Antimicrobial and Resistance Modifying Activities of Cerevisterol Isolated from Trametes Species

Abstract

Background: The development of resistance by pathogenic microorganisms has renewed the worldwide search for novel antimicrobial agents. Mushrooms are of recent interest because a wide variety of biologically active compounds have been isolated from them. This study isolated antimicrobial compound from two wood decaying mushrooms, Trametes gibbosa and Trametes elegans, and determined the resistance modifying activities of the isolated compound. Methods: Bioactivity guided isolation of active principles from the methanol extract of T. gibbosa and T. elegans was performed using column and preparative high-performance liquid chromatography. The structures of isolated compounds were elucidated using nuclear magnetic resonance spectroscopy. Broth micro-dilution assay was used to determine the antimicrobial and resistance modifying activities of the isolated compounds against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Streptococcus pyogenes, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Candida albicans, Aspergillus niger, Aspergillus flavus and Aspergillus tamarii. Results: Bioactivity guided isolation lead to the isolation of cerevisterol (ergosta-7, 22E-diene-3β5α, 6β- triol) from both T. gibbosa and T. elegans. The isolated cerevisterol inhibited the growth of S. typhi, S. aureus and A. niger with MICs of 25 µg/mL each and 50 μg/mL against E. faecalis. The MBCs of cerevisterol against S. typhi S. aureus, E. faecalis and A. niger were 50, 100, 200 and 100 µg/mL, respectively. The sub-inhibitory concentration (3 µg/mL) of cerevisterol modified the activity of erythromycin, ampicillin, ciprofloxacin, tetracycline and amoxicillin either by potentiating or reducing their activities. Conclusion: Cerevisterol possesses both antimicrobial and resistance modifying activities.