Preparation of lutein nanoemulsion by ultrasonic homogenization method: Stability and in vitro anti-inflammatory activity

Lutein is a natural antioxidant that has anti-inflammatory activity; thus, lutein-enriched anti-inflammatory agents have the potential for development. Nanoemulsions represent an effective molecular liquid for improving the solubility and stability of lutein. The oil and surfactant components, preparation method and preparation conditions are highly related to the stability and biological activity of nanoemulsions. In this study, lutein nanoemulsions were prepared by the ultrasonic homogenization method, the components and preparation conditions were optimized by the response surface methodology, and the final preparation conditions were confirmed. The contents of medium chain triglyceride (MCT) and Tween 80 were 1.5 wt% and 11 wt%, respectively, and the ultrasonic time was 8.5 min. The anti-inflammatory activities and long-term stability of the prepared lutein nanoemulsion were then evaluated. Lutein affected the secretion levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and monocyte chemotactic and activating factor (MCAF), especially IL-6 and MCAF. On Day 28, the lutein retention rates of lutein nanoemulsion with Propyl gallate (PG) at 4 °C, 25 °C and 37 °C were 97.75 ± 0.43 %, 75.77 ± 0.45 % and 47.72 ± 0.19 %, respectively. The addition of PG greatly improved the retention rate of lutein and the particle size stability of the lutein nanoemulsion at high temperature (37 °C). The current results demonstrated the potential utilization of lutein emulsion as anti-inflammatory agents.