The Chemical Profiling, Docking Study, and Antimicrobial and Antibiofilm Activities of the Endophytic fungi Aspergillus sp. AP5

Abstract

Growing data suggest that <i>Aspergillus niger</i>, an endophytic fungus, is a rich source of natural compounds with a wide range of biological properties. This study aimed to examine the antimicrobial and antibiofilm capabilities of the <i>Phragmites australis</i>-derived endophyte against a set of pathogenic bacteria and fungi. The endophytic fungus <i>Aspergillus</i> sp. AP5 was isolated from the leaves of <i>P. australis</i>. The chemical profile of the fungal crude extract was identified by spectroscopic analysis using LC-HRESIMS. The fungal-derived extract was evaluated for its antimicrobial activity towards a set of pathogenic bacterial and fungal strains including <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, <i>Proteus vulgaris</i>, <i>Klebsiella</i> sp., <i>Candida albicans</i>, and <i>Aspergillus niger</i>. Moreover, antibiofilm activity toward four resistant biofilm-forming bacteria was also evaluated. Additionally, a neural-networking pharmacophore-based visual screening predicted the most probable bioactive compounds in the obtained extract. The AP5-EtOAc extract was found to have potent antibacterial activities against <i>S. aureus</i>, <i>E. coli</i>, and <i>Klebsiella</i> sp., while it exhibited low antibacterial activity toward <i>P. Vulgaris</i> and <i>P. aeruginosa</i> and displayed anticandidal activity. The AP5-EtOAc extract had significant antibiofilm activity in <i>S. aureus,</i> followed by <i>P. aeruginosa.</i> The active metabolites' antifungal and/or antibacterial activities may be due to targeting the fungal CYP 51 and/or the bacterial Gyr-B.