Oral bioavailability of curcumin in rat and the herbal analysis from Curcuma longa by LC–MS/MS

This study presents a validated liquid chromatography technique coupled with tandem mass spectrometry (LC–MS/MS) to measure curcumin in rat plasma and provide curcuminoids analysis from the extract of Curcumin longa L. This method was applied to investigate the pharmacokinetics of curcumin in a freely moving rat. The analytes were separated by a reversed phase C18 column (150 × 4.6 mm I.D., particle size 5 μm) and eluted with acetonitrile-1 mM HCOOH mobile phase (70:30, v/v) with a flow rate of 0.8 ml/min in rat plasma and herbal extracts. Multiple reaction monitoring (MRM) was used to monitor the transition of the deprotonated molecule m/z of 367 [M − H]− to the product ion 217 for curcumin, a m/z of 337–217 for demethoxycurcumin and a m/z of 265–224 for honokiol (internal standard) analysis. The limit of detection (LOD) and quantification (LOQ) of curcumin in the rat plasma were 1 and 5 ng/ml, respectively. The method was linear in the range of 5–1000 ng/ml with a coefficient of correlation greater than 0.996 in the rat plasma. After curcumin (500 mg/kg, p.o.) administration, the maximum concentration (Cmax) and the time to reach maximum concentration (Tmax) were 0.06 ± 0.01 μg/ml and 41.7 ± 5.4 min, respectively. The elimination half-life (t1/2,β) were 28.1 ± 5.6 and 44.5 ± 7.5 min for curcumin (500 mg/kg, p.o.) and curcumin (10 mg/kg, i.v.), respectively. The oral bioavailability was about 1%.