Cytotoxic metabolites from Botryotinia fuckeliana A-S-3: An endophytic fungus from Ajuga decumbens

Available online from an cytotoxic endophytic fungus Botryotinia fuckeliana A-S-3, three cytochalasans phenochalasin B (4), [12]-cytochalasin (5) and one [1,3] dioxacyclotridecino (6), along with two new ent-eudesmane sesquiterpenes, 1-keto-4α,15-epoxyeudesm-11-ol (1), and ent-4(15)-eudesmen-5,6-ol-1-one (2), and one known ent-eudesmane sesquiterpene ent-4(15)-eudesmen-11-ol-1-one (3) were isolated. The structures of these compounds were elucidated by interpretation of spectroscopic data. Among these compounds, two cytotoxic constituents were identified.     

Paeonol produced by Chaetomium sp., an endophytic fungus isolated from Paeonia suffruticosa

In order to research the relationship between endophytic fungus and active ingredients in medicinal Paeonia suffruticosa, a total of 57 fungal isolates were isolated from the roots, stems, leaves and buds of medicinal plant Paeonia ostii; mycelium was collected after these fungal isolates were fermented on PDA medium for a few days; then the mycelium products were extracted; their extracts were analyzed by gas chromatography–mass spectrometry. With this method, a strain endophytic fungi named J1-2 which can produce paeonol was screened. Paeonol produced by J1-2 was analyzed by using a high resolution mass spectrometer (HRMS) and nuclear magnetic resonance (NMR). The potential paeonol-procucing named J1-2 was identified Chaetomium based on morphological characteristics and ITS sequence analysis. The current research initially indicates that endophytic fungi can affect the potency of peony. At the same time it also indicates that the numerous endophytic fungi inside the medicinal Paeonia suffruticosa are precious resource for the pharmaceutical natural products that are originally from the Paeonia suffruticosa.     

Acrocalysterols A and B,two new steroids from endophytic fungus Acrocalymma sp

Two new steroids, named acrocalysterols A (1) and B (2), together with five known compounds were isolated and characterized from an endophytic fungus Acrocalymma sp., isolated from the tender stems of Sinomenium acutum. The structures of the isolated metabolites were identified based on UV, IR NMR (1D and 2D), HR-ESI-TOF-MS, single-crystal X-ray diffraction experiment using Cu Kα radiation and CD spectra associated with TD-DFT calculation. The bioassay showed that compound 2 displayed potent cytotoxicity against three cancer cell lines HeLa, HCC-1806, and RKO with IC₅₀ values ranging from 18.37 to 19.64 μM.     

Myrotheciumones: Bicyclic cytotoxic lactones isolated from an endophytic fungus of Ajuga decumbens

Two new bicyclic lactones, myrotheciumones A (1) and B (2) which possessed a rare ring-fusion system were isolated from Myrothecium roridum (M. roridum), an endophytic fungus of the medicinal herb plant Ajuga decumbens (A. decumbens) via an in vitro cytotoxicity assay. Structures were deduced from 1D and 2D NMR (Nuclear magnetic resonance) data. Myrotheciumone A’s in vitro cytotoxicity and apoptotic activity were evaluated and myrotheciumone A was shown to exert cytotoxicity via inducing apoptosis in cancer cell line.     

Two new alkaloids from Penicillium oxalicum EN-201, an endophytic fungus derived from the marine mangrove plant Rhizophora stylosa

Two new alkaloids including a new prenylated indole derivative possessing a piperidine moiety, penioxamide A (1), and a new decaturin analogue, 18-hydroxydecaturin B (2), were isolated and identified from Penicillium oxalicum EN-201, an endophytic fungus obtained from the inner tissue of the fresh leaves of marine mangrove plant Rhizophora stylosa. Their structures and absolute configurations were elucidated on the basis of the spectral data and CD analysis. Compound 1 bears the rare anti relative configuration in the bicyclo[2.2.2]diazaoctane ring, while compound 2 has a pyridinyl-α-pyrone substructure which is rare among natural products. Compounds 1 and 2 showed potent brine shrimp lethality with LD₅₀ values of 5.6 and 2.3 μM, 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).     

