Aspergillus Flavipes Research Articles

Cytotoxic cytochalasans from Aspergillus flavipes PJ03-11 by OSMAC method

Two new cytochalasans flavichalasine N (1), flavichalasine O (2), together with six known cytochalasans (3–8), were isolated from Aspergillus flavipes PJ03-11 through the application of OSMAC (one strain many compounds) strategy. Flavichalasine O (2) represented the first example of cytochalasans possessing a nitrogen-oxygen heterocycle at the macrocyclic ring part. Their structures were established on the base of extensive spectroscopic analysis. Compounds 1–4 exhibited significant cytotoxic activities against three human cancer cell lines (THP1, HL-60 and PC3) with IC50 values ranging from 3.00 to 15.10 μM.

Optimized production and isolation of antibacterial agent from marine Aspergillus flavipes against Vibrio harveyi.

Statistical methodologies, including Plackett-Burman design and Box-Behnken design, were employed to optimize the fermentation conditions for the production of active substances against aquatic pathogen Vibrio harveyi by marine-derived Aspergillus flavipes strain HN4-13. The optimal crucial fermentation values for maximum production of active substances against V. harveyi were obtained as follows: X1 (peptone)=0.3%, X2 (KCl)=0.25%, and X3 (inoculum size)=4.5%. The predicted diameter of inhibitory zone against V. harveyi was 23.39mm, and the practical value reached 23.71±0.98mm with a 62.3% increase. Bioassay-guided fractionation resulted in the acquisition of two compounds whose structures were identified as questin (1) and emodin (2). Questin exhibited the same antibacterial activity against V. harveyi as streptomycin (MIC 31.25µg/mL). This is the first time to report questin as a potential antibacterial agent against aquatic pathogen V. harveyi.

Azacoccones A − E, five new aza-epicoccone derivatives from Aspergillus flavipes

Azacoccones A–E (1–5), five new aza-epicoccone derivatives, were isolated from the culture of Aspergillus flavipes. Their structures were determined by extensive NMR spectroscopic analyses and the absolute configuration of 5 was determined by electronic circular dichroism (ECD) calculation. Compounds 1–5 are proposed to be generated via a Pictet-Spengler reaction-based biosynthetic route starting from the precursor flavipin. Pictet–Spengler reaction is rarely found in the fungal kingdom, which indicated the distinctive nature of 1–5. Compounds 3 and 5 exhibit significant free radical scavenging activities with IC50 values of 4.0 and 2.4μg/mL, respectively, which are better than the positive control trolox (4.55μg/mL).

Aspergilasines A-D: Four Merocytochalasans with New Carbon Skeletons from Aspergillus flavipes QCS12.

Aspergilasines A-D (1-4), four merocytochalasans with new skeletons, were isolated from the liquid culture broth of Aspergillus flavipes QCS12. Aspergilasine A (1) possesses a uniquely caged pentacyclo[7.2.0.14,11.02,7.05,10]dodecane skeleton with an unexpected cyclobutane ring that formed by the fusion of two epicoccine moieties via two [3 + 2] cycloadditions. Aspergilasines B-D (2-4) are key biosynthetic intermediates of epicochalasine B that fit well with our previous biosynthetic proposal.

Isolation and structure elucidation of a new compound from the fungus Aspergillus flavipes PJ03-11

A new diphenyl ether 3-methylpentyl-2, 4-dichloroasterrate (2), along with a known diphenyl ether butyl 2, 4-dichloroasterrate (1) were isolated from the metabolites of a wetland fungus Aspergillus flavipes. PJ03-11. The structures of 1 and 2 were determined by extensive NMR and HR–ESI–MS experiments. Compounds 1 and 2 showed weak cytotoxic activity, but both of them showed no antimicrobial activity.

