Secalonic acid F1 derived from an endophytic fungus Periconia verrucosa as a potential antimicrobial agent against...

To investigate the antimicrobial potential of a secalonic acid F1 derivative produced by an endophytic Periconia verrucosa.

The endophyte RDE85 was characterized as P. verrucosa by morphological and phylogenetic analysis. We characterized a major compound from RDE85 as Secalonic acid F1 (SF1) with a 2,4'-linkage. SF1 demonstrated antimicrobial activity with an IC50 of 7.6 µg mL-1 against Staphylococcus aureus. It inhibited the biofilm formation, causing morphological changes and disruption of cell membrane integrity in the pathogen, confirmed by scanning electron microscopy (SEM). The compound depicted strong synergistic potential with ciprofloxacin and reduced DNA and RNA synthesis. The time-kill kinetics demonstrate that SF1 is an effective concentration-dependent bactericidal agent. Further, SF1 severely affected the respiratory chain dehydrogenase activity, confirmed by in-silico studies, revealing its interaction with respiratory chain succinate dehydrogenase. The treatment with this compound downregulated the staphylococcal accessory gene regulator and enterotoxin gene, two important virulence factors of the organism, and reduced the staphyloxanthin production, which is also an important virulence trait.

SF1 is a potential antimicrobial agent against S. aureus.