The discovery of novel, targeted cholesterol-lowering agents holds clinical value for cardiovascular disease (CVD) prevention and management. Here, we report the isolation of a naturally occurring polyketide, enterocin, from the marine-derived Streptomyces sp. FXY-T25 using a cholesterol-modulating activity-guided assay. Enterocin, with a unique tricyclic caged core skeleton, enhanced cholesterol efflux in Huh-7 and HepG2 liver cells by directly binding to ASGR1 and promoting its proteasomal degradation without transcriptional alteration. This ASGR1 inhibition triggered AMPKα activation and subsequent LXRα-mediated upregulation of cholesterol efflux. The accelerated degradation of ASGR1 was confirmed to be proteasome-dependent, as evidenced by lysosomal or proteasomal inhibitors. In high-fat-diet (HFD)-fed wild-type mice, enterocin significantly reduced visceral and subcutaneous fat, improved serum lipid profiles (decreasing TC, TG, and LDL-C while elevating HDL-C), attenuated hepatic lipid accumulation, and enhanced fecal cholesterol excretion. Consistent with the in vitro findings, enterocin downregulated hepatic ASGR1 protein levels and subsequently activated the AMPKα-LXRα-ABCA1/G1/G5/G8 pathway in mouse liver. In HFD-fed LDLR-/- mice, enterocin exhibited lipid-lowering activity comparable or superior to that of the positive controls atorvastatin and GW3965. Notably, enterocin demonstrated no significant effect on intestinal fat absorption, highlighting its targeted activity in hepatic cholesterol metabolism. These findings establish enterocin as a novel therapeutic candidate that uniquely modulates cholesterol homeostasis, offering potential for the treatment of both hypercholesterolemia and metabolic dysfunction-associated fatty liver disease.

Three bianthrones, brevianthrones A2, A3, and B2 (1–3), were isolated as pure compounds for the first time. In addition, two known bianthrones (4 and 5) and three known anthraquinones (6–8) were obtained from the endophytic Colletotrichum gloeosporioides D177, obtained from the salt-tolerant plant Astilboides tabularis (Hemsl.) Engl. Furthermore, nine semisynthetic derivatives (9–17) were prepared via esterification and amination. Their structures were determined by detailed analyses of NMR and HRMS data, ECD calculations and 13C NMR calculations. Bianthrones 1–4 exhibited significant cytotoxic activity against the 4T1 cancer cell line, with IC₅₀ values ranging from 1.23 to 2.90 μmol/L. These findings provide preliminary structural insights for the optimization of bianthrone-based bioactive compounds.

Rubromycins constitute a unique group of aromatic polyketides with diverse biological activities. Two novel rubromycin analogs, mutgriseorhodins D1 and D2 (1 and 2) with a new pyrrole-2,5-dione ring, were generated by the heterologous expression of the grhM-deleted grh gene cluster in Streptomyces albus J1074. Their structures were elucidated by the analysis of HRMS, NMR, calculated 13C chemical shifts, and ECD calculations. Compound 2 displayed potent anti-inflammatory effects in LPS-induced BV2 microglial cells by inhibiting the NF-κB pathway and promoting M2 polarization, highlighting its potential as a promising lead compound.

The P2X7R/NLRP3 inflammasome axis plays a critical role in the pathogenesis of ulcerative colitis (UC) and sepsis. We previously demonstrated 12-O-deacetyl-phomoxanthone A (12-ODPXA), a representative xanthone dimer extracted from fungi, exhibit an effective anti-tumor property; however, it is totally unknown whether 12-ODPXA has any effects against UC and sepsis; and if so, whether it exerts anti-inflammatory effects by blocking P2X7R/NLRP3 inflammasome. In the present study, we first observed that 12-ODPXA significantly inhibited pyroptosis and the expression of inflammatory factors in both LPS/ATP-stimulated immortalized bone marrow-derived macrophages (iBMDMs) and peritoneal macrophages (PMs), and attenuated inflammatory response in intestinal epithelial cells (IECs). 12-ODPXA targeted P2X7R and NLRP3 to suppress the activation of NLRP3 inflammasome via P2X7R/Ca2+ and NF-κB signaling pathways. 12-ODPXA also significantly ameliorated UC and sepsis. Moreover, 12-ODPXA dose-dependently induced vasorelaxation of mesenteric arterioles predominantly via EDH mechanism, and rescued the impaired ACh/EDH-mediated vasorelaxation in sepsis. Overall, this study highlights the efficacy of 12-ODPXA against intestinal and vascular inflammation in mice through inhibition of the P2X7R/NLRP3 inflammasome pathway, identifying 12-ODPXA as a promissing therapeutic candidate for UC and sepsis.

