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Urinary metabolites from mango ( Mangifera indica L. cv. Keitt) galloyl derivatives and in vitro hydrolysis of gallotannins in physiological conditions
Author(s) -
Barnes Ryan C.,
Krenek Kimberly A.,
Meibohm Bernd,
MertensTalcott Susanne U.,
Talcott Stephen T.
Publication year - 2016
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.201500706
Subject(s) - chemistry , gallic acid , urine , mangifera , polyphenol , metabolism , metabolite , excretion , hydrolysis , food science , chromatography , biochemistry , botany , biology , antioxidant
Scope The absorption, metabolism, and excretion of mango galloyl derivatives (GD) has not yet been investigated in humans, and studies investigating repeated dosages of polyphenols are limited. Methods and results In this human pilot trial, healthy volunteers (age = 21–38 y, n = 11) consumed 400 g/day of mango‐pulp (cv. Keitt) for 10 days, and seven metabolites of gallic acid (GA) were characterized and quantified in urine excreted over a 12 h period. Pyrogallol‐ O ‐sulfate and deoxypyrogallol‐ O ‐sulfate were found to be significantly more excreted between days 1 and 10 ( p < 0.05) from 28.5 to 55.4 mg and 23.6 to 47.7 mg, respectively. Additionally, the in vitro hydrolysis of gallotannins (GTs) was monitored at physiological pH and temperature conditions, and after 4 h a significant ( p < 0.05) shift in composition from relativity high to low molecular weight GTs was observed. Conclusion Seven metabolites of GA were identified in the urine of healthy volunteers, and two microbial metabolites were found to be significantly more excreted following 10 days of mango consumption. Mango GTs were also found to release free GA in conditions similar to the intestines. GTs may serve as a pool of pro‐GA compounds that can be absorbed or undergo microbial metabolism.