Enhanced anti-inflammatory potential of degradation resistant curcumin/ferulic acid eutectics embedded in triglyceride-based microemulsions

Abstract Negligible solubility of curcumin in water combined with rapid degradation have limited its medical applications. In this contribution, eutectic mixture of curcumin with one of its degradation products (ferulic acid) was encapsulated into long and medium chain triglycerides oils and stabilised by the non-ionic surfactant polyoxyethylene oleyl ether Brij® O10 (C18:1E10) and bile acid derivative (sodium deoxycholate). Thermal and spectroscopic analysis confirmed the presence of curcumin as solid nanocrystals embedded within the microemulsion droplets. UV-spectroscopy and LC-MS studies of formed microemulsions revealed that degradation of curcumin in water was significantly reduced with more than 83% of curcumin remained intact after 24 hours. 1H NMR results showed that curcumin remained stable upon heating in the range between 297K-327 K with no signs of degradation to ferulic acid. The results showed solubility enhancement of curcumin with a range of 3-5 mg/mL. NF-κB reporter cell assay revealed low cytotoxicity and three folds stronger anti-inflammatory potential compared to curcumin. Microemulsions remained stable for over 12 months with extended stability of formulations that contained curcumin/ferulic acid in glyceryl tricaprate based microemulsions. Overall these results suggest novel role for particle engineering via using ferulic acid as stability and activity enhancer for curcumin through free radicals scavenging mechanism.