Naphtho-Gamma-Pyrones Produced by Aspergillus tubingensis G131: New Source of Natural Nontoxic Antioxidants

Abstract

Seven naphtho-gamma-pyrones (NγPs), including asperpyrone E, aurasperone A, dianhydroaurasperone C, fonsecin, fonsecinone A, fonsecin B, and ustilaginoidin A, were isolated from Aspergillus tubingensis G131, a non-toxigenic strain. The radical scavenging activity of these NγPs was evaluated using ABTS assay. The Trolox equivalent antioxidant capacity on the seven isolated NγPs ranged from 2.4 to 14.6 μmol L−1. The toxicity and ability of the NγPs to prevent H2O2-mediated cell death were evaluated using normal/not cancerous cells (CHO cells). This cell-based assay showed that NγPs: (1) Are not toxic or weakly toxic towards cells and (2) are able to protect cells from oxidant injuries with an IC50 on H2O2-mediated cell death ranging from 2.25 to 1800 μmol mL−1. Our data show that A. tubingensis G131 strain is able to produce various NγPs possessing strong antioxidant activities and low toxicities, making this strain a good candidate for antioxidant applications in food and cosmetic industries.

Statistical approach to evaluate effect of temperature and moisture content on the production of antioxidant naphtho-gamma-pyrones and hydroxycinnamic acids by Aspergillus tubingensis in solid-state fermentation

“…In a strategy of maximization of the antioxidant properties of the crude extract, fonsecin and ustilaginoidin A are the most desirable compounds of the crude extract as they are the most antioxidant compounds [23]. Therefore, to obtain a crude extract with maximum antioxidant properties and because there is a net quantitative difference in the production between fonsecin and the other compounds, fonsecin production must be favored.…”

“…Among the various metabolites that own antioxidant properties, fonsecin and ustilaginoidin A exhibit the highest potentials of 13.32 ± 0.08 and 14.59 ± 1.75, respectively (not significantly different from the radical scavenging activity of ascorbic acid: 13.23 ± 0.05), when measured with an ABTS assay. This antioxidant potential then decreases as follows: trans-ethyl 1 3 ferulate (8.32 ± 0.85), p-coumaric acid (6.86 ± 0.43), fonsecin B (5.12 ± 0.08), dianhydroaurasperone C (4.57 ± 0.36) and asperpyrone E (3.29 ± 0.11) [23].…”

“…Isolation and radical scavenging capacity assays of the compounds were studied in a previous work [23]. Briefly, the radical scavenging capacity assay was carried out as follows: a solution of radical monocation ABTS •+ reacted with 10 µmol L −1 of the assayed compound for 5 min, at 25 °C, in 96-well plates.…”

“…A. tubingensis strain G131 isolated from grape from a vineyard in Southern France can produce naphtho-gamma-pyrones (NγPs) [20]. These secondary metabolites exhibit a broad spectrum of biological activities and particularly radical scavenging activities which depend on the number of hydroxyl groups on the NγP skeleton [21][22][23]. Also, this fungus is non-mycotoxigenic as genome sequencing revealed that the synthetic genes required for the production of ochratoxin A and fumonisin are absent [24].…”

Biomolecules from Different Angles

“…Therefore, this Special Issue is a snapshot of a collective view of Biomolecules on biomolecules. The covered topics range from the description of secondary metabolites produced by fungi [ 1 ] to the overview of the phytochemical composition and pharmacological and food applications of Prosopis plants [ 2 ], to comparative evaluation of the antiproliferative activity of plant-derived silver nanoparticles synthesized using callus and anthocyanin extracts of purple basil (BC-AgNPs and AE-AgNPs, respectively) [ 3 ], to systematic description of the utilization of natural products as a source of antitumor drugs [ 4 ], to the analysis of the effects of caffeine and other methylxanthines on Aβ-homeostasis by shifting the α- and β-secretase-based processing of amyloid precursor protein (APP) from the Aβ-producing amyloidogenic to the non-amyloidogenic pathway [ 5 ], to the topoisomerase I and radical trapping antioxidant activities of a series of N-alkyl-acridones and N,N′-dialkyl-9,9′-biacridylidenes [ 6 ], to the analysis of the effects of phytoalexins in soybeans via synergistic inhibition on α-glucosidase [ 7 ], to functional and structural characterization of several important proteins (such as the analysis of the general and genomic DNA-binding specificity of a transcription factor TTHB023 from Thermus thermophilus HB8 [ 8 ], investigation of the voltage sensing in protein translocation via the bacterial channel SecYEG [ 9 ], and structural characterization of the terminase (packaging protein) pUL15, which is the most conserved among all the Herpes Simplex Virus 1 (HSV1) gene products [ 10 ]), to the description of utilization of kinetic transition in amyloid assembly for screening fluorophores for preferential responses to oligomer over fibril formation [ 11 ], to the description of the utilization of amyloid fibril biomaterials, designer amyloid cell-penetrating peptides comprised of β-sheet cores derived from naturally occurring protein sequences and designed positively charged and aromatic residues exposed at key residue positions as gene transfer vehicles capable of self-assembling and promoting the DNA condensation and cell internalization [ 12 ], to the introduction of the use of phage display system for generation of lamprey monoclonal antibodies, lampribodies, which are the variable lymphocyte receptors (VLRs) consisting of leucine rich repeats (LRRs), whose diversity is generated by stepwise genomic rearrangements of LRR cassettes dispersed throughout the VLRB locus [ 13 ], to the description of changes in the N-glycomic profile associated with post-traumatic stress disorder (PTSD) via comparative analysis of the N-glycomic profiles in 543 male Caucasian individuals (299 veterans with PTSD and 244 control subjects) [ 14 ], to the analysis of the effect of macromolecular crowding on the functionality of tumor suppressors ING containing a plant homeodomain (PHD) and their ability to interact with the histone H3 trimethylated at lysine 4 (H3K4me3) [ 15 ], and to the compariso...…”