Lipid-Lowering Polyketides from the Fungus Penicillium Steckii HDN13-279

Endophytic fungus Penicillium steckii DF33 promoted tanshinones biosynthesis in Salvia miltiorrhiza by regulating the expression of CYP450 genes

Salvia miltiorrhiza, a prominent traditional Chinese medicinal resource, has been extensively employed in the management of cardiovascular and cerebrovascular ailments. Ensuring the consistency of S. miltiorrhiza raw materials revolves around the imperative task of maintaining stable tanshinones content and composition. An effective approach in this regard involves the utilization of endophytic fungi as inducers. Within this context, our study spotlights an endophytic fungus, Penicillium steckii DF33, isolated from the roots of S. miltiorrhiza. Remarkably, this fungus has demonstrated a significant capacity to boost the biosynthesis and accumulation of tanshinones. The primary objective of this investigation is to elucidate the underlying regulatory mechanism by which DF33 enhances and regulates the biosynthesis and accumulation of tanshinones. This is achieved through its influence on the differential expression of crucial CYP450 genes within the S. miltiorrhiza hairy roots system. The results revealed that the DF33 elicitor not only promotes the growth of hairy roots but also enhances the accumulation of tanshinones. Notably, the content of cryptotanshinone was reached 1.6452 ± 0.0925 mg g-1, a fourfold increase compared to the control group. Our qRT-PCR results further demonstrate that the DF33 elicitor significantly up-regulates the expression of most key enzyme genes (GGPPS, CPS1, KSL1, CYP76AH1, CYP76AH3, CYP76AK1, CYP71D411) involved in the tanshinone biosynthesis pathway. This effect is particularly pronounced in certain critical CYP450 genes and Tanshinone ⅡA synthase (SmTⅡAS), with their expression levels peaking at 7 days or 14 days, respectively. In summary, endophytic P. steckii DF33 primarily enhances tanshinone biosynthesis by elevating the expression levels of pivotal enzyme genes associated with the modification and transformation stages within the tanshinone biosynthesis pathway. These findings underscore the potential of employing plant probiotics, specifically endophytic and root-associated microbes, to facilitate the biosynthesis and transformation of vital constituents in medicinal plants, and this approach holds promise for enhancing the quality of traditional Chinese medicinal materials.

Identifying Marine-Derived Tanzawaic Acid Derivatives as Novel Inhibitors against Osteoclastogenesis and Osteoporosis via Downregulation of NF-κB and NFATc1 Activation

To discover novel osteoclast-targeting antiosteoporosis leads from natural products, we identified 40 tanzawaic acid derivatives, including 22 new ones (1-8, 14-19, 27-32, 37, and 38), from the South China Sea mangrove-derived fungus Penicillium steckii SCSIO 41025. Penicisteck acid F (2), one of the new derivatives showing the most potent NF-κB inhibitory activity, remarkably inhibited osteoclast generation in vitro. Mechanistically, 2 reduced RANKL-induced IκBα degradation, NF-κB p65 nuclear translocation, the activation and nuclear translocation of NFATc1, and the relevant mRNA expression. NF-κB p65 could be a potential molecular target for 2, which has been further determined by the cellular thermal shift assay, surface plasmon resonance, and the gene knock-down assay. Moreover, 2 could also alleviate osteoporosis in ovariectomized mice by reducing the quantities of osteoclasts. Our finding offered a novel potential inhibitor of osteoclastogenesis and osteoporosis for further development of potent antiosteoporosis agents.

First Total Synthesis of Tanzawaic Acid B

The first total synthesis of (+)-tanzawaic acid B, a natural polyketide bearing a pentadienoic ester and octalin moiety, has been accomplished. The synthetic improvement from previous synthetic conditions facilitated our gram-scale synthesis of the chiral octalin that possesses seven stereogenic centers and that is the core skeleton of almost all of the tanzawaic acid family.

Tanzawaic Acid Derivatives from the Marine-Derived Penicillium steckii as Inhibitors of RANKL-Induced Osteoclastogenesis

Seven new tanzawaic acid derivatives, steckwaic acids E-K (1-7), and one new benzene derivate (8), together with seven known tanzawaic acid analogues (9-16) were isolated from the marine algicolous fungus Penicillium steckii SCSIO 41040. The structures and absolute configurations of these new compounds (1-8) were determined by spectroscopic analyses, X-ray diffraction, and comparison of ECD spectra to calculations. Compounds 2, 10, and 15 inhibited lipopolysaccharide (LPS)-induced nuclear factor kappa-B (NF-κB) with IC₅₀ values of 10.4, 18.6, and 15.2 μM, respectively. Compound 2 could suppress the receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation in bone marrow macrophage cells (BMMCs). To the best of our knowledge, this is the first report of osteoclastogenesis inhibitory activity for tanzawaic acid derivatives.

