Oxepine-containing pyrazinopyrimidine alkaloids and quinolinone derivatives produced by Aspergillus versicolor AS-212, a deep-sea-derived endozoic fungus.

Four new oxepine-containing pyrazinopyrimidine alkaloids, versicoxepines A - D (1-4), two quinolinone alkaloid analogs including 3-hydroxy-6-methoxy-4-phenylquinolin-2(1H)-one (5) and 3-methoxy-6-hydroxy-4-phenylquinolin-2(1H)-one (6) which were new naturally occurring compounds, together with two known compounds (7 and 8) were isolated from Aspergillus versicolor AS-212, an endozoic fungus isolated from the deep-sea coral Hemicorallium cf. imperiale, which was collected from the Magellan Seamounts in the Western Pacific Ocean. Their structures were determined by extensive analysis of the spectroscopic and X-ray crystallographic data as well as by chiral HPLC analysis, ECD calculation, and DP4+ probability prediction. Structurally, versicoxepines B and C (2 and 3) represent the first example of a new oxepine-containing pyrazinopyrimidine alkaloid whose cyclic dipeptide moiety is composed of the same type of amino acid (Val or Ile). Compound 5 displayed antibacterial activity against aquatic pathogens, Vibrio harveyi and V. alginolyticus, with MICs of 8 µg/mL.

Secondary metabolites from the Cordyceps-colonizing fungus Aspergillus versicolor ZJUTE2.

Two new polyketides versicolorones A-B (1-2), one new diketopiperazine derivative aspergiamide B methyl ester (3), along with twenty known compounds 4-23, were obtained from the EtOAc extract of the Cordyceps-colonizing fungus Aspergillus versicolor ZJUTE2. The structures of 1-3 were established by detailed interpretation of the spectroscopic data and their absolute configurations were established by comparative analyses of the calculated and experimental ECD spectra. In the in-vitro bioassay, compounds 8 and 21 exhibited significant inhibitory activity against the Escherichia coli ß-glucuronidase (EcGUS) with IC50 values of 54.73 ± 2.69 and 56.59 ± 1.77 µM, respectively.

Discovery of a novel jellyfish venom metalloproteinase inhibitor from secondary metabolites isolated from jellyfish-derived fungus Aspergillus versicolor SmT07.

The major jellyfish stings that occur in China are caused by scyphozoan Nemopilema nomurai, whose venom exhibits significant metalloproteinase activity that contributes to the toxic effects of jellyfish envenomation. Researching effective inhibitors suppressing the metalloproteinase activity of jellyfish venom represents a new attempt to cure jellyfish envenomations. In the present study, secondary metabolites produced by the jellyfish-associated fungus Aspergillus versicolor SmT07 were isolated and evaluated for their anti-proteolytic activities. Two xanthones, sterigmatocystin (JC-01) and oxisterigmatocystin C (JC-06), and four alkaloids, cottoquinazoline A (JC-02), phenazine-1-carboxylic acid (JC-03), viridicatin (JC-04) and viridicatol (JC-05), were isolated and identified. Only phenazine-1-carboxylic acid (PCA) showed significant anti-proteolytic activity of jellyfish venom assayed on azocasein, and the IC50 value was 2.16 mM. PCA also significantly inhibited fibrinogenolytic activity, protecting the Bß chain of fibrinogen from degradation when preincubated with jellyfish venom at a ratio of >1:0.6 (PCA:venom, w/w). Molecular docking with several well-characterized snake venom metalloproteinases suggested the venom metalloproteinases inhibitory property of PCA by forming complex interactions with the active site via hydrogen bonds, π-π stacking and salt bridges, which was distinct from the binding mode of batimastat. The present study represents the first study identifying natural jellyfish venom metalloproteinase inhibitors from marine natural products, which may provide an alternative to develop therapeutic agents for treating jellyfish envenomations.