Antiproliferative metabolites from the endophytic fungus Penicillium sp. FJ-1 isolated from a mangrove Avicennia marina

Two new compounds, named as 4-(2′,3′-dihydroxy-3′-methyl-butanoxy)-phenethanol (1), and 15-hydroxy-6α,12-epoxy-7β,10αH,11βH-spiroax-4-ene-12-one (2), were isolated from the endophytic fungus Penicillium sp.FJ-1 of Avicennia marina. Their structures were elucidated on the basis of spectroscopic analysis. Additionally, compounds 1 and 2 exhibited antiproliferative activities, and compound 2 significantly inhibited the tumor growth of human xenograft osteosarcoma in nude mice.     

Neuroprotective metabolites from the endophytic fungus Penicillium citrinum of the mangrove Bruguiera gymnorrhiza

Two new compounds, named as (Z)-7,4′-dimethoxy-6-hydroxy-aurone-4-O-β-glucopyranoside (1), and (1S,3R,4S)-1-(4′-hydroxyl-phenyl)-3,4-dihydro-3,4,5-trimethyl-1H-2-benzopyran-6,8-diol (2), were isolated from the endophytic fungus Penicillium citrinum of Bruguiera gymnorrhiza. Their structures were elucidated on the basis of spectroscopic analysis. Additionally, compound 1 exhibited potent neuroprotective activity in 1-methyl-4-phenylpyridinium-induced oxidative damage in PC12 cells.     

Toxic polyketides produced by Fusarium sp., an endophytic fungus isolated from Melia azedarach

A new isocoumarin derivative named fusariumin (1), together with two known related resorcylic acid lactones aigialomycin D (2) and pochonin N (3), has been isolated from the cultures of Fusarium sp. LN-10, an endophytic fungus originated from the leaves of Melia azedarach. Their structures were established on the basis of extensive spectroscopic analyzes including 1D- and 2D- NMR (¹H-¹H COSY, HSQC, HMBC, and NOESY) experiments. Compounds 1-3 displayed significant growth inhibitory activity against the brine shrimp (Artemia salina).     

Two new cytochalasins from an endophytic fungus,KL-1.1 isolated from Psidium guajava leaves

Chemical investigation of the endophytic fungus, KL-1.1, isolated from the leaves of Psidium guajava (Linn) led to the isolation of two new cytochalasin derivatives, 18-desoxy-19,20-epoxycytochalasin C and 18-desoxycytochalasin C, together with five other known derivatives. The structures of the isolated compounds were elucidated by one and two dimensional nuclear magnetic resonance spectroscopy as well as by mass spectrometry. These compounds represent novel chemical scaffold with potential for development into anticancer agents.     

Two pairs of new dihydrobenzophenanthridine alkaloid isolated from the root of Macleaya cordata

Two pairs of dihydrobenzophenanthridine alkaloid, named (±)(S)-6-((R)-1-hydroxyethy) dihydrochelerythrine (1a, 1b) and (±)(S)-6-((R)-1-hydroxyethyl)dihydro-sangunarine (2a, 2b) were isolated from the root of Macleaya cordata. Their chemical structures were elucidated by analysis of the spectroscopic data including one-dimensional (1D) and two-dimensional (2D) NMR spectra, and were further confirmed by X-ray crystallographic analysis.     

Piperine production by endophytic fungus Colletotrichum gloeosporioides isolated from Piper nigrum

Many endophytic fungi have been reported with the biosynthetic potential to produce same or similar metabolites present in host plants. The adaptations that might have acquired by these fungi as a result of the long-term association with their host plants can be the possible basis of their biosynthetic potential. The bioactive compounds originated from endophytes are currently explored for their potential applications in pharmaceutical, agriculture and food industries. Piper nigrum, a plant of the Piperaceae is very remarkable because of the presence of the alkaloid piperine. Piperine has been reported to have broad bioactive properties ranging from antimicrobial, antidepressant, anti-inflammatory, antioxidative to anticancer activities. Interestingly, piperine also plays a vital role in increasing the bioavailability of many drugs which again is a promising property. The current study was carried out to identify piperine producing endophytic fungus from Piper nigrum L. By screening various endophytic fungi, the isolate which was identified as member of Colletotrichum gloeosporioides was found to have the ability to form piperine and was confirmed by HPLC and LCMS. Considering the broad bioactive potential of piperine, the piperine producing fungi identified in the study can expect to have much industrial potential.     

