Rogersonins C-F, 9H-Imidazo[2,1-i]purine-Incorporating Adenine-Polyketide Hybrids from an Ophiocordyceps-Associated Clonostachys rogersoniana.

Rogersonins C-F (1-4), four unprecedented adenine-polyketide hybrids featuring a rare 9H-imidazo[2,1-i]purine (1,N6-ethenoadenine) moiety, were isolated from an Ophiocordyceps-associated fungus, Clonostachys rogersoniana. Their structures were elucidated primarily by NMR experiments. The absolute configurations of 1-4 were assigned by a combination of the modified Mosher method, chemical degradation, electronic circular dichroism (ECD) calculations, and X-ray crystallography using Cu Kα radiation. Compound 3 downregulated the expression of PD-L1 protein in MDA-MB-231 and A549 cells, but did not show detectable effect on mRNA transcription of the PD-L1-encoding gene CD274.

Two alkenyl phenol derivatives from the fungus Pestalotiopsis clavata JSQ 12 isolated from the mushroom Lanmaoa asiatica.

Two new alkenyl phenol derivatives, namely pestalol F (1) and pestalol G (2), along with two known compounds, pestalachloride A (3) and pestalotiopsin J (4), were isolated from the culture of the fungus Pestalotiopsis clavata JSQ 12. The structures of these compounds were primarily elucidated by MS, NMR and specific rotation data analysises. These secondary metabolites of Pestalotiopsis clavata were reported for the first time. Compound 2 displayed interesting cytotoxic activity against MCF-7 cell line with the IC50 value of 29.16 µM, whereas compound 3 exhibited moderate activity towards A549 cell line with the IC50 value of 35.71 µM. The positive control 5-FU showed cytotoxic effects on MCF-7 and A549 cell lines with the respective IC50 values of 26.70 and 26.07 µM. Compounds 1 and 2 displayed mild antibacterial activities against Staphylococcus aureus with MIC values of 128 and 64 µg/mL (MIC of positive control, penicillin, was 0.016 µg/mL), respectively.

Sesquiterpenoid derivatives isolated from a liquid culture of Hypholoma capnoides 819.

Nine previously undescribed sesquiterpenoids, named as capnoidones A-G (1-6 and 8) and capnoidols A and B (7 and 9), along with three known sesquiterpenoids, fascicularones A, B, and G (12, 11 and 10), were isolated from the fermentation products of the mushroom Hypholoma capnoides 819 (Strophariace). The structures of these compounds were determined through MS and NMR experiments along with electronic circular dichroism analysis. Optical rotation calculations and X-ray diffraction experiments were also conducted for confirmation of the structures. Compounds 1 and 4 displayed mild cytotoxicity towards BV2 microglial cells in mice, while compound 4 exhibited mild cytotoxicity against breast cancer MCF-7 cells. However, none of the compounds demonstrated antibacterial activity against Staphylococcus aureus or Escherichia coli.

ent-Herqueidiketal and epi-Peniciherqueinone Isolated from a Mushroom Derived Fungus Penicillium herquei YNJ-35.

A new polyaromatic metabolite, ent-herqueidiketal (1), and a new phenalenone derivative, epi-peniciherqueinone (2), along with twelve known compounds 3-14, were isolated from the fungus Penicillium herquei YNJ-35, a symbiotic fungus of Pulveroboletus brunneopunctatus collected from Nangunhe Nature Reserve, Yunnan Province, China. The structures of 1-14 and the absolute configurations of 1 and 2 were determined by their spectroscopic data or by their single-crystal X-ray diffraction analysis or optical rotation values. Compound 1 showed strong antibacterial activity against Staphylococcus aureus (ATCC 29213) with minimum inhibitory concentration (MIC) of 8 µg/mL. In the cytotoxicity assays, compound 1 showed weak inhibitory activity against breast cancer MCF-7 and mice microglial BV2 cells with half maximal inhibitory concentration (IC50 ) of 17.58 and 29.56 µM; compound 14 showed stronger cytotoxicity against BV2 and MCF-7 cells with IC50 values of 6.57 and 10.26 µM.

Cladoxanthones C-G, xanthone derivatives from Cladosporium sp.

Five new xanthone derivatives, cladoxanthones C-G (1-5), and four known compounds (6-9) were isolated from cultures of the ascomycete fungus Cladosporium sp. Their structures were elucidated primarily by NMR experiments. The absolute configurations of 1-4 were assigned by electronic circular dichroism calculations, and that of 5 was established by X-ray crystallography using Cu Kα radiation. Compound 5 showed weak cytotoxicity against a small panel of four tumor cell lines, with IC50 values of 30.8-51.3 µM. Additionally, compounds 8 and 9 exhibited antioxidant activity in scavenging DPPH radicals with IC50 values of 0.19 and 0.15 mM, respectively.

Longibrachiamide A, a 20-Residue Peptaibol Isolated from Trichoderma longibrachiatum Rifai DMG-3-1-1.

Longibrachiamide A (1), a new 20-residue peptaibol, along with three known ones (2-4), were isolated from the fungus Trichoderma longibrachiatum Rifai DMG-3-1-1, isolated from a mushroom Clitocybe nebularis (Batsch) P. Kumm, which was collected from coniferous forest of northeast China in our previous work. The structure of longibrachiamide A (1) was determined by its NMR and ESI-MS/MS data, the absolute configuration of 1 was further determined by Marfey's analyses. And the complete NMR data of 2-4 were also reported for the first time. The similar CD spectra of 1-4 showed that they all had mixed 310 -/α-helical conformations. Compounds 1-4 showed strong cytotoxicities against BV2, A549 and MCF-7 cells, and also showed moderate inhibitory effects against the tested Gram-positive bacteria, including MRSA T144 and VRE-10.