A bioassay-guided chemical investigation of the endophytic fungus Chaetomium nigricolor F5 resulted in the discovery of two novel sesquiterpenes, chamilactones A and B (1 and 2), with a new 9,10-seco-15-nor-isoilludalane carbon skeleton, together with several biosynthetically related precursors (3-8). Their structures and absolute configurations were elucidated by the analysis of MS, NMR, calculated 13C chemical shifts, ECD calculations, and single-crystal X-ray diffraction data. It was proposed that an unprecedented carbon-carbon bond cleavage between C-9 and C-10 in 3-8 was the key step in the biosynthetic pathway of 1 and 2. Compound 3 displayed potent neuroprotective effects by reducing the phosphorylation level of p65 and inhibiting its nuclear translocation in the TLR4-mediated NF-κB signaling pathway in LPS-induced BV2 microglial cells.

Three undescribed 20-membered macrolides, fusarolides A-C (1-3), with relatively rare pyran-macrolide structures and complex chiral centers, were isolated from a marine derived fungal Fusarium verticillioide G102. Their chemical structures and stereoconfigurations were well elaborated. Compound 1 promoted cholesterol efflux from Huh-7 cells in a concentration-dependent manner by inhibiting Asialoglycoprotein receptor 1 (ASGR1), which was identified as a new therapeutic target in hypercholesterolemia in liver. Besides, compounds 1-3 exhibited obvious anti-phytopathogenic fungal activities.

Covering: up to December 2024Microbial metabolic pathways, including those of endophytic fungi, offer significant potential for synthesizing secondary metabolites, regardless of their ecological niche. These pathways can be modulated at the molecular level through genome and epigenome manipulation. The metabolic activation of fungal endophytes using epigenetics presents an exciting frontier in science, paving the way for advanced biotechnological applications and enhancing our understanding of these microorganisms' roles in ecosystems. This review examines the significant role of epigenetics in the biosynthesis of secondary metabolites from fungal endophytes, which is vital for drug discovery. Our primary focus centers on studies that explore the epigenetic modulation of endophytic fungi up until December 2024. Acknowledging the rapidly evolving landscape of epigenetic research in this field, which has limited examples for endophytic fungi, we provide crucial foundational insights into fungal epigenetics and relate these insights to the broader context of plant-microbe interactions and endophytic fungal epigenetics, supported by relevant examples. Key mechanisms, such as histone acetylation, histone methylation, and DNA methylation, are discussed alongside recent advances in small-molecule epigenetic modulators that can activate silent biosynthetic gene clusters (BGCs). Further, chromatin-dependent regulation of these BGCs and methods for probing chromatin modifications and secondary metabolism in fungi are discussed. The role of CRISPR-Cas9 genome editing, combined with epigenetic strategies, is highlighted, showcasing its ability to alter the metabolite profiles of fungal endophytes. Finally, we explore how artificial intelligence (AI), machine learning (ML), and deep learning (DL) innovations are transforming research in chemical epigenomics at the plant-microbe interface.

Gibberellin A3 (GA3, 1), a well-known member of the ent-kaurene tetracyclic diterpenoid family, exhibits diverse bioactivities. It serves as a lead compound in medicinal chemistry. In this study, inspired by the chemical structure of anticancer vorinostat and the bioactive α,β-unsaturated ketone unit in gibberellins, five new GA3-based derivatives (2-6) were designed and synthesised. Their antiproliferative activity against five cancer cells was evaluated. Compound 4 and 5 with a ketone group at C-3 exhibited selective cytotoxicity against human renal carcinoma 786-O cells. Specifically, compound 4 displayed the most potent antiproliferative effect on 786-O cells with an IC50 value of 12.93 μM.

