Antimicrobial potential of Aspergillus fumigatiaffinis and A. sclerotiorum: Insights from in vitro and molecular docking investigations

This study was conducted to evaluate the antimicrobial activity of metabolites produced by two Aspergillus species: A. fumigatiaffinis and A. sclerotiorum, against six bacterial strains and a yeast. An extraction of metabolites was carried out using three solvents, after selection of the best solvent, the obtained organic extracts were exposed to extreme conditions to test their stability. furthermore, three culture media with different compositions were used to select the best medium. The obtained results showed that the two Aspergillus species have interesting antimicrobial activity. Chloroform proved to be the best solvent for the extraction of bioactive metabolites. Additionally, the stability study showed that the majority of active extracts retain their activity after heat treatment (up to 100 °C) and exposure to light. However, the most suitable medium for antimicrobial activity was PDB. Molecular docking techniques were employed to explore the interactions between secondary metabolites from Aspergillus strains and the gyrase enzyme of Staphylococcus aureus, which was further supported by in vitro tests demonstrating strong antimicrobial activity of Aspergillus strains extracts against this bacterium. Docking analysis revealed compelling binding affinities of selected Aspergillus-derived secondary metabolites to the gyrase enzyme active site, characterized by diverse interaction patterns. These interactions offer insights into potential inhibitory effects on the gyrase enzyme, and suggest promising avenues for the development of therapeutic interventions against S. aureus infections.