Resveratrol Demonstrates Antimicrobial Effects Against Propionibacterium acnes In Vitro

INTRODUCTION Resveratrol (3,5,4'-trihydroxystilbene) is an antioxidant that has multiple biologic effects including antimicrobial properties. Acne vulgaris is a disease of the pilosebaceous unit, characterized by an inflammatory host immune response to the bacteria Propionibacterium acnes (P. acnes). This study sought to determine whether resveratrol may be a potential treatment for acne vulgaris. METHODS Colony-forming unit (CFU) assays together with transmission electron microscopy using P. acnes treated with resveratrol or benzoyl peroxide were used to assess antibacterial effects. Blood was drawn from healthy human volunteers, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays were used to assess cytotoxicity in monocytes and keratinocytes. RESULTS Resveratrol demonstrated sustained antibacterial activity against P. acnes, whereas benzoyl peroxide, a commonly used antibacterial treatment for acne, demonstrated a short-term bactericidal response. A combination of resveratrol and benzoyl peroxide showed high initial antibacterial activity and sustained bacterial growth inhibition. Electron microscopy of P. acnes treated with resveratrol revealed altered bacterial morphology, with loss of membrane definition and loss of well-defined extracellular fimbrial structures. Resveratrol was less cytotoxic than benzoyl peroxide. CONCLUSION The sustained antibacterial activity and reduced cytotoxicity versus benzoyl peroxide demonstrated by resveratrol in this study highlight its potential as a novel therapeutic option or adjuvant therapy in the treatment of acne vulgaris.