Acnocure, a Synergistic Anti-Microbial and Anti-Inflammatory Combination of Thymol and Curcuma Turmerones, Formulation and Time-Kill Studies Against C. acnes

Today, most anti-acne treatments employ topical and systemic antibiotics such as erythromycin and clindamycin, which induce cutaneous dysbiosis with adverse side effects to the skin’s normal microbiota, consequently leading to the emergence of antimicrobial resistance. In our quest to discover natural anti-acne bioactives as alternatives, we undertook a research program with the aim to identify a new blend of active ingredients based on the monoterpene phenol moiety. Within this program, we evaluated the in vitro anti-acne efficacy of thymol, Curcuma turmerones and their patented combination “Acnocure” in a cosmetic formulation. The minimum inhibitory concentration (MIC) of Acnocure against C. acnes (ATCC 6919), S. aureus (ATCC 6538), S. epidermidis (ATCC 12228) and C. freneyi (CIP 52.16) was determined to be 0.32, 0.26, 0.47 and 0.11 mg/mL, respectively. In the time-kill curve study against C. acnes, Acnocure, containing thymol 0.25% and 0.1% Curcuma turmerone as well as thymol 0.1% and 0.1% Curcuma turmerone in a cosmetic simplex formulation, demonstrated rapid bactericidal activity with a 4.7 log reduction at pH 5.5, occurring within just two hours of the study and lasting for over 24 h. The killing efficacy was similar to our cosmetic reference benchmark, Effaclar DUO serum, used in the same study. Additionally, thymol, Curcuma turmerones and Acnocure were evaluated in an anti-inflammatory efficacy assay in lipopolysaccharide (LPS)-primed U937 macrophages model and demonstrated moderate inhibition of interleukin-1β (IL-1β) at 100 µg/mL and significant inhibition of prostaglandin E-2 (PGE-2) at 1 µg/mL, respectively. Further evidence gathered on thymol and Curcuma turmerones in an IL-1α-stimulated dermal fibroblast model showed >90% inhibition of PGE-2 release between 2 µg/mL and 30 µg/mL concentrations. These promising results position Acnocure as a natural alternative for the replacement of synthetic corticosteroids and antibiotics with potent anti-acne skincare properties.