Bioactive metabolites produced by Chaetomium globosum,an endophytic fungus isolated from Ginkgo biloba

A novel cytotoxic chlorinated azaphilone derivative named chaetomugilin D (1), together with three known metabolites, chaetomugilin A (2), chaetoglobosins A (3) and C (4), has been isolated by a bioassay-guided fractionation from the EtOAc extract of the cultures of Chaetomium globosum, an endophytic fungus found in the leaves of Ginkgo biloba. Structure of 1 was established by analyses of spectroscopic methods, including 2D-NMR experiments (COSY, NOESY, HMQC, and HMBC). Compounds 1–4 displayed significant growth inhibitory activity against the brine shrimp (Artemia salina) and Mucor miehei.     

Alkaloids from the mangrove endophytic fungus Diaporthe phaseolorum SKS019

Six new alkaloids including four new chromeno[3,2-c]pyridines, diaporphasines A-D (1–4), and two new isoindolinones, meyeroguillines C and D (6–7), as well as three known compounds meyeroguilline A (5), 5-deoxybostrycoidin (8), and fusaristatin A (9), were isolated from an endophytic fungus Diaporthe phaseolorum SKS019. Their structures were determined by analysis of 1D and 2D NMR and mass spectroscopic data. Compounds 1–9 are alkaloid components reported for the first time from the Diaporthe sp., and diaporphasines A-D (1–4) are the third examples of alkaloids possessing the unique chromeno[3,2-c]pyridine nucleus. All isolated compounds 1–9 were evaluated for their cytotoxic activity in vitro using MDA-MB-435, HepG2, MCF10A, HCT116, and NCI-H460 human cell lines. Compound 8 exhibited cytotoxicity against MDA-MB-435 and NCI-H460 human cancer cell lines with IC₅₀ values of 5.32 and 6.57 μM, respectively, and compound 9 showed growth-inhibitory activity against MDA-MB-435 human cancer cell line with IC₅₀ value of 8.15 μM.     

Xanthine oxidase inhibitors from an endophytic fungus Lasiodiplodia pseudotheobromae

Two new compounds, lasdiplactone (1) and lasdiploic acid (2) and one known compound 3 were isolated from the chloroform extract of cell free filtrate of the endophytic fungus Lasiosdiplodia pseudotheobromae. The structures of new compounds were determined by interplay of spectral techniques (IR, mass, ¹H NMR, ¹³C NMR, DEPT, and 2D NMR). The absolute configuration at C-4 position of 1 was established as S using a process similar to modified Mosher’s method. The absolute configuration of 2 was established by comparing its ECD spectrum with the calculated ECD spectra of all possible isomers. In the in vitro XO inhibition assay, the highest inhibition was exhibited by 3 with an IC₅₀ of 0.38 ± 0.13 μg/ml, followed by 2 with an IC₅₀ of 0.41 ± 0.1 μg/ml and the least in 1. The oxidized form of 1 also showed high XO inhibition with IC₅₀ of 0.35 ± 0.13 μg/ml.     

Bioactive metabolites from the endophytic fungus Ampelomyces sp. isolated from the medicinal plant Urospermum picroides

Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their ¹H and ¹³C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds 1, 3, 6 and 8. When grown on solid rice medium the fungus yielded three compounds 4, 5 and 11 in addition to several known metabolites including 6, 8, 10, 12, 13 and 14. Compounds 4, 8 and 10 showed the strongest cytotoxic activity against L5178Y cells with EC₅₀ values ranging from 0.2–7.3 μg/ml. Furthermore, 8 and 10 displayed antimicrobial activity against the Gram-positive pathogens, Staphylococcus aureus, S. epidermidis and Enterococcus faecalis at minimal inhibitory concentrations (MIC) of 12.5 μg/ml and 12.5–25 μg/ml, respectively. Interestingly, 6 and 8 were also identified as constituents of an extract derived from a healthy plant sample of the host plant U. picroides thereby indicating that the production of bioactive natural products by the endophyte proceeds also under in situ conditions within the host plant.     

