Since plants may contain hundreds or even thousands metabolites, the vegetable kingdom can be a posible source of new compounds for introduction into therapeutical screenning programmes. A realistic approach to this fascinating challenge is the development of the ethnopharmacology. In contrast to medicinal chemistry, ethnopharmacology can start from an observed activity of a drug used in man or animals. Subsequent bioassay-direct fractionation can lead to the discovery of previosly unknown chemical structures for further structure-activity studies. With automated sample injection and fraction collection, HPLC systems can readily and rapidly be used to isolale tens of milligrams of pure compound, whose structure is usually resolved by use of NMR spectroscopy. Finally, we have two strong recommendations to phytochemists entering this field: (i) Never launch a major project unless a suffici...

Since plants may contain hundreds or even thousands metabolites, the vegetable kingdom can be a posible source of new compounds for introduction into therapeutical screenning programmes. A realistic approach to this fascinating challenge is the development of the ethnopharmacology. In contrast to medicinal chemistry, ethnopharmacology can start from an observed activity of a drug used in man or animals. Subsequent bioassay-direct fractionation can lead to the discovery of previosly unknown chemical structures for further structure-activity studies. With automated sample injection and fraction collection, HPLC systems can readily and rapidly be used to isolale tens of milligrams of pure compound, whose structure is usually resolved by use of NMR spectroscopy. Finally, we have two strong recommendations to phytochemists entering this field: (i) Never launch a major project unless a suffici...