CONTRIBUTION TO THE QUANTITATIVE AND ENANTIOSELECTIVE DETERMINATION OF KAVAPYRONES BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ON CHIRASPHER NT MATERIAL

A simultaneous HPLC separation of the enantiomers of kavain, dihydroka vain, methysticin and dihydromethysticin, as well as the achiral dieno lides yangonin and desmethoxyyangonin was carried out on a ChiraSpher NT column. For quantitative determinations, calibration curves with co rrelation coefficients between 0.9982 and 0.9996 were established for the genuine kavapyrones. Detection limits between 0.25 mu g and 0.5 mu g per injection were measured at 240 nm. The defined scopes of work c orresponded with the different kavapyrone amounts, depending on growth factors of distinct plant locations The precision of the method was v erified by analysing a phytopharmacon with a nominal value of 40 mg ka vapyrones per tablet. The evaluation revealed 39.62 mg per tablet by t he sum of single calculated kavapyrones. Relative standard deviations between 1.06% and 2.39% were found for the compounds under investigati on. The accuracy of the method was proved by a recovery of 99.7%. To s implify the determination of the total kavapyrone amount, response fac tors and correlation factors for (+)-dihydrokavain, (+)-methysticin, ( +)-dihydromethysticin, yangonin and desmethoxyyangonin were calculated relative to (+)-kavain. (C) 1997 Elsevier Science B.V.