Citrinin as a potential anti-cancer therapy: A comprehensive review

Citrinin (CIT) is a polyketide-derived mycotoxin, which is produced by many fungal strains belonging to the gerena Monascus, Aspergillus, and Penicillium. It has been postulated that mycotoxins have several toxic mechanisms and are potentially used as antineoplastic agents. Therefore, the present study carried out a systematic review, including articles from 1978 to 2022, by collecting evidence in experimental studies of CIT antiplorifactive activity in cancer. The Data indicate that CIT intervenes in important mediators and cell signaling pathways, including MAPKs, ERK1/2, JNK, Bcl-2, BAX, caspases 3,6,7 and 9, p53, p21, PARP cleavage, MDA, reactive oxygen species (ROS) and antioxidant defenses (SOD, CAT, GST and GPX). These factors demonstrate the potential antitumor drug CIT in inducing cell death, reducing DNA repair capacity and inducing cytotoxic and genotoxic effects in cancer cells.

Identification of the polyketide synthase gene responsible for the synthesis of tanzawaic acids in Penicillium steckii IBWF104-06

Microorganisms have been used as biological control agents (BCAs) in agriculture for a long time, but their importance has increased dramatically over the last few years. The Penicillium steckii IBWF104-06 strain has presented strong BCA activity in greenhouse experiments performed against phytopathogenic fungi and oomycetes. P. steckii strains generally produce different antifungal tanzawaic acids; interesting compounds known to be catalyzed by polyketide synthetases in other fungi. Since the decalin structure is characteristic for tanzawaic acids, two polyketide synthase genes (PsPKS1 and PsPKS2) were selected for further analysis, which have similarity in sequence and gene cluster structure with genes that are known to be responsible for the biosynthesis of decalin-containing compounds. Subsequently, gene-inactivation mutants of both PsPKS1 and PsPKS2 have been generated. It was found, that the ΔPspks1 mutant cannot produce tanzawaic acids any more, whereas reintegration of the original PsPKS1 gene into the genome of ΔPspks1 reestablished tanzawaic acid production. The mutant ΔPspks2 is not altered in tanzawaic acids production. Interestingly, both mutants ΔPsPKS1 and ΔPsPKS2 still display strong BCA activity, indicating that the mechanism of action is not related to the production of tanzawaic acids.

Uncommon Polyketides from Penicillium steckii AS-324, a Marine Endozoic Fungus Isolated from Deep-Sea Coral in the Magellan Seamount

Four unusual steckwaic acids E–H (1–4), possessing a rarely described acrylic acid unit at C-4 (1–3) or a double bond between C-12 and C-13 (4) are reported for the first time, along with four new analogues (5–8) and two known congeners (9 and 10). They were purified from the organic extract of Penicillium steckii AS-324, an endozoic fungus obtained from a deep-sea coral Acanthogorgiidae sp., which was collected from the Magellan Seamount at a depth of 1458 m. Their structures were determined by the interpretation of NMR and mass spectroscopic data. The relative and absolute configurations were determined by NOESY correlations, X-ray crystallographic analysis, and ECD calculations. All compounds were tested for their antimicrobial activities against human- and aquatic-pathogenic bacteria and plant-related pathogenic fungi.

Tanzawaic Acid Derivatives: Fungal Polyketides from the Deep-Sea Coral-Derived Endozoic Penicillium steckii AS-324

Ten new tanzawaic acids, namely, steckwaic acids A-D (1-4), 11-ketotanzawaic acid D (5), 6,15-dihydroxytanzawaic acid M (6), 15R-methoxytanzawaic acid M (7), 15S-methoxytanzawaic acid M (8), 8-hydroxytanzawaic acid M (9), and 8-hydroxytanzawaic acid B (10), together with four known analogues (11-14), were isolated and identified from the endozoic fungus Penicillium steckii AS-324, which was obtained from a deep-sea Acanthogorgiidae sp. coral that was collected from the Magellan seamount in the Western Pacific Ocean. Structurally, steckwaic acids A-D (1-4) represent the first tanzawaic acid derivatives containing a naphthalene ring. Their structures were elucidated by detailed interpretation of the NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis and ECD calculations confirmed their structures and absolute configurations. New compounds 1, 5, and 9 exhibited activities against aquatic pathogenic bacteria Micrococcus luteus, Vibrio anguillarum, and Pseudomonas aeruginosa with MICs of 2, 4, and 4 μg/mL, respectively.

