Simultaneous determination of 12 major constituents in Forsythia suspensa by high performance liquid chromatography--DAD method.

A high performance liquid chromatographic method was developed to simultaneously determine the 12 major constituents of Forsythia suspensa, namely R-suspensaside, S-suspensaside, S-suspensaside methyl ether, (+)-pinoresinol-beta-d-glucoside, forsythiaside, (+)-epipinoresinol-4'-O-glucoside, suspensaside A, rutin, phillyrin, (+)-pinoresinol, (+)-epipinoresinol and phillygenin. The HPLC assay was performed on a Zorbax XDB C(18) column with gradient elution of methanol and 0.3% aqueous acetic acid within 55 min. The detection wavelength was 280 nm. All the compounds showed good linearity (r(2)>0.9998). The method was reproducible with intra- and inter-day variation less than 3%. The recovery of the assay was in the range of 91.2-104.9%. The method was successfully applied to the quantification of 12 constituents in 33 F. suspensa samples. The results indicated that the developed assay could be considered as a suitable quality control method for F. suspensa.