Combined Use of Extract Libraries and HPLC-Based Activity Profiling for Lead Discovery: Potential, Challenges, and Practical Considerations

A 96-well format plant extract library and a tailored technology platform have been set up for the discovery of new natural product lead compounds. The considerable advantages of the library approach are discussed. Key considerations such as sample generation, logistics, and data management are addressed. The potential of a HPLC-based profiling approach combining off-line bioassays with in-line and off-line spectroscopy (including HR-ESIMS and microprobe NMR) for tracking bioactivity is demonstrated with a selection of examples encompassing different types of bioassay formats. The information generated by this approach with regards to hit prioritization and preliminary structure activity-relationships is discussed. Practical aspects, such as validation of profiling protocols, the amounts of extracts to be applied, and the re-dissolution of fractions are addressed. Such information is intended for scientists aiming at implementing library-based discovery platforms in their own laboratory.