Cyanidin 3-Gentiobioside from Primary Leaves of Rye (Secale cereale L.)

Primary leaves of rye (Secale cereale L. cv. Kustro) show a heterogeneous, tissue-specific pattern of flavonoids being composed of the two C-glycosylflavone glycosides isovitexin 2"-0-arabinoside and isovitexin 2"-0-galactoside (located in the epidermal layers) [1, 2], the two flavone glycosides luteolin 7O-diglucuronide and luteolin 7-O-diglucuronide 4'O-glucuronide [3] and the two anthocyanins cyanidin 3-O-glucoside [2, 4] and cyanidin 3-O-diglycoside [2], both flavones and anthocyanins located in the mesophyll [2], The latter awaited structural elucida­ tion and we report here its isolation and identifica­ tion as cyanidin 3-O-gentiobioside. This completes the structure elucidation of flavonoids from rye pri­ mary leaves and will be the basis of a study of the turnover [2] and enzymatic synthesis of the antho­ cyanins in rye primary leaves.