A new lumazine peptide penilumamide E from the fungus Aspergillus terreus

Biosynthesis of the fungal nonribosomal peptide penilumamide A and biochemical characterization of a pterin-specific adenylation domain

We report the characterization of the penilumamide biosynthetic cluster from Aspergillus flavipes CNL-338. In vitro reconstitution experiments demonstrated that three nonribosomal peptide synthetases are required for constructing the tripeptide and studies with dissected adenylation domains allowed for the first biochemical characterization of a domain that selects a pterin-derived building block.

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.

Diversity and Biosynthetic Potential of Fungi Isolated from St. John's Island, Singapore

Adaptation to a wide variety of habitats allows fungi to develop unique abilities to produce diverse secondary metabolites with diverse bioactivities. In this study, 30 Ascomycetes fungi isolated from St. John's Island, Singapore were investigated for their general biosynthetic potential and their ability to produce antimicrobial secondary metabolites (SMs). All the 30 fungal isolates belong to the Phylum Ascomycota and are distributed into 6 orders and 18 genera with Order Hypocreales having the highest number of representative (37%). Screening for polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes using degenerate PCR led to the identification of 23 polyketide synthases (PKSs) and 5 nonribosomal peptide synthetases (NRPSs) grouped into nine distinct clades based on their reduction capabilities. Some of the identified PKSs genes share high similarities between species and known reference genes, suggesting the possibility of conserved biosynthesis of closely related compounds from different fungi. Fungal extracts were tested for their antimicrobial activity against S. aureus, Methicillin-resistant S. aureus (MRSA), and Candida albicans. Bioassay-guided fractionation of the active constituents from two promising isolates resulted in the isolation of seven compounds: Penilumamides A, D, and E from strain F4335 and xanthomegnin, viomellein, pretrichodermamide C and vioxanthin from strain F7180. Vioxanthin exhibited the best antibacterial activity with IC50 values of 3.0 μM and 1.6 μM against S. aureus and MRSA respectively. Viomellein revealed weak antiproliferative activity against A549 cells with an IC50 of 42 μM. The results from this study give valuable insights into the diversity and biosynthetic potential of fungi from this unique habitat and forms a background for an in-depth analysis of the biosynthetic capability of selected strains of interest with the aim of discovering novel fungal natural products.

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

Bioactive pulvinones from a marine algicolous fungus Aspergillus terreus NTU243

Marine fungi are regarded as an under-explored source of structurally interesting and bioactive natural products with the potential to provide attractive lead compounds for drug discovery. In this study, several fungal strains were isolated from marine algae collected from the northeastern coast of Taiwan. In the preliminary antimicrobial screening against bacteria and fungi, the ethyl acetate extract of the fermented products of Aspergillus terreus NTU243 derived from a green alga Ulva lactuca was found to exhibit significant antimicrobial activities. Therefore, bioassay-guided separations of the active principle from liquid and solid fermented products of A. terreus NTU243 were undertaken, which resulted in the isolation and purification of 16 compounds. Their structures were elucidated by spectroscopic analysis to be four previously undescribed aspulvinones S-V as well as twelve known compounds. All the isolates were assessed for anti-inflammatory activity by measuring the amount of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 cells, and aspulvinone V, butyrolactone I, and (+)-terrein inhibited 45.0%, 34.5%, and 49.2% of NO production, respectively, at 10 μM concentration. Additionally, zymography showed that the conditioned medium of THP-1 cells post-LPS challenged significantly enhanced matrix metalloproteinase (MMP)-9-mediated gelatinolysis, and pretreatment with aspulvinones U and V significantly attenuated MMP-9-mediated gelatinolysis by 56.0% and 67.8%, separately.

New Tripeptide Derivatives Asperripeptides A-C from Vietnamese Mangrove-Derived Fungus Aspergillus terreus LM.5.2

Three new tripeptide derivatives asterripeptides A-C (1-3) were isolated from Vietnamese mangrove-derived fungus Aspergillus terreus LM.5.2. Structures of isolated compounds were determined by a combination of NMR and ESIMS techniques. The absolute configurations of all stereocenters were determined using the Murfey's method. The isolated compounds 1-3 contain a rare fungi cinnamic acid residue. The cytotoxicity of isolated compounds against several cancer cell lines and inhibition ability of sortase A from Staphylococcus aureus of asterripeptides A-C were investigated.

