The Separation of Flavonoids by Column and Thin Layer Chromatography

Abstract

Charcoal is useful for the preliminary purification of a mixture of flavonoids, particularly flavonoid glycosides, which are usually present in a crude aqueous or aqueous-methanolic extract of plant material [1]. The charcoal procedure described below separates flavonoids from most non-aromatic plant constituents such as the common carbohydrates. The method is especially useful for flavonoid glycosides which are readily recovered almost quantitatively from the charcoal with water containing 7% phenol (i. e. a saturated aqueous solution at room temperature). Although many aglycones can also be recovered, at least in part, from the charcoal, the procedure is not recommended for their purification. Aglycones can often be extracted directly from a crude syrup obtained from a plant extract with a solvent such as ethyl acetate, while their complete recovery from charcoal many require the use of pyridine as eluent. A typical charcoal procedure is presented below for the preliminary purification of the flavonoids in a crude extract obtained from Baptisia lecontei plant material.