Antimicrobial Effect of Piceatannol, a Resveratrol Metabolite, on Staphylococcus Aureus

Objectives: Staphylococcus aureus (S. aureus) is one of the major human pathogens in both community acquired and nosocomial infections. Heavy increase of antibiotic resistance between S. aureus strains became an important public health problem in progress of time. In this study, the antimicrobial effects of piceatannol on S. aureus growth was investigated. Patients and Methods: The antimicrobial effect of piceatannol on a standard S. aureus (DSMZ 6148) strain and two clinical S. aureus strains (C1 and C2) was tested in vitro at concentrations between 0 and 750 μg/ mL. Tigecycline and gentamicin were used as positive controls. For each strain, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of piceatannol and the control antibiotics were determined separately using the broth microdilution method according to CLSI (Clinical and Laboratory Standards Institute) standards at 24 and 48 h. Results: After 24 and 48 h of treatment with piceatannol, the average MIC for all tested strains was 283 μg/mL and 383 μg/mL, respectively. Bactericidal activity increased as piceatannol concentration increased for one of the three strains. After 24 and 48 h of treatment with piceatannol, the average MBC for all strains was 717 μg/ mL and 583 μg/ mL, respectively. The S. aureus strains were found to be susceptible to tigecycline and gentamicin. Conclusion: Piceatannol has antimicrobial effect against S. aureus; however, more data regarding the effects of this compound on other microorganisms and its bioavailability are needed.