High performance liquid chromatography tandem mass spectrometry dual extraction method for identification of green tea catechin metabolites excreted in human urine

Synthetic and analytical strategies for the quantification of phenyl-γ-valerolactone conjugated metabolites in human urine

“…The method developed allowed the simultaneous resolution and quantification of 12 authentic standards of phenyl-␥-valerolactones within 12 min. The analysis time was short if compared to other methods that detected phenyl-␥-valerolactones as well as other flavan-3-ol metabolites over 26-70 min [11,13,14,18,19,35,36], and in line with other UHPLC methods resolving a high number of phenolic metabolites for quantitation over 10-12 min [21][22][23][24].…”

“…The most abundant compounds were 5, 10/10 , and 11, although the relative contribution of each phenyl-␥-valerolactone to the total urinary excretion varied notably among subjects. With respect to minimum urinary concentrations, it should be noted that some phenyl-␥-valerolactones were not produced/excreted by some volunteers (Table 3), and this can be related to the large inter-individual variability existing in the production of these colonic metabolites, which may well relate to differences in microbiota patterns [3,18,26,35,[39][40][41][42][43][44]. It is known that some steps in the degradation of flavan-3-ols monomers are mediated by specific bacteria [40].…”

“…The urinary concentrations recorded for some phenyl-␥-valerolactones, in particular 5, 10/10 , and 11 were quite high (reaching 132 M). Comparison of concentration with previous reports is avoided, since most quantified phenyl-␥-valerolactones without using synthesised exact standards, or because the analysed samples were hydrolysed by using sulphatase and β-glucuronidase enzymes before (10 of 12) 1700077 analysis [14,35,36]. In this sense, the accurate quantification of phenyl-␥-valerolactones with their respective reference compounds, as presented here, may lead to the redefinition of the recovery and bioavailability of flavan-3-ols in humans.…”

An Update on the Health Benefits of Green Tea

“…Studies on bioavailability are often conducted collecting specimens at timed intervals (after ingestion). Various studies have been conducted using normally prepared green tea beverages [14][15][16], ingested green tea extract (total catechins) [14,17,18], or ingestion of specific catechins [19][20][21]. These studies have shown that ECG and EGCG, and metabolites of EC and EGC can be detected and measured in blood plasma.…”

Cellular Asymmetric Catalysis by UDP-glucuronosyltransferase 1A8 Shows Functional Localization to the Basolateral Plasma Membrane

“…The flow rate was 0.4 ml/min. The solvent gradient started at 0% B for 3 min, a linear increase to 50% solvent B from 3 to 16 min, 100% solvent B for 4 min, and return to 0% solvent B at 23 min (39). Epicatechin aglycone and conjugates were detected with an Agilent 6410 triple quadrupole LC-MS/MS in negative MRM mode for the following transitions: epicatechin (m/z ϭ 289 3 245), methyl-epicatechin (m/z ϭ 303 3 165), epicatechin-sulfate (m/z ϭ 369 3 289), epicatechin-glucuronide (m/z ϭ 465 3 289), methyl-epicatechin-sulfate (m/z ϭ 383 3 303), methyl-epicatechin-glucuronide (m/z ϭ 479 3 303).…”