Endophytic Fungus Phoma Research Articles

A new compound, phomaherbarine A, induces cytolytic reactivation in epstein-barr virus-positive B cell lines

Epstein-Barr virus (EBV), the first virus found to induce cancer in humans, has been frequently detected in various types of B cell lymphomas. During its latent phase, EBV expresses a limited set of proteins crucial for its persistence. Induction of the lytic phase of EBV has shown promise in the treatment of EBV-associated malignancies. The present study assessed the ability of phomaherbarine A, a novel compound derived from the endophytic fungus Phoma herbarum DBE-M1, to stimulate lytic replication of EBV in B95-8 cells. Phomaherbarine A was found to efficiently initiate the expression of both early and late EBV lytic genes in B95-8 cells, with this initiation being further heightened by the addition of phorbol myristate acetate and sodium butyrate. Moreover, phomaherbarine A demonstrated notable cytotoxicity against the EBV-associated B cell lymphoma cell lines B95-8 and Raji. Mechanistically, phomaherbarine A induces apoptosis in these cells through the activation of caspase-3/7. When combined with ganciclovir, phomaherbarine A does not interfere with the reduction of viral replication by ganciclovir and sustains its apoptosis induction. In conclusion, these findings indicate that phomaherbarine A may be a promising candidate for therapeutic intervention in patients with EBV-associated B cell lymphomas.

Fungal polyketides produced by an endophytic fungus Phoma sp. associated with Gastrodia elata

Two novel fungal polyketides, phometides A (1) and B (2), together with four known compounds (3–6), were isolated from the endophytic fungus Phoma sp. YUD17001 obtained from Gastrodia elata Blume. The structures were elucidated based on spectroscopic analyses, X-ray crystal diffraction, and time-dependent density functional theory/electronic circular dichroism (TDDFT/ECD) calculations. Structurally, phometide A (1) represented the first example of C12 polyketide characterized by an unusual tetrahydrobenzofuran-3(2H)-one core with an α,β-unsaturated ketone functionality, while phometide B (2) was an unprecedented molecule containing a 2-pentylcycloheptan-1-one scaffold. In an antimicrobial activity assay, phometide A (1) exhibited significant inhibitory activity against Staphylococcus aureus with MIC value of 4 μg/mL. Phometide B (2) showed moderate antifungal activity against Candida albicans with an MIC value of 16 μg/mL. Furthermore, compounds 1 and 2 were evaluated for their acetylcholinesterase inhibitory and cytotoxic activities.

Draft genome sequence of the endophytic fungus Phoma sp. strain YAFEF320, isolated from Gerbera jamesonii.

Here, we report a draft genome sequence of endophytic fungus Phoma sp. strain YAFEF320, isolated from the roots of Gerbera jamesonii. The genome size of Phoma sp. YAFEF320 was 32,542,820 bp with 52.08% GC content. The genome resource will support future research into potential secondary metabolite diversity of this fungus.

Pyranone Derivatives With Antitumor Activities, From the Endophytic Fungus Phoma sp. YN02-P-3

Two new pyranone derivatives phomapyrone A (2) and phomapyrone B (3), one new coumarin 11S, 13R-(+)-phomacumarin A (1), three known pyranones (4–6), together with three known amide alkaloids fuscoatramides A-C (7–9), as well as 9S, 11R-(+)-ascosalitoxin (10) were isolated from the endophytic fungus Phoma sp. YN02-P-3, which was isolated from the healthy leaf tissue of a Paulownia tree in Yunnan Province, China. Their structures were elucidated using extensive NMR spectroscopic and HRESIMS data and by comparing the information with literature data. In addition, all compounds were tested for their cytotoxicity activity against human tumor cell lines, and the results showed that new compounds 1-3 showed moderate inhibitory activity against the HL-60 cell line with IC50 values of 31.02, 34.62, and 27.90 μM, respectively.

Undescribed diphenyl ethers betaethrins A-I from a desert plant endophytic strain of the fungus Phoma betae A.B. Frank (Didymellaceae)

Ten diphenyl ethers (DPEs), including nine undescribed analogs named betaethrins A-I, were isolated from the desert plant endophytic fungus Phoma betae A.B. Frank (Didymellaceae). Their structures were determined mainly by NMR, HR-ESI-MS spectral and X-ray diffraction experiments. Betaethrins D-I possessed different fatty acid chains connected with the B-ring, which was the first report in all DPEs. The shielding effect of the B-ring on H-6 (A-ring) in methyl barceloneate, betaethrin A and betaethrins D-F (asterric acid analogs) was first observed and analyzed, which could differentiate the 1H-NMR chemical shift values of H-4/H-6 without the assistance of 3-OH. An empirical rule was then suggested: the steric hindrance between the A- and B-rings in asterric acid analogs might prevent these two aromatic rings from rotating freely, which led to the 1H-NMR chemical shift value of H-6 being in the high field zone due to the shielding effect of the B-ring on H-6. Based on the empirical rule, the chemical shift values of the A-ring in methyl barceloneate were revised. The possible biosynthesis of these isolates was postulated. Betaethrin H showed moderate cytotoxicity against MCF-7 and HepG2 cancer cell lines. Betaethrins A-F, H and I displayed strong antioxidant activities. These results further implied that endophytic fungi from unique environments, such as desert plants, with few chemical studies are an important resource of undescribed and bioactive metabolites.