Asperflavipine A: A Cytochalasan Heterotetramer Uniquely Defined by a Highly Complex Tetradecacyclic Ring System from Aspergillus flavipes QCS12

AbstractAsperflavipines A (1) and B (2), two structurally complex merocytochalasans, were isolated from Aspergillus flavipes. Asperflavipine A (1), which contains two cytochalasan moieties and two epicoccine moieties, is the first cytochalasan heterotetramer to be discovered. It is uniquely defined by 5/6/11/5/6/5/6/5/6/5/5/11/6/5 fused tetradecacyclic rings with three continuous bridged ring systems. Asperflavipine B (2) is a cytochalasan heterotrimer containing a cytochalasan and two epicoccine moieties with a 5/6/11/5/5/6/5/6/5 nonacyclic ring system. The hypothetical biosynthesis of 1 and 2 is proposed to involve Diels–Alder and [3+2] cycloaddition reactions as key steps and reveals unparalleled plasticity in the biosynthesis of merocytochalasans. The existence of 1 adds a new dimension to the diversity of the cytochalasan family. Compound 1 showed moderate cytotoxicity and induced apoptosis in Jurkat, NB4, and HL60 cells through the activation of caspase‐3 and degradation of poly(ADP‐ribose) polymerase (PARP).

Asperflavipine A: A Cytochalasan Heterotetramer Uniquely Defined by a Highly Complex Tetradecacyclic Ring System from Aspergillus flavipes QCS12.

Asperflavipines A (1) and B (2), two structurally complex merocytochalasans, were isolated from Aspergillus flavipes. Asperflavipine A (1), which contains two cytochalasan moieties and two epicoccine moieties, is the first cytochalasan heterotetramer to be discovered. It is uniquely defined by 5/6/11/5/6/5/6/5/6/5/5/11/6/5 fused tetradecacyclic rings with three continuous bridged ring systems. Asperflavipine B (2) is a cytochalasan heterotrimer containing a cytochalasan and two epicoccine moieties with a 5/6/11/5/5/6/5/6/5 nonacyclic ring system. The hypothetical biosynthesis of 1 and 2 is proposed to involve Diels-Alder and [3+2] cycloaddition reactions as key steps and reveals unparalleled plasticity in the biosynthesis of merocytochalasans. The existence of 1 adds a new dimension to the diversity of the cytochalasan family. Compound 1 showed moderate cytotoxicity and induced apoptosis in Jurkat, NB4, and HL60 cells through the activation of caspase-3 and degradation of poly(ADP-ribose) polymerase (PARP).

Biosynthesis of lovastatin using agro-industrial wastes as carrier substrates

Purpose : To compare fungal strains including Aspergillus flavipes GCBL-72, Aspergillus flavus GCBL-60, and Aspergillus niger GCBL-45 and determine whether solid- or liquid-state fermentation (SSF or LSF) is more appropriate for lovastatin production using various inexpensive raw materials. Methods : LSF and SSF techniques were used to produce the drug lovastatin. High-performance liquid chromatography was performed out to quantify lovastatin production. A kinetic growth model was applied to estimate product formation at the expense of substrate utilization. Results : Aspergillus flavus GCBL-60 was a superior lovastatin-producing strain consuming wheat bran as the raw material in SSF. The optimum lovastatin production was 28.36 ± 0.76 mg/100mL at 35 °C, pH 5.5, inoculum size 2 mL, 96 h incubation time, and 60 % moisture content. Evaluation of the kinetic growth parameters for lovastatin production confirmed that product formation was improved after fermentation parameter optimization. Conclusion : Our results indicate that Aspergillus flavus GCBL-60 was best lovastatin-producing strain and that SSF was superior to LSF for maximum production. Careful optimization can enhance product formation. Keywords : Hypercholesterolemia, Kinetics, Optimization, Lovastatin, Solid-State Fermentation, Raw materials