Depsidones from Talaromyces stipitatus SK-4, an endophytic fungus of the mangrove plant Acanthus ilicifolius

An endophytic fungus (Talaromyces stipitatus SK-4) was isolated from the leaves of a mangrove plant Acanthus ilicifolius. Its crude extract exhibited significant antibacterial activity and was purified to afford two new depsidones, talaromyones A and B (1 and 2), along with five known depsidone analogs (3–7). Their structures, including absolute configuration, were elucidated through extensive spectroscopic data analysis and modified Mosher's method. Compound 2 showed antibacterial activity against Bacillus subtilis with an MIC value of 12.5 μg/mL. In the inhibitory assay against α-glucosidase, compounds 2, 4 and 5 displayed moderate activities with IC₅₀ values ranging from 48.4 to 99.8 μM.     

Taxol from Tubercularia sp. strain TF5, an endophytic fungus of Taxus mairei

The diterpenoid taxol is an important anticancer agent used widely in the clinic. The purpose of this work was to identify a taxol-producing endophytic fungus (strain TF5) isolated from Taxus mairei and study its anticancer activities. Strain TF5 was identified as a Tubercularia sp. according to the morphology of the fungal culture, the mechanism of spore production and the characteristics of the spores. Strain TF5 produced taxol, when grown in potato dextrose liquid medium and analyzed by thin layer chromatography, high performance liquid chromatography, ultraviolet and mass spectrometry. The fungal taxol, which was isolated from the organic extract of the TF5 culture, had strong cytotoxic activity towards KB and P388 cancer cells in vitro, tested by the MTT assay. Observed with immunofluorescence and electron microscopy, the fungal taxol enhanced microtubule stability and bundling in culture cells and induced tubulin polymerization in vitro similar to the authentic taxol.     

内生真菌X1-2次级代谢产物研究

在从神农架地区特有植物内生真菌中寻找各种活性次级代谢产物的过程中,从濒危植物珙桐叶片中分离得到一株内生真菌X1-2。经过高效液相色谱(HPLC)和薄板色谱(TLC)分析其固体发酵产物多样性,通过正相硅胶柱层析、重结晶、高效液相色谱制备等手段纯化次级代谢产物,从该真菌中分离获得四个次级代谢产物。经核磁共振波谱(NMR),质谱(MS)等波谱学方法鉴定其结构,四个化合物分别为icosalide A1(1),militarinone A(2),(+)-N-deoxymilitarinone A(3),β-hydroxytetradecanoyl-β-hydroxyl tetraecanoyl-Rha-Rha-C_(14)-C_(14)(4),其中icosalide A1(1),militarinone A(2),(+)-N-deoxymilitarinone A(3)为三个复杂的生物碱类化合物,而化合物4是首次从真菌中获得。     

Zinniol analogues from the endophytic fungus Arcopilus sp. YUD20001 associated with Gastrodia elata

Three undescribed zinniol derivatives, arcopiniols A-C (1-3), together with three known compounds zinniol (4), 8-zinniol methyl ether (5), and maristachone B (6), were isolated from the endophytic fungus Arcopilus sp. YUD20001 associated with Gastrodia elata using various chromatographic separation techniques. Arcopiniol A (1) was a new compound, while the spectroscopic data of arcopiniols B-C (2-3) are reported here for the first time. Their structures were determined using spectroscopic methods and their absolute configurations were confirmed by performing TDDFT calculations. A putative biosynthetic pathway for all the compounds was proposed. The anti-inflammatory and cytotoxic activities of compounds 1-3 were investigated.