Thiocytochalasins A−D, four sulfur-containing cytochalasans from an endophytic fungus Phoma multirostrata XJ-2-1

Four unprecedented sulfur-containing cytochalasans, thiocytochalasins A−D (1−4), were isolated from an endophytic fungus Phoma multirostrata XJ-2-1. Thiocytochalasins A (1) and B (2) feature a novel 5/6/14/5 tetracyclic scaffold, which are the first examples of cytochalasan containing a thiophene moiety. Thiocytochalasins C (3) and D (4) are epimeric cytochalasan homodimers formed via a thioether bridge. Their structures with absolute configurations were established by detailed analysis of the HRESIMS, NMR, and X-ray crystallography. The plausible biogenetic pathway of 1−4 was postulated. Compounds 3 and 4 exhibited significant cytotoxicity against CT26 cells with IC50 values of 0.85 and 0.76 µmol/L, respectively.

Oblongolides from endophytic fungus Phoma bellidis Neerg. harbored in Tricyrtis maculata (D. Don) J.F.Macbr.

Five previously undescribed oblongolides, namely phomaones A-E, along with four known compounds, were isolated from the endophytic fungus Phoma bellidis Neerg.. Their structures and absolute configurations were determined by extensive experimental spectroscopic methods as well as single crystal X-ray diffractions, ECD calculations and GIAO 13C NMR calculations. Phomaone A represent the first example of oblongolides with glycol directly linked by two C–C bonds, and its biosynthetic pathway were proposed. The cytotoxicity of obtained compounds was evaluated against human cancer cell lines MCF-7, DU145, and SW480. All compounds except phomaone A showed the cytotoxicity against MCF-7 with IC50 value ranging from 12.45 to 49.84 μM.

A new anti-proliferative compound from an endophytic fungus, Phoma sp.

A new oxazole-type compound (1), named macrooxazole E, and three known macrooxazoles A-C (2–4), were isolated from ethyl acetate (EtOAc) extracts of Phoma sp. JS0228 cultures, an endophytic fungus of Morus alba (M. alba). Structures of the isolated compounds were determined using spectroscopic methods, such as 1 D- and 2 D-nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Macrooxazole E (1) differed from macrooxazole C only in the presence of methyl carboxylate instead of free carboxylic acid. Macrooxazole C showed moderate anti-proliferative activities against human breast cancer (MCF-7) and prostate cancer (LNCaP) cell lines with IC50 values of 0.29 mM and 0.36 mM, respectively. This study presents the possibility of the endophytic fungus Phoma sp. JS0228 to produce new bioactive natural compounds.

A New Diphenyl Ether Derivative from a Mangrove Endophytic Fungus Phoma sp. L28

A New Diphenyl Ether Derivative from a Mangrove Endophytic Fungus Phoma sp. L28

Metabolites with anti-inflammatory and α-glucosidase inhibitory activities from the mangrove endophytic fungus Phoma sp. SYSU-SK-7

Four new steroids phomosterols A-B (1–2), phomopenes A-B (3–4) and one known analogue (5) were isolated from the mangrove endophytic fungus Phoma sp. SYSU-SK-7. Their structures and absolute configurations were determined via NMR data, single-crystal X-ray diffraction analysis, and ECD calculations. Compounds 1–2 contain an unusual aromatic B ring skeleton in sterols, and compound 1 represent the first crystal structure described. Compounds 1, 2 and 5 showed inhibitory activities against nitric oxide (NO) production in lipopolysaccharides (LPS) induced RAW 264.7 cells with IC50 values of 13.5, 25.0 and 12.5 μM, respectively. Then, the affinities between new bioactive compounds (1 and 2) with nitric oxide synthase (iNOS) were researched by molecular docking studies.

