Determination of a novel diarylheptanoid (Juglanin B) from green walnut husks ( Juglans regia L.) in rat plasma by high‐performance liquid chromatography

A simple and reliable analytical method based on high‐performance liquid chromatography (HPLC) coupled with a diode array detector (DAD) was developed for the determination of a novel diarylheptanoid (Juglanin B) from green walnut husks ( Juglans regia L.) in rat plasma using rhoiptelol as an internal standard. Chromatographic separation was carried out on a Sinochrom ODS‐AP C 18 column (250 × 4.6 μm i.d., 5 mm) with acetonitrile–10 mM postassium dihydrogen phosphate (pH = 3; 55:45, v/v) as mobile phase, and the detection wavelength was set at 214 nm. The plasma samples were prepared using methanol as protein precipitator. The extraction recovery of Juglanin B ranged from 70.26 to 78.59%, and the calibration curve had a good linearity in the range 0.08–50 μg/mL ( r 2 = 0.9932). The RSDs of intra‐ and inter‐day precision ranged from 1.19 to 4.92% and 4.35 to 4.54%, respectively. The HPLC‐DAD method described is a simple, rapid and reliable method for the determination of Juglanin B level and for use in studies involving pharmacokinetics. Copyright © 2009 John Wiley & Sons, Ltd.