ABSTRACT
Natural products have served as an important source of drugs since ancient times and
about half of the useful drugs today are derived from natural sources. Chemodiversity in
nature, e.g. in plants, microorganisms and marine organisms, still offers a valuable
source for novel lead discovery, but rapid identification of the bioactive compounds of
natural product mixtures remains a critical factor to ensure that this tool of drug discov-
ery can compete with recent developed technologies such as chemical compound
libraries and high-throughput screening of combinatorial synthetic efforts. Rapid screen-
ing of natural product mixtures requires the availability of a library of reference of
natural compounds and methods for simple identification of putative lead structural
classes avoiding, to a large extent, the potential for false-positive results. The coupling of
chromatographic methods such as high pressure liquid chromatography (HPLC) with
diode array detection, mass spectrometry (MS) or nuclear magnetic resonance spec-
troscopy (NMR) or, and with, on-line bioactivity assays, is an important tool for high
throughput screening of natural product mixtures. The introduction of a dereplication
step after extraction by using a reproducible preseparation method would enable the
rapid elimination of false positives (Verpoorte, 1998). The effective use of automated
procedures and databases in the isolation, identification and biological profiling of
bioactive compounds from natural sources will be the best guarantee to the continued
discovery of novel chemotypes from nature (Hook et al., 1997).
