Characteristics of two cedarwood essential oil emulsions and their antioxidant and antibacterial activities

Cedarwood essential oil (CEO) has the effect of anti-inflammatory and anti-bacteria. However, the application of this essential oil is limited due to its strong volatility and poor water solubility. To address this issue, two types of oil-in-water CEO emulsions including CEO nanoemulsion (CEO-NE) and CEO Pickering emulsion (CEO-PE) were prepared. CEO-NE with 5% surfactant, had a smaller particle size (135.14 ± 1.1 nm) and higher absolute zeta potential value (32.75 mV) compared with CEO-PE (1% starch) which particle size was 626.21 ± 6.05 nm, zeta potential was 27.58 mV. The stability of CEO-NE and CEO-PE were tested by multiple light scattering, results showed that Turbiscan Stability Index (TSI) value of CEO-NE was much lower than that of CEO-PE. CEO-NE and CEO-PE exerted higher free radical scavenging activities, iron reducing power and antibacterial ability than CEO itself. These results indicated that emulsification is a feasible method to extend application of CEO.