Encapsulation of curcumin in recombinant human H-chain ferritin increases its water-solubility and stability

Abstract Curcumin is a natural bioactive agent found in turmeric ( Curcuma longa ) and has many health-promoting benefits. However, its poor water-solubility and thermal and photostability limit its application in foodstuffs. In the present study, recombinant human H-chain ferritin (rHuHF), a typical shell-like protein with an inner diameter as ~ 8 nm was used to encapsulate curcumin by taking advantage of the reversible dissociation and reassembly characteristic of apoferritin at different pH values. We demonstrated that curcumin molecules were successfully encapsulated within protein cages with a curcumin/protein molar ratio of 14.7 to 1. Upon such molecular encapsulation, curcumin molecules become greatly water-soluble, while their thermal and photostability were greatly improved due to protection by protein cages as compared to free analogs. This novel approach reported in this study has a potential to be applied in other poorly water-soluble bioactive compounds.