Heptacyclic oligophenalenones from the soil fungus Talaromyces bacillisporus BCC17645

Exploring the Nonenzymatic Origin of Duclauxin-like Natural Products

Chemical-biological efforts to increase the diversity of duclauxin (1)-like molecules for medicinal chemistry purposes unveiled the reactivity of duclauxin (1) toward amines and alcohols. To expand the compound class, a semisynthetic strategy conjugating amines to duclauxin (1) was employed. Insights gained from this approach led to the hypothesis that certain duclauxin-like "natural products" such as talaromycesone B (2), bacillisporin G (3), xenoclauxin (4), bacillisporins F (5/6), bacillisporins J (8/9), bacillisporins I (12/13), and verruculosin A (38) may be isolation artifacts rather than enzymatic products. Further experimentation, involving adsorption of 1 onto silica gel, resulted in the production of 2-6. To gain insights into the conditions that generate such molecules, one-step reactions under mild conditions were set. Outcomes from both experiments confirmed that duclauxin-like molecules are generated via nonenzymatic reactions. This article presents analytical evidence, indicating that these molecules originate from 1, with the epimeric mixture of bacillisporins J (8 and 9) acting as the primary intermediate.

Adpressins A-G: Oligophenalenone Dimers from Talaromyces adpressus

Nine new oligophenalenone dimers, adpressins A-G (1-9), together with nine known compounds (10-18), were isolated from the fungus Talaromyces adpressus. Their chemical structures were determined on the basis of spectroscopic and mass spectral analyses. Their relative and absolute configurations were identified by 1H and 13C NMR calculations followed by DP4+ analyses, electronic circular dichroism (ECD) calculations, and ECD spectra comparison with related compounds. Compound 1 is the first example of a duclauxin derivative featuring an unusual 6/6/6/5/6/6/6 ring system, while compounds 6 and 7 contained a novel pyrrolidine ring. Compounds 5, 9, and 18 exhibited moderate inhibition against LPS-induced B lymphocyte proliferation with IC50 values ranging from 1.6 to 8.6 μM. Additionally, compounds 9 and 18 exhibited moderate inhibition against Con A-induced T lymphocyte proliferation with IC50 values of 9.3 and 2.6 μM, respectively.

Polyketides with potential bioactivities from the mangrove-derived fungus Talaromyces sp. WHUF0362

Metabolites of microorganisms have long been considered as potential sources for drug discovery. In this study, five new depsidone derivatives, talaronins A-E (1-5) and three new xanthone derivatives, talaronins F-H (6-8), together with 16 known compounds (9-24), were isolated from the ethyl acetate extract of the mangrove-derived fungus Talaromyces species WHUF0362. The structures were elucidated by analysis of spectroscopic data and chemical methods including alkaline hydrolysis and Mosher's method. Compounds 1 and 2 each attached a dimethyl acetal group at the aromatic ring. A putative biogenetic relationship of the isolated metabolites was presented and suggested that the depsidones and the xanthones probably had the same biosynthetic precursors such as chrysophanol or rheochrysidin. The antimicrobial activity assay indicated that compounds 5, 9, 10, and 14 showed potent activity against Helicobacter pylori with minimum inhibitory concentration (MIC) values in the range of 2.42-36.04 μmol/L. While secalonic acid D (19) demonstrated significant antimicrobial activity against four strains of H. pylori with MIC values in the range of 0.20 to 1.57 μmol/L. Furthermore, secalonic acid D (19) exhibited cytotoxicity against cancer cell lines Bel-7402 and HCT-116 with IC50 values of 0.15 and 0.19 μmol/L, respectively. The structure-activity relationship of depsidone derivatives revealed that the presence of the lactone ring and the hydroxyl at C-10 was crucial to the antimicrobial activity against H. pylori. The depsidone derivatives are promising leads to inhibit H. pylori and provide an avenue for further development of novel antibiotics.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00170-5.

