Folin–Ciocalteu reagent

The Folin–Ciocalteu reagent (FCR) or Folin's phenol reagent or Folin–Denis reagent, also called the Gallic Acid Equivalence method (GAE), is a mixture of phosphomolybdate and phosphotungstate used for the colorimetric assay of phenolic and polyphenolic antioxidants.[1] It works by measuring the amount of the substance being tested needed to inhibit the oxidation of the reagent.[2]

However, this reagent does not only measure total phenols and will react with any reducing substance. The reagent therefore measures the total reducing capacity of a sample, not just the level of phenolic compounds. This reagent forms part of the Lowry protein assay and will also react with some nitrogen-containing compounds such as hydroxylamine and guanidine.[3] The reagent has also been shown to be reactive towards thiols, many vitamins, the nucleotide base guanine, the trioses glyceraldehyde and dihydroxyacetone, and some inorganic ions. Copper complexation increases the reactivity of phenols towards this reagent.[4]

This reagent should not be confused with Folin's reagent, which is used to detect amines and sulfur-containing compounds.

A 1951 paper entitled "Protein measurement with the Folin phenol reagent"[5] was the most cited paper in the 1945–1988 Science Citation Index, with 187,652 citations[6]

See also

References

  1. ^ Singleton, Vernon L.; Orthofer, Rudolf; Lamuela-Raventós, Rosa M. (1999). [14] Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent. 299. pp. 152. doi:10.1016/S0076-6879(99)99017-1. 
  2. ^ Vinson J, Zubik L, Bose P, Samman N, Proch J (1 February 2005). "Dried fruits: excellent in vitro and in vivo antioxidants". J Am Coll Nutr 24 (1): 44–50. PMID 15670984. http://www.jacn.org/cgi/content/full/24/1/44. 
  3. ^ Ikawa M, Schaper TD, Dollard CA, Sasner JJ (2003). "Utilization of Folin-Ciocalteu phenol reagent for the detection of certain nitrogen compounds". J. Agric. Food Chem. 51 (7): 1811–5. doi:10.1021/jf021099r. PMID 12643635. 
  4. ^ Everette, Jace D.; Bryant, Quinton M.; Green, Ashlee M.; Abbey, Yvonne A.; Wangila, Grant W.; Walker, Richard B. (2010). "Thorough Study of Reactivity of Various Compound Classes toward the Folin−Ciocalteu Reagent". J. Agric. Food Chem. 58 (14): 8139. doi:10.1021/jf1005935. PMID 20583841. 
  5. ^ Oliver H. Lowry,Nira J. Rosebrough,A. Lewis Farr, and Rose J. Randall (1951). "Protein Measurement with the Folin Phenol Reagent". J. Biol. Chem. 193 (1): 265–275. PMID 14907713. http://www.jbc.org/content/193/1/265. 
  6. ^ [1]

External links