites, including esters, terpenes, steroids, alkaloids, polyketides, and anthraquinones, some of which have biological activities such as anti-inflammatory, bacteriostatic, and antitumor activities. The chemical constituents of fungi belonging to the genus Talaromyces that have been studied by researchers over the past several years, as well as their biological activities, are reviewed here to provide a reference for the development of high-value natural products and innovative uses of these resources.

Aromatic Polyketides from the Deep-Sea Cold-Seep Mussel Associated Endozoic Fungus Talaromyces minioluteus CS-138

Five new aromatic polyketides, including a unique benzofuran derivative, talarominine A (1), and four chromone analogs talamins A–D (2–5), along with one known related metabolite, 5-hydroxy-7-methoxy-2,3-dimethylchromone (6), were isolated and identified from the Talaromyces minioluteus CS-138, an endozoic fungus obtained from the deep-sea cold seep mussel Gigantidas platifrons. Their chemical structures were elucidated by detailed analysis of their NMR spectra, HRESIMS and X-ray crystallographic data, and by comparison with literature data as well. The antibacterial and DPPH scavenging activities of compounds 1–6 were evaluated. Compounds 1–3 showed inhibitory activity against some of the tested bacteria whereas compounds 2 and 5 showed potent DPPH radical scavenging activities, which were better than that of the positive control butylated hydroxytoluene (BHT). This work is likely the first report on marine natural products of mussel-derived fungus living in cold seep environments.

Chemical Diversity and Biosynthesis of Drimane-Type Sesquiterpenes in the Fungal Kingdom

Drimane-type sesquiterpenes are a class of compounds produced by a wide range of organisms, initially isolated and characterized in plants. Meanwhile, in the past 20-30 years, a large number of novel structures from many divergent fungi have been elucidated. Recently, the biosynthesis of drimane-type sesquiter-penes and their esters has been explained in two filamentous fungi, namely Aspergillus oryzae and Aspergillus calidoustus, disclosing the basic biosynthetic principles needed to identify similar pathways in the fungal kingdom.

Halogenation in Fungi: What Do We Know and What Remains to Be Discovered?

In nature, living organisms produce a wide variety of specialized metabolites to perform many biological functions. Among these specialized metabolites, some carry halogen atoms on their structure, which can modify their chemical characteristics. Research into this type of molecule has focused on how organisms incorporate these atoms into specialized metabolites. Several families of enzymes have been described gathering metalloenzymes, flavoproteins, or S-adenosyl-L-methionine (SAM) enzymes that can incorporate these atoms into different types of chemical structures. However, even though the first halogenation enzyme was discovered in a fungus, this clade is still lagging behind other clades such as bacteria, where many enzymes have been discovered. This review will therefore focus on all halogenation enzymes that have been described in fungi and their associated metabolites by searching for proteins available in databases, but also by using all the available fungal genomes. In the second part of the review, the chemical diversity of halogenated molecules found in fungi will be discussed. This will allow the highlighting of halogenation mechanisms that are still unknown today, therefore, highlighting potentially new unknown halogenation enzymes.

Anticancer Activity of Natural and Semi-Synthetic Drimane and Coloratane Sesquiterpenoids

Drimane and coloratane sesquiterpenoids are present in several plants, microorganisms, and marine life. Because of their cytotoxic activity, these sesquiterpenoids have received increasing attention as a source for new anticancer drugs and pharmacophores. Natural drimanes and coloratanes, as well as their semi-synthetic derivatives, showed promising results against cancer cell lines with in vitro activities in the low micro- and nanomolar range. Despite their high potential as novel anticancer agents, the mode of action and structure–activity relationships of drimanes and coloratanes have not been completely enlightened nor systematically reviewed. Our review aims to give an overview of known structures and derivatizations of this class of sesquiterpenoids, as well as their activity against cancer cells and potential modes-of-action. The cytotoxic activities of about 40 natural and 25 semi-synthetic drimanes and coloratanes are discussed. In addition to that, we give a summary about the clinical significance of drimane and coloratane sesquiterpenoids.

