Phenolic compounds in systematics and phylogeny of the family Polygonaceae Juss. VI. Genus Knorringia (Chukav.) Tzvel

Results of the study of phenolic compounds – flavonols and anthraquinones in plants of the genus Knorringia (Czukav.) Tzvel., K. sibirica (Laxm.) Tzvel. and K. pamirica (Korsh.) Tzvel., are given. Amount of flavonol-glycosides in samples of leaves varies from 0,94 to 5,31%, and does not correlate with locality. Content of anthraglycosides is low – 0–0,38%, of free аglycones (emodin + fiscion) is 0–0,63%. Two “chemical forms” of K. sibirica are found: “having anthraquinones” and “anthraquinones free”, also different in structure of flavonol-glycosides. The last form occurs in the south of Eastern Siberia. The data favor recognition of Knorringia as a separate genus.