Determination of naringin and naringenin in human plasma by high-performance liquid chromatography.

An HPLC method for determining a flavonoid, naringin, and its metabolite, naringenin, in human plasma is presented for application to the pharmacokinetic study of naringin. Isocratic reversed-phase HPLC was employed for the quantitative analysis by using genistin (for naringin) or diadzein (for naringenin) as an internal standard and solid-phase extraction using s Sep-Pak t C18 cartridge. For the determination, HPLC was carried out using an Inertsil ODS-2 column (250 x 4.6 m I.D., 5 microns particle size). The mobile phases were acetonitrile-0.1 M ammonium acetate 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 naringenin. The flow-rate was 1 ml min-1. The analyses were performed by monitoring the wavelength of maximum UV absorbance at 280 nm for naringin and at 292 nm for naringenin. The detection limits on-column were about 0.2 ng for the two flavonoids.