Clinical Evidence

Randomized Pharmacokinetic Crossover Study Comparing 2 Curcumin Preparations in Plasma and Rectal Tissue of Healthy Human Volunteers 
J Clin Pharmacol.  2017;57(2):185-193
Absorption, metabolism, and elimination are very crucial parameters that influence the pharmacological benefits of any phyto-actives. Curcumin, though a potent agent influencing various physiological processes, is poorly absorbed. Hence, various formulations have been designed aiming to improve the bioavailability parameters of curcumin. However, little is known about variations in its pharmacokinetics and tissue bioavailability between formulations.

To evaluate the pharmacokinetic parameters of phosphatidylcholine curcumin preparations.


The study was conducted in 12 healthy volunteers aged between 18-65 years and was a randomized, crossover-type evaluating the relationship between steady-state plasma and rectal tissue curcuminoid concentrations using standard and phosphatidylcholine curcumin extracts.

  • There was no difference in the geometric mean plasma AUCs when adjusted for the 10-fold difference in curcumin dose between the 2 formulations
  • Phosphatidylcholine curcumin extract yielded only 20% to 30% plasma demethoxycurcumin and bisdemethoxycurcumin conjugates compared to standard extract yet yielded 20-fold greater hexahydrocurcumin
  • When adjusting for curcumin dose, tissue curcumin concentrations were 5-fold greater for the phosphatidylcholine extract

Improvements in curcuminoid absorption due to phosphatidylcholine are not uniform across the curcuminoids. Furthermore, curcuminoid exposures in the intestinal mucosa are most likely due to luminal exposure rather than to plasma disposition. Finally, once-daily dosing is enough to maintain detectable curcuminoids at steady state in both plasma and rectal tissues.