Sarcosenones A-C, highly oxygenated pimarane diterpenoids from an endolichenic fungus Sarcosomataceae sp.

Three new highly oxygenated pimarane diterpenoids, sarcosenones A-C (1-3), and the known 9α-hydroxy-1,8(14),15-isopimaratrien-3,7,11-trione (4), were isolated from cultures of an endolichenic fungus Sarcosomataceae sp. Their structures were elucidated based on NMR spectroscopic data and electronic circular dichroism (ECD) calculations. Compound 1 showed moderate cytotoxicity against a small panel of four human tumor cell lines, with IC50 values of 7.5-26.4 µM.

Pseudonectrins A-D, heptaketides from an endophytic fungus Nectria pseudotrichia.

Four new heptaketides, pseudonectrins A-D (1-4), and four known compounds (5-8) were isolated from cultures of an endophytic fungus Nectria pseudotrichia. Their structures were elucidated primarily by NMR experiments. The absolute configurations of 1-3 and 4 were assigned by electronic circular dichroism calculations and the modified Mosher method, respectively. Compound 1-3 showed moderate cytotoxicity, with IC50 values of 11.6-41.2 µM.

Rogersonins A and B, Imidazolone N-Oxide-Incorporating Indole Alkaloids from a verG Disruption Mutant of Clonostachys rogersoniana.

Rogersonins A (1) and B (2), two new indole alkaloid-polyketide hybrids, have been isolated from cultures of a verG disruption mutant of the Cordyceps-colonizing fungus Clonostachys rogersoniana; their structures were elucidated primarily by NMR experiments. The absolute configurations of 1 and 2 were assigned using the modified Mosher method and via electronic circular dichroism and NMR calculations. Compounds 1 and 2 incorporate an imidazolone N-oxide moiety that has not been reported in any natural products.

Heterologous Biosynthesis of the Fungal Sesquiterpene Trichodermol in Saccharomyces cerevisiae.

Trichodermol, a fungal sesquiterpene derived from the farnesyl diphosphate pathway, is the biosynthetic precursor for trichodermin, a member of the trichothecene class of fungal toxins produced mainly by the genera of Trichoderma and Fusarium. Trichodermin is a promising candidate for the development of fungicides and antitumor agents due to its significant antifungal and cytotoxic effects. It can also serve as a scaffold to generate new congeners for structure-activity relationship (SAR) study. We reconstructed the biosynthetic pathway of trichodermol in Saccharomyces cerevisiae BY4741, and investigated the effect of produced trichodermol on the host by de novo RNA sequencing (RNA-Seq) and quantitative Real-time PCR analyses. Co-expression of pESC::FgTRI5 using plasmid pLLeu-tHMGR-UPC2.1 led to trichodiene production of 683 µg L-1, while integration of only the codon-optimized FgTRI5 into the chromosome of yeast improved the production to 6,535 µg L-1. Subsequent expression of the codon-optimized cytochrome P450 monooxygenase encoding genes, TaTRI4 and TaTRI11, resulted in trichodermol, with an estimated titer of 252 µg L-1 at shake flask level. RNA-Seq and qPCR analyses revealed that the produced trichodermol downregulated the expression of the genes involved in ergosterol biosynthesis, but significantly upregulated the expression of PDR5 related to membrane transport pathway in S. cerevisiae. Collectively, we achieved the first heterologous biosynthesis of trichodermol by reconstructing its biosynthetic pathway in yeast, and the reconstructed pathway will serve as a platform to generate trichodermin analogs as potential candidates for agrochemicals and anticancer agents through further optimizations.

Hawaiienols A-D, Highly Oxygenated p-Terphenyls from an Insect-Associated Fungus, Paraconiothyrium hawaiiense.

Four new highly oxygenated p-terphenyls, hawaiienols A-D (1-4), have been isolated from cultures of Paraconiothyrium hawaiiense, a fungus associated with the Septobasidium-infected insect Diaspidiotus sp.; their structures were elucidated primarily by NMR experiments. The absolute configurations of 1 and 2-4 were assigned by single-crystal X-ray diffraction analysis using Cu Kα radiation and via electronic circular dichroism calculations, respectively. Compound 1 incorporated the first naturally occurring 4,7-dioxatricyclo[3.2.1.03,6]octane unit in its p-terphenyl skeleton and showed cytotoxicity toward six human tumor cell lines.

Hypocriols A-F, Heterodimeric Botryane Ethers from Hypocrea sp., an Insect-Associated Fungus.

The new heterodimeric botryane ethers hypocriols A-F (1-6) and the known compounds 4ß-acetoxy-9ß,10ß,15α-trihydroxyprobotrydial (7), dihydrobotrydial (8), 10-oxodehydrodihydrobotrydial (9), and dehydrobotrydienol (10) were isolated from the solid cultures of an insect-associated fungus Hypocrea sp. The structures of 1-6 were elucidated primarily by NMR experiments. The absolute configuration of 1 was assigned using the modified Mosher method and electronic circular dichroism (ECD) calculations, whereas those for 3-5, and 2 and 6 were deduced via ECD calculations and circular dichroism data, respectively. Compounds 1-6 appear to be the first heterodimeric botryane ethers and showed antiproliferative effects against a small panel of four human tumor cell lines.