Flavichalasines A\u2013M, cytochalasan alkaloids from Aspergillus flavipes

Two new tetracyclic cytochalasans, flavichalasines A and B (1 and 2), three new pentacyclic cytochalasans, flavichalasines C–E (3–5), and eight new tricyclic cytochalasans, flavichalasines F–M (6–13), together with eight known analogues (14–21), were isolated from the solid culture of Aspergillus flavipes. Structures of these new compounds were elucidated on the basis of extensive spectroscopic analyses including 1D, 2D NMR and HRESIMS data. Their absolute configurations were determined by comparison of their experimental ECD with either computed ECD or experimental ECD spectrum of known compound. The structure and absolute configuration of 2 were further determined by X-ray crystallographic diffraction. Flavichalasine A (1) represents the first example of cytochalasan with a terminal double bond at the macrocyclic ring and flavichalasine E (5) is the only cytochalasan with an α-oriented oxygen-bridge in D ring. These new compounds were evaluated for their cytotoxic activities against seven human cancer cell lines, of which, 6 and 14 displayed moderate inhibitory activities against tested cell lines. In addition, compounds 6 and 14 induced apoptosis of HL60 cells by activation of caspase-3 and degradation of PARP.

Ability of extracellular proteinases of micromycetes Aspergillus flavipes, Aspergillus fumigatus, and Aspergillus sydowii to affect proteins of the human haemostatic system

The effect of extracellular proteinases of A. flavipes A17, A. fumigatus D1, and A. sydowii 1 on proteins of the human haemostasis system was studied. It was shown that A. fumigatus D1 proteinases are able to hydrolyze a wide range of chromogenic peptide substrates of specific human proteinases of the haemostatic system. Proteinases formed by A. flavipes A17 and A. sydowii 1 have a narrow specificity, mainly to thrombin and plasmin substrates. It was first shown that proteinase of A. flavipes A17 is capable to activate protein C and Factor X. Extracellular proteinase produced by A. sydowii 1 has greater fibrinolytic activity as compared with proteinases produced by A. flavipes A17 and A. fumigatus D1.

Scaling-up and ionic liquid-based extraction of pectinases from Aspergillus flavipes cultures

The viability of the scaling-up of pectinases production by Aspergillus flavipes at 5L-bioreactor scale has been demonstrated by keeping constant the power input, and a drastic increase in the endo- and exopectinolytic enzyme production was recorded (7- and 40-fold, respectively). The main process variables were modelled by means of logistic and Gompertz equations. In order to overcome the limitations of the conventional downstream strategies, a novel extraction strategy was proposed on the basis of the adequate salting-out potential of two biocompatible cholinium-based ionic liquids (N1112OHCl and N1112OHH2PO4) in aqueous solutions of Tergitol, reaching more than 90% of extraction.

α-Glucosidase Inhibitors from the Marine-Derived Fungus Aspergillus flavipes HN4-13.

Three new butenolide derivatives, flavipesolides A-C (1-3), along with 13 known compounds (4-13, aspulvinone Q, monochlorosulochrin, and dihydrogeodin), were isolated from the marine-derived Aspergillus flavipes HN4-13 from a Lianyungang coastal sediment sample. The structures were elucidated by spectroscopic evidence. Compounds 4-6 and 9 were noncompetitive α-glucosidase inhibitors with Ki/IC50 values of 0.43/34, 2.1/37, 0.79/19, and 2.8/90 μM, respectively. Compounds 1-3, 8, 10, and 13 are mixed α-glucosidase inhibitors with Ki/IC50 values of (2.5, 19)/44, (3.4, 14)/57, (9.2, 4.7)/95, (6.3, 5.5)/55, (1.4, 0.60)/9.9, and (2.5, 7.2)/33 μM, respectively (IC50 101 μM for acarbose and 79 μM for 1-deoxynojirimycin).

Antibacterial Metabolites from the Sri Lankan Demosponge-Derived Fungus, <i>Aspergillus flavipes</i>

Sri Lankan sponge-derived fungi are an unexploited resource awaiting exploration for drug leads. Three fungi from the internal tissues of a demosponge collected on the west coast of Sri Lanka were isolated and antimicrobial activities of their crude extracts were evaluated. Aspochalasin B, D, M, asperphenamate and 4-OMe asperphenamate were isolated from the crude ethyl acetate extract of the fungus Aspergillus flavipes . Aspochalasin B and D showed antibacterial activities against Bacillus subtilis (MIC, 16 and 32 μg ml -1 respectively), Staphylococcus aureus and MRSA (MIC, 32 μg ml -1 ). The results highlight the potential of isolating bioactive secondary metabolites from Sri Lankan sponge-derived fungi.

