Background: A specific and sensitive UPLC-qTOF-MS/MS method has been developed for the simultaneous determination of curcuminoids. These Curcuminoids comprises of curcumin, a principal curcuminoid and other two namely, demethoxycurcumin, and bisdemethoxycurcumin obtained from rhizomes of Curcuma longa an ancient Indian curry spice turmeric, family (Zingiberaceae).
Methods: These analytes were separated on a reverse phase C18 column by using a mobile phase of acetonitrile: 5% acetonitrile in water with 0.07% acetic acid (75:25 v/v), flow rate of 100 μL/min was maintained. The qTOF-MS was operated under multiple reaction monitoring (MRM) mode using electro-spray ionization (ESI) technique with positive ion polarity. The major product ions in the positive mode for curcuminoids were at m/z 369.1066, 339.1023 and 309.0214 respectively. The recovery of the analytes from mouse plasma was optimized using solid phase extraction technique.
Results: The total run time was 5 min and the peaks of the compounds, bisdemethoxycurcumin, demethoxycurcumin and curcumin occurred at 2.06, 2.23 and 2.40 min respectively. The calibration curves of bisdemethoxycurcumin, demethoxycurcumin and curcumin were linear over the concentration range of 2-1000 ng/mL (r2, 0.9951), 2-1000 ng/mL (r2, 0.9970) and 2-1000 ng/mL (r2, 0.9906) respectively.Intra-assay and inter-assay accuracy in terms of % bias for curcumin was in between -7.95to +6.21, and -7.03 to + 6.34; for demethoxycurcumin was -6.72 to +6.34, and -7.86 to +6.74 and for bisdesmetoxycurcumin was -8.23 to +6.37 and -8.47 to +7.81. The lower limit of quantitation for curcumin, demethoxycurcumin and bisdemethoxycurcumin was 2.0 ng/mL. Analytes were stable under various conditions (in autosampler, during freeze-thaw, at room temperature, and under deep-freeze conditions). This validated method was used during pharmacokinetic studies of curcumin in the mouse plasma.
Conclusions: A specific, accurate and precise UPLC-qTOF-MS/MS method for the determination of curcumin, demethoxycurcumin and bisdemethoxycurcumin both individually and simultaneously was optimized.