Cytochalasins from an endophytic fungus Phoma multirostrata XJ-2-1 with cell cycle arrest and TRAIL-resistance-overcoming activities

Nine new (1–9) and four known (10–13) [13]cytochalasins, along with three known 24-oxa[14]cytochalasins (14–16), were isolated from the culture of Phoma multirostrata XJ-2-1, an endophytic fungus obtained from the fibrous root of Parasenecio albus. Their structures were elucidated by interpretation of the nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS). The absolute configurations were assigned by single-crystal X-ray crystallography, modified Mosher′s method, and by analysis of their experimental electronic circular dichroism (ECD) spectra. Compound 6 could induce cell cycle arrest at G2-phase in CT26 and A549 cells, and displayed moderate cytotoxicity against CT26 and A549 cell lines with IC50 values of 6.03 and 5.04 μM, respectively. Co-treatment of 7–9, 13 and 16 with tumor necrosis factor related apoptosis inducing ligand (TRAIL) could significantly decrease the cell viability of A549, which revealed that cytochalasins could possibly be a new group of TRAIL sensitizers in lung cancer therapy.

Ergocytochalasin A, a polycyclic merocytochalasan from an endophytic fungus Phoma multirostrata XJ-2-1.

Ergocytochalasin A (1), an unprecedented merocytochalasan formed via Diels-Alder cycloaddition of a cytochalasin with an ergosterol, was isolated from an endophytic fungus Phoma multirostrata XJ-2-1. Compound 1 possessed a unique 5/6/14/6/5/6/6/6 fused octacyclic ring system and its structure was established by detailed NMR and HRESIMS spectroscopic analyses. The absolute configuration of 1 was determined by single-crystal X-ray diffraction. A plausible biogenetic pathway of 1 was postulated. Compound 1 was evaluated for its cytotoxicity against six cancer cell lines and showed inhibitory effects with IC50 values ranging from 6.92 to 26.63 μM. The in vitro immunosuppressive activity of 1 against ConA-induced T cell and LPS-induced B cell proliferation, as well as its antiviral activity against Human dengue virus type 3 (DV3), influenza A virus (H1N1) and respiratory syncytial virus (RSV), was also evaluated. Ergocytochalasin A is the first example of a merocytochalasan which consists of one cytochalasin moiety and one ergosterol moiety. Containing eighteen chiral centers, ergocytochalasin A owns a folded framework, which makes it extremely compact in space.

Phomretones A-F, C12 polyketides from the co-cultivation of Phoma sp. YUD17001 and Armillaria sp.

Six new C12 polyketides, phomretones A–F (1–6), were isolated from the co-culture of Armillaria sp. and the endophytic fungus Phoma sp. YUD17001 associated with Gastrodia elata. Neither fungus produced these compounds when cultured alone. The structures of 1–6 were established on the basis of comprehensive spectroscopic analyses, while their absolute configurations were determined by the comparsion of experimental and calculated ECD spectra. Compounds 2–4 are diastereoisomers of each other and featured high levels of stereoisomerization and oxidation.

Bioactive polyketides from the mangrove endophytic fungi Phoma sp. SYSU-SK-7

Five new polyketides, colletotric B (2), 3-hydroxy-5-methoxy-2,4,6-trimethylbenzoic acid (3), colletotric C (4), chaetochromone D (6) and 8-hydroxy-pregaliellalactone B (9), together with four known analogues (1, 5 and 7–8) were isolated from the mangrove endophytic fungus Phoma sp. SYSU-SK-7. Their structures were elucidated by analysis of extensive spectroscopic data and mass spectrometric data. Compounds 1–2 showed strong antimicrobial activity against the P. aeruginosa, MRSA and C. albicans with the MIC values in the range of 1.67–6.28 μg/ml. Furthermore, Compounds 1–5 also exhibited significant α-glucosidase inhibitory activity with the IC50 values in the range of 36.2–90.6 μM. Compound 7 was found to inhibited radical scavenging activity against DPPH with the EC50 value of 11.8 μM.

Inducing Secondary Metabolite Production by Co-culture of the Endophytic Fungus Phoma sp. and the Symbiotic Fungus Armillaria sp.

Co-culturing the endophytic fungus Phoma sp. YUD17001 from Gastrodia elata with Armillaria sp. in liquid nutrient medium resulted in the production of five new secondary metabolites, including two phenolic compounds, phexandiols A and B (1 and 2), three aliphatic ester derivatives, phomesters A-C (3-5), and a known fatty acid (6). The structures and absolute configurations of these compounds were elucidated by the interpretation of data from detailed spectroscopic analysis, Mosher's method, and electronic circular dichroism spectra, together with consideration of the biogenetic origins. None of the five new compounds were detected in single-strain cultures under identical fermentation conditions. The results of this work indicated that the production of 1-5 involved a complicated interaction process. None of the new compounds possessed significant cytotoxicity or antimicrobial activities.

