Pharmacokinetics of luteolin and tetra‐acetyl‐luteolin assayed by HPLC in rats after oral administration

Abstract

Accurate and reproducible HPLC methods were developed and validated for the determination of concentrations of luteolin (LT) and tetra-acetyl-luteolin (TALT) in rat plasma. HPLC analyses were performed on an Agilent TC-C(18) column protected by a guard Agilent Zorbax Eclipse Plus. The mobile phase for LT was a binary mixture of acetonitrile-water (40:60, v/v) containing 0.5% phosphoric acid at a flow rate of 1.0 mL/min, and that for TALT was a binary mixture of methanol-water (70 : 30, v/v) containing 0.5% glacial acetic acid at the same flow rate. The UV detection wavelength for both analytes was set at 350 nm. The calibration curve was linear over the range of 40-1800 ng/mL, the lower limit of quantitation was 40 ng/mL and the lower limit of detection was 20 ng/mL for both LT and TALT. The intra- and inter-day precision (RSD) values for all samples were within 7.9%. The concentration-time curves of LT and TALT after oral administration (30 mg/kg) were both fitted to a two-compartment model. The pharmacokinetic characteristics of TALT were better than that of LT in the maximum plasma concentration (C(max)) and the area under the concentration-time curve (AUC).