Enhancement of the intestine permeability of curcumin using Pickering emulsions stabilized by starch crystals and chitosan1Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, US
2Center for Food and Bioconvergence, Seoul National University, Gwanakgu, Seoul 08826, Republic of Korea
Introduction: The intestine permeability of curcumin was improved by using Pickering emulsion stabilized with starch crystals and chitosan
Method: We designed curcumin-loaded chitosan-coated Pickering emulsions and examined digestibility, bioaccessibility, mucoadhesiveness, and intestinal absorption of curcumin using in vitro models of the human GI tract. In digestion studies, changes in D3,2, ζ-potential (ZP), and the lipolysis patterns of the emulsions were monitored after treatment with simulated digestion fluids, and the amount of curcumin solubilized in the mixed micellar fraction was determined. The permeation rate of curcumin across an intestinal monolayer membrane was assessed using the Caco-2 cell-membrane model covered with biosimilar mucus.
Results: The chitosan-coated emulsions, differed from uncoated emulsions, underwent the gastric condition with no size change and exhibited relatively slow lipolysis pattern in the small intestinal condition. Additionally, > 70% of curcumin was soluble in the micellar fraction after all the digestion, irrespective of the chitosan coating. Curcumin loaded in > 0.1% chitosan-coated emulsions adhered more robustly onto porcine intestinal mucosa than did curcumin powder and chitosan-uncoated emulsions. Curcumin incorporated in the chitosan-coated emulsions showed relatively rapid and large permeation pattern, ~9.5-times apparent permeability compared to curcumin solution.
Discussion: Based on the results obtained using microscopic images of porcine intestinal mucosa and mucus-covered Caco-2 membrane, the increased permeability of curcumin is due to the electrostatic mucoadhesion and epithelial tight junction opening effects by the chitosan-coating. Our findings will facilitate the rational design for oral delivery systems incorporating food-grade lipophilic bioactives such as curcumin.