Isolation, Identification and Insecticidal Activity of the Secondary Metabolites of Talaromyces purpureogenus BS5

The fungal strain BS5 was isolated from a soil sample collected in the Tibetan Plateau, which displayed good insecticidal activity and was identified as Talaromyces purpureogenus based on morphological and molecular analysis. This study aimed to evaluate the insecticidal activity and identify the active compound of the strain BS5 against the locust Locusta migratoria manilensis. The insecticidal activity of the fermented broth of BS5 was at 100% after 7 days against locusts. We extracted the fermented broth of BS5 and then evaluated the insecticidal activity of the extracts against locusts. The ethyl acetate extract exhibited promising activity levels with an LC₅₀ value of 1077.94 μg/mL and was separated through silica gel column chromatography. The UPLC-Q-Exactive Orbitrap/MS system was employed to analyze the active fraction Fr2.2.2 (with an LC₅₀ value of 674.87 μg/mL), and two compounds were identified: phellamurin and rubratoxin B.

Antikinetoplastid Activity of Sesquiterpenes Isolated from the Zoanthid Palythoa aff. clavata

Leishmaniasis and Chagas disease are neglected tropical diseases that cause problems in developing countries. The causative agents, Leishmania spp. and Trypanosoma cruzi, produce a clinical picture that can be fatal for the patient, such as Chagas heart disease, visceral leishmaniasis and megacolon, among others. Current treatments for these diseases are not very effective and highly toxic, since they require very prolonged treatments. The development of innovative, effective and safe drugs to fight infections caused by these parasites remains a challenge. For this reason, in recent years, there has been an increase in the search for new therapies. In this study, the antikinetoplastid activity of 13 sesquiterpene lactones obtained from Palythoa aff. clavata was screened against L. amazonensis, L. donovani and T. cruzi. The results revealed that the sesquiterpene lactones anhydroartemorin (2), cis,trans-costunolide-14-acetate (3) and 4-hydroxyarbusculin A (11) were the most selective against the kinetoplastid species studied. These molecules seem to induce the mechanisms involved in an apoptotic-like death or programmed cell death (PCD) in the kinetoplastids, and since they do not cause necrosis, the inflammatory events associated with this type of cell death will not be triggered.

A Review: Halogenated Compounds from Marine Fungi

Marine fungi produce many halogenated metabolites with a variety of structures, from acyclic entities with a simple linear chain to multifaceted polycyclic molecules. Over the past few decades, their pharmaceutical and medical application have been explored and still the door is kept open due to the need of new drugs from relatively underexplored sources. Biological properties of halogenated compounds such as anticancer, antiviral, antibacterial, anti-inflammatory, antifungal, antifouling, and insecticidal activity have been investigated. This review describes the chemical structures and biological activities of 217 halogenated compounds derived mainly from Penicillium and Aspergillus marine fungal strains reported from 1994 to 2019.

A Review of Terpenes from Marine-Derived Fungi: 2015-2019

Marine-derived fungi are a significant source of pharmacologically active metabolites with interesting structural properties, especially terpenoids with biological and chemical diversity. In the past five years, there has been a tremendous increase in the rate of new terpenoids from marine-derived fungi being discovered. In this updated review, we examine the chemical structures and bioactive properties of new terpenes from marine-derived fungi, and the biodiversity of these fungi from 2015 to 2019. A total of 140 research papers describing 471 new terpenoids of six groups (monoterpenes, sesquiterpenes, diterpenes, sesterterpenes, triterpenes, and meroterpenes) from 133 marine fungal strains belonging to 34 genera were included. Among them, sesquiterpenes, meroterpenes, and diterpenes comprise the largest proportions of terpenes, and the fungi genera of Penicillium, Aspergillus, and Trichoderma are the dominant producers of terpenoids. The majority of the marine-derived fungi are isolated from live marine matter: marine animals and aquatic plants (including mangrove plants and algae). Moreover, many terpenoids display various bioactivities, including cytotoxicity, antibacterial activity, lethal toxicity, anti-inflammatory activity, enzyme inhibitor activity, etc. In our opinion, the chemical diversity and biological activities of these novel terpenoids will provide medical and chemical researchers with a plenty variety of promising lead compounds for the development of marine drugs.

Natural Nitrogenous Sesquiterpenoids and Their Bioactivity: A Review

Nitrogenous sesquiterpenoids fromnatural sourcesare rare, so unsurprisingly neither the potentially valuable bioactivity nor thebroad structural diversity of nitrogenous sesquiterpenoids has been reviewed before. This report covers the progressduring the decade from 2010 to February 2020 on the isolation, identification, and bioactivity of 391 nitrogen-containing natural sesquiterpenes from terrestrial plant, marine organisms, and microorganisms. This complete and in-depth reviewshouldbe helpful for discovering and developing new drugs of medicinal valuerelated to natural nitrogenous sesquiterpenoids.

