Enhancement of Anti-Inflammatory Properties of Nobiletin in Macrophages by a Nano-Emulsion Preparation

Lots of active substances are hydrophobic materials at ambient and body temperatures, decreasing their bioavailability and posing great challenges to successful incorporation into medication and functional foods. The goal of this research was to develop a nanoemulsion delivery system containing a hydrophobic crystalline bioactive component (nobiletin) to improve the anti-inflammatory activity. Nobiletin was incorporated into the oily phase, and the nanoemulsions were fabricated using high-speed and high-pressure homogenization. Particle size, polydispersity index (PDI), and zeta potential were evaluated by a commercial laser light scattering instrument. The anti-inflammatory activities were performed in LPS-stimulated RAW 264.7 cells. The developed nobiletin nanoemulsion had an average droplet size of 168.6 ± 3.8 nm and a PDI of 0.168, while the average diameter of the blank nanoemulsion was 157.3 ± 1.9 nm and its PDI was 0.161. The zeta potential values of nobiletin nanoemulsion and blank nanoemulsion were −68.45 ± 0.64 and −62.75 ± 0.21 mV, respectively. All obtained nanoemulsions kept physically stable during storage at 4, 25, and 37 °C. A nobiletin-loaded nanoemulsion showed an enhanced anti-inflammatory activity in LPS-induced macrophages, with a decrease in pro-inflammatory mediators and cytokines. The findings suggested that the nanoemulsion would be used as an effective delivery system for nobiletin to improve its anti-inflammatory activity.