Two new benzoic acid derivatives from endophytic fungus Aspergillus versicolor.

Two new benzoic acid derivatives, named methyl(S)-3-hydroxy-4-(2- hydroxy -6-methylheptan-2-yl)benzoate (1) and 2-hydroxy-3-(6- hydroxy-6-methylhept-1-en-2-yl)benzoic acid (2), were isolated from the ethanol extract of an endophytic fungus Aspergillus versicolor derived from the medicinal plant Euphorbia royleana. The structures of compounds (1-2) were elucidated using NMR and MS methods.

Novel kojic acid derivatives with anti-inflammatory effects from Aspergillus versicolor.

Two novel kojic acid derivatives, kojicones A and B (1 and 2), along with the precursors kojic acid (3) and (2R,4R)-4-hydroxy-5-methoxy-2,4-dimethyl-2- [(2R)-2-methylbutyryloxy]-5-cyclohexen-1,3-dione (4), were isolated from a fungal strain Aspergillus versicolor. Their structures and absolute configurations were accurately confirmed by HRESIMS data, NMR analysis, and electronic circular dichroism (ECD) calculations. Kojicones A and B were the first examples of kojic acid adducts with cyclohexen-1,3-dione possessing unprecedented tricycle skeletons. Compounds 1-3 were found to have inhibition on the NO production of murine RAW 264.7 cells. They can also reduce the mRNA expression of four cytokines (IL-6, IL-1ß, TNF-α, and iNOS) and promote the expression of IL-4 at 20 µM. Moreover, kojic acid (3) could treat the DSS (dextran sulfate sodium)-induced colitis on mice with the effectiveness similar to that of the positive control. The results suggested that kojic acid and its derivatives could be a promising anti-inflammatory source for the medicinal and cosmetic industry.

Bioactive Indolyl Diketopiperazines from the Marine Derived Endophytic Aspergillus versicolor DY180635.

Four new indolyl diketopiperazines, aspamides A-E (1-4) and two new diketopiperazines, aspamides F-G (5-6), along with 11 known diketopiperazines and intermediates were isolated from the solid culture of Aspergillus versicolor, which is an endophyte with the sea crab (Chiromantes haematocheir). Further chiral high-performance liquid chromatography resolution gave enantiomers (+)- and (-)-4, respectively. The structures and absolute configurations of compounds 1-6 were determined by the comprehensive analyses of nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HR-MS), and electronic circular dichroism (ECD) calculation. All isolated compounds were selected for the virtual screening on the coronavirus 3-chymoretpsin-like protease (Mpro) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and the docking scores of compounds 1-2, 5, 6, 8 and 17 were top among all screened molecules, may be helpful in fighting with Corona Virus Disease-19 (COVID-19) after further studies.

New bioactive secondary metabolites from the Anoectochilus roxburghii endophytic fungus Aspergillus versicolor.

Six new compounds, including two new isochromane lactones, versicoisochromanes A and B (1 and 2), two new benzolactones, versicobenzos A and B (3 and 4), one furancarboxylic derivate, asperfuran A (6) and one ergosterol-type steroid, asperergoster A (7), along with five known steroids (8-12), were isolated from the Anoectochilus roxburghii endophytic fungus Aspergillus versicolor. The structures of these new compounds were determined by extensive spectroscopic techniques and electronic circular dichroism (ECD) calculations. It is notable that the new compound 7 exhibited obvious IL-1ß, NO and TNF-α inhibitory activity in LPS-stimulated RAW264.7 macrophages, with IC50 values of 35.5, 33.9 and 31.3 µM, respectively. Furthermore, compounds 7 and 8 displayed potential inhibitory effects on murine splenocytes proliferation stimulated by anti-CD3/anti-CD28 monoclonal antibodies (mAbs), meanwhile suppress the lipopolysaccharide (LPS) irritated murine splenocytes proliferation.

Antibacterial anthraquinone dimers from marine derived fungus Aspergillus sp.

