APPLICATION OF THIN LAYER CHROMATOGRAPHY IN THE STUDY OF NATURAL PRODUCTS——Ⅵ.IDENTIFICATION OF FLAVONOIDS

The method of the thin layer chromatography on polyamide was applied to identify eleven kinds of flavonoids,including five aglucones, five glucosides, and one unknown sample. By experiment,the following solvent systems were found to be more suitable than others for developing glucosides: EtOAc/H₂O,n-BuOH/H₂O-HAc(100:1), (100:2),Me₂CO-H₂O(1:1), Me₂CO-95%EtOH-H₂O(2:1:2),95% EtOH-HAc(100:2), (CH)₂CHOH-H₂O(3:2),etc.(see Figs.1—7).n-BuOH/H₂O-HAc(100:2)has been successfully used as a solvent system for separating and identifyinlg the mixture of paracitrin and an unknown sample of"Ji-sheng",the mixture of G, F of"Pei-Chi-Sheng" and paracitin, and three parts of the total flavonoids from"Ji-Sheng"(see Figs.8—10).On the other hand it was found that if the polarity of flavonoid is increased then its R_f value will be increased in polar solvents.