Macrocyclic trichothecenes from Myrothecium verrucaria PA 57 and their cytotoxic activity.

Four novel macrocyclic trichothecenes, termed mytoxins D-G (1-4), along with four known analogs (5-8), were isolated from the ethyl acetate extract of fermented rice inoculated with the fungus Myrothecium verrucaria PA57. Each compound features a tricyclic 12,13-epoxytrichothec-9-ene (EPT) core. Notably, mytoxin G (4) represents the first instance of a macrocyclic trichothecene incorporating a glucosyl unit within the trichothecene structure. The structures of the newly identified compounds were elucidated through comprehensive spectroscopic analysis combined with quantum chemical calculations. All isolated compounds demonstrated cytotoxic activity against the CAL27 and HCT116 cell lines, which are models for human oral squamous cell carcinoma and colorectal cancer, respectively. Specifically, mytoxin D (1) and mytoxin F (3) exhibited pronounced cytotoxic effects against both cancer cell lines, with IC50 values ranging from 3 to 6 nmol·L-1. Moreover, compounds 1 and 3 were found to induce apoptosis in HCT116 cells by activating caspase-3.

Binding uric acid: a pure chemical solution for the treatment of hyperuricemia.

Hyperuricemia, characterized by elevated uric acid levels and subsequent crystal deposition, contributing to conditions such as gout, cardiovascular events, and kidney injury, poses a significant health threat, particularly in developed countries. Current drug options for treatment are limited, with safety concerns, leading to suboptimal therapeutic outcomes in symptomatic hyperuricemia patients and a lack of pharmaceutical interventions for asymptomatic cases. Distinguishing from the previous drug design strategies, we directly target uric acid, the pathological molecule of hyperuricemia, resulting in a pyrimidine derivative capable of increasing the solubility and excretion of uric acid by forming a complex with it. Its prodrug showed an anti-hyperuricemia activity comparable to benzbromarone and a favorable safety profile in vivo. Our finding provides a strategy purely based on organic chemistry to address the largely unmet therapeutic needs on novel anti-hyperuricemia drugs.

Activation of a Silent Gene Cluster from the Endophytic Fungus Talaromyces sp. Unearths Cryptic Azaphilone Metabolites.

Fungal azaphilones have attracted widespread attention due to their significant potential as sources of food pigments and pharmaceuticals. Genome mining and gene cluster activation represent powerful tools and strategies for discovering novel natural products and bioactive molecules. Here, a putative azaphilone biosynthetic gene cluster lut from the endophytic fungus Talaromyces sp. was identified through genome mining. By overexpressing the pathway-specific transcription factor LutB, five new sclerotiorin-type azaphilones (1, 6, 8, and 10-11) together with seven known analogues (2-5, 7, 9, 12) were successfully produced. Compounds 8 and 9 exhibited antibacterial activity against Bacillus subtilis with MIC values of 64 and 16 µg/mL, respectively. Compound 11 showed cytotoxic activity against HCT116 and GES-1 with IC50 values of 10.9 and 4.9 µM, respectively, while 1, 4, 5, and 7-10 showed no obvious cytotoxic activity. Gene inactivation experiments confirmed the role of the lut cluster in the production of compounds 1-12. Subsequent feeding experiments unveiled the novel functional diversity of the dual megasynthase system. Furthermore, a LutC-LutD binary oxidoreductase system was discovered, and in combination with DFT calculations, the basic biosynthetic pathway of the sclerotiorin-type azaphilones was characterized. This study provided a good example for the discovery of new azaphilones and further uncovered the biosynthesis of these compounds.

Challenging Aromaticity: Revealing a Thioesterase Domain in a Fungal Nonreducing Polyketide Synthase Governing the Production of 3-Methylene Isochromanone.

Thioesterase (TE) domain exerts a great influence over the structure of the final product and TE-released nonreduced polyketides (nrPKs) retain aromaticity. 3-Methylene isochromanones are lactones with a unique olefin at C3 that disrupts the aromaticity, whose biosynthetic details are speculative. Our study unveils the complete biosynthesis of ascochin, in which the construction of the 3-methylene isochromanone backbone is achieved by a nonreducing polyketide synthase (nrPKS) alone and two subsequent oxidations are involved. Intriguingly, the TEAscD serves as a gatekeeper to direct the product release toward formation of nonaromatic 3-methylene isochromanone, rather than the typical aromatic product.

A Very Deep Graph Convolutional Network for 13C NMR Chemical Shift Calculations with Density Functional Theory Level Performance for Structure Assignment.

