Synergistic Antioxidant and Anti-Inflammatory Pickering Emulsions of Paeonol−Camellia Oil Stabilized by Cellulose Nanocrystals and Nanofibrils

Abstract Camellia oil is prone to oxidation, while paeonol suffers from poor water solubility and photothermal instability, which limit their coapplication. Although nanocellulose-based Pickering emulsions offer a promising route for codelivery, achieving satisfactory stability at relatively low particle loadings without additional hydrophobic modification or conventional surfactants remains of practical interest. To address these issues, cellulose nanocrystals (CNC) and TEMPO-oxidized cellulose nanofibrils (CNF) were used as composite stabilizers at a relatively low concentration of 0.6 wt %, with the assistance of NaCl. Hydroxyethyl cellulose (HEC) was further introduced to reinforce the continuous-phase network, thereby forming paeonol-loaded Camellia oil Pickering emulsions. The results showed that the CNC/CNF composite stabilizers, in combination with NaCl, provided effective particulate stabilization, while HEC further enhanced coalescence resistance by reinforcing the continuous-phase network. High-pressure microfluidization reduced the droplet size to approximately 3 μm. At a paeonol loading of 0.6 wt %, the emulsion showed notable antioxidant activity and potential anti-inflammatory effects in vitro, with DPPH and ABTS radical scavenging rates of 77.05% and 77.38%, and an inhibition rate of 51.56%. In this way, good storage stability was achieved with a relatively low CNC/CNF loading and without additional hydrophobic modification or surfactants, providing a green strategy for the codelivery of Camellia oil and paeonol for potential topical applications.