Terretonin O: a new meroterpenoid from Aspergillus terreus

Undescribed cytotoxic butenolides; asperterreunolides A-E, isolated from endophytic fungus Aspergillus terreus derived from Artemisia arborescens L. supported with in silico study

Chemical investigation of the ethyl acetate extract of the endophytic fungus Aspergillus terreus AArEF2 found in the fresh leaves of Artemisia arborescens L. led to isolation of five previously undescribed butenolides, asperterreunolides A-E (1-5), along with the known metabolite butyrolactone IV (6). The structure elucidation of these metabolites was established by detailed spectroscopic analyses (1D, 2D NMR and HR-ESI-MS analyses). The absolute configuration of compounds 4 and 5 was determined using the modified Mosher's method. The isolated metabolites (1-6) were evaluated for their cytotoxic activity against A-431, C4-2B, and MDA PCa 2b cell lines by MTT assay using a 96-well microplate. The findings revealed that all the isolated compounds had notable cytotoxic properties with IC50 values ranging from 3.72 to 6.27 μmol/L. Moreover, molecular docking was applied to propose the mechanism of action for the potential antitumor activity of the five previously undescribed butenolides, asperterreunolides A-E (1-5), along with known metabolite butyrolactone IV (6) to be attributed to type IIA topoisomerase inhibition. Furthermore, molecular dynamic simulations were implemented for 200 ns to study the stability of the asperterreunolides A-E (1-5) and butyrolactone IV (6) inside the active site of the type IIA topoisomerase.

Newly isolated terpenoids (covering 2019-2024) from Aspergillus species and their potential for the discovery of novel antimicrobials

The rapid emergence of drug-resistant microbial pathogens has posed challenges to global health in the twenty-first century. This development has significantly made most antibiotics ineffective in the treatment of infections they cause, resulting in increasing treatment costs and annual death rates. To address the challenge posed by these pathogens, we explore the potential of secondary metabolites from Aspergillus species as a source of new and effective therapeutic agents to treat drug-resistant infections. Terpenoids, a distinct group of natural products, are extensively distributed in plants and fungi, and have been attributed with significant antibacterial, anticancer, and antiviral activities. In this review, we present an overview of Aspergillus species, and review the novel terpenoids isolated from them from 2019 to April 2024, highlighting anti-infective activity against members of the ESKAPE pathogens. We further focus on the strategies through which the structural framework of these new terpenoids could be modified and/or optimized to feed a pipeline of new lead compounds targeting microbial pathogens. Overall, this review provides insight into the therapeutic applications of terpenoids sourced from Aspergillus species and the potential for the discovery of new compounds from these fungi to combat antimicrobial resistance.

Diverse bioactive secondary metabolites from Aspergillus terreus: antimicrobial, anticancer, and anti-SARS-CoV-2 activity studies

Owing to its high interest as prolific source of diverse bioactive compounds referred in our previous research work, we have scaled-up the fermentation of the marine Aspergillus terreus LGO13 on a liquid culture medium to isolate and identify the very minor/further promising bioactive secondary metabolites and to study their antibacterial, cytotoxic, and antiviral properties. Twenty-three known bioactive metabolites, including the recently discovered microbial natural product N-benzoyl-tryptophan (1), were obtained herein. Their structures were determined using HR-ESI-MS 1D/2D NMR spectroscopy and data from the literature. The biological properties of the microbial extract and the resulting compounds were examined using a set of microorganisms, cervix carcinoma KB-3-1, nonsmall cell lung cancer (NSCLC) A549, and coronavirus (SARS-CoV-2), respectively. Molecular docking (MD) simulations were used to investigate the potential targets of the separated metabolites as anti-SARS-CoV-2 drugs. According to the current study, a viral protein that may be the target of anticovid drugs is a papain-like protease (PLpro), and chaetominine (2) appears to be a viable choice against this protein. We evaluated the antiviral efficacy of chaetominine (2), fumitremorgin C (6), and azaspirofuran A (9) against SARS-CoV-2 based on MD data. Chaetominine (2) and azaspirofuran A (9) displayed intermediate selectivity indices (SI = 6.6 and 3.2, respectively), while fumitremorgin C (6) displayed a high selectivity index (SI = 19.77). These findings show that fumitremorgin C has promising antiviral action against SARS-CoV-2.

