DETERMINATION OF NARINGIN AND NARINGENIN IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

An HPLC method for determining a flavonoid, naringin, and its metaboli te, naringenin, in human plasma is presented for application to the ph armacokinetic study of naringin. Isocratic reversed-phase HPLC was emp loyed for the quantitative analysis by using genistin (for naringin) o r daidzein (for naringenin) as an internal standard and solid-phase ex traction using a Sep-Pak t C-18 cartridge. For the determination, HPLC was carried out using an Inertsil ODS-2 column (250X4.6 m I.D., 5 mu m particle size). The mobile phases were acetonitrile-0.1 M ammonium a cetate solution (20:80, v/v; pH 7.1) for naringin and acetonitrile-0.1 M ammonium acetate solution-acetic acid (30:69:1, v/v; pH 4.9) for na ringenin. The flow-rate was 1 ml min(-1). The analyses were performed by monitoring the wavelength of maximum UV absorbance at 280 nm for na ringin and at 292 nm for naringenin. The detection limits on-column we re about 0.2 ng for the two flavonoids.