Background: Acne vulgaris is a complex, chronic, and common skin disorder of pilosebaceous units. The major pathogenic factors involved are ductal hyperkeratinization, obstruction of sebaceous follicles resulting from abnormal keratinization of the infundibular epithelium, stimulation of sebaceous gland secretion by androgens, and microbial colonization of pilosebaceous units by Propionibacterium acnes, which promotes perifollicular inflammation.
Aim: The aim of the study was to investigate the therapeutic effects of resveratrol, a natural phytoalexin produced by some spermatophytes, such as grapes and other plants, on acneic skin.
Methods: Resveratrol was incorporated in a carboxymethylcellulose-based gel. The chemical stability of resveratrol after storage at 4°C for 30 days was investigated by high-performance liquid chromatography (HPLC). The resveratrol-containing hydrogel was administered to 20 patients affected by acne vulgaris enrolled in this single-blind study. The resveratrol-containing formulation was applied daily as a solo treatment on the right side of the face for 60 days, while the hydrogel vehicle was applied to the left side of the face as a control. To objectively evaluate the results, a digital photographic database was used to collect images. The number and type of lesions were recorded for each patient, to compare the Global Acne Grading System (GAGS) score before treatment with that obtained at the end of the study. Moreover, with the innovative technique of follicular biopsy, areas of acneic skin were prepared for histopathology. The average area occupied by microcomedones at baseline was compared with that at the end of treatment.
Results: HPLC analysis demonstrated that resveratrol, upon incorporation into the gel, did not convert to its cis-isomer when stored at 4°C for 30 days. All patients were satisfied with the active treatment and none experienced adverse effects. Clinical evaluation showed a 53.75% mean reduction in the GAGS score on the resveratrol-treated sides of the face compared with 6.10% on the vehicle-treated sides of the face. These data were supported by histologic analysis, which showed a 66.7% mean reduction in the average area of microcomedones on the resveratrol-treated sides of the face. The comparison with the vehicle-treated side of the face (9.7% reduction) showed a clinically relevant and statistically significant decrease of lesions in areas treated with resveratrol-containing hydrogel.
Conclusion: This pilot study showed positive results for resveratrol gel in acne, and should be considered a valid starting point for further testing of the effectiveness of this molecule in different concentrations and formulations and in a larger group of patients.