Nuclear magnetic resonance (NMR) chemical shift calculations are powerful tools for structure elucidation and have been extensively employed in both natural product and synthetic chemistry. However, density functional theory (DFT) NMR chemical shift calculations are usually time-consuming, while fast data-driven methods often lack reliability, making it challenging to apply them to computationally intensive tasks with a high requirement on quality. Herein, we have constructed a 54-layer-deep graph convolutional network for 13C NMR chemical shift calculations, which achieved high accuracy with low time-cost and performed competitively with DFT NMR chemical shift calculations on structure assignment benchmarks. Our model utilizes a semiempirical method, GFN2-xTB, and is compatible with a broad variety of organic systems, including those composed of hundreds of atoms or elements ranging from H to Rn. We used this model to resolve the controversial J/K ring junction problem of maitotoxin, which is the largest whole molecule assigned by NMR calculations to date. This model has been developed into user-friendly software, providing a useful tool for routine rapid structure validation and assignation as well as a new approach to elucidate the large structures that were previously unsuitable for NMR calculations.

The ethnopharmacology, phytochemistry and pharmacology of the genus Hericium.

ETHNOPHARMACOLOGICAL RELEVANCE: Mushrooms in the genus Hericium are used as functional food and traditional medicines for a long history in East Asian countries such as China, India, Japan, and Korea. Some species of Hericium are called as monkey head mushroom (Houtougu) in China and Yamabushitake in Japan, which are traditionally considered as rare and precious health promoting food and medicinal materials for the treatment of dyspepsia, insomnia, chronic gastritis, and digestive tract tumors. THE AIM OF THE REVIEW: This review aims to summarize the ethnopharmacology and structural diversity of secondary metabolites from Hericium species, as well as the pharmacological activities of the crude extracts and pure compounds from Hericium species in recent years. MATERIALS AND METHODS: All the information was gathered by searching Scifinder, PubMed, Web of Science, ScienceDirect, Springer, Wiley, ACS, CNKI, Baidu Scholar, Google Scholar databases and other published materials (books and Ph.D. and M. Sc. Dissertations) using the keywords "Hericium", "Traditional uses", "Chemical composition", "Quality control" and "Pharmacological activity" (1971-May 2023). The species name was checked with https://www.mycobank.org/. RESULTS: The traditional uses of Hericium species were summarized, and 230 secondary metabolites from Hericium species were summarized and classified into six classes, mainly focusing on their chemical diversity, biosynthesis, biological activities. The modern pharmacological experiments in vivo or in vitro on their crude and fractionated extracts showed that the chemical components from Hericium species have a broad range of bioactivities, including neuroprotective, antimicrobial, anticancer, α-glucosidase inhibitory, antioxidant, and anti-inflammatory activities. CONCLUSIONS: The secondary metabolites discovered from Hericium species are highly structurally diverse, and they have the potential to be rich resources of bioactive fungal natural products. Moreover, the unveiled bioactivities of their crude extracts and pure compounds are closely related to critical human health concerns, and in-depth studies on the potential lead compounds, mechanism of pharmacological effects and pharmaceutical properties are clearly warranted.

A new abietane diterpenoid from Lycopodium complanatum.

A new abietane diterpenoid, 1ß, 11-epoxyabieta-12-hydroxy-8, 11, 13-triene-7-one (1), along with three known compounds (2-4), was isolated from Lycopodium complanatum. Their structures were confirmed by the analysis of 1D, 2D NMR and HRESIMS data, and comparison with previous spectral data. All compounds were tested for inhibitory activities against A549, HepG2 and MCF-7 tumor cell lines. [Figure: see text].

Liver-cell protective pyridones from the fungi Tolypocladium album dws120.

Five previously undescribed pyridone derivatives, tolypyridones I-M, were identified from the solid rice medium fermented by Tolypocladium album dws120, along with two known compounds tolypyridone A (or trichodin A) and pyridoxatin. Their planar structures and partial relative configurations have been determined by careful interpretation of their spectroscopic data. The full assignment of the relative and absolute configurations of tolypyridones I-M was achieved by gauge-independent atomic orbital 13C NMR calculation, quantitative nuclear Overhauser effects based interatomic distance calculation, and electronic circular dichroism calculation. In addition, we have fully determined the configuration of tolypyridone A by X-ray diffraction analysis. In bioassay, tolypyridones I was able to restore cell viability and inhibit the release of alanine aminotransferase and aspartate aminotransferase for ethanol-induced LO2 cells, suggesting its potential as a liver protective agent.

Elucidation of a Dearomatization Route in the Biosynthesis of Oxysporidinone Involving a TenA-like Cytochrome P450 Enzyme.