Three new indole diterpenoids from Aspergillus aculeatus KKU-CT2

Three new indole diterpenoids, aculeatupenes A-C (1-3), together with four known compounds (4-7), were isolated from the mycelium of Aspergillus aculeatus KKU-CT2. Their structures were established by spectroscopic evidence and absolute configurations of 1-3 were determined by comparison of their experimental and calculated ECD spectra. Compounds 1, 2, and emindole SB (4) showed weak cytotoxicity against HelaS3, KB, HepG2, MCF-7, and A549 cancer cell lines with IC₅₀ values in the range of 11.12-67.81 μM. Compound 3 showed weak cytotoxicity against HelaS3 cell lines with an IC₅₀ value of 17.48 μM but non-cytotoxicity against Vero cell line. In addition, compound 1 exhibited weak antibacterial activity against Bacillus cereus.

Isolation, chemistry, and biology of pyrrolo[1,4]benzodiazepine natural products

The isolation of the antitumor antibiotic anthramycin in the 1960s prompted extensive research into pyrrolo[1,4]benzodiazepines (PBD) as potential therapeutics for the treatment of cancers. Since then, nearly 60 PBD natural products have been isolated and evaluated with regard to their biological activity. Synthetic studies and total syntheses have enabled access to PBD analogues, culminating in the development of highly potent anticancer agents. This review provides a summary of the occurrence and biological activity of PBD natural products and covers the strategies employed for their total syntheses.

Bioactive secondary metabolites from the deep-sea derived fungus Aspergillus sp. SCSIO 41029

Two new compounds classified as one new lumazine peptide, penilumamide K (1) and one new sesquiterpene (2), were obtained from the deep-sea derived fungus Aspergillus sp. SCSIO 41029, together with eleven known compounds (3-13). The structures of 1-13 including absolute configurations were determined by detailed NMR spectroscopy, HR-ESI-MS, chemical derivatization, and optical rotation data. Among them, compound 1 represents the first lumazine peptide reported from deep-sea derived fungus. The bioactive assay exhibited that compounds 1, 3, 4, 5, 7 and 10 had significant potency against α-glucosidase with IC₅₀ values ranging from 18.61 to 109.06 μΜ. In addition, compounds 4 and 9 showed strong antibacterial activity against Staphylococcus aureus with MIC values of 0.78 and 6.25 μg ml^-1, respectively.

Antibacterial and NF-κB Inhibitory Lumazine Peptides, Aspochalasin, γ-Butyrolactone Derivatives, and Cyclic Peptides from a Hawaiian Aspergillus flavipes

Five new lumazine peptides (1-5), a new aspochalasin derivative (6), and a new γ-butyrolactone derivative (7), together with seven known compounds (8-14), were isolated from a Hawaiian fungal strain, Aspergillus flavipes FS888. Compound 1 is an uncommon natural product containing an isocyano group. The structures of the new compounds 1-7 were elucidated by NMR spectroscopy, HRESIMS, chemical derivatization, and ECD analysis. Compounds 12-14 showed significant antibacterial activity against S. aureus when in combination with disulfiram. Additionally, compounds 9 and 13 showed NF-κB inhibitory activity with IC50 values of 3.1 ± 1.0 and 10.3 ± 2.0 μM, respectively.

Naturally Occurring Lumazines

Natural products containing a lumazine motif were first isolated from natural sources in 1940. These natural products are relatively rare, with fewer than 100 lumazines known to occur in Nature. This review discusses the isolation of lumazines, their biological activity, and their biosynthesis, where known.