Aspergillus flavipes methionine γ-lyase-dextran conjugates with enhanced structural, proteolytic stability and anticancer efficiency

Aspergillus flavipesl-methionine γ-lyase (AfMGL) has been recognized as a powerful broad range anticancer agent. However, catalytic instability and antigenicity are the main challenges of its applications in vivo. Thus, the objective of this study was to investigate the influence of conjugation with dextran on AfMGL biochemical properties and functionality. The activity of dextran AfMGL conjugates was 50% of the free MGL that consistent with the extent of occupied surface reactive amino groups. The accessibility of reactive ε-amino groups on dextran AfMGL surface was reduced by 70% normalizing to free enzyme. The thermal stability of dextran AfMGL was increased by two folds over the free enzyme. The dextran AfMGL had a higher resistance to proteinase K, retaining about 70% of its initial activity comparing to 20% to the native enzyme after 30min of proteolysis at 37°C. The in vivo half-life time of dextran modified AfMGL in New Zealand rabbits was increased by 2.3 folds comparing to free enzyme. The in vitro anticancer activity of the free and modified AfMGL was evaluated against five tumor cell lines (MCF-7, HEPG-2, HCT, PC3, HEP-2). The activity of AfMGL towards the tested tumor cells was significantly increased upon dextran conjugation suggesting the dramatic increasing of MGL hydrophilicity and catalytic efficiency. Dextran solution was used as negative control.

Molecular and Spectroscopic Characterization of Aspergillus flavipes and Pseudomonas putida L-Methionine γ-Lyase in Vitro.

Pseudomonas putida L-methionine γ-lyase (PpMGL) has been recognized as an efficient anticancer agent, however, its antigenicity and stability remain as critical challenges for its clinical use. From our studies, Aspergillus flavipes L-methionine γ-lyase (AfMGL) displayed more affordable biochemical properties than PpMGL. Thus, the objective of this work was to comparatively assess the functional properties of AfMGL and PpMGL via stability of their internal aldimine linkage, tautomerism of pyridoxal 5'-phosphate (PLP) and structural stability responsive to physicochemical factors. The internal Schiff base of AfMGL and PpMGL have the same stability to hydroxylamine and human serum albumin. Acidic pHs resulted in strong cleavage of the internal Schiff base, inducing the unfolding of MGLs, compared to neutral-alkaline pHs. At λ 280nm excitation, both AfMGL and PpMGL have identical fluorescence emission spectra at λ 335nm for the intrinsic tryptophan and λ 560nm for the internal Schiff base. The maximum PLP tautomeric shift of ketoenamine to enolimine was detected at acidic pH causing complete enzyme unfolding, subunits dissociation and tautomeric shift of intrinsic PLP, rather than neutral-alkaline ones. The T m of AfMGL and PpMGL in presence of thermal stabilizer/ destabilizer was assayed by DSF. The T m of AfMGL and PpMGL was 73.1°C and 74.4°C, respectively, suggesting the higher proximity to the tertiary structure of both enzymes. The T m of AfMGL and PpMGL was slightly increased by trehalose and EDTA in contrast to guanidine HCl and urea. The active site and PLP-binding domains are identically conserved in both AfMGL and PpMGL.

