Asperidines A-C, pyrrolidine and piperidine derivatives from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178

Synthesis and potential antidiabetic and lipid-lowering activities of putative asperidine B and its desmethyl analogue

Putative asperidine B is an unnatural 2,6-disubstituted piperidin-3-ol and a structural isomer of (+)-preussin, a well-known pyrrolidin-3-ol alkaloid. This work reports the first enantioselective synthesis of putative asperidine B and its desmethyl analogue via a chiron approach starting from d-isoascorbic acid as well as evaluation of their free-radical scavenging, antidiabetic, and anti-hyperlipidemic activities. Both putative asperidine B and its desmethyl analogue markedly reduced the total reactive oxygen species (ROS) without cytotoxicity in hepatocellular carcinoma (HepG2) cells. The desmethyl analogue was a potent inducer for two antioxidant gene expression, glutathione peroxidase and superoxide dismutase, whereas putative asperidine B only induced superoxide dismutase. In addition, putative asperidine B exerted potent antidiabetic activity via α-glucosidase inhibition (IC50 = 0.143 ± 0.001 mg/mL) comparable to that of acarbose, an antidiabetic drug. Consistent with the parent asperidine B (preussin), both putative asperidine B and its desmethyl analogue inhibited cholesterol absorption in the intestinal Caco-2 cells. These novel and promising antioxidant, antidiabetic, and lipid-lowering effects of piperidin-3-ols could offer a starting point for this class of compounds for obesity and diabetic drug discovery.

The Novel Compounds with Biological Activity Derived from Soil Fungi in the Past Decade

The secondary metabolites isolated from soil fungi have received more and more attention, especially new compounds that exhibited good biological activities. In this review, a total of 546 new compounds are included in the relevant literature since 2011. The new compounds are isolated from soil fungi, We divided these compounds into seven categories, including alkaloids, terpenoids, steroids, ketones, phenylpropanoids, quinones, esters, lactones, etc. In addition, the biological activities and structure-activity relationships of these compounds have also been fully discussed. The activities of these compounds are roughly divided into eight categories, including anticancer activity, antimicrobial activity, anti-inflammatory activity, antioxidant activity, antiviral activity, antimalarial activity, immunosuppressive activity and other activities. Since natural products are an important source of new drugs, this review may have a positive guiding effect on drug screening.

Asperbenzophenone A and Versicolamide C, New Fungal Metabolites from the Soft Coral Derived Aspergillus sp. SCSIO 41036

Two new compounds, asperbenzophenone A (1) and versicolamide C (5), together with fifteen known compounds were isolated from a soft coral derived fungus Aspergillus sp. SCSIO 41036. Their structures were elucidated by spectroscopic methods, ECD analysis, and by a comparison with data from the literature. In bioassay, compound 8 showed significant inhibitory activity against lipopolysaccharide-inducted nitric oxide (NO) in RAW264.7 cells at the concentration of 10 μM. Additionally, the anti-acetylcholinesterase activity assay showed that 14 exhibited weak inhibition with an IC₅₀ value of 157.8 μM.

A nonadride derivative from the marine-derived fungus Aspergillus chevalieri PSU-AMF79

One new nonadride enantiomer, ent-epiheveadride, along with five known dioxopiperazine derivatives were isolated from the marine-derived fungus Aspergillus chevalieri PSU-AMF79. Their structures were identified by extensive spectroscopic analysis. The absolute configuration of ent-epiheveadride was determined by comparison of the specific rotation and electronic circular dichroism data with those of related known compounds. It exhibited antifungal activity against Cryptococcus neoformans ATCC90113 flucytosine-resistant and Candida albicans NCPF3153 with the MIC values of 128 and 200 µg/mL, respectively. In addition, the known L-alanyl-L-tryptophan anhydride displayed TMEM16A inhibitory activity with 65.0% inhibition at a concentration of 5 µg/mL.