Multitude of natural products have the ability to demonstrate inhibitory effects on cancer cells by regulating ion channels/transporters functions. Eighteen xanthone dimers (Xds), including five new dimers diaporxanthones H, I, J-L (1, 2, and 12-14), were isolated and characterized through co-culture and chemical conversion methods. ECD Cotton effect analyses and chemical communication method provided fundamental role in addressing the challenges of elucidating their absolute configurations. Structure-activity relationship (SAR) analysis showed that eight xanthone-xanthone Xds (2-7, 15 and 16) demonstrated marked cytotoxic effects against gastric cancer (GC) cell line AGS, with undetectable inhibition on human colon cancer cells. The anti-proliferative potency of Xds was 2-5 fold higher than positive control drug cisplatin. Mechanistic studies were conducted on a high-yield compound, 12-O-deacetyl-phomoxanthone A (4). Compound 4 activated Na+/Ca2+ exchanger 1 (NCX1), thereby causing an increase in cellular Ca2+ signaling and subsequent inhibition of the downstream PI3K/AKT/β-catenin pathway, ultimately leading to GC cell death. Like anti-GC, Xds also possessed anti-melanoma activity in vitro and in vivo. We demonstrate Xds have effective cytotoxic actions against GC and melanoma by targeting NCX1/Ca2+ signaling in cancer cells.

Three isocoumarins, ascoisocoumarin A (1), embeurekol (2), and sclerotinin A (3), and five biosynthetically related derivatives, ascospinols A-C (4, 6, and 7), and talaflavuols C and B (5 and 8), together with twelve polyketides or terpenes (9-20) were isolated from the fungus Aspergillus sp. LY-1-2 inhabited in a sample of Cordyceps sp. Most of them belong to the family of oxygen-containing aromatic compounds and compounds 1, 4, 6, and 7 are previously undescribed compounds. Their planar structures were established by a combined spectroscopic analysis of HRESIMS and NMR, and their stereochemistry was determined by 13C NMR calculations with sorted training set (STS) protocol analysis, and ECD calculations. New compounds 1 and 6 displayed potential anti-inflammatory effects in lipopolysaccharide (LPS)-induced BV2 microglia cells.

Four new monomeric sorbicillinoids, trichillinoids A - D (1-4), along with two known dimeric sorbicillinoids (5 and 6), and five known monomeric sorbicillinoids (7-11), were obtained from the marine-fish-derived fungus Trichoderma sp. G13. They were structurally characterized on the basis of comprehensive spectroscopic investigations (NMR, HRESIMS, and ECD). Compounds 1-4 displayed moderate anti-inflammatory activities, according to inhibiting the production of NO in RAW264.7 cells activated with IC50 values ranging from 14 to 20

One novel polyketide, fusaritide A (1), was isolated from a marine fish-derived halotolerant fungal strain Fusarium verticillioide G102. The structure was determined through extensive spectroscopic analysis and high-resolution electrospray ionization mass spectrometry. Fusaritide A (1) with unprecedented structure reduced cholesterol uptake by inhibiting Niemann-Pick C1-Like 1 (NPC1L1).

Oligomycins are potent antifungal and antitumor agents. Mass spectrometry (MS)- and nuclear magnetic resonance (NMR)-based metabolomic fingerprinting analysis of marine-derived actinomycetes in our in-house library provided an oligomycin-producing strain, Streptomyces sp. FXY-T5. Chemical investigation led to the discovery of five new oligomycins, 24-lumooligomycin B (1), 4-lumooligomycin B (2), 6-lumooligomycin B (3), 40-homooligomycin B (4), and 15-hydroxy-oligomycin B (5), together with seven biosynthetically related known derivatives. Their structures were assigned by MS, NMR, electronic circular dichroism (ECD), and single-crystal X-ray diffraction analyses. The biosynthesis pathway of oligomycins was first proposed based on the analysis of a type I modular polyketide synthase (PKS) system and targeted gene disruption. As expected, the isolated oligomycins showed significant antiagricultural fungal pathogen activity and antiproliferative properties from which the possible structure-activity relationships were first suggested. More importantly, oligomycins induced significant G1-phase cell cycle arrest on cancer cells and significantly attenuated their Cyclin D1 and PCNA expression through a β-catenin signaling pathway.

A new anthraquinone, altermodinacid A (1), and five known derivatives, pachybasic acid (2), emodic acid (3), emodin (4), phomarin (5), and 1,7-dihydroxy-3-methylanthracene-9,10-dione (6), were discovered from a halotolerant fungus Alternaria sp. X112 isolated from a marine fish Gadus macrocephalus. Their structures were determined by analysing MS and NMR data. The cytotoxic effect, antiagricultural pathogens activity, antibacterial activity and quorum sensing inhibitory potential of new compound 1 were evaluated.

