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Polyphenol Phase‐II Metabolites are Detectable in Human Plasma after Ingestion of 13 C Labeled Spinach—a Pilot Intervention Trial in Young Healthy Adults
Author(s) -
Passon Maike,
Bühlmeier Judith,
Zimmermann Benno F.,
Stratmann Anja,
Latz Stefan,
Stehle Peter,
Galensa Rudolf
Publication year - 2018
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201701003
Subject(s) - spinach , glucuronide , spinacia , ingestion , polyphenol , sulfate , chemistry , metabolism , food science , biochemistry , antioxidant , chloroplast , organic chemistry , gene
Scope After intrinsic labeling of spinach ( Spinacia oleracea L., Chenopodiaceae) with 13 CO 2 , we investigated if labeled polyphenol metabolites were detectable in human plasma. Methods and result In a pilot intervention trial, five healthy men consumed 5 g freeze‐dried 13 C labeled spinach, including a total amount of 160 μmol methoxyflavonols, including 70 μmol 5,3′,4′‐trihydroxy‐3‐methoxy‐6,7‐methylendioxyflavone‐4′‐glucuronide. Plasma samples of all subjects were analyzed with regard to their 13 C/ 12 C ratio. Additionally, 13 C labeled metabolites of patuletin, spinacetin, and 5,3′,4′‐trihydroxy‐3‐methoxy‐6,7‐methylendioxyflavone (TMM) were analyzed in plasma samples in a subgroup of three subjects. TMM‐glucuronide, TMM‐sulfate, and spinacetin‐glucuronide‐sulfate, the latter as 12 C 1 13 C 16 and 13 C 17 isotopologs, were tentatively identified. Plasma concentration of TMM‐glucuronide and TMM‐sulfate reached c max from 19.1–54.3 and 22.5–125.5 nmol L –1 , respectively, 7–9 h post‐ingestion. Conclusion It seems likely that 13 C labeled TMM‐glucuronide and TMM‐sulfate are phase‐II metabolites which were converted after colonic transformation. Variations in plasma kinetics were observed for these two metabolites and may be attributed to the individual composition of the microbiota. We conclude that 13 C labeled polyphenol metabolites are detectable and quantifiable in human plasma.