GC/MS spectroscopic approach and antifungal potential of bioactive extracts produced by marine macroalgae

The antifungal activity and the chemical constituents of selected macroalgae collected from the Egyptian Mediterranean coast of Alexandria have been investigated. Agar well diffusion assay was used to determine the antifungal potential of the extractable matter against Fusarium solani, Fusarium oxysporum, Tricoderma hamatum, Aspergillus flavipes and Candida albicans. The ethyl acetate and methanolic extracts (ULE2 and ULM5) of Ulva lactuca obtained from Al Selsela exhibited the highest activity with (AI)=1.05±0.053 and 1.03±0.052, respectively, compared with fluconazole. However, the methanolic extract of U. lactuca (ULM1) from Abu Qir Bay showed (AI)=0.73±0.037. This followed by methanolic extracts of Pterocladia capillacea (PCM1: AI=0.70±0.035 and Ulva fasciata (UFM1: AI=0.69±0.035). GC/MS analysis of ULM1 and ULM5 indicated the existence of different constituents revealing ecological impacts. The methanolic extract (UFM1) contains six major components including palmitic acid, methylester, trichloromethyloxirane, linolenic acid, ethylester, 3,7,11,15-tetramethyl-2-hexadecen-1-ol, 11-octadecenoic acid, methylester and 12,15-octadecadienoic acid, methylester. High percentages of palmitic acid, n-heptacosane, 2-methylhexadecan-1-ol, methoxy acetic acid, 2-tridecylester and myristic acid are found in the methanolic extract of P. capillacea (PCM1). Most of the identified components have been reported to possess antimicrobial activity that could be responsible for the antifungal potential reported in the present study.

Zirconium-Doped Fungal Sorbents: Preparation, Characterization, Adsorption Isotherm, and Kinetic and Mathematical Modelling Study for Removal of Fluoride

The present study involves usage of more efficient and eco-friendly zirconium-doped, fluoride-resistant fungal biosorbents for removal of excess fluoride from groundwater. It was observed that >94% fluoride removal was possible at optimal conditions for the four fungal species studied. The adsorption isotherm studies indicated that zirconium-doped Aspergillus ficuum SIT-CH-2, Aspergillus terreus SIT-CH-3, and Aspergillus flavipes SIT-CH-4 were best described by Freundlich isotherm and zirconium-doped Penicillium camemberti SIT-CH-1 fitted well with Langmuir adsorption isotherm equation. The pseudo-second-order kinetics model showed the best fit for all of the four zirconium-doped fungal species for the fluoride biosorption.

ChemInform Abstract: Polyketide Butenolide, Diphenyl Ether, and Benzophenone Derivatives from the Fungus Aspergillus flavipes PJ03‐11.

AbstractFive new polyketides (Ia), (Ib), (II), (III), and (IV) are isolated from the wetland fungus Aspergillus flavipes PJ03‐11 together with 11 known compounds.

ChemInform Abstract: Epicochalasines A and B: Two Bioactive Merocytochalasans Bearing Caged Epicoccine Dimer Units from Aspergillus flavipes.

Abstractisolation, structure elucidation, biogenetic pathway, and bioactivity of the new title cytochalasans possessing a hendecacyclic ring system containing an adamantyl cage

Epicochalasines A and B: Two Bioactive Merocytochalasans Bearing Caged Epicoccine Dimer Units from Aspergillus flavipes

AbstractTwo bioactive merocytochalasans, epicochalasines A (1) and B (2), a new class of cytochalasans bearing unexpected scaffolds consisting of fused aspochalasin and epicoccine dimer moieties, were isolated from the liquid culture broth of Aspergillus flavipes. Both 1 and 2 possess a hendecacyclic 5/6/11/5/6/5/6/5/6/6/5 ring system containing an adamantyl cage and as many as 19 stereogenic centers; however, the fusion patterns of 1 and 2 differ greatly, thus resulting in different carbon skeletons. The absolute configurations of 1 and 2 were determined by X‐ray diffraction and calculated ECD, respectively. The biogenetic pathways of 1 and 2 are proposed to involve Diels–Alder and nucleophilic addition reactions. Both 1 and 2 induced significant G2/M‐phase cell‐cycle arrest. Furthermore, we found that merocytochalasans induce apoptosis in leukemia cells through the activation of caspase‐3 and the degradation of PARP.