The Incorporation of Curcuminoids in Gamma-Cyclodextrins Improves Their Poor Bioaccessibility, Which Is due to Both Their Very Low Incorporation into Mixed Micelles and Their Partial Adsorption on Food

ScopeTurmeric curcuminoids mainly consist of curcumin (CUR), demethoxycurcumin (dCUR), and bisdemethoxycurcumin (bdCUR). CUR displays low bioavailability, partly due to poor solubilization in the intestinal lumen during digestion, while data for dCUR and bdCUR are scarce. The study aims to investigate the bioaccessibility of curcuminoids from turmeric extracts or from gamma-cyclodextrins, considering potential interactions with food. Methods and resultsUsing an in vitro digestion model (correlation with CUR bioavailability: r = 0.99), the study shows that curcuminoid bioaccessibility from turmeric extract without food is low: bdCUR (11.5 +/- 0.6%) > dCUR (1.8 +/- 0.1%) > CUR (0.8 +/- 0.1%). Curcuminoids incorporated into gamma-cyclodextrins display higher bioaccessibilities (bdCUR: 21.1 +/- 1.6%; dCUR: 14.3 +/- 0.9%; CUR: 11.9 +/- 0.7%). Curcuminoid bioaccessibility is highest without food (turmeric extract: 2.0 +/- 0.1%; gamma-cyclodextrins: 12.4 +/- 0.8%) and decreases with a meat- and potato-based meal (turmeric extract: 1.1 +/- 0.2%; gamma-cyclodextrins: 2.4 +/- 0.3%) or a wheat-based meal (turmeric extract: 0.1 +/- 0.0%; gamma-cyclodextrins: 0.3 +/- 0.1%). Curcuminoids exhibit low (<10%) incorporation efficiencies into synthetic mixed micelles (bdCUR > dCUR > CUR). ConclusionsbdCUR and dCUR show greater bioaccessibilities versus CUR. Food diminishes curcuminoid bioaccessibility, likely by adsorption mechanisms. Gamma-cyclodextrins improve curcuminoid bioaccessibility.

Automated summary

Turmeric curcuminoids, including curcumin, demethoxycurcumin, and bisdemethoxycurcumin, have low bioavailability. This study found that the bioaccessibility of curcuminoids decreases when consumed with food, while curcuminoids incorporated into gamma-cyclodextrins show higher bioaccessibility.