Acute human pharmacokinetics of a lipid-dissolved turmeric extract

Curcumin is a lipophilic compound found in the rhizome of turmeric (Curcuma longa Linn.) that targets several inflammatory and neurological pathways. Dosing of turmeric extract is associated with safety and tolerability in humans, yet literature on its efficacy is limited, possibly due to its low bioavailability in plasma and high rate of metabolism, mainly to glucuronide conjugate. The primary aim of this study was to quantify plasma and red blood cell levels of curcumin by HPLC after ingestion of 40mg curcumin from a lipid-dissolved turmeric extract formulation (SLCP-1) at a dosage of 200mg in healthy human volunteers. The secondary aim of this study was to determine the relationship between plasma and red blood cell (RBC) curcumin in blood samples treated with and without glucuronidase enzyme. An HPLC system (Shimadzu 1100) with PDA detector and C18 column using mobile phase gradient of 0.1% phosphoric acid and acetonitrile was used, as previously published. The mean peak concentration (Cmax) of free curcumin in blood prepared with and without glucuronidase was 48.3 and 39.2ng/mL, respectively, with time of maximum concentration (Tmax) occurring at 6 hours. Most of the curcumin from dosing of the formulation was detected in blood in free form in plasma and RBC fractions. The concentrations of curcumin detected are in the range offering therapeutic impact in various models.