Purpose: This study aimed to evaluate the antimicrobial and biofilm-formation inhibition properties of polyols—1,2-hexanediol, 1,3-propanediol, and 1,2-butanediol—and acids—potassium benzoate and levulinic acid—as alternative preservatives for use in cosmetics.Methods: Minimum inhibitory concentration, minimum bactericidal concentration, and biofilm inhibition activities were ascertained. Representative pathogenic bacteria, such as Staphylococcus aureus and Pseudomonas aeruginosa, as well as beneficial skin bacteria, including Staphylococcus epidermidis and Corynebacterium accolens, were tested.Results: Among the three polyols, 1,2-hexanediol, which had the longest carbon chain, exhibited the most potent antimicrobial and biofilm-formation inhibitory activities against all tested species. Among the acids, levulinic acid was more effective than potassium benzoate. Notably, it demonstrated selective and potent suppression of pathogenic bacteria at low concentrations; however, higher concentrations were required with to inhibit beneficial bacteria. Additionally, all alternative preservatives exhibited superior biofilm suppression abilities compared to the positive control, ethanol. These effects demonstrated a dose-dependent increase and were quantitatively compared using the IC90 values.Conclusion: The findings provide fundamental data for the development of safe and effective alternative preservatives that can maintain the homeostasis of the skin microbiome. They offer important insights for future in vivo studies and innovations in cosmetic formulations.
Baek et al. (Thu,) studied this question.