Isolation Techniques for Flavonoids

Abstract

Within the last five years, numerous new chromatographic techniques have become available for the flavonoid chemist. They not only reduce the separation time, but simplify the isolation of previously unknown or unstable constituents from crude plant extracts or other complex biological sources. High-performance liquid chromatography (HPLC) and droplet counter-current chromatography (DCCC) are major innovations and are complementary to each other. Whereas HPLC has been extensively used for analytical separations, DCCC is an ideal method for the isolation of flavonoids on a preparative scale. Centrifugal thin-layer chromatography and rotation locular counter-current chromatography are other new promising techniques, but at this date, little is known about their application in the field of flavonoids. However, there is no single method of separation capable of solving all isolation problems. Classical techniques such as column chromatography and thin-layer chromatography are still very useful.