Glyclauxins A-E: Dimeric Oxaphenalenone Aminoglycosides from an Australian Wasp Nest-Derived Fungus Talaromyces sp. CMB-MW102

Chemical analysis of cultures of a Queensland mud dauber wasp nest-derived fungus, Talaromyces sp. CMB-MW102, yielded the known dimeric oxaphenalenone duclauxin (1) along with a family of new 1-deoxy-d-glucosamine adducts, glyclauxins A-E (2-6). Despite 1D NMR spectra of 2-6 being compromised by broadening of selected resonances, structures inclusive of absolute configuration were assigned on the basis of detailed spectroscopic analysis and biogenetic considerations, as well as biomimetic semisynthesis and chemical interconversion. For example, exposure of duclauxin (1) to synthetic 1-deoxy-d-glucosamine yielded glyclauxin B (3), while on handling and storage, glyclauxins C (4) and D (5) (bearing a 7-OMe moiety) proved chemically labile and underwent quantitative transformation to glyclauxins B (3) and A (2), respectively. These latter observations on chemical reactivity and stability informed a proposed biogenetic relationship linking all known members of the extended duclauxin family. Notwithstanding their potential status as artifacts, the detection of glyclauxins B (3) and A (2) in a fresh CMB-MW102 culture extract confirmed their natural product status.

The Novel Compounds with Biological Activity Derived from Soil Fungi in the Past Decade

The secondary metabolites isolated from soil fungi have received more and more attention, especially new compounds that exhibited good biological activities. In this review, a total of 546 new compounds are included in the relevant literature since 2011. The new compounds are isolated from soil fungi, We divided these compounds into seven categories, including alkaloids, terpenoids, steroids, ketones, phenylpropanoids, quinones, esters, lactones, etc. In addition, the biological activities and structure-activity relationships of these compounds have also been fully discussed. The activities of these compounds are roughly divided into eight categories, including anticancer activity, antimicrobial activity, anti-inflammatory activity, antioxidant activity, antiviral activity, antimalarial activity, immunosuppressive activity and other activities. Since natural products are an important source of new drugs, this review may have a positive guiding effect on drug screening.

Talaverrucin A, Heterodimeric Oxaphenalenone from Antarctica Sponge-Derived Fungus Talaromyces sp. HDN151403, Inhibits Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway is an evolutionarily conserved signaling cascade involved in a broad range of biological roles. Dysregulation of the Wnt/β-catenin pathway is implicated in congenital malformations and various kinds of cancers. We discovered a novel Wnt/β-catenin inhibitor, talaverrucin A (1), featuring an unprecedented 6/6/6/5/5/5/6 fused ring system, from an Antarctica sponge-derived fungus Talaromyces sp. HDN151403. Talaverrucin A exhibits inhibitory activity on the Wnt/β-catenin pathway in both zebrafish embryos in vivo and cultured mammalian cells in vitro, providing a naturally inspired small molecule therapeutic lead to target the Wnt/β-catenin pathway.

New Antibacterial Secondary Metabolites from a Marine-Derived Talaromyces sp. Strain BTBU20213036

New polyketide-derived oligophenalenone dimers, bacillisporins K and L (1 and 2) and xanthoradone dimer rugulosin D (3), together with four known compounds, bacillisporin B (4), macrosporusone D (5), rugulosin A and penicillide (6 and 7), were isolated from the marine-derived fungus Talaromyces sp. BTBU20213036. Their structures were determined by detailed analysis of HRESIMS, 1D and 2D NMR data, and the absolute configurations were determined on the basis of calculated and experimental electronic circular dichroism (ECD). The antibacterial and antifungal activities of these compounds were tested against Gram-positive—Staphylococcus aureus, Gram-negative—Escherichia coli, and fungal strain—Candida albicans. These compounds showed potential inhibitory effects against S. aureus with minimum inhibitory concentrations ranging from 0.195 to 100 µg/mL.

