ABSTRACT
Natural products continue to play an important role in pharmaceutical, cosmetics, and food industries. About 50% of the drugs introduced into the market during the last 20 years are derived directly or indirectly from natural sources. In the future, natural products will continue to play a part as protagonists for discovering new drugs.1 Discovery of the well-known antitumor drug taxol and
the antimalarial drug artemisinin further stimulated the interest in searching for biologically active compounds from natural sources. For lead compound discovery, or for scientifi c validation of a traditional medicinal plant or a phytopharmaceutical, the bioactive components in natural sources need to be identifi ed. How to access these diverse compounds effectively from natural sources is an exciting challenge. The isolation of bioactive compounds from natural sources, such as plant extracts, microbial fermentation products, or animal tissues, presents a number of practical diffi culties because target compounds are often present as minor components of extremely complex mixtures.
