When I assayed total phenols with the Folin ciocalteau assay in different plant extracts, I found an amount, espressed as gallic acid equivalents, substantially lower than that I found for flavonoids (measured by the aluminium chloride method and expressed as rutin equivalents). As far as I know Flavonoids are a class of phenols and should be included in total phenol amount. Does anybody have an explanation for this discrepacy?
Yes This test gives us total polyphenols including flavonoids,Tannins and other characteristic phenols.
So why if I assay flavonoids with alluminium chloride in a metanolic extract from pumpkin seeds I heve four time more rutin equivalents than gallic acid equivalents measured in the same extract with Folin Ciocalteu?
@ Morris I agree with you. We calculate the equivalents but Total polyphenols includes Flavanoids and Tannins also as we have seen case of Green tea extract.
No, folein only to determine total phenols or tannins, flavonoids by sodium nitrate and alominum chloride
It is also a question how deep you would like to go in your analysis, but all methods mentioned above are only related to more or less unspecific RedOx-reactions. If you really like to give answers on different chemical classes I would like to recommend at least some chromatographic separation before.
LC-MS/MS would be most beneficial.
Folin-Ciocalteu reagent has been shown to be non-specific regarding phenolic assay. See the following three publications:
Journal of Functional Foods 3 (2011) 79-87 Marjorie B. Medina
Journal of Agricultural and Food Chemistry 2011, 59, 1565-1571 Marjorie B. Medina
Journal of Food Composition and Analysis 27 (2012) 102-107 Gene E. Lester et. al.
- Badges
- Science topic
- Similar topics
- Biological Science
- Botany