Isolation and Purification of Phytoconstituents

Once a crude extract has been recovered by conventional or modern extraction, the individual phytoconstituents it contains must be separated from one another and purified to a defined level before they can be structurally characterised or evaluated for biological activity. Column chromatography and preparative or semi-preparative HPLC serve as the principal isolation and purification tools for this purpose, providing progressively finer resolution as a sample moves from an open gravity or flash column toward a final HPLC purification step. The two chapters that follow set out these techniques in turn — column chromatography as the primary fractionation step, and flash chromatography and preparative HPLC as the accelerated and high-resolution methods used to carry a fraction through to a purity suitable for spectroscopic identification or biological testing.