TY - JOUR
T1 - Structurally related (-)-epicatechin metabolites in humans
T2 - Assessment using de novo chemically synthesized authentic standards
AU - Ottaviani, Javier I.
AU - Momma, Tony Y.
AU - Kuhnle, Gunter K.
AU - Keen, Carl L
AU - Schroeter, Hagen
PY - 2012/4/15
Y1 - 2012/4/15
N2 - Accumulating data suggest that diets rich in flavanols and procyanidins are beneficial for human health. In this context, there has been a great interest in elucidating the systemic levels and metabolic profiles at which these compounds occur in humans. Although recent progress has been made, there still exist considerable differences and various disagreements with regard to the mammalian metabolites of these compounds, which in turn are largely a consequence of the lack of availability of authentic standards that would allow for the directed development and validation of expedient analytical methodologies. In this study, we developed a method for the analysis of structurally related flavanol metabolites using a wide range of authentic standards. Applying this method in the context of a human dietary intervention study using comprehensively characterized and standardized flavanol- and procyanidin-containing cocoa, we were able to identify the structurally related (-)-epicatechin metabolites (SREM) postprandially extant in the systemic circulation of humans. Our results demonstrate that (-)-epicatechin-3′- β-d-glucuronide, (-)-epicatechin-3′-sulfate, and a 3′-O-methyl-(-)-epicatechin-5/7-sulfate are the predominant SREM in humans and further confirm the relevance of the stereochemical configuration in the context of flavanol metabolism. In addition, we also identified plausible causes for the previously reported discrepancies regarding flavanol metabolism, consisting, to a significant extent, of interlaboratory differences in sample preparation (enzymatic treatment and sample conditioning for HPLC analysis) and detection systems. Thus, these findings may also aid in the establishment of consensus on this topic.
AB - Accumulating data suggest that diets rich in flavanols and procyanidins are beneficial for human health. In this context, there has been a great interest in elucidating the systemic levels and metabolic profiles at which these compounds occur in humans. Although recent progress has been made, there still exist considerable differences and various disagreements with regard to the mammalian metabolites of these compounds, which in turn are largely a consequence of the lack of availability of authentic standards that would allow for the directed development and validation of expedient analytical methodologies. In this study, we developed a method for the analysis of structurally related flavanol metabolites using a wide range of authentic standards. Applying this method in the context of a human dietary intervention study using comprehensively characterized and standardized flavanol- and procyanidin-containing cocoa, we were able to identify the structurally related (-)-epicatechin metabolites (SREM) postprandially extant in the systemic circulation of humans. Our results demonstrate that (-)-epicatechin-3′- β-d-glucuronide, (-)-epicatechin-3′-sulfate, and a 3′-O-methyl-(-)-epicatechin-5/7-sulfate are the predominant SREM in humans and further confirm the relevance of the stereochemical configuration in the context of flavanol metabolism. In addition, we also identified plausible causes for the previously reported discrepancies regarding flavanol metabolism, consisting, to a significant extent, of interlaboratory differences in sample preparation (enzymatic treatment and sample conditioning for HPLC analysis) and detection systems. Thus, these findings may also aid in the establishment of consensus on this topic.
KW - Cocoa
KW - Flavanols
KW - Flavonoids
KW - Metabolism
KW - Polyphenols
KW - Procyanidins
UR - http://www.scopus.com/inward/record.url?scp=84859010162&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84859010162&partnerID=8YFLogxK
U2 - 10.1016/j.freeradbiomed.2011.12.010
DO - 10.1016/j.freeradbiomed.2011.12.010
M3 - Article
C2 - 22240152
AN - SCOPUS:84859010162
VL - 52
SP - 1403
EP - 1412
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 8
ER -