Isolation, structural modification of macrophin from endophytic fungus Phoma macrostoma and their cytotoxic potential

Four known metabolites, macrophin (1), rosellisin (2), 2-(2-hydroxy-5-6-methoxy-3-methylene-1,4-benzodioxin-2(3H)-one (3), and methoxyphenoxyacrylic acid (4) were isolated, for the first time, from an endophytic fungus, Phoma macrostoma inhabiting the inner tissue of medicinal plant Glycyrrhiza glabra Linn. Their structures were characterized by comparison of their NMR data with literature data, and X-ray diffraction data of macrophin (1) as described herein for the first time. The compounds (1–4) were evaluated for their growth-inhibitory activities against a panel of cancer cell lines. Of these substances, macrophin (1) showed prominent cytotoxic activity against the MDA-MB-231, T47D, MCF-7, and MIAPaCa-2 cancer-cell lines with IC50 values of 14.8, 8.12, 13.0, and 0.9 μM, respectively. This biological significance has prompted us to generate a series of five acylated analogs (1a–1e) of 1 to conduct structure–activity relationship (SAR) study. The result illustrates all the analogues (1a–1e) were more potent than 1 against MDMB-231 and MIAPaCa-2 cancer cell lines. The compound 1d, an n-butanoyl substituent, has been proven to be three-fold more potent than 1 with IC50 values of 0.3 and 3.7 µM against MIAPaCa-2 and MDMB-231 cell lines, respectively.

Bioactive secondary metabolites from an endophytic fungus Phoma sp. PF2 derived from Artemisia princeps Pamp.

Two new isochromanone derivatives, (3S,4S)-3,8-dihydroxy-6-methoxy-3,4,5-trimethylisochroman-1-one (1) and methyl (S)-8-hydroxy-6-methoxy-5-methyl-4a-(3-oxobutan-2-yl)benzoate (2), together with six known compounds (3‒8) were isolated from thecultures of an endophytic fungus Phoma sp. PF2 obtained from Artemisia princeps. The chemical structures of the isolated compounds were elucidated by interpretation of spectroscopic data (1D, 2D NMR, HRESIMS, and CD) and calculation of ECD. All the isolated compounds (1‒8) showed moderate inhibitory activities on nitric oxide levels in lipopolysaccharide-induced RAW264.7 machrophage cells.

A new antiviral 14-nordrimane sesquiterpenoid from an endophytic fungus Phoma sp.

A new rare 14-nordrimane-type sesquiterpenoid, named phomanolide (1), together with five known compounds, (–)-6-methoxymellein (2), 7-hydroxy-3, 5-dimethyl-isochromen-1-one (3), norlichexanthone (4), 6-methylsalicylic acid (5), and gentisyl alcohol (6), were obtained from the culture broth of an endophytic fungus Phoma sp. isolated from the roots of Aconitum vilmorinianum. The structure of compound 1 was established based on extensive spectroscopic analysis. Compound 1 was the first example of 14-nordrimane-type sesquiterpene up to now. Compounds 1 and 2 showed antiviral activities against influenza A virus (A/Puerto Rico/8/34, H1N1) with IC50 values of 2.96 ± 0.64 and 20.98 ± 2.66 μg/mL, respectively.

Cytotoxic polyketides from endophytic fungus Phoma bellidis harbored in Ttricyrtis maculate

Four new polyketides, namely bellidisins A-D (1-4), were isolated from rice fermentation extract of endophytic fungus Phoma bellidis, along with three known compounds pinolidoxin (5), 5,6-epoxypinolidoxin (6), and 2-epi-herbarumin II (7). Their structures and absolute configurations were determined by 1D and 2D NMR, HRESIMS and ECD calculation. Their cytotoxicity was evaluated against human cancer cell lines HL-60, A549, SMMC-7721, MCF-7, and SW480. Compound 4 showed significant cytotoxicity on these five cell lines with IC50 value ranged from 3.40 to 15.25 μM, which is stronger than cisplatin (4.86–27.70 μM).

Spiciferone analogs from an endophytic fungus Phoma betae collected from desert plants in West China.

Endophytic fungi from desert, arid, and grassland areas are an ecologically important but unique group with poor chemical investigation. During our ongoing study to mine bioactive secondary metabolites from unique fungal environments, a new shunt product spiciferone F (1) including two new analogs spiciferones G (2) and H (3) together with four known ones spiciferone A (4), spiciferol A (5), 6, and 7 were isolated from endophytic fungus Phoma betae inhabiting in plant Kalidium foliatum (Pall.) Moq from Ningxia Province of West China. The planar, relative, and absolute configurations of these new compounds were elucidated by nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, and electronic circular dichroism experiments. According to the shunt products, intermediates and analogs isolated from this endophytic fungus, the possible biosynthetic pathway of spiciferones was reconstructed. Compounds 1-7 were evaluated cytotoxic activities against three cancer cell lines HCT 116, HeLa, and MCF7, and only did 1 display strong biological effect against MCF7 with a half-maximal inhibitory concentration value at 7.73 ± 0.11 μM compared with the cis-platinum (14.32 ± 1.01 μM).