Target identification and validation of natural products with label-free methodology: A critical review from 2005 to 2020

Pharmacol Ther. 2020 Dec;216:107690. doi: 10.1016/j.pharmthera.2020.107690. Epub 2020 Sep 25.


Natural products (NPs) have been an important source of therapeutic drugs in clinic use and contributed many chemical probes for research. The usefulness of NPs is however often marred by the incomplete understanding of their direct cellular targets. A number of experimental methods for drug target identification have been developed over the years. One class of methods, termed "label-free" methodology, exploits the energetic and biophysical features accompanying the association of macromolecules with drugs and other compounds in their native forms. Herein we review the working principles, assay implementations, and key applications of the most important approaches, and also give examples where they have been applied to NPs. We also assess the key advantages and limitations of each method. Furthermore, we address when and how the label-free methodology can be particularly useful considering some of the unique features of NP chemistry and bioactivation.

Keywords: Label-free methodology; Mechanism of action; Natural product; Target identification; Target validation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Drug Discovery*
  • High-Throughput Screening Assays*
  • Humans
  • Models, Molecular
  • Protein Conformation
  • Protein Stability
  • Proteins / chemistry
  • Proteins / metabolism*
  • Proteolysis
  • Proteomics*
  • Reproducibility of Results
  • Structure-Activity Relationship


  • Proteins