Tanzawaic Acids from a Deep-Sea Derived Penicillium Species

Twelve new tanzawaic acid derivatives, penitanzacids A-F (1-6), and G-J (9-12), and hatsusamides C-D (13-14), together with two revised structures [tanzawaic acids I-J (7-8)] and three known compounds (15-17) were isolated from the deep-sea-derived fungus Penicillium sp. KWF32. Their structures including absolute configurations were elucidated by spectroscopic data analysis, HRESIMS data, modified Mosher's method, chemical degradation studies, ECD calculations, single crystal X-ray diffraction, and biogenic considerations in comparison with reported known analogues. Penitanzacids H-J (10-12) represent the first examples of this family with a C₃ side chain and support the proposed biosynthetic pathway in which the side chain is connected to the decalin backbone. Hatsusamides C-D (13-14) have a hybrid skeleton formed by linking a tanzawaic acid and a diketopiperazine through an ester bond. Compounds 13 and 14 exhibit weak cytotoxicity against the A549 cell line.

Talarodrides A-F, Nonadrides from the Antarctic Sponge-Derived Fungus Talaromyces sp. HDN1820200

Six new nonadride derivatives, named talarodrides A-F (1-6), were isolated from the Antarctic sponge-derived fungus Talaromyces sp. HDN1820200. All structures including the absolute configurations were deduced by extensive spectroscopic analysis and computational ECD calculations. Compounds 1-4 share a rare caged bicyclo[4.3.1]-deca-1,6-diene with a bridgehead olefin and maleic anhydride core skeleton, while compounds 5 and 6 possess the first case of a naturally occurring 5/7/6 methanocyclonona[c]furan skeleton. Talarodride A (1) and talarodride B (2) showed selective inhibitory effects against Proteus mirabilis and Vibrio parahemolyticus with MICs of 3.13-12.5 μM.

Penicisteckins A-F, Isochroman-Derived Atropisomeric Dimers from Penicillium steckii HNNU-5B18

Penicisteckins A-D (1-4), two pairs of atropodiastereomeric biaryl-type hetero- and homodimeric bis-isochromans with 7,5'- and 7,7'-linkages and a pair of atropodiastereomeric 2-(isochroman-5-yl)-1,4-benzoquinone derivatives [penicisteckins E (5) and F (6)], were isolated from the Penicillium steckii HNNU-5B18. Their structures including the absolute configuration were determined by extensive spectroscopic and single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Both the bis-isochromans and the isochroman/1,4-benzoquinone conjugates represent novel biaryl scaffolds containing both central and axial chirality elements. The monomer anserinone B (8) exhibited potent antibacterial activities against Staphylococcus aureus ATCC 29213 and methicillin-resistant Staphylococcus aureus with minimal inhibition concentration values ranging from 2 to 8 μg mL^-1. Plausible biosynthetic pathways of 1-6 are proposed, which suggest how the absolute configurations of the isolates were established during the biosynthetic scheme.

Secondary metabolites from mangrove-associated fungi: source, chemistry and bioactivities

Covering 1989 to 2020The mangrove forests are a complex ecosystem occurring at tropical and subtropical intertidal estuarine zones and nourish a diverse group of microorganisms including fungi, actinomycetes, bacteria, cyanobacteria, algae, and protozoa. Among the mangrove microbial community, mangrove associated fungi, as the second-largest ecological group of the marine fungi, not only play an essential role in creating and maintaining this biosphere but also represent a rich source of structurally unique and diverse bioactive secondary metabolites, attracting significant attention of organic chemists and pharmacologists. This review summarizes the discovery relating to the source and characteristics of metabolic products isolated from mangrove-associated fungi over the past thirty years (1989-2020). Its emphasis included 1387 new metabolites from 451 papers, focusing on bioactivity and the unique chemical diversity of these natural products.

Amphiepicoccins A-J: Epipolythiodioxopiperazines from the Fish-Gill-Derived Fungus Epicoccum nigrum HDN17-88

Ten new epipolythiodioxopiperazines (ETPs), namely, amphiepicoccins A-J (1-10), were isolated from the fish-gill-derived fungus Epicoccum nigrum HDN17-88. Their structures were deduced from extensive spectroscopic data and electronic circular dichroism (ECD) calculations. Amphiepicoccin A (1) which contains an aromatic indole motif is unprecedented among the epicoccin type of ETPs. Compounds 1, 3, and 6 displayed anti-HSV-2 activities, with IC₅₀ values of 70, 64, and 29 μM, respectively (acyclovir as positive control with an IC₅₀ value of 31 μM), while 5 and 6 also revealed inhibitory activity against Bacillus subtilis with minimum inhibitory concentration (MIC) values of 13 and 25 μM, respectively.