As a continue investigation of the bioactive secondary metabolites from marine derived fungi, two new anthraquinone dimers (1, 2), along with three known anthraquinones (3-5) and two known xanthones (6, 7) were isolated from the marine-derived fungus Aspergillus versicolor. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and comparison with reported ones. Among them, compounds 1 and 2 were identified as anthraquinone dimers which dimerized by a rare C-O-C ether linkage, and both of them showed selective antibacterial activity against Gram-positive Staphylococcus aureus; whilst compound 6 exhibited moderate cytotoxicity against human cancer cell lines.

Optimization of Storage Conditions of the Medicinal Herb Ilex asprella against the Sterigmatocystin Producer Aspergillus versicolor Using Response Surface Methodology.

The root of Ilex asprella is a commonly used herb in Southern China, and also constitutes the main raw material of Canton herbal tea. I. asprella is readily contaminated by mildew because of rich nutrients. Aspergillus versicolor producing sterigmatocystin is one of the most common molds that contaminate foodstuffs and medicinal herbs. Previous study on the evaluation of fungal contamination on samples of I. asprella revealed that A. versicolor was the dominant contaminant. In this study, experiments based on response surface methodology combined with central composite design were carried out to determine the optimal storage conditions of I. asprella to minimize the contamination of sterigmatocystin. The herb, manually innoculated with A. versicolor, was stored under different temperatures (20⁻40 °C) and humidity (80⁻95%) for seven days. The effects of temperature and humidity were evaluated using total saponin, polysaccharide and the sterigmatocystin levels as quality indexes. The results showed that A. versicolor grew quickly and produced large amounts of sterigmatocystin on I. asprella, at humidity ranging from 85% to 90% and temperatures above 26 °C. Meanwhile, total saponin and polysaccharide amounts were reduced significantly. These findings suggested that I. asprella samples should be stored in an environment with humidity and temperature below 85% and 26 °C, respectively, to reduce A. versicolor growth and sterigmatocystin production.

Antioxidant xanthones and anthraquinones isolated from a marine-derived fungus Aspergillus versicolor.

Chemical examination of an EtOAc extract of cultured Aspergillus versicolor fungus from deep-sea sediments resulted in the isolation of four xanthones, eight anthraquinones and five alkaloids, including a new xanthone, oxisterigmatocystin D (1) and a new alkaloid, aspergillusine A (13). High resolution electron impact mass spectrometry (HR-EI-MS), FT-IR spectroscopy, and NMR techniques were used to elucidate the structures of these compounds, and the absolute configuration of compound 1 was established by its NMR features and coupling constant. Furthermore, the biosynthesis pathway of these xanthones and anthraquinones were deduced, and their antioxidant activity and cytotoxicity in human cancer cell lines (HTC-8, Bel-7420, BGC-823, A549, and A2780) were evaluated. The trolox equivalent antioxidant capacity (TEAC) assay indicated most of the xanthones and anthraquinones possessing moderate antioxidant activities. The Nrf2-dependent luciferase reporter gene assay revealed that compounds 6, 7, 9, and 12 potentially activated the expression of Nrf2-regulated gene. In addition, compounds 5 and 11 showed weak cytotoxicity on A549 with the IC50 values of 25.97 and 25.60 µmol·L-1, respectively.

Antimicrobial activity and molecular docking studies of a novel anthraquinone from a marine-derived fungus Aspergillus versicolor.

A novel anthraquinone, 2-(dimethoxymethyl)-1-hydroxyanthracene-9,10-dione (1), together with nine known compounds (2-10), were isolated from the fermentation of Aspergillus versicolor derived from deep sea sediment. Their structures were established through spectroscopic methods. Compound 1 exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of 3.9 and 7.8 µg/mL respectively) and moderate activities against tested strains of Vibrio (with MIC values ranging from 15.6 to 62.5 µg/mL). Compound 1 was subjected to molecular docking studies for inhibition of topoisomerase IV and AmpC ß-lactamase enzymes indicating its usefulness as antimicrobial agent.

