Žáková T., Rondevaldová J., Bernardos A., Landa P., Kokoška L.
ACTA MICROBIOLOGICA ET IMMUNOLOGICA HUNGARICA 65(4): 467–476, 2018

Keywords: antimicrobial activity, natural antibacterial agents, minimum inhibitory concentration, Staphylococcus aureus, structure–activity relationships
Abstract: Staphylococcus aureus is a major human pathogen that is responsible for both hospital- and community-acquired infections. Stilbenes are polyphenol compounds of plant origin known to possess a variety of pharmacological properties, such as antibacterial, antiviral, and antifungal effects. This study reports the in vitro growth-inhibitory potential of eight naturally occurring stilbenes against six standard strains and two clinical isolates of S. aureus, using a broth microdilution method, and expressing the results as minimum inhibitory concentrations (MICs). Pterostilbene (MICs=32–128 μg/ml), piceatannol (MICs=64–256 μg/ml), and pinostilbene (MICs=128 μg/ml) are among the active compounds that possess the strongest activity against all microorganisms tested, followed by 3′-hydroxypterostilbene, isorhapontigenin, oxyresveratrol, and rhapontigenin with MICs 128–256 μg/ml. Resveratrol (MIC=256 μg/ml) exhibited only weak inhibitory effect. Furthermore, structure–activity relationships were studied. Hydroxyl groups at ortho-position (B-3′ and -4′) played crucial roles for the inhibitory effect of hydroxystilbene piceatannol. Compounds with methoxy groups at ring A (3′-hydroxypterostilbene, pinostilbene, and pterostilbene) produced stronger effect against S. aureus than their analogues (isorhapontigenin and rhapontigenin) with methoxy groups at ring B. These findingsprovideargumentsforfurtherinvestigationofstilbenesasprospectiveleading structures for development of novel antistaphylococcal agents for topical treatment of skin infections.
DOI: 10.1556/030.65.2018.040 IEB authors: Přemysl Landa