Duclauxin Derivatives From Fungi and Their Biological Activities

Duclauxin is a heptacyclic oligophenalenone dimer consisting of an isocoumarin and a dihydroisocoumarin unit. These two tricyclic moieties are joined by a cyclopentane ring to form a unique hinge or castanets-like structure. Duclauxin is effective against numerous tumor cell lines because it prevents adenosine triphosphate (ATP) synthesis by inhibiting mitochondrial respiration. There are about 36 reported natural duclauxin analogs mainly produced by 9 Penicillium and Talaromyces species (T. duclauxii, T. aculeatus, T. stipitatus, T. bacillisporus, T. verruculosus, T. macrosporus, P. herquei, P. manginii, and Talaromyces sp.). These metabolites exhibit remarkable biological activities, including antitumor, enzyme inhibition, and antimicrobial, showing tremendous potential in agricultural and medical applications. This review highlights the chemical structures and biological activities of fungal duclauxins, together with biosynthesis, absolute configuration, and mode of action for important duclauxins. Furthermore, phylogenetic analysis and correct names of Penicillium and Talaromyces species producing duclauxins are presented in this review.

Talaromyoxaones A and B: Unusual Oxaphenalenone Spirolactones as Phosphatase Inhibitors from the Marine-Derived Fungus Talaromyces purpureogenus SCSIO 41517

(+)- and (-)-talaromyoxaones A and B (1 and 2, respectively), two new oxaphenalenone derivatives with a hemiacetal frame and an unprecedented spirolactone frame of a 2'H,3H,4'H-spiro[isobenzofuran-1,3'-pyran]-3-one unit that show biosynthetic enantiodivergence, and two new oxaphenalenone analogues (±)-11-apopyrenulin (3) and (+)- or (-)-abeopyrenulin (4) were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures were elucidated by spectroscopic analysis, single-crystal X-ray diffraction, and quantum chemical calculations of ECD spectra. Compounds 1 and 2 showed selective inhibitory activity against phosphatases SHP1, SHP2, and MEG2 with IC₅₀ values of 1.3-3.4 μM, and the potential modes of action for 1 were investigated by a preliminary molecular docking study.

New Pyrrolobenzoxazine Sesquiterpenoid Derivatives from the Fungus Talaromyces trachyspermus

Three new pyrrolobenzoxazine sesquiterpenoids, talatrachyoxazines A - C (1:  - 3: ), together with fourteen known compounds (4:  - 17: ), were isolated from the fungus Talaromyces trachyspermus EU23. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of 1:  - 3: were determined by NOESY data and comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 1: showed cytotoxic activity against HelaS3, KB, HT-29, MCF-7, and HepG2 cell lines with IC₅₀ values of 7, 11, 10, 12, and 10 µM, respectively. Compounds 1: and 14: showed weak antibacterial activity against the gram-positive bacteria Bacillus cereus and Bacillus subtilis, while 1:  - 3: and 14: showed weak antibacterial activity against the gram-negative bacterium Pseudomonas aeruginosa. In addition, compound 1: showed weak antibacterial activity against Escherichia coli.

Natural isocoumarins: Structural styles and biological activities, the revelations carry on …

Isocoumarins and dihydroisocoumarins are lactonic phytochemicals plentiful in microbes and higher plants. These are an amazing small scaffolds consecrated with all types of pharmacological applications. Our previous review covered the period 2000-2016, documenting the then known natural products of this class; the current article is a critical account of discovery of known as well as undescribed structural types and pharmacological activities reported in the course of 2016-2020. The classification revealed in our previous review based on the biogenetic origin is further buttressed by discovery of new members of each class and some new structural types hitherto unknown have also been identified. Similarly, the biological activities and SAR conclusions identified were found to be valid as well, nonetheless with new accompaniments. The most recent available literature on the structural diversity and biological activity of these natural products has been included. The information documented in this article are collected from scientific journals, books, electronic search engines and scientific databases.