A new butenolide derivative from the deep-sea fungus Aspergillus terreus SCSIO FZQ028

New butanolide derivatives from the marine derived fungus Aspergillus terreus GZU-31-1 by chemical epigenetic manipulation

Chemical epigenetic manipulation of Aspergillus terreus GZU-31-1 led to the discovery of five butanolide derivatives (1-5), including two new ones (1 and 2), and four known diphenyl ether derivatives (6-9). Compound 1 featured a Z-configuration double bond in the isoprenyl group was a potential anti-inflammatory bioactive group. Compound 2 was a new natural product. Moreover, compound 3 with a deacetylated group at C-4 was rarely reported as a butanolide analogue, which was isolated from the liquid culture treated with polyketide pathway inhibitor sodium citrate dihydrate. All of the isolates (1-9) were tested for their anti-inflammatory effects on the production of nitric oxide in lipopolysaccharide-induced microglial cells (RAW 264.7 cells). Compounds 1, 7, 8 and 9 exhibited more potent anti-inflammatory activity with IC50 values of 16.31, 20.16, 9.53 and 21.64 μM than the positive control (indomethacin, IC50, 24.0 μM).

Antimicrobial and antibiofilm activity of fungal metabolites on methicillin-resistant Staphylococcus aureus (ATCC 43300) mediated by SarA and AgrA

Methicillin-resistant Staphylococcus aureus (MRSA) increases its antibiotic resistance by forming biofilms. Natural products (NP) or specialized metabolites have demonstrated their ability to decrease the virulence and pathogenesis of MRSA infections by inhibiting biofilm formation. The present study evaluated the antimicrobial and antibiofilm potential against MRSA of a small library of fungal NP isolated from Mexican biodiversity. The most potent antibacterial activity was observed for myrotecisin B, epiequisetin, equisetin, stachybotrolide acetate, monorden A, zearalenone, fuscin, and fusarubin. On the other hand, epifiscalin C, fiscalin C, dimethylglyotoxin, aspernolide B, and butyrolactones I and IV inhibited the biofilm formation without decreasing bacterial growth. To determine the putative mechanism of action of these compounds, docking analyses were performed against SarA and AgrA proteins, targets known to regulate biofilm production in MRSA. Overall, the results demonstrate that fungal NP may act as potential antibiofilm agents for treating MRSA infections.

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.

γ-Aromatic Butenolides of Microbial Source - A Review of Their Structures, Biological Activities and Biosynthesis

γ-Aromatic butenolides (γ-AB) are an important type of structures found in many bioactive microbial secondary metabolites (SMs). γ-AB refer to a group of natural products (NPs) containing five-membered (unsaturated) lactones with 3-phenyl and 4-benzyl substituents. Their wide-range biological activities have inspired pharmaceutical chemists to explore its biosynthesis mechanisms and design strategies to construct the γ-AB skeleton. Recently, there are a great deal of interesting research progress on the structures, biological activities and biosynthesis of γ-AB. This review will focus on these aspects and summarize the important achievements of γ-AB from 1975 to 2021.

Marine natural products

Covering: 2020This review covers the literature published in 2020 for marine natural products (MNPs), with 757 citations (747 for the period January to December 2020) 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 (1407 in 420 papers for 2020), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. A meta analysis of bioactivity data relating to new MNPs reported over the last five years is also presented.

Diverse Secondary Metabolites from the Coral-Derived Fungus Aspergillus hiratsukae SCSIO 5Bn1003

Three new metabolites, including a cyclic tetrapeptide asperhiratide (1), an ecdysteroid derivative asperhiratine (2), and a sesquiterpene lactone asperhiratone (3), were isolated and identified from the soft coral-derived fungus Aspergillus hiratsukae SCSIO 5Bn1003, together with 10 known compounds. Their structures were elucidated via spectroscopic analysis, X-ray diffraction analysis, and electronic circular dichroism calculations. In addition, the absolute configuration of 1 was determined by Marfey's technique and an analysis of the acid hydrolysates using a chiral phase HPLC column. Among all the compounds, 6 and 8 showed medium cytotoxic activities against four tumor cell lines (SF-268, HepG-2, MCF-7, and A549), with IC50 values ranging from 31.03 ± 3.04 to 50.25 ± 0.54 µM. Meanwhile, they strongly inhibited α-glucosidase activities, with IC50 values of 35.73 ± 3.94 and 22.00 ± 2.45 µM, which were close to and even stronger than the positive control acarbose (IC50 = 32.92 ± 1.03 µM). Compounds 6-8 showed significant antibacterial activities against Bacillus subtilis, with MIC values of 10.26 ± 0.76 µM, 17.00 ± 1.25 µM, and 5.30 ± 0.29 µM, respectively. Compounds 9 and 12 exhibited potent radical scavenging activities against DPPH, with IC50 values of 12.23 ± 0.78 µM and 7.38 ± 1.16 µM. In addition, asperhiratide (1) was evaluated for anti-angiogenic activities in the in vivo zebrafish model, which showed a weak inhibitory effect on intersegmental vessel (ISV) formation.

Structurally Diverse Polycyclic Salicylaldehyde Derivative Enantiomers from a Marine-Derived Fungus Eurotium sp. SCSIO F452

To enlarge the chemical diversity of Eurotium sp. SCSIO F452, a talented marine-derived fungus, we further investigated its chemical constituents from a large-scale fermentation with modified culture. Four pairs of new salicylaldehyde derivative enantiomers, euroticins F-I (1–4), as well as a known one eurotirumin (5) were isolated and characterized. Compound 1 features an unprecedented constructed 6/6/6/5 tetracyclic structures, while 2 and 3 represent two new types of 6/6/5 scaffolds. Their structures were established by comprehensive spectroscopic analyses, X-ray diffraction, ¹³C NMR, and electronic circular dichroism calculations. Selected compounds showed significant inhibitory activity against α-glucosidase and moderate cytotoxic activities against SF-268, MCF-7, HepG2, and A549 cell lines.

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.

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.