Marine Fungi Bioactives with Anti-Inflammatory, Antithrombotic and Antioxidant Health-Promoting Properties Against Inflammation-Related Chronic Diseases

Fungi play a fundamental role in the marine environment, being promising producers of bioactive molecules in the pharmacological and industrial fields, which have demonstrated potential health benefits against cardiovascular and other chronic diseases. This review pertains to the analysis of the lipid compositions across various species of marine fungi and their constantly discovered substances, as well as their anti-inflammatory, antioxidant, and antithrombotic effects. The health-promoting aspects of these microorganisms will be explored, through the investigation of several mechanisms of action and interference of their bioactives in biochemical pathways. Despite exceptional results in this field, the potential of marine microorganisms remains largely unexplored due to the limited number of specialists in marine microbiology and mycology, a relatively recent science with significant contributions and potential in biodiversity and biotechnology.

Abdel-Maksoud M, Fatima S, Almutairi S, Kiani BH, Hashem AH. Anabasis setifera leaf extract from arid habitat: A treasure trove of bioactive phytochemicals with potent antimicrobial, anticancer, and antioxidant properties

The main objective of this study was to evaluate the biological activities of Anabasis setifera extract, including its antimicrobial, anticancer, and antioxidant properties. In the current study, Anabasis setifera leaves extract was evaluated for antimicrobial, anticancer, antioxidant activities and phytochemical analyses. Ethyl acetate extract of Anabasis setifera (EA-AS) exhibited promising antimicrobial activity toward Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus subtilis, Candida albicans, Aspergillus brasiliensis, Aspergillus fumigatus with MICs 62.5, 125, 62.5, 31.25, 62.5, 125 and 125 μg/mL respectively. Moreover, EA-AS showed anticancer activity at safe concentrations, where IC50 were 36.4 and 44 μg/mL toward Hep-G2 and MCF-7 cancerous cell lines. EA-AS was found to contain 55 significant compounds identified through gas chromatography mass spectrophotometry (GCMS). The most abundant compounds were 1,4-dimethoxy-6,7,8,9-tetrahydro-5-benzocycloheptenone (26.04%), hexa-2,4-diyn-1-ylbenzene (8.40%), dihydrobenzo[b]fluoranthene (6.10%), ethanone, 1-[2,3-dihydro-2-(1-methylethenyl)-5-benzofuranyl (6.10%), and valerenol (4.08%). GC mass analysis confirmed the antioxidant properties of AS by detecting several compounds with antioxidant activity, including hexa-2,4-diyn-1-ylbenzene, nerolidol, spathulenol, -naphthalenem ethanol, decahydro-4-trimethyl-8-methylene, hexadecenoic acid, tremetone, desmethoxyencecalin, heptadecyn-1-ol, thunbergol, hexadecanol, dotriacontane, taylorione, ligulatin, retinoic acid, and falcarinol. The analysis of EA-AS reveals that it is a rich source of valuable phytochemicals: total Phenolic Content: a promising 4,264 μg/mL /, suggesting substantial biological and pharmacological potential. Total tannin content: 391.17 μg/mL, indicating potential applications in industries like nutraceuticals, pharmaceuticals, and cosmetics. Total flavonoid content exceptionally high at 5,163 μg/mL, while the total alkaloid content measured 1,036.26 μg/mL. Additionally, EA-AS demonstrated antioxidant activity with an EC50 of 30.6 μg/mL. In conclusion, the comprehensive analysis of the EA-AS reveals its immense potential as a rich source of valuable phytochemicals with diverse bioactivities, warranting further in-depth studies to unlock its full pharmaceutical and commercial prospects. Our results suggest substantial biological and pharmacological prospects for EA-AS as a promising antimicrobial, anticancer, and potent antioxidant.

