Estimation of total phenolic content and other oxidation substrates in plant tissues using Folin-Ciocalteu reagent

Nat Protoc. 2007;2(4):875-7. doi: 10.1038/nprot.2007.102.


Non-structural phenolic compounds perform a variety of functions in plants, including acting as antioxidants. We describe a microplate-adapted colorimetric total phenolics assay that utilizes Folin-Ciocalteu (F-C) reagent. The F-C assay relies on the transfer of electrons in alkaline medium from phenolic compounds to phosphomolybdic/phosphotungstic acid complexes, which are determined spectroscopically at 765 nm. Although the electron transfer reaction is not specific for phenolic compounds, the extraction procedure eliminates approximately 85% of ascorbic acid and other potentially interfering compounds. This assay is performed in microcentrifuge tubes and assessed in a 96-well plate reader. At least 64 samples can be processed in 1 d.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Colorimetry / methods*
  • Indicators and Reagents
  • Molybdenum*
  • Oxidation-Reduction
  • Phenols / analysis*
  • Phenols / metabolism
  • Plants / chemistry
  • Plants / metabolism*
  • Spectrum Analysis / methods
  • Tungsten Compounds*


  • Folin's phenol reagent
  • Indicators and Reagents
  • Phenols
  • Tungsten Compounds
  • Molybdenum