Influence of Storage Time on the Physical-Chemical Properties of Cinnamon Bark (Cinnamomum cassia) Essential Oil Nanoemulsions.

The development of antimicrobial resistance against traditionally used drugs has become a current problem. To address these problems, essential oil emulsions have emerged as one of the solutions. Emulsions, however, may exhibit instability phenomena due to storage time. This study investigated the influence of storage time on the physicochemical properties of cinnamon bark essential oil emulsions. These emulsions were produced using: cinnamon bark essential oil (Cinnamomum cassia) (CEO), coconut oil as the Ostwald ripening inhibitor (OR), and 10 and 20 % (v/v) of polysorbate 80 (CEOE-1 and CEOE-2, respectively) as the surfactant by spontaneous emulsification. The visual appearance of emulsions CEOE-1 and CEOE-2 were evaluated at 0, 15, and 30 days. For these emulsions, the physicochemical properties investigated were: pH, turbidity, and dynamic viscosity at 0, 15 and 30 days. Dynamic light scattering results revealed that the average particle size for CEOE-1 and CEOE-2 are in nanometric dimensions, 176.79 ± 3.13 nm and 182.53 ± 1.47 nm, respectively. Our results demonstrated marginal variations in the physicochemical properties of CEOE-2 at 0, 15 and 30 days. In addition, the antimicrobial activity against Escherichia coli and Candida albicans was found for CEOE-1 and CEOE-2, but not to Staphylococcus aureus.