Bioactive metabolites identified from Aspergillus terreus derived from soil

Aspergillus terreus has been reported to produce many bioactive metabolites that possess potential activities including anti-inflammatory, cytotoxic, and antimicrobial activities. In the present study, we report the isolation and identification of A. terreus from a collected soil sample. The metabolites existing in the microbial ethyl acetate extract were tentatively identified by HPLC/MS and chemically categorized into alkaloids, terpenoids, polyketides, γ-butyrolactones, quinones, and peptides. In addition, a new triglyceride (1) and a diketopiperazine derivative namely asterrine (4), together with two known butyrolactone (2-3) were purified from the extract. The chemical skeleton of the purified compounds was established by comprehensive analysis of their ESI/MS, 1 and 2D-NMR data. The extract and compounds 3,4 exhibited a strong inhibitory activity for the binding of ACE2 to SARS-CoV-2 spike-protein receptor with IC50 7.4, 9.5, and 8.5 µg/mL, respectively. In addition, the extract, 1 and 2 displayed a potent anti-inflammatory effect with IC50 51.31 and 37.25 pg/mL (Il-6) and 87.97, 68.22 pg/mL (TNF-α), respectively, in comparison to LPS control. In addition, the extract and compound 4 displayed an antimicrobial effect towards S. aureus by MIC 62.5 and 125 μg/mL, while the extract exhibited a potent effect against C. albicans (MIC of 125 μg/mL). Collectively, our data introduce novel bioactivities for the secondary metabolites produced by the terrestrial fungus Aspergillus terreus.

Bioactive Aspergteroids G-J from Soft-Coral-Associated Symbiotic and Epiphytic Fungus Aspergillus terreus EGF7-0-1

Two new disubstituted maleimides, aspergteroids G-H (1-2), and two trisubstituted butenolides aspergteroids I-J (3-4), along with four known analogs, were isolated and structurally identified from the fermentation extract of soft-coral-associated symbiotic and epiphytic fungus Aspergillus terreus EGF7-0-1. The structures of the new compounds were established mainly via spectroscopic data analyses, and their absolute configurations were determined via X-ray diffraction analysis and comparison of the calculated and experimental electronic circular dichroism. Myocardial protection assays showed that compounds 1, 2, 5, and 6 possess protective effects against tert-butyl hydroperoxide (TBHP)-induced H9c2 (rat myocardial cells) apoptosis at low concentrations. Based on the analyses of the protein-protein interaction (PPI) network and Western blotting, compound 1 may inhibit the apoptosis and inflammatory response of cardiomyocytes after TBHP induction and improve the antioxidant capacity of cardiomyocytes. We speculate that the anti-inflammatory response of compound 1 is suppressed by the glycogen synthase kinase-3 beta (GSK-3β), downregulated by the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome activation, and suppressed by the expression of cysteinyl aspartate specific proteinase-3 (caspase-3) and B-cell lymphoma-2 associated X protein (Bax).

Unearthing the fungal endophyte Aspergillus terreus for chemodiversity and medicinal prospects: a comprehensive review

Aspergillus terreus microorganism represents a promising prospective source for drug discovery since it is rich in diverse kinds of bioactive secondary metabolites. It contributed to many biotechnological applications and its metabolites are used in the synthesis of certain pharmaceuticals and food products, in addition to its useful uses in fermentation processes. There are about 346 compounds identified from marine and terrestrial-derived A. terreus from 1987 until 2022, 172 compounds of them proved a vast array of bioactivity. This review aimed to create an up-to-date comprehensive literature data of A. terreus's secondary metabolites classes supported by its different bioactivity data to be a scientific record for the next work in drug discovery.

Anti-prostate cancer metabolites from the soil-derived Aspergillus neoniveus

Prostate cancer (PCa) ranks as one of the most commonly diagnosed malignancies worldwide. Toxicity, lack of clinical efficacy, and development of resistance phenotypes are the main challenges in the control of prostate malignancies. Notably, castration-resistance prostate cancer (CRPCa) is a highly aggressive and metastatic phenotype of the disease with a poor prognosis and very limited therapeutic options. Herein, we report the isolation and genotypic identification of a soil-derived fungus Aspergillus neoniveus using the PCR-based internal transcribed spacer (ITS) region amplification approach. HPLC/MS investigation of the metabolic profile of the ethyl acetate extract from the fungal biomass revealed tentative identification of forty-five compounds belonging to various chemical classes including γ-butyrolactones, alkaloids, phenolics, and quinoids. Furthermore, the chromatographic purification of microbial extract enabled the identification of nervonic acid methyl ester (1) for the first time from endophytic fungi, as well as acetyl aszonalenin (2), and butyrolactone II (3) for the first time from A. neoniveus. The chemical frameworks of the isolated compounds were identified via extensive spectral analysis including 1 and 2D NMR and MS. The X-ray crystal structure and absolute configuration of acetyl aszonalenin (2) were also determined. Additionally, screening of in vitro anticancer activity of the fungal extract revealed its potential antiproliferative and anti-migratory activities against five different prostate cancer cells (PC3, PC-3M, DU-145, CWR-R1ca, and 22Rv1), including different cells with the castration-resistance phenotype. Moreover, the isolated metabolites significantly inhibited the proliferation, migration, and colonization of human prostate cancer cells at low micromolar levels, thus providing credence for future investigation of these metabolites in relevant anti-prostate cancer animal models. Furthermore, computational target prediction tools identified the cannabinoid G-protein coupled receptors type 1 (CB1) as a potential biological target mediating, at least in part, the anticancer effects of acetylaszonalenin (2). Moreover, molecular modeling and docking studies revealed a favorable binding pose at the CB1 receptor orthosteric ligand pocket aided by multiple polar and hydrophobic interactions with critical amino acids. In conclusion, the Aspergillus neoniveus-derived prenylated indole alkaloid acetylaszonalenin has promising anticancer activity and is amenable to further hit-to-lead optimization for the control of prostate malignancies via modulating CB1 receptors