Secondary Metabolites Produced by Combined Culture of Penicillium crustosum and a Xylaria sp

Four new alkyl aromatics, penixylarins A-D (1-4), along with the known biogenetically related 1,3-dihydroxy-5-(12-hydroxyheptadecyl)benzene (5) and 1,3-dihydroxy-5-(12-sulfoxyheptadecyl)benzene (6), were isolated from a mixed culture of the Antarctic deep-sea-derived fungus Penicillium crustosum PRB-2 and the mangrove-derived fungus Xylaria sp. HDN13-249. UPLC-MS data and an analysis of structural features showed that compounds 1 and 2 were produced by collaboration of the two fungi, while compounds 3-6 could be produced by Xylaria sp. HDN13-249 alone, but in noticeably increased quantities by cocultivation. Compounds 2, 3, 5, and 6 showed antibacterial activity against a panel of strains, and compound 3 possessed potential antituberculosis effects (MIC = 6.25 μM against Mycobacterium phlei).

Methylsulfonylated Polyketides Produced by Neosartorya udagawae HDN13-313 via Exogenous Addition of Small Molecules

Two new polyketides modified with a rare methylsulfonyl group, 3-methoxy-6-methyl-5-(methylsulfonyl)benzene-1,2,4-triol (1) and neosartoryone A (2), along with a biogenetically related compound (3), were isolated from Neosartorya udagawae HDN13-313 cultivated with the DNA methyltransferase inhibitor 5-azacytidine. The methylsulfonyl group of 1 and 2 was proven to be derived from DMSO, which was used as the solvent to dissolve 5-azacytidine. This is the first report of a fungus that can achieve a sulfonylation-like modification of natural products utilizing DMSO as a sulfur source. Compound 2 showed lipid-lowering activity in vitro comparable to simvastatin.

Cytotoxic Tetrahydroxanthone Dimers from the Mangrove-Associated Fungus Aspergillus versicolor HDN1009

Three new tetrahydroxanthone dimers, 5-epi-asperdichrome (1), versixanthones N (2), and O (3), were isolated from the mangrove-derived fungus Aspergillus versicolor HDN1009. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and circular dichroism (CD) experiments. Among them, compound 1 was the second example of tetrahydroxanthone dimers, which dimerized by a rare diaryl ether linkage and showed promising antibacterial activities against Vibrio parahemolyticus, Bacillus subtilis, Mycobacterium phlei, and Pseudomonas aeruginosa, with MIC values ranging from 100 μM to 200 μM; whilst compounds 2 and 3 exhibited extensive cytotoxicities against five cancer cell lines (HL-60, K562, H1975, MGC803, and HO-8910), with IC₅₀ values ranging from 1.7 μM to 16.1 μM.

Sorbicillasins A⁻B and Scirpyrone K from a Deep-Sea-Derived Fungus, Phialocephala sp. FL30r

Two new nitrogen-containing sorbicillinoids named sorbicillasins A and B (1 and 2) and a new 3,4,6-trisubstituted α-pyrone derivative, scirpyrone K (3), together with two known biosynthetically related polyketides (4⁻5), were isolated from the deep-sea-derived fungus Phialocephala sp. FL30r by using the OSMAC (one strain-many compounds) method. The structures of 1⁻3, including absolute configurations, were deduced based on MS, NMR, and time-dependent density functional theory (TD-DFT) calculations of specific ECD (electronic circular dichroism) spectra. Compounds 1 and 2 possessed a novel hexahydropyrimido[2,1-a] isoindole moiety, and compound 3 exhibited weak radical scavenging activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) with an IC50 value of 27.9 μM.

Tanzawaic acid derivatives from freshwater sediment-derived fungus Penicillium sp

Chemical investigation of a freshwater sediment-derived fungus, Penicillium sp. (S1a1), led to the isolation of three new tanzawaic acid derivatives, including penitanzchroman (1), tanzawaic acids Y (2) and Z (3), along with six known tanzawaic acid analogues (4-9), three known isochromans (10-12) and two known benzoquinones (13 and 14). The structures of the new compounds were established based on high-resolution mass spectrometry, and detailed analysis of one- and two-dimensional NMR spectroscopy. The relative configuration of the new compounds was assigned on the basis of NMR spectroscopic data including ROESY spectra. The absolute configuration was determined based on the specific optical rotation, in addition to biogenetic considerations in comparison with related co-isolated known metabolites. Penitanzchroman (1) constitutes a hitherto unprecedented skeleton, formed of tanzawaic acid A (5) and (3S)-6-hydroxy-8-methoxy-3,5-dimethylisochroman (10) linked by a CC bond. Moreover, all compounds were evaluated for their antibacterial and cytotoxic activities.