Antispasmodic Effect of Asperidine B, a Pyrrolidine Derivative, through Inhibition of L-Type Ca2+ Channel in Rat Ileal Smooth Muscle

Antispasmodic agents are used for modulating gastrointestinal motility. Several compounds isolated from terrestrial plants have antispasmodic properties. This study aimed to explore the inhibitory effect of the pyrrolidine derivative, asperidine B, isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178, on spasmodic activity. Isolated rat ileum was set up in an organ bath. The contractile responses of asperidine B (0.3 to 30 µM) on potassium chloride and acetylcholine-induced contractions were recorded. To investigate its antispasmodic mechanism, CaCl2, acetylcholine, Nω-nitro-l-arginine methyl ester (l-NAME), nifedipine, methylene blue and tetraethylammonium chloride (TEA) were tested in the absence or in the presence of asperidine B. Cumulative concentrations of asperidine B reduced the ileal contraction by ~37%. The calcium chloride and acetylcholine-induced ileal contraction was suppressed by asperidine B. The effects of asperidine B combined with nifedipine, atropine or TEA were similar to those treated with nifedipine, atropine or TEA, respectively. In contrast, in the presence of l-NAME and methylene blue, the antispasmodic effect of asperidine B was unaltered. These results suggest that the antispasmodic property of asperidine B is probably due to the blockage of the L-type Ca2+ channel and is associated with K+ channels and muscarinic receptor, possibly by affecting non-selective cation channels and/or releasing intracellular calcium.

Classification of Aspergillus, Penicillium, Talaromyces and related genera (Eurotiales): An overview of families, genera, subgenera, sections, series and species

The Eurotiales is a relatively large order of Ascomycetes with members frequently having positive and negative impact on human activities. Species within this order gain attention from various research fields such as food, indoor and medical mycology and biotechnology. In this article we give an overview of families and genera present in the Eurotiales and introduce an updated subgeneric, sectional and series classification for Aspergillus and Penicillium. Finally, a comprehensive list of accepted species in the Eurotiales is given. The classification of the Eurotiales at family and genus level is traditionally based on phenotypic characters, and this classification has since been challenged using sequence-based approaches. Here, we re-evaluated the relationships between families and genera of the Eurotiales using a nine-gene sequence dataset. Based on this analysis, the new family Penicillaginaceae is introduced and four known families are accepted: Aspergillaceae, Elaphomycetaceae, Thermoascaceae and Trichocomaceae. The Eurotiales includes 28 genera: 15 genera are accommodated in the Aspergillaceae (Aspergillago, Aspergillus, Evansstolkia, Hamigera, Leiothecium, Monascus, Penicilliopsis, Penicillium, Phialomyces, Pseudohamigera, Pseudopenicillium, Sclerocleista, Warcupiella, Xerochrysium and Xeromyces), eight in the Trichocomaceae (Acidotalaromyces, Ascospirella, Dendrosphaera, Rasamsonia, Sagenomella, Talaromyces, Thermomyces, Trichocoma), two in the Thermoascaceae (Paecilomyces, Thermoascus) and one in the Penicillaginaceae (Penicillago). The classification of the Elaphomycetaceae was not part of this study, but according to literature two genera are present in this family (Elaphomyces and Pseudotulostoma). The use of an infrageneric classification system has a long tradition in Aspergillus and Penicillium. Most recent taxonomic studies focused on the sectional level, resulting in a well-established sectional classification in these genera. In contrast, a series classification in Aspergillus and Penicillium is often outdated or lacking, but is still relevant, e.g., the allocation of a species to a series can be highly predictive in what functional characters the species might have and might be useful when using a phenotype-based identification. The majority of the series in Aspergillus and Penicillium are invalidly described and here we introduce a new series classification. Using a phylogenetic approach, often supported by phenotypic, physiologic and/or extrolite data, Aspergillus is subdivided in six subgenera, 27 sections (five new) and 75 series (73 new, one new combination), and Penicillium in two subgenera, 32 sections (seven new) and 89 series (57 new, six new combinations). Correct identification of species belonging to the Eurotiales is difficult, but crucial, as the species name is the linking pin to information. Lists of accepted species are a helpful aid for researchers to obtain a correct identification using the current taxonomic schemes. In the most recent list from 2014, 339 Aspergillus, 354 Penicillium and 88 Talaromyces species were accepted. These numbers increased significantly, and the current list includes 446 Aspergillus (32 % increase), 483 Penicillium (36 % increase) and 171 Talaromyces (94 % increase) species, showing the large diversity and high interest in these genera. We expanded this list with all genera and species belonging to the Eurotiales (except those belonging to Elaphomycetaceae). The list includes 1 187 species, distributed over 27 genera, and contains MycoBank numbers, collection numbers of type and ex-type cultures, subgenus, section and series classification data, information on the mode of reproduction, and GenBank accession numbers of ITS, beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) gene sequences.

