A pharmacokinetic study on oleracone C after oral and intravenous administration

Oleracone C, a new homoisoflavanone recently isolated from the plant Portulaca oleracea L., has obvious pharmacological activities. Subsequently, its pharmacokinetic profiles in rats' plasma after oral and intravenous administrations were studied by a simple and rapid ultra high-performance liquid chromatography electrospray ionization quadrupole-time of flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) with apigenin as an internal standard (IS). The analysis was performed on an Agilent Zorbax Eclipse Plus C₁₈ Column (2.1 × 50 mm, 1.8 μm) by elution with acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. Electrospray ionization in negative ion mode was used to quantify oleracone C and apigenin, with monitored ion m/z values of 299.0915 [M - H]^- and 269.0455 [M - H]^-. The linear range was established over the concentration range 10-2000 ng/mL (r = 0.9971). The limit of detection (LOD) and limit of quantification (LOQ) were 3 and 10 ng/mL for oleracone C, respectively. The RSD and RE of intra- and inter- day accuracy and precision were all less than 15%. The pharmacokinetic results indicated that oleracone C was rapidly distributed with the time to peak concentrations of 0.03 h and 0.33 h, respectively after intravenous and oral administrations and presented a low absolute bioavailability of 8.32%. This is the first study to successfully examine the pharmacokinetics of homoisoflavanone in rats' plasma after oral and intravenous administrations, using rapid, sensitive and specific UHPLC-ESI-Q-TOF/MS method.