Document Detail

Urinary excretion of phenolic acids in rats fed cranberry.
MedLine Citation:
PMID:  20052972     Owner:  NLM     Status:  MEDLINE    
Dietary flavonoids can be converted into phenolic acids by colonic microflora. Phenolic acids can then be absorbed into the circulation and may contribute to the health-promoting effects of the parent compounds. Phenolic acids can be further metabolized in other tissues via methylation and conjugation with glucuronide or sulfate. The objectives of this study were to identify and quantify the urinary excretion of 19 phenolic acids and their conjugates in rats fed three levels of a concentrated cranberry powder (3.3, 6.6, and 33 mg/kg of diet). The basic diet used was AIN93G diet containing very low amounts of any polyphenolic compounds. Of the phenolic acids studied, the amounts excreted varied by 4 orders of magnitude, with hippuric acid being excreted in the highest quantities. Amounts of 4-hydroxyphenylacetic acid (4HPAA), 3-hydroxyphenylacetic acid (3HPAA), 3-hydroxyphenylpropionic acid (3HPPA), and 4-hydroxycinnamic acid (4HCA) excreted were in the range of 18-33 microg/mg creatinine in animals fed the highest level of cranberry powder, whereas phenylacetic acid (PAA), gallic acid (GA), 3,4-dihydroxyphenylacetic acid (34HPAA), 3,4-dihydroxybenzoic acid (34HBA), 3,4-dihydroxycinnamic acid (34HCA), and 4-hydroxy-3-methoxycinnamic acid (FA) were excreted in the urine in concentrations of 0.1-2 microg/mg creatinine. As the amount of cranberry in the diet was increased, the amount of 4HPAA excreted decreased but the percentage of conjugated 4HPAA excreted increased (from 57 to 91%). For other phenolic acids analyzed, the percentage excreted in the conjugated form was approximately constant across levels of cranberry in the diet and ranged from 65 to 100% for the individual phenolic acids. Studies of bioactivity and health effects need to consider more than just the compound(s) in the food, because they can be metabolized to other lower molecular weight compounds, which in turn may also be methylated or conjugated in some form that may affect the perceived health effects.
Ronald L Prior; Theodore R Rogers; Ramesh C Khanal; Samuel E Wilkes; Xianli Wu; Luke R Howard
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  58     ISSN:  1520-5118     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-07     Completed Date:  2010-08-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3940-9     Citation Subset:  IM    
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MeSH Terms
Dietary Supplements / analysis
Hydroxybenzoic Acids / administration & dosage,  urine*
Plant Extracts / administration & dosage,  urine*
Random Allocation
Rats, Sprague-Dawley
Vaccinium macrocarpon / chemistry*
Reg. No./Substance:
0/Hydroxybenzoic Acids; 0/Plant Extracts; 29656-58-4/phenolic acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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