Determination of nobiletin in rat plasma after ingestion of citrus depressa juice by capillary liquid chromatography with electrochemical detection using boron-doped diamond electrode

Abstract

Voltammetric detection using a boron doped diamond (BDD) electrode coupled with capillary liquid chromatography (CLC) was developed for determining nobiletin, one of the polymethoxyflavones (PMFs), in plasma samples. CLC with electrochemical detection (CLC-ECD) was performed using a capillary octadecylsilica (ODS) column, wateracetonitrile-phosphoric acid (65:35:0.5, v/v/v), as a mobile phase, and an applied potential at +1.45V vs. Ag/AgCl. Chromatographic peak heights were found linearly related to the amounts of nobiletin injected from 0.48 pg to 0.40 ng (r = 0.999). The detection limit (S/N = 3) was 0.13 pg. The concentrations of nobiletin in rat plasma after oral ingestion of 5.0mLkg-1 Citrus depressa juice, corresponding to 0.17mgkg-1 nobiletin, were determined to obtain a concentration-time profile of nobiletin by the present CLC-ECD method, which required only 30 μL of plasma sample for each time point. Based on the concentration-time profile of nobiletin in the rat plasma, the pharmacokinetic parameters of maximum drug concentration (Cmax), maximum drug concentration time (tmax), and area under the concentration-time curve (AUC0-3 h) were obtained.