Discovery of GOT1 Inhibitors from a Marine-Derived Aspergillus terreus That Act against Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating digestive system carcinoma with high incidence and death rates. PDAC cells are dependent on the Gln metabolism, which can preferentially utilize glutamic oxaloacetate transaminase 1 (GOT1) to maintain the redox homeostasis of cancer cells. Therefore, small molecule inhibitors targeting GOT1 can be used as a new strategy for developing cancer therapies. In this study, 18 butyrolactone derivatives (1–18) were isolated from a marine-derived Aspergillus terreus, and asperteretone B (5), aspulvinone H (AH, 6), and (+)-3′,3′-di-(dimethylallyl)-butyrolactone II (12) were discovered to possess significant GOT1-inhibitory activities in vitro, with IC₅₀ values of (19.16 ± 0.15), (5.91 ± 0.04), and (26.38 ± 0.1) µM, respectively. Significantly, the molecular mechanism of the crystal structure of GOT1–AH was elucidated, wherein AH and the cofactor pyrido-aldehyde 5-phosphate competitively bound to the active sites of GOT1. More importantly, although the crystal structure of GOT1 has been discovered, the complex structure of GOT1 and its inhibitors has never been obtained, and the crystal structure of GOT1–AH is the first reported complex structure of GOT1/inhibitor. Further in vitro biological study indicated that AH could suppress glutamine metabolism, making PDAC cells sensitive to oxidative stress and inhibiting cell proliferation. More significantly, AH exhibited potent in vivo antitumor activity in an SW1990-cell-induced xenograft model. These findings suggest that AH could be considered as a promising lead molecule for the development of anti-PDAC agents.

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.

Production of Terretonin N and Butyrolactone I by Thermophilic Aspergillus terreus TM8 Promoted Apoptosis and Cell Death in Human Prostate and Ovarian Cancer Cells

The anticancer activity of terretonin N (1) and butyrolactone I (2), obtained from the thermophilic fungus Aspergillus terreus TM8, was intensively studied against prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines. According to this study, both compounds showed potent cytotoxicity towards ovarian adenocarcinoma cells (SKOV3) with IC₅₀ 1.2 and 0.6 μg/mL, respectively. With respect to metastatic prostate cells (PC-3), the two compounds 1 and 2 showed a significantly promising cytotoxicity effect with IC₅₀ of 7.4 and 4.5 μg/mL, respectively. The tested fungal metabolites showed higher rates of early and late apoptosis with little or no necrotic apoptotic pathway in all treated prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines, respectively. The results reported in this study confirmed the promising biological properties of terretonin N (1) and butyrolactone I (2) as anticancer agents via the induction of cellular apoptosis. However, further studies are needed to elucidate the molecular mechanism by which cellular apoptosis is induced in cancer cells.