[A new cytotoxic isocoumarin from endophytic fungus Aspergillus versicolor].

A new isocoumarin, along with five known ones,were isolated from the fermentation products of an endophytic fungus Aspergillus versicolorby using various chromatographic techniques.Their structures were elucidated on the basis of extensivespectroscopic analysis, including 1D-and 2D-NMR techniques. Compound 1 was evaluated for cytotoxicity against five human tumor cell lines. The results showed that 1 exhibited weak cytotoxicityagainst NB4, SHSY5Y and MCF7 cells with IC50 values of 6.8, 4.3,8.8 µmol•L⁻¹, respectively.

Identification and biological evaluation of secondary metabolites from the endolichenic fungus Aspergillus versicolor.

A chemical investigation of the endolichenic fungus Aspergillus versicolor (125a), which was found in the lichen Lobaria quercizans, resulted in the isolation of four novel diphenyl ethers, named diorcinols F-H (1-3, resp.) and 3-methoxyviolaceol-II (4), eight new bisabolane sesquiterpenoids, named (-)-(R)-cyclo-hydroxysydonic acid (5), (-)-(7S,8R)-8-hydroxysydowic acid (6), (-)-(7R,10S)-10-hydroxysydowic acid (7), (-)-(7R,10R)-iso-10-hydroxysydowic acid (8), (-)-12-acetoxy-1-deoxysydonic acid (9), (-)-12-acetoxysydonic acid (10), (-)-12-hydroxysydonic acid (11), and (-)-(R)-11-dehydrosydonic acid (12), two new tris(pyrogallol ethers), named sydowiols D (13) and E (14), and fifteen known compounds, 15-29. All of the structures were determined by spectroscopic analyses, and a number of them were further identified through chemical transformations and electronic circular dichroism (ECD) calculations. Preliminary bioassays of these isolates for the determination of their inhibitory activities against the fungus Candida albicans, and their cytotoxicities against the human cancer cell lines PC3, A549, A2780, MDA-MB-231, and HEPG2 were also evaluated.

Solid-state fermentation of Jatropha seed cake for optimization of lipase, protease and detoxification of anti-nutrients in Jatropha seed cake using Aspergillus versicolor CJS-98.

This study focused on the solid-state fermentation of Jatropha seed cake (JSC), a byproduct generated after biodiesel production. Presence of anti-nutritional compounds and toxins restricts its application in livestock feed. The disposal of the JSC is a major environmental problem in the future, due to the generation of huge quantity of JSC after biodiesel extraction. Hence the JSC was assessed for its suitability as substrate for production and optimization of lipase and protease from Aspergillus versicolor CJS-98 by solid-state fermentation (SSF). The present study was also focused on the biodetoxification of anti-nutrients and toxins in JSC. The SSF parameters were optimized for maximum production of lipase and protease. Under the optimized conditions, the JSC supplemented with maltose and peptone (2%), adjusted to pH 7.0, moisture content 40%, inoculated with 1 × 10(7) spores per 5 g cake and incubated at 25°C, produced maximum lipase, 1288 U/g and protease, 3366 U/g at 96 h. The anti-nutrients like phytic acid (6.08%), tannins (0.37%), trypsin inhibitors (697.5 TIU/g), cyanogenic glucosides (692.5 µg/100 g), and lectins (0.309 mg/ml), were reduced to 1.70%, 0.23%, 12.5 TIU/g, 560.6 µg/100 g and 0.034 mg/ml respectively. The main toxic compound phorbol esters content in the JSC was reduced from 0.083% to 0.015% after SSF. Our results indicate that viability of SSF to utilize the huge amount of seed cake generated after extraction of biodiesel, for production of industrial enzymes and biodetoxification of anti-nutrients, toxins.