Development of stable cinnamon essential oil emulsions using natural extracts from Gleditsia sinensis Lam rich in galactomannan and saponin

The application of essential oils in cosmetics and personal care products is limited due to their poor water solubility and sensitivity to external factors. This study aims to explore the effectiveness of using aqueous extracts from Gleditsia sinensis Lam seeds (AEGS) and Gleditsia sinensis Lam pods (GSW) to stabilize cinnamon essential oil emulsions. By combining single-factor and orthogonal experiments, the optimal microwave-assisted extraction parameters was determined for aqueous extracts from Gleditsia sinensis Lam seeds to enhance extraction efficiency. The results showed that GSW was rich in saponin components, primarily serving as an emulsifier, while AEGS was rich in galactomannan, primarily acting as a stabilizer. The combination of AEGS and GSW significantly improved the physical stability of cinnamon essential oil emulsions, particularly demonstrating excellent stability under high ionic strength and across a wide pH range. In addition to stabilizing the activity of essential oils, the natural emulsion itself possesses with multiple biological activities. When the emulsion was loaded with essential oils, the entire emulsion system showed even more pronounced antioxidant properties, tyrosinase inhibition activity, and anti-Malassezia activity, highlighting their substantial potential for application in the cosmetics and skincare industry. This research provides new insights for developing stable emulsions with multiple biological activities based on natural ingredients.