Antibiotics from Extremophilic Micromycetes

Extremophilic microorganisms, which are capable of functioning normally at extremely high or low temperatures, pressure, and in other environmental conditions, have been in the focus of microbiologists' attention for several decades due to the biotechnological potential of enzymes inherent in extremophiles. These enzymes (also called extremozymes) are used in the production of food and detergents and other industries. At the same time, the inhabitants of extreme econiches remained almost unexplored for a long time in terms of the chemistry of natural compounds. In recent years, the emergence of new antibiotic-resistant strains of pathogens, which affect humans and animals has become a global problem. The problem is compounded by a strong slowdown in the development of new antibiotics. In search of new active substances and scaffolds for medical chemistry, researchers turn to unexplored natural sources. In recent years, there has been a sharp increase in the number of studies on secondary metabolites produced by extremophiles. From the discovery of penicillin to the present day, micromycetes, along with actinobacteria, are one of the most productive sources of antibiotic compounds for medicine and agriculture. Many authors consider extremophilic micromycetes as a promising source of small molecules with an unusual mechanism of action or significant structural novelty. This review summarizes the latest (for 2018-2019) experimental data on antibiotic compounds, which are produced by extremophilic micromycetes with various types of adaptation. Active metabolites are classified by the type of structure and biosynthetic origin. The data on the biological activity of the isolated metabolites are summarized.

Chemistry, biosynthesis and biological activity of terpenoids and meroterpenoids in bacteria and fungi isolated from different marine habitats

The marine environment with its vast biological diversity encompasses many organisms that produce bioactive natural products. Marine microorganisms are rich sources of compounds from many structural classes with a multitude of biological activities. The biosynthesis of microbial natural products depends on a variety of biotic and abiotic factors in the marine environment, including temperature, nutrients, salinity and interaction with other microorganisms. Terpenoids, as one of the most important groups of natural products in terrestrial microorganisms are important metabolites for marine microorganisms. Here, we have reviewed the chemistry, biosynthesis and pharmacological activities of terpenoids, extracted from marine microbes, and then survey their potential applications in drug development. We also discussed the different habitats in which marine microorganisms are found including sediments, the flora, such as seaweeds, sea grasses, and mangroves as well as the fauna like sponges and corals. Amongst these habitats, marine sediments are the major source for terpenoids producing microorganisms. The marine bacteria produce mostly meroterpenoids, while the fungi are well known for production of isoprenoids. Interestingly, marine-derived microbial terpenoids have some structural characteristics such as halogenation, which are catalyzed by specific enzymes with distinct substrate specificity. These compounds have anticancer, antibacterial, antifungal, antimalarial and anti-inflammatory properties. The information collected here might provide useful clues for developing new medications.

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.

Molecules derived from the extremes of life: a decade later

Covering: Early 2008 until the end of 2019Microorganisms which survive (extreme-tolerant) or even prefer (extremophilic) living at the limits of pH, temperature, salinity and pressure found on earth have proven to be a rich source of novel structures. In this update we summarise the wide variety of new molecules which have been isolated from extremophilic and extreme-tolerant microorganisms since our original 2009 review, highlighting the range of bioactivities these molecules have been reported to possess.

Chemical Diversity and Biological Activities of Meroterpenoids from Marine Derived-Fungi: A Comprehensive Update

Meroterpenoids are a class of hybrid natural products, partially derived from a mixed terpenoid pathway. They possess remarkable structural features and relevant biological and pharmacological activities. Marine-derived fungi are a rich source of meroterpenoids featuring structural diversity varying from simple to complex molecular architectures. A combination of a structural variability and their myriad of bioactivities makes meroterpenoids an interesting class of naturally occurring compounds for chemical and pharmacological investigation. In this review, a comprehensive literature survey covering the period of 2009–2019, with 86 references, is presented focusing on chemistry and biological activities of various classes of meroterpenoids isolated from fungi obtained from different marine hosts and environments.

Bioactive secondary metabolites from new endophytic fungus Curvularia. sp isolated from Rauwolfia macrophylla

Over the last decades, endophytic fungi represent a new source of pharmacologically active secondary metabolites based on the underlying assumption that they live symbiotically within their plant host. In the present study, a new endophytic fungus was isolated from Rauwolfia macrophylla, a medicinal plant from Cameroon. The fungus showed a highest homology to Curvularia sp. based on complete nucleotide sequence data generated from the internal transcribed spacer (ITS) of ribosomal DNA region. Large scale fermentation, working-up and separation of the strain extract using different chromatographic techniques afforded three bioactive compounds: 2'-deoxyribolactone (1), hexylitaconic acid (2) and ergosterol (3). The chemical structures of compounds 1–3 were confirmed by 1 and 2D NMR spectroscopy and mass spectrometry, and comparison with corresponding literature data. Biologically, the antimicrobial, antioxidant activities and the acetylcholinesterase inhibitory of the isolated compounds were studied.