Oxidative dearomatization of phenols is an important transformation for synthesis of complex molecules. Oxysporidinone and related 2-pyridones feature a hydroxy-substituted cyclohexanone ring, which has been proposed to form by phenol dearomatization, although the details of the biochemical process are still unknown. In this study, we identified the oxysporidinone biosynthetic gene cluster in Fusarium oxysporum by regulator activation and gene knockout studies. Through in vivo and in vitro studies, we confirmed that the phenol dearomatization process involves two enzymes. OsdM, a TenA-like cytochrome P450 with expected ring-expansion activity, converts the phenol ring and the 4-hydroxy-2-pyridone core into an unexpected fused [6-5-6] ring system. OsdN, on the other hand, catalyzes two successive ene reduction reactions, followed by hydroxylation by OsdM. This new route enriches current knowledge on enzymatic phenol dearomatization and the mechanism of TenA-like P450s.

Design, synthesis and evaluation of nitric oxide releasing derivatives of 2,4-diaminopyrimidine as novel FAK inhibitors for intervention of metastatic triple-negative breast cancer.

To search for novel medicines for intervention of triple-negative breast cancer (TNBC), a series of phenylsulfonyl furoxan-based 2,4-diaminopyrimidine derivatives (8a-t) were designed and synthesized based on blocking FAK-mediated signaling pathways through both kinase-dependent and -independent manners. The most active compound 8f not only significantly inhibited FAK kinase activity (IC50 = 27.44 nM), displayed potent inhibitory effects on the proliferation (IC50 = 0.126 µM), invasion and migration of MDA-MB-231 cells, superior to the most widely studied FAK inhibitor, TAE226, bearing 2,4-diaminopyrimidine, but also released high levels of NO, contributing to blockage of FAK mediated-signaling pathways by upregulating of p53 as well as suppressing the Y397 phosphorylation and its downstream effectors, including p-Akt, MMP-2, and MMP-9 via kinase-independent manner, leading to apoptosis induction and decrease of FAs and SFs in TNBC cells. Importantly, 8f inhibited the lung metastasis of TNBC in vivo. Together, 8f may serve as a promising candidate for the treatment of metastatic TNBC.

Dearomative gem-diprenylation of hydroxynaphthalenes by an engineered fungal prenyltransferase.

Prenylation usually improves structural diversity and bioactivity in natural products. Unlike the discovered enzymatic gem-diprenylation of mono- and tri-cyclic aromatic systems, the enzymatic approach for gem-diprenylation of bi-cyclic hydroxynaphthalenes is new to science. Here we report an enzymatic example for dearomative C4 gem-diprenylation of α-hydroxynaphthalenes, by the F253G mutant of a fungal prenyltransferase CdpC3PT. Experimental evidence suggests a sequential electrophilic substitution mechanism. We also explained the alteration of catalytic properties on CdpC3PT after mutation on F253 by modeling. This study provides a valuable addition to the synthetic toolkit for compound prenylation and it also contributes to the mechanistic study of prenylating enzymes.

Brasesquilignan A-E, Five New Furofurans Lignans from Selaginella braunii Baker.

Five new furofurans lignans, Brasesquilignan A-E (1-5), were isolated from the aqueous ethanol extract of Selaginella braunii Baker. Their structures were elucidated by extensive analysis of NMR and HRESIMS data. Their absolute configurations were determined by CD spectra, enzymatic hydrolysis, and GCMS analysis. Furthermore, all compounds were evaluated for anti-proliferative activities against various human cancer cellsin vitro. Compounds 2 and 3 exhibited weak inhibitorypotency against five human cancer cells.

Two New C21 Steroidal Glycosides from Selaginella Braunii Baker.

Two new C21 steroidal glycosides, brapreguanes A and B (1-2) were isolated from 75 % aqueous ethanol extract of Selaginella braunii Baker. Their structures were established by spectroscopic analyses (1D/2D NMR spectra and HR-ESI-MS). The absolute configurations of sugar were elucidated by enzymatic hydrolysis and GCMS analysis. In addition, all compounds were evaluated for the anti-proliferative activities against various human cancer cells in vitro. Compounds exhibited no inhibition to various human cancer cells.

Discovery of novel chloropyramine-cinnamic acid hybrids as potential FAK inhibitors for intervention of metastatic triple-negative breast cancer.

To search for novel focal adhesion kinase (FAK) inhibitors for intervention of metastatic triple-negative breast cancer (TNBC), a series of hybrids 7a-s from chloropyramine and cinnamic acid analogs were designed, synthesized and biologically evaluated. The most active compound 7d could potently inhibit the proliferation, invasion and migration of TNBC cells in vitro. The docking analysis of 7d was performed to elucidate its possible binding modes to focal adhesion targeting (FAT) domain of FAK scaffold. Further mechanism studies indicated the ability of 7d in disrupting Y925 autophosphorylation of FAK, reducing formation of focal adhesions (FAs) and stress fibers (SFs) as well as inducing apoptosis of TNBC cells. Together, 7d is a novel FAK inhibitor to inhibit the essential nonkinase scaffolding function of FAK via binding FAT domain and may be worth studying further for intervention of TNBC.