Newly reported alkaloids produced by marine-derived Penicillium species (covering 2014-2018)

Alkaloids, especially heterocyclic alkaloids, have received remarkable attention due to their intriguing structures and potential pharmacological activities. The marine fungi residing in extreme environmental conditions are among the richest sources of these basic nitrogen-containing compounds. Fungal species belonging to the genus Penicillium have been studied worldwide for their biosynthetic potential for generating bioactive alkaloids. This paper offers a systematic review of the newly reported alkaloids produced by marine-derived Penicillium species over the past five years (covering the literature from the beginning of 2014 through the end of 2018) and describes the structural diversity, biological activities, and plausible biosynthetic pathway of the reported compounds. A total of 106 alkaloids and 81 references are included in this review, which is expected to be beneficial for drug development and biosynthesis in the near future.

Talaromyces minioluteus: New Postharvest Fungal Pathogen in Serbia

Talaromyces minioluteus is one of the important species of genus Talaromyces, which has cosmopolitan distribution and is encountered on a wide range of different habitats. This species has not been considered as an important plant pathogen, even though it has been isolated from various plant hosts. Fruits and vegetables with Penicillium-like mold symptoms were collected from 2015 to 2017 from markets in Serbia. Isolates originating from quince, tomato, and orange fruits, onion bulbs, and potato tubers were identified and characterized on a morphological, physiological, and molecular level. Morphological and physiological examination included observing micromorphology, testing growth on six different media and at five different temperatures, and production of three enzymes. Molecular identification and characterization were performed using four molecular markers: internal transcribed spacer, β-tubulin, calmodulin, and DNA-dependent RNA polymerase II second largest subunit. The results of morphological and molecular analyses were in agreement, and they proved that the obtained isolates are T. minioluteus. In the pathogenicity assay, T. minioluteus was confirmed as a pathogen of all species tested with the exception of potato tubers. This is the first report of T. minioluteus as a postharvest plant pathogen on quince, tomato, and orange fruit and onion bulbs. Also, this is the first record of T. minioluteus in Serbia.

Biological and Chemical Diversity of Marine Sponge-Derived Microorganisms over the Last Two Decades from 1998 to 2017

Marine sponges are well known as rich sources of biologically natural products. Growing evidence indicates that sponges harbor a wealth of microorganisms in their bodies, which are likely to be the true producers of bioactive secondary metabolites. In order to promote the study of natural product chemistry and explore the relationship between microorganisms and their sponge hosts, in this review, we give a comprehensive overview of the structures, sources, and activities of the 774 new marine natural products from sponge-derived microorganisms described over the last two decades from 1998 to 2017.

Isolation, structural elucidation, and antimicrobial evaluation of the metabolites from a marine-derived fungus Penicillium sp. ZZ1283

A crude extract prepared from a culture of marine-sourced fungus Penicillum ZZ1283 in the medium of potato dextrose broth was found to have antimicrobial activities. Chemical investigation on this active extract resulted in the isolation of eighteen metabolites, including purpuride D, a new analogue of drimane-type sesquiterpene lactones conjugated with N-acetyl-L-valine. Structure of the new purpuride D was determined based on its HRESIMS data, NMR spectroscopic analyses, single-crystal X-ray diffraction and ECD calculation. Purpuride D showed activities in inhibiting the growth of methicillin-resistant Staphylococcus aureus, Escherichia coli and Candida albicans with MIC values of 4, 3 and 8 μg/mL, respectively.

(±)-Peniorthoesters A and B, Two Pairs of Novel Spiro-Orthoester en-antiomers With an Unusual 1,4,6-Trioxaspi-ro[4.5]decane-7-One Unit From Penicillium minioluteum

(±)-Peniorthoesters A and B (±1 and ±2), two pairs of unprecedented spiro-orthoester enantiomers with a 1,4,6-trioxaspiro[4. 5]decane-7-one unit, were obtained from Penicillium minioluteum. Their structures were determined by spectroscopic methods, X-ray diffraction analyses, and ECD calculations. (±)-Peniorthoesters A and B are the first examples of spiro-orthoester enantiomers, and they represent the first spiro-orthoesters originating from fungi. All compounds showed potential inhibitory activities comparable to dexamethasone against NO production with IC₅₀ values ranging from 14.2 to 34.5 μM.

