High-performance liquid chromatographic determination of flavonoids in Betula pendula and Betula pubescens leaves

A high-performance liquid chromatography (HPLC) procedure based on a water-methanol gradient with tetrahydrofuran for simultaneous, analysis of flavonoids and other phenolics of differing polarities in birch leaves was developed. Mobile phases with and without tetrahydrofuran or orthophosphoric acid provided additional information for tentative identification of the compounds. Forty-five compounds were determined from Betula pendula and B. pubescens leaves. Five of the isolated flavonol glycosides have nor been reported earlier from B. pendula. B. pendula leaves have a range of myricetin and quercetin glycosides with the same sugar moieties in roughly the same proportions. Flavonoid aglycones were deposited on leaf surfaces. (C) 1998 Elsevier Science B.V.