A SIMULTANEOUS DETERMINATION OF HONOKIOL AND MAGNOLOL IN KAMPO MEDICINES CONTAINING MAGNOLIA BARK BY ION-PAIR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple and precise method was established for the determination of h onokiol (I) and magnolol (II) in kampo medicines containing Magnolia B arks using high-performance liquid chromatography with tetra-n-amylamm onium bromide (TAA) as an ion-pair reagent. The optimum conditions for extracting both components from these kampo medicines were 15-min ref lux with methanol. I and II were eluted within 9 min and 12 min, respe ctively, without interference from co-existing components using an ODS column and a mixture of water-acetonitrile containing 1OmM TAA as a m obile phase.