F r o m the f lowers of Ci r s ium arvense (Canada thistle) previous ly t reated with ch loroform we have obtained an ethanolie extract . By separat ing this on a polyamide sorbent we have isolated four individual flavonoid substances. Substance I, C15H1005. Mp 349-351 ° C (from ethanol), kmax 270 and 336 m#. For the acetate mp 183-185 ° C, Rf 0.86 [benzene-e thy l a c e t a t e a c e t i c acid (formamide) (24.5 : 73.5 : 2)]. The constants of I correspond to those of apigenin [1]. Substance II, C15H1006. Mp above 300 ° C, kmax 268 and 352 m#. For the acetate mp 224-226 ° C, Rf 0.63 [benzene-e thyl a c e t a t e a c e t i c acid (formamide) (24.5 : 73.5 : 2)]. This substance is identical with luteolin. Substance III, C2IH20010. Mp 222-225 ° C, ~-max 268 and 333 mtz, [a]D -62"2° (dimethylformamide) , Rf 0.77 [ b u t a n l o l a c e t i c a c i d w a t e r (4 : 1 : 5)]. The hydrolysis of III with 10% H2SO 4 gave an aglyeone Cl~H1005 with mp 349-351 ° C, identical with substance I. In the mother l iquor after hydrolys is , D-glucose was detected by paper chromatography. On the basis of the hydrolys is products, and UV and IR spect ra , substance III was cha rac te r i zed as apigenin 7-glucoside [2]. Substance IV, C27H30014. Mp 250-260 ° C, hmax 268 and 333 m#, Rf 0.55 [ b u t a n l o l a c e t i c a c i d w a t e r (4 : 1 : 5)]. The hydrolys is of IV with 10% H2SO 4 gave an aglycone with mp 349-350 ° C identified as an apigenin (UV and IR spec t ra , Rf , rap). D-Glucose and Lrhamnose were identified by paper chromatography. The constants of substance IV correspond to roifol in (apigen 7-rhamnoglucoside) . R E F E R E N C E S 1. Ya. K. Yatsyuk and S. S. Lyashehenko, KhPS [Chemis t ry of Natural Compounds], 5, 54, 1969. 2. T. A. Geissman, The Chemis t ry of Flavonoid Compounds, Pe rgamon P r e s s , New York, 227, 1962. 12 January 1970 Vitebsk Medical Insti tute