Reassignment of the structures of pestalopyrones A-D.

Pestalopyrones A-D are four unusual tricyclic pyrone derivatives with flexible chiral structures, isolated from the endophytic fungus Pestalotiopsis neglecta S3. The full elucidation of their structures was a challenging task, and remained unsolved in the original article. Herein, the relative configurations of pestalopyrones A and pestalopyrones B were unambiguously assigned by detailed analyses on spectroscopic data and GIAO 13C NMR calculation method with sorted training sets (STS). The planar structures of pestalopyrones C and pestalopyrones D were revised by reinterpretation of their reported spectroscopic data, and then their relative configurations were deduced by STS GIAO 13C NMR calculation and NOE analysis. The absolute configurations of all the mentioned compounds were determined by the comparison of their experimental and calculated ECD curves.

Hypoglycemic flavonoids from Selaginella tamariscina (P.Beauv.) Spring.

Six flavonoids, namely, three undescribed biflavonoids, one undescribed 8-aryl flavonoid, and two known compounds, were isolated from Selaginella tamariscina (P.Beauv.) Spring. The structures and absolute configurations of those undescribed compounds were established by NMR spectroscopy data, HRESIMS analyses and electronic circular dichroism (ECD) analyses. In addition, all the isolates were evaluated for their hypoglycemic activity in HepG2 cells. Involvenflavone H, I, and J significantly increased glucose consumption in both normal and insulin-resistant HepG2 cells. Interestingly, these three compounds can effectively upregulate the protein expression of glucokinase (GCK) and adenylate cyclases (ADCYs). These results suggested that involvenflavone H, I, and J (especially involvenflavone J) may have potent hypoglycemic activity, which also provided promising molecular targets for the treatment of diabetes.

Four new prenylflavonol glycosides from the leaves of Cyclocarya paliurus.

Four new prenylflavonol glycosides (1-4) along with two known analogues (5-6) were isolated from the leaves of Cyclocarya paliurus for the first time. The structures of these compounds were characterized by comprehensive analysis of 1 D, 2 D NMR, HRESIMS, UV data and enzymatic hydrolysis. In bioassays, compounds 1-4 were evaluated for inhibitory effects on xanthine oxidase (XOD) and effects on the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS) induced RAW264.7 cells. Moreover, compounds 1 and 2 showed outstanding XOD inhibitions with IC50 values of 18.16 ± 3.91 and 37.65 ± 5.67 µM, and exhibited inhibitions against LPS-induced NO production with IC50 values of 80.50 ± 3.09 and 82.28 ± 2.87 µM.

Strategies for Prevention and Control of Vibriosis in Asian Fish Culture.

It is estimated that vibriosis account for about half of the economic losses in Asian fish culture. Consequently, the prevention and control of vibriosis is one of the priority research topics in the field of Asian fish culture disease. Relevant measures have been proposed to control some Vibrios that pose a threat to Asian fish culture, but there are currently only a few effective vaccines available to combat these Vibrios. The purpose of our review is to sum up the main prevention methods and the latest control strategies of seven Vibrio species that cause great harm to Asian aquaculture, including Vibrio harveyi, Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio mimicus, Vibrio anguillarum, Vibrio alginolyticus and Vibrio cholerae. Strategies such as antibiotics, probiotics, bacteriophages, antimicrobials from plants and other natural sources, as well as vaccines, are compared and discussed here. We expect this review will provide some new views and recommendations for the future better prevention and control of vibriosis in Asian fish culture.

Two new triterpenoid glycosides from leaves of Cyclocarya paliurus.

Two dammarane glycosides (1-2) were isolated from the leaves of Cyclocarya paliurus. The structures of new compounds were established by application of spectroscopic methods, including one-dimensional and two-dimensional NMR, HRESIMS, and chemical hydrolysis. When evaluated against seven human cancer cell lines, the two compounds exhibited selective cytotoxicity to MCF-7 cells.[Formula: see text].

Diaportones A-C: Three New Metabolites From Endophytic Fungus Diaporthe foeniculina BZM-15.

Phytochemical investigation of Diaporthe foeniculina BZM-15 led to one new γ-butyrolactone derivative, diaportone A (1), one cyclopentenone derivative, diaportone B (3), and one monoterpene derivative, diaportone C (5), along with six known compounds (2, 4, and 6-9). Their structures as well as the absolute configurations were characterized by means of NMR, HRESIMS, and ECD spectroscopy and quantum chemistry calculation, respectively. Furthermore, all compounds were evaluated for their cytotoxic activity and antibacterial activity, and compounds 7 and 8 displayed significant antiproliferative effects on three human cancer cell lines (SF-268, MCF-7, and HepG2) with IC50 values ranging from 3.6 to 15.8 µM.