Collacyclumines A-D from the endophytic fungus Colletotrichum salsolae SCSIO 41021 isolated from the mangrove Kandelia candel

Four undescribed alkaloids, namely collacyclumines A-D, along with a known analogue, agrocybenine, were isolated from the endophytic fungus Colletotrichum salsolae SCSIO 41021 derived from the mangrove plant Kandelia candel (L.) Druce. Collacyclumine A represents the first case of dimeric pyrrolidine alkaloid in nature. The structures of these compounds were elucidated by a combination of NMR spectra, HRESIMS data, and X-ray diffraction experiment. A proposed biosynthetic pathway of these isolated compounds were also discussed. None of compounds showed cytotoxic effects against ten cell lines.

Cytotoxic alkaloids from the marine shellfish-associated fungus Aspergillus sp. XBB-4 induced by an amino acid-directed strategy

Eight different culture media were used to culture shellfish Panopea abbreviate associated fungus Aspergillus sp. XBB-4. In a glucose-peptone-yeast (GPY) culture medium supplied with amino acids, this fungus can produce chemodiversity metabolites. Four new alkaloids including three β-carboline alkaloids, aspercarbolines A–C (1–3) and one piperazinedione, asperdione A (13) along with nine known compounds were isolated. The structures were elucidated mainly based on the NMR, MS, ECD and X-ray single-crystal diffraction data. The possible biosynthetic pathways of aspercarbolines A–C (1–3) were proposed. All compounds (1–13) were evaluated for their cytotoxicity against six cancer cell lines, including human nasopharyngeal carcinoma cell lines CNE1, CNE2, HONE1 and SUNE1, and human hepatocellular carcinoma cell lines hepG2 and QGY7701.

Cytotoxic alkaloids from marine fungus Aspergillus sp. XBB-4 induced by an amino acid-directed strategy.

Screening and identification of Aspergillus activity against Xanthomonas oryzae pv. oryzae and analysis of antimicrobial components

To screen for Aspergillus activity against Xanthomonas oryzae pv. oryzae and analyse the antimicrobial components involved, 60 Aspergillus spp. were isolated and purified from fruits, soil and other habitats. As-75, an Aspergillus strain that can antagonize Xanthomonas oryzae pv. oryzae, was identified based on the zone of inhibition formed during co-culture. According to morphological, ITS rDNA gene sequencing and phylogenetic tree results, the strain showed close homology to Aspergillus sclerotiorum. The biochemical characterization tests showed that the fermentation broth of strain As-75 exhibited a high capacity for environmental adaptation. The results of the antimicrobial spectrum experiments demonstrated that As-75 exhibited fairly strong antagonistic activity against five plant pathogenic fungi and six plant pathogenic bacteria in vitro. The fermentation broth of strain As-75 displayed maximum stability under fluorescent illumination at temperatures below 60°C at pH 6.5. A substance with antagonistic activity was obtained from strain As-75 via fractional extraction, silica gel column chromatography and thin-layer chromatography. Through mass spectrometry, nuclear magnetic resonance and electrospray ionization mass spectrometry (ESI-MS) analyses, the target compound was identified as (2Z)-2-butenedioic acid-2-(1-methylethenyl)-4-methyl ester; its molecular weight of 170.06 daltons and formula of C₈H₁₀O₄ identify it as a novel compound. Trials of the preventative and curative effects demonstrated that compound S1 exhibited a better control efficiency than the control against rice bacterial blight. Additionally, the M1 processing method was better, and the efficiency of compound S1 in preventing rice bacterial blight in six rice varieties, TN1, IR24, ZF802, Zhonghua 11, Wuyunjing 21, and Nipponbare, was 78.3%, 77.5%, 74.2%, 75.3%, 70.9%, and 72.1%, respectively.