Beta vulgaris L.: The characterization of three polyphenols isolated from the leaves

Abstract

An alcoholic extract of leaves of Beta vulgaris L. was found to contain five phenolic compounds. Two of these compounds were characterized using chromatographic and absorption spectral techniques. One of them yielded glucose and quercetin upon acid hydrolysis; the second yielded xylose, glucose and a C-glycoside whose spectral and chromatographic behavior was similar to those of vitexin. An isolation procedure for milligram quantities of the C-glycoside was devised. An acetyl derivative was prepared. A third phenolic compound was shown to be 3-hydroxytyramine by i.r. and u.v. spectra and further confirmed by the preparation of two derivatives. Previous work has shown this phenol when oxidized to be closely associated with resistance to the causal organism of sugar beet leaf spot Cercospora beticola in culture.