QUANTITATIVE TLC-DENSITOMETRY OF ISOFLAVONES IN PUERARIA LOBATA (WILLD.) OHWI

This paper reports a TLC-densitometric method to determine the isoflavones content in the Pueraria lobata (Willd.) Ohwi and its extract tablets. The developing solvent toluene-methanol-10% formic acid (7:3:0.02) was used for seperation of daidzein, daidzin and puerarin, and ethyl acetate-methanol-50% formic acid (8:2:0.2) for daidzein-4',7-diglucoside. The densitometric determination was carried out with a Shimadzu TLC-scanner CS-910. The parameter for the linearization of the working curves were: λ_s=250nm, λ_R=360nm, reflectance mode, zig-zag scanning, SX=3. The working curves were obtained, all passing through the origin. The four isoflavones content in Pueraria lobata (Willd.) Ohwi for two species from eight areas were determined. The coefficient of variation was 1.5～1.6%.