Butyrolactone-I from Coral-Derived Fungus Aspergillus terreus Attenuates Neuro-Inflammatory Response via Suppression of NF-κB Pathway in BV-2 Cells

Butyrolactone-I (ZB5-1) from the coral-derived fungus Aspergillus terreus was investigated in this study to estimate its anti-neuroinflammatory effects on lipopolysaccharide (LPS)-induced BV-2 microglia cells. MTT assay indicated that ZB5-1 in tested concentrations had no cytotoxicity on BV-2 cells, and significantly reduced the production of nitric oxide (NO), measured using Griess reagent, and interleukin-1 beta (IL-1β), detected by enzyme-linked immunosorbent assay (ELISA). ZB5-1 also down-regulated the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner by Western blot analysis. Moreover, the effect of ZB5-1 on the nuclear factor-κB (NF-κB) signaling pathway was studied via the expression of phosphorylation of NF-κB p65 and inhibitor of NF-κB (IκB), and the nuclear translocation of NF-κB p65 respectively. The results showed that ZB5-1 could inhibit the phosphorylation of p65 and IκB. Furthermore, molecular docking study suggested that ZB5-1 bound at the active sites of NF-κB to prevent its translocation to the nucleus. Therefore, we suggest ZB5-1 has a potential to reduce the anti-inflammatory response in LPS-induced BV-2 cells.

Cytotoxic isocoumarin derivatives from the mangrove endophytic fungus Aspergillus sp. HN15-5D

Five isocoumarin derivatives including three new compounds, aspergisocoumrins A-C (1-3), together with two known analogues, 8-dihydroxyisocoumarin-3-carboxylic acid (4) and dichlorodiaportin (5) were obtained from the culture of the endophytic fungus Aspergillus sp. HN15-5D derived from the fresh leaves of the mangrove plant Acanthus ilicifolius. Their structures were elucidated using comprehensive spectroscopic methods. The double bond geometry of compounds 1 and 2 were assigned as E and Z on the basis of the distinct coupling constants, respectively. Compounds 1 and 2 showed cytotoxicity against MDA-MB-435 with IC₅₀ values of 5.08 ± 0.88 and 4.98 ± 0.74 μM, respectively.

Terretonin M: A new meroterpenoid from the thermophilic Aspergillus terreus TM8 and revision of the absolute configuration of penisimplicins

Terretonin M (1), a new highly oxygenated tetracyclic meroterpenoid, was isolated from the thermophilic fungus Aspergillus terreus TM8 together with 10 known metabolites: terrelumamide A, asterrelenin, 7-prenyl-indolyl-3-carbaldehyde, (3β,5α,6β)-3,5,6-trihydroxy-ergosta-7,22-diene, sitostenone, linoleic acid, ergosterol, uracil, p-hydroxy-benzoic acid, and indole-3-carboxylic acid. The chemical structure of the new compound was elucidated by extensive 1D, 2D NMR, and ESI HR mass measurements, and by comparison with literature data. The absolute configuration of 1 was resolved by analysis of its NOESY spectrum and comparison of its experimental ECD spectrum with DFT calculations. In parallel to this work, revision of the absolute configuration of penisimplicins 3a and 3b is proposed on the basis of their ECD and ORD data. The isolation and taxonomic characterisation of A. terreus TM8 is reported, and the antimicrobial activity of the crude extract and the isolated compounds was studied as well.

Isolation and structure determination of a new diketopiperazine dimer from marine-derived fungus Aspergillus sp. SF-5280

A new diketopiperazine dimer designated as SF5280-415 (1) was isolated from an EtOAc extract of the marine-derived fungus Aspergillus sp. SF-5280 by various chromatographic methods. The structure of 1 was mainly determined by analysis of the NMR spectroscopic data and MS data, along with Marfey's method. This compound is a new diastereoisomer of known bispyrrolidinoindoline diketopiperazine alkaloid WIN 64745, which possesses unique architecture biosynthetically derived from an indole oxidation reaction of tryptophan.

Isolation and structure elucidation of a new compound from the fungus Aspergillus flavipes PJ03-11

A new diphenyl ether 3-methylpentyl-2, 4-dichloroasterrate (2), along with a known diphenyl ether butyl 2, 4-dichloroasterrate (1) were isolated from the metabolites of a wetland fungus Aspergillus flavipes. PJ03-11. The structures of 1 and 2 were determined by extensive NMR and HR-ESI-MS experiments. Compounds 1 and 2 showed weak cytotoxic activity, but both of them showed no antimicrobial activity.