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The C ‐glycosyl flavonoid, aspalathin, is absorbed, methylated and glucuronidated intact in humans
Author(s) -
Courts Fraser L.,
Williamson Gary
Publication year - 2009
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.200800569
Subject(s) - flavonoid , chemistry , glucuronidation , glycosyl , bioavailability , biochemistry , microsome , pharmacology , enzyme , biology , antioxidant
Human bioavailability of the flavonoid dihydrochalcones is little understood, and no evidence exists for C ‐glycosyl flavonoid absorption in humans. The present study uses catechol‐ O ‐methyltransferase to generate methylated metabolites of aspalathin (a C ‐glycosyl dihydrochalcone from rooibos tea). One of the methylated forms, both with and without glucuronidation, was detected using LC‐MS/MS in the urine of human subjects ( n = 6), demonstrating that deglycosylation is not a prerequisite for C ‐glycosyl flavonoid absorption. Methylation is catalysed by both intestine and liver cytosolic extracts. The results show that flavonoid C ‐glycosides are methylated and glucuronidated in vivo in an intact form in humans.