Four New Chromones from the Endophytic Fungus Phomopsis asparagi DHS-48 Isolated from the Chinese Mangrove Plant Rhizophora mangle.

Four new chromones, phomochromenones D-G (1-4), along with four known analogues, diaporchromone A (5), diaporchromanone C (6), diaporchromanone D (7), and phomochromenone C (8), were isolated from the culture of Phomopsis asparagi DHS-48 from Chinese mangrove Rhizophora mangle. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configurations of 1 and 4 were assigned on the basis of experimental and calculated electronic circular dichroism (ECD) data, and those of enantiomers 2 and 3 were determined by a modified Mosher's method and basic hydrolysis. To the best of our knowledge, phomochromenones D-F (1-4) possessing a 3-substituted-chroman-4-one skeleton are rarely found in natural sources. Diaporchromone A (5) showed moderate to weak immunosuppressive activity against T and/or B lymphocyte cells with IC50 of 34 µM and 117 µM.

Five new secondary metabolites from the fungus Phomopsis asparagi.

Five new compounds, including a pair of diphenylcyclopentenone enantiomers (±)-phomopsisin A (1), a sesquiterpenoid 15-hydroxylithocarin A (2), a new diketopiperazine alkaloid prenylcyclotryprostatin A (3) and 7-hydroxy-cis-L(-)-3,6-dibenzyl-2,5-dioxopiperazine (6), along with five known compounds were isolated from the fungus Phomopsis asparagi. Their structures were elucidated on the basis of spectroscopic analyses (1D and 2D NMR), theoretical electronic circular dichroism (ECD) calculation, modified Mosher's method, and X-ray crystallography. The racemates of (±)-phomopsisin A showed inhibition on α-glucosidase with IC50 of 30.07 ± 0.75 µM (positive control acarbose, 121 ± 2.7 µM).

Bioactive sesquiterpene derivatives from mangrove endophytic fungus Phomopsis sp. SYSU-QYP-23: Structures and nitric oxide inhibitory activities.

Eight new sesquiterpene derivatives (2, 4-6 and 10-13), along with five known analogues were isolated from the mangrove endophytic fungus Phomopsis sp. SYSU-QYP-23. Their structures of new compounds were established by spectroscopic methods, and the absolute configurations were confirmed by single-crystal X-ray diffraction analysis and comparison of the experimental ECD spectra. The absolute configuration of the side chain in 1 was first defined by modified Mosher's method. Compounds 1-7 showed potent inhibitory activities against nitric oxide (NO) production in lipopolysaccharides (LPS) induced RAW 264.7 cells with IC50 values ranging from 8.6 to 14.5 µM. The molecular docking results implied that the bioactive sesquiterpenes may directly bind with targeting residues in the active cavity of iNOS protein.

Characterization and chemical modification of PLN-1, an exopolysaccharide from Phomopsis liquidambari NJUSTb1.

Phomopsis liquidambari is a classical endophytic fungus with great application potential in ecology and agriculture; however, studies on its exopolysaccharides are lacking. Here, we aimed to evaluate the structure and bioactivity of PLN-1, an exopolysaccharide derived from the P. liquidambari NJUSTb1 strain. The structure was elucidated by chromatography/spectral methods and hydrolyzation. Immunomodulation, moisture absorption, and retention properties were investigated after sulfation and carboxymethylation modification. Results showed that PLN-1 contained a linear repeating unit of →[4)-α-d-Glcp-(1→6)-α-d-Glcp-(1→4)-α-d-Glcp-(1→4)-α-d-Glcp-(1→]n, with a molecular weight of 343 kDa. The degrees of substitution of sulfated polysaccharide (S-PLN-1) and carboxymethylated polysaccharide (C-PLN-1) were 1.228 and 0.903, respectively. S-PLN-1 showed stronger moisture absorption and retention properties than PLN (crude EPS), C-PLN1, and PLN-1. Furthermore, PLN, S-PLN-1, and C-PLN-1 stimulated the proliferation of RAW 264.7 cells with no cytotoxicity. The elucidation of PLN-1 in this study paves the way for future applications.

Epoxyquinophomopsins A and B from endophytic fungus Phomopsis sp. and their activity against tyrosine kinase.

Two new quinone derivatives, epoxyquinophomopsins A (1) and B (2), were purified from the EtOAc extract of endophytic fungus Phomopsis sp isolated from Morus cathayana. The structures of both compounds were determined based on 1D and 2D NMR and mass spectral data, as well as by x-ray diffraction analysis for 1. Compounds 1 and 2 were screened against eight receptor- (RTKs) and eight non-receptor tyrosine kinases (nRTKs). Both compounds showed strong inhibitory properties against Bruton's Tyrosine Kinase (nRTK) with their kinase activity were 19% and 20%, respectively. Only compound 1 that showed strong inhibitory properties against RTKs EGFR and HER-4 with its kinase activity were 16 and 15%, respectively. Thus, both compounds have potential as tyrosine kinase inhibitors.

