A liquid chromatography–tandem mass spectrometric method for quantification of curcumin-O-glucuronide and curcumin in human plasma

Curcumin is a widely used herbal medicine for various human diseases including inflammation and cancer. The demonstration and optimization of curcuminʹs activities in the clinical setting, however, have been compromised by its poor bioavailability and the lack of analytic methods to monitor its absorption. In this paper, we report the first validated liquid chromatography–tandem mass spectrometric method for simultaneous quantification of curcumin and its major metabolite: curcumin-O-glucuronide (COG), in the linear range of 2.0–2000 ng/mL in human plasma. The intra-day and inter-day accuracies of curcumin and COG in human plasma were in the range of 91.3–111.5% and 82.7–109.2% and their co-efficiency of variations were in the range of 3.5–12.7% and 3.1–11.3%, respectively. This method was capable of detecting only COG in human plasma samples from two healthy volunteers after an oral ingestion of curcumin.