New Method To Estimate Total Polyphenol Excretion: Comparison of Fast Blue BB versus Folin–Ciocalteu Performance in Urine

Abstract

Polyphenols are bioactive substances of vegetal origin with a significant impact on human health. The assessment of polyphenols intake and excretion is therefore important. The Folin-Ciocalteu (F-C) method is the reference assay to measure polyphenols in foods as well as their excretion in urine. However, many substances can influence the method, making it necessary to conduct a prior clean up using solid phase extraction (SPE) cartridges. In this paper we demonstrate the use of the Fast Blue BB reagent (FBBB) as a new tool to measure the excretion of polyphenols in urine. Contrary to F-C, FBBB showed no interference in urine, negating the time-consuming and costly SPE clean up. In addition, it showed excellent linearity (r2 = 0.9997) with a recovery of 96.4% and a precision of 1.86-2.11%. The FBBB method was validated to measure the excretion of polyphenols in spot urine samples from Spanish children, showing a good correlation between polyphenols intake and excretion.