Sesquiterpenoids with a cage-like multiring frame are rarely found in nature. Mining of the isopod-derived fungus Aspergillus parasiticus SDU001 by the one strain-many compounds (OSMAC) strategy unexpectedly led to the discovery of fungal drimane-type sesquiterpenoids astellolide R (1), featuring an unusual cage-like 6/6/5/6/5 pentacyclic ring system, astellolide S (2), possessing a rare nicotinic acid building block, and astellolides T-W (3-6). Their structures were comprehensively assigned by spectroscopic data analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Furthermore, compounds 3 and 5 exhibited anti-inflammatory activity by inhibiting the lipopolyssacharide-induced NO production in RAW264.7 macrophages with IC50 values of 6.1 ± 0.8 and 6.8 ± 0.8 μM, respectively. A putative biosynthetic pathway for 1 is proposed. Our results enlarge the chemical space of the drimane-type sesquiterpenoids generated from endophytic fungi.

In our process of studying fusidane-type antibiotics, metabolomics-guided chemical investigation on the endophytic Acremonium pilosum F47 led to the isolation of two unique heterodimers, acremonidiols B and C (1 and 2) consisting of a fusidane-type triterpenoid motif and a steroid unit. Four biosynthetically related known natural products including fusidic acid (FA, 3), as well as ergosterol derivatives (4-6) were also obtained. Their structures were determined by the analyses of ESI-HRMS and NMR data. Compounds 1 and 2, as hybrid molecules comprising the fusidane triterpenoid and steroid, are rare in nature. Compared with the clinically used antibiotic FA (3), new compounds 1 and 2 showed no obvious antibiotic activity, indicating the importance of free C-21 carboxyl group for antibacterial activity.

Eleven new pyridone alkaloids, penicipyridones A-K (1-11), and three new tetramic acids, tolypocladenols D-F (12-14), were isolated from rice media cultures of the marine-derived fungus Penicillium oxalicum QDU1. Their structures, including absolute configurations, were determined by comprehensive analyses of spectroscopic data, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction data. Interestingly, several of the penicipyridones undergo interconversions between hydroxy and methoxy groups at C-4 in acidic MeOH solution. Furthermore, in an acidic aqueous solution, OH-4 could be replaced by diverse substituent groups. Compounds 1, 4, 5, 8, 10, 11, and 14 exhibited moderate inhibitory effects on NO production in the LPS-induced RAW264.7 macrophages, with IC50 values ranging from 9.2 to 19 μM.

Mass spectrometry (MS)-based metabolic profiling of the endophytic fungus Chaetomium nigricolor F5 guided the isolation of five novel cytochalasans, chamisides B-F (1-5), and two known ones, chaetoconvosins C and D (6 and 7). Their structures including stereochemistry were unambiguously determined by MS, nuclear magnetic resonance, and single-crystal X-ray diffraction analyses. Compounds 1-3 share a new 5/6/5/5/7-fused pentacyclic skeleton in cytochalasans and are appropriately proposed to be the key biosynthetic precursors of co-isolated cytochalasans with a 6/6/5/7/5, 6/6/5/5/7, or 6/6/5 ring system. Remarkably, compound 5 with a relatively flexible side chain showed promising inhibition activity against the cholesterol transporter protein Niemann-Pick C1-like 1 (NPC1L1), expanding the function of cytochalasans.

Twelve new and four known alkaloids including five different structural scaffolds were isolated from the sponge Stylissa massa collected in the South China Sea. Compound 1 is the first identified precursor metabolite of the classic 5/7/5 tricyclic skeleton with unesterified guanidine and carboxyl groups, compounds 2–5 and 13–15 belong to the spongiacidin-type pyrrole imidazole alkaloids (PIAs). Z- and E-configurations of the spongiacidin-type PIAs often appeared concomitantly and were distinguished by the chemical shift analysis of 13C NMR spectra. The structures of all twelve new compounds were determined by NMR, MS, and ECD analysis combined with single-crystal data of compounds 1, 5, and 10. In the aldose reductase (ALR2) inhibitory assay, six 5/7/5 tricyclic compounds (2–5, 13–15) displayed significant activities. Compounds 13 and 14, as the representative members of spongiacidin-PIAs, demonstrated their ALR2-targeted activities in SPR experiments with KD values of 12.5 and 6.9 µM, respectively.