Carneic Acids from an Endophytic Phomopsis sp. as Dengue Virus Polymerase Inhibitors.

Thirteen carneic acids were isolated from the fungal endophyte Phomopsis sp. SNB-LAP1-7-32. Their structures were identified by mass spectrometry and extensive one- and two-dimensional NMR spectroscopy and through comparison with data reported in the literature. Compounds 1-13 were investigated for their antipolymerase activities against DENV polymerase and Zika NS5. Five of them exhibited significant inhibition of dengue polymerase with IC50 values in the 10 to 20 µM range without cytotoxicity. None inhibited Zika virus NS5 protein.

Carbamoyl-Phosphate Synthase 1 as a Novel Target of Phomoxanthone A, a Bioactive Fungal Metabolite.

Phomoxanthone A, a bioactive xanthone dimer isolated from the endophytic fungus Phomopsis sp., is a mitochondrial toxin weakening cellular respiration and electron transport chain activity by a fast breakup of the mitochondrial assembly. Here, a multi-disciplinary strategy has been developed and applied for identifying phomoxanthone A target(s) to fully address its mechanism of action, based on drug affinity response target stability and targeted limited proteolysis. Both approaches point to the identification of carbamoyl-phosphate synthase 1 as a major phomoxanthone A target in mitochondria cell lysates, giving also detailed insights into the ligand/target interaction sites by molecular docking and assessing an interesting phomoxanthone A stimulating activity on carbamoyl-phosphate synthase 1. Thus, phomoxanthone A can be regarded as an inspiring molecule for the development of new leads in counteracting hyperammonemia states.

Anti-inflammatory activities of alkaloids from the mangrove endophytic fungus Phomopsis sp. SYSUQYP-23.

Five new maleimide derivatives, (+)- and (-)- farinomalein F (1), (+)- and (-)- farinomalein G (2), farinomalein H (3) and one new linearly fused prenylated indole alkaloid phomoamide (8), along with five known compounds 4-7 and 9 were isolated from the mangrove endophytic fungus Phomopsis sp. SYSUQYP-23. Their structures and absolute configurations were determined by HRESIMS, spectroscopic and electronic circular dichroism (ECD) calculations. Bioassay results showed that compounds 3-9 exhibited significant inhibitory activities against nitric oxide (NO) production in lipopolysaccharides (LPS) induced RAW 264.7 cells, with IC50 values ranging from 4.5 to 25 µM. Moreover, the molecular docking study implied the probable binding interaction of compounds 4 and 5 with nitric oxide synthase.

New azaphilones, phomopsones A-C with biological activities from an endophytic fungus Phomopsis sp. CGMCC No.5416.

Three undescribed azaphilones, phomopsones A-C (1-3) and two known azaphilones (4-5) were isolated from the culture of endophytic fungus Phomopsis sp. CGMCC No.5416 from the stems of Achyranthes bidentata. Their structures were determined by spectroscopic analysis (HRESIMS, 1D and 2D NMR), and the absolute configurations were determined by CD spectroscopy. Compounds 2 and 3 showed significant inhibitory activities against HIV-1 with against HIV-1 with IC50 values of 7.6 and 0.5 µmol/L, respectively. Compounds 2 and 3 also displayed moderate cytotoxicity with CC50 values of 3.2-303 µmol/L against A549, MDA-MB-231 and PANC-1 cell lines. Moreover, compound 3 can induce the early apoptosis of PANC-1 cancer cells with the apoptosis rate of 28.54%.

Characterization of Biomolecules with Antibiotic Activity from Endophytic Fungi Phomopsis Species.

Recently, growing interest is devoted to investigation of bioactive secondary metabolites of endophytic fungi. Thus, as an extension to our previous achievements related to antimicrobial potential of endophytic fungi, Phomopsis species isolated from conifer needles was selected as appropriately promising natural source for drug discovery. Its dichloromethane and ethanol extracts considerably inhibited growth of Escherichia coli and Staphylococcus aureus. Moreover, the individual compounds of dichloromethane extract have been separated, collected and purified using semi preparative liquid chromatographic analysis and comprehensively characterized using mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). Based on their antimicrobial activity and unique structural characteristics in comparison with well-established drugs from the same therapeutic category, two dominant compounds (Z)-(Z)-2-acetoxyprop-1-en-1-yl-3-(3-((E)-3,4-dihydroxypent-1-en-1-yl)oxiran-2-yl)acrylate (denoted as 325-3) and (Z)-(Z)-2-acetoxyprop-1-en-1-yl 3-(3-((E)-4-hydroxy-3-oxopent-1-en-1-yl)oxiran-2-yl)acrylate (denoted as 325-5) were recognized as valuable leading structures for future discovery of novel antibiotics.