A selective and accurate HPLC-MS/MS method was established to simultaneously quantify luteolin and its active metabolites (diosmetin, chryseriol, and luteolin-7-O-glucuronide) in rat plasma. The analytes were separated on a C18 column with a mobile phase of water containing 0.5% formic acid and acetonitrile under gradient elution to shorten the total chromatographic run time and increase the resolution of diosmetin and chryseriol. A triple quadruple mass spectrometer coupled with an electrospray ionization source in the negative ion mode was used to detect the analytes. The multiple reaction monitoring transitions were of m/z 284.9→132.9 for luteolin, m/z 298.9→283.9 for diosmetin and chryseriol, m/z 461.1→284.9 for luteolin-7-O-glucuronide, and m/z 300.9→150.9 for the internal standard. The method was linear within the concentration ranges of 0.06-90 μg/mL for luteolin, 0.03-12 μg/mL for diosmetin, 0.015-4.8 μg/mL for chryseriol, and 0.06-60 μg/mL for luteolin-7-O-glucuronide. The intra- and interday precisions were all within 6.0%. Accuracy ranged from -3.2 to 6.4%. The matrix effect and instability were not observed during bioanalysis. This method was used to study the pharmacokinetic characteristics of luteolin and its metabolites in rats after treatment with luteolin.
Keywords: luteolin; mass spectrometry; metabolite; pharmacokinetics.
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