Immunomodulatory Effects of Cinnamaldehyde in Staphylococcus aureus-Infected Wounds

Cinnamaldehyde (CNM) is an essential-oil component with reported anti-infective, anti-inflammatory, and healing effects, making it an interesting compound for the treatment of wound infection. Herein, we evaluated the effects of topical administration of CNM in experimental wounds infected by Staphylococcus aureus. Swiss mice (n = 12/group) were randomly allocated into three groups (CON: animals with uninfected lesions; Sa: animals with untreated infected lesions; Sa + CNM: animals with infected wounds and treated with CNM). Excisional lesions (64 mm²) were induced at the dorsal area followed by the addition of S. aureus (80 μL of a 1.5 × 10⁸ CFU/mL bacterial suspension). The wounds were treated with CNM (200 μg/wound/day) or vehicle (2% DMSO) for 10 days. Skin samples were taken on the 3^rd or 10^th treatment day for quantification of inflammatory mediators, bacterial load, immunophenotyping, and histological analysis. The treatment with CNM improved the healing process and attenuated the severity of skin lesions infected by S. aureus. These effects were associated with significant decreases in bacterial loads in CNM-treated wounds. The levels of neutrophils, TNF-α, IL-6, NO, and VEGF were decreased in the lesions treated with CNM. Taken together, these data provide further evidence of the effectiveness of CNM for the treatment of skin infections.