Anti-inflammatory meroterpenoids from the mangrove endophytic fungus Talaromyces amestolkiae YX1

Four previously undescribed meroterpenoids, amestolkolides A-D, along with three known compounds were isolated from the mangrove endophytic fungus Talaromyces amestolkiae YX1 cultured on wheat solid-substrate medium culture. Their structures were elucidated by a combination of spectroscopic analyses. The absolute configurations of amestolkolides B and C, and purpurogenolide E were determined by single-crystal X-ray diffraction using Cu Kα radiation, and those of amestolkolides A and D were elucidated on the basis of experimental and calculated electronic circular dichroism spectra. The absolute configuration of amestolkolides A-D, and purpurogenolide E (9R) at C-9 was different from that of analogues (9S) in references, so that their plausible and distinct biosynthetic pathways were proposed. Amestolkolide B showed strong anti-inflammatory activity in vitro by inhibiting nitric oxide (NO) production in lipopolysaccharide activated in RAW264.7 cells with IC₅₀ value of 1.6 ± 0.1 μM.

Antimicrobial activity and acetylcholinesterase inhibition by extracts from chromatin modulated fungi

Major health challenges as the increasing number of cases of infections by antibiotic multiresistant microorganisms and cases of Alzheimer's disease have led to searching new control drugs. The present study aims to verify a new way of obtaining bioactive extracts from filamentous fungi with potential antimicrobial and acetylcholinesterase inhibitory activities, using epigenetic modulation to promote the expression of genes commonly silenced. For such finality, five filamentous fungal species (Talaromyces funiculosus, Talaromyces islandicus, Talaromyces minioluteus, Talaromyces pinophilus, Penicillium janthinellum) were grown or not with DNA methyltransferases inhibitors (procainamide or hydralazine) and/or a histone deacetylase inhibitor (suberohydroxamic acid). Extracts from T. islandicus cultured or not with hydralazine inhibited Listeria monocytogenes growth in 57.66±5.98% and 15.38±1.99%, respectively. Increment in inhibition of acetylcholinesterase activity was observed for the extract from P. janthinellum grown with procainamide (100%), when compared to the control extract (39.62±3.76%). Similarly, inhibition of acetylcholinesterase activity increased from 20.91±3.90% (control) to 92.20±3.72% when the tested extract was obtained from T. pinophilus under a combination of suberohydroxamic acid and procainamide. Concluding, increases in antimicrobial activity and acetylcholinesterase inhibition were observed when fungal extracts in the presence of DNA methyltransferases and/or histone deacetylase modulators were tested.

Marine natural products

Covering: 2015. Previous review: Nat. Prod. Rep., 2016, 33, 382-431This review covers the literature published in 2015 for marine natural products (MNPs), with 1220 citations (792 for the period January to December 2015) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1340 in 429 papers for 2015), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Talarolutins A-D: Meroterpenoids from an endophytic fungal isolate of Talaromyces minioluteus

Four meroterpenoids [talarolutins A-D] and one known compound [purpurquinone A] were characterized from an endophytic fungal isolate of Talaromyces minioluteus (G413), which was obtained from the leaves of the medicinal plant milk thistle [Silybum marianum (L.) Gaertn. (Asteraceae)]. The structures of talarolutins A-D were determined by the analysis of various NMR and MS techniques. The relative and absolute configuration of talarolutin A was determined by X-ray diffraction analysis. A combination of NOESY data and comparisons of ECD spectra were employed to assign the relative and absolute configuration of the other analogs. Talarolutins B-D were tested for cytotoxicity against human prostate carcinoma (PC-3) cell line, antimicrobial activity, and induction of quinone reductase; no notable bioactivity was observed in any assay.

Bioactive Compounds Produced by Strains of Penicillium and Talaromyces of Marine Origin

In recent years, the search for novel natural compounds with bioactive properties has received a remarkable boost in view of their possible pharmaceutical exploitation. In this respect the sea is entitled to hold a prominent place, considering the potential of the manifold animals and plants interacting in this ecological context, which becomes even greater when their associated microbes are considered for bioprospecting. This is the case particularly of fungi, which have only recently started to be considered for their fundamental contribution to the biosynthetic potential of other more valued marine organisms. Also in this regard, strains of species which were previously considered typical terrestrial fungi, such as Penicillium and Talaromyces, disclose foreground relevance. This paper offers an overview of data published over the past 25 years concerning the production and biological activities of secondary metabolites of marine strains belonging to these genera, and their relevance as prospective drugs.

The Bioactive Secondary Metabolites from Talaromyces species

The focus of this review is placed on the chemical structures from the species of the genus Talaromyces reported with reference to their biological activities. 221 secondary metabolites, including 43 alkaloids and peptides, 88 esters, 31 polyketides, 19 quinones, 15 steroid and terpenoids, and 25 other structure type compounds, have been included, and 66 references are cited.