Abstract
Rapid detection of biologically active natural products plays a strategical role in
the phytochemical investigation of crude plant extracts. In order to perform an efficient
screening of the extracts, both biological assays and HPLC analysis with various detection
methods are used. Combined techniques such as HPLC coupled to UV photodiode array
detection (LC/UV) and to mass spectrometry (LC/MS or LC/MS/MS) provide useful structural
information on the metabolites on-line prior to isolation. The recent introduction
of HPLC coupled to nuclear magnetic resonance (LC/NMR) represents a powerful complement
to the LC/UV/MS screening. Various plants belonging to the Gentianaceae and Leguminosae
families have been analysed by LC/UV, LC/MS, LC/MS/MS, and LC/NMR. The use of all
these coupled techniques allows the structural determination of known plant constituents
rapidly and with only a minute amount of plant material. With such an approach, the
time-consuming isolation of common natural products is avoided and an efficient targeted
isolation of compounds presenting interesting chemical or biological features can
be performed.
Key words
Plant extracts - LC coupled techniques - LC/UV - LC/MS - LC/MS/MS - LC/NMR
