PURIFICATION OF BIOACTIVE NATURAL PRODUCTS BY CENTRIFUGAL PARTITION CHROMATOGRAPHY (CPC)

CPC is a continued liquid-to-liquid solvent partition where the target compounds are competitively distributed between the two-phase solvents due to their different partition coefficient. Using a centrifugal force, one phase is kept stationary while the other phase is pumped through the stationary one. There is no solid chromatographic support and the great advantage of this feature is that it allows higher yields of pure compounds when compared to other currently available preparative techniques. In this work, three case studies on the purification of natural products from plants will emphasize the great potential of the CPC technique. Centaurium erythraea Rafn. (Gentianaceae) is a widespread herbaceous plant used in the traditional medicine in more than 20 countries worldwide. The most abundant seco-iridoid glycosides, swertiamarin, sweroside and gentiopicrin, three structurally closely-related target natural products, were separated by CPC with swertiamarin purified from 8.72 mg/g in the crude extract until 770 mg/g (98.2%S) in enriched fractions. Experimental conditions were optimized in a different elution mode and different CPC devices coupled with MS detector allowed purification of the compounds for a shorter period of time and by using lower amounts of organic solvents. Cyclitols, indolizidine alkaloids, one ent-kaurane diterpene and its glycoside are some of the compounds isolated from two other species – an Argentinean spiny deciduous tree from Prosopis spp (Fabaceae) and the above ground parts of Achillea clypeolata Sibth. et Sim (Asteraceae), a Balkan endemic species. Therefore, we conclude that a suitable elution system using the CPC technology coupled to MS can afford good results in natural compound isolation and purification, with the great advantage of higher yields when compared to other separation techniques.