Ferulic Acid Sugar Esters Are Recovered in Rat Plasma and Urine Mainly as the Sulfoglucuronide of Ferulic Acid

Zhaohui Zhao, Yukari Egashira, Hiroo Sanada
2003 Journal of Nutrition  
Ferulic acid sugar esters, the common form of ferulic acid (FA) in cereals, show a stronger antioxidant potential than FA in vitro. However, there is little information on their metabolism and excretion in vivo. In the present study, we investigated the metabolic derivatives of FA in the plasma, urine and feces of rats administered 70 mol/kg body of 5-O-feruloyl-L-arabinofuranose (FAA), feruloyl-arabinoxylan (FAXn) or the same molar amount of FA as a comparison. Administered FA and its sugar
more » ... ers were recovered in rat plasma and urine in the form of free FA, FA-glucuronide, FA-sulfate and FA-sulfoglucuronide (FA-diconjugate with sulfate and glucuronide). The recovery of administered FA in urine was 72%, which was higher than that of administered FAA (54%) or FAXn (20%). Free FA and its derivatives were not recovered in rat feces after FA or FAA administration, but 20% of the administered FA moiety was recovered when FAXn was administered. Moreover, administered FA, in contrast to FA esters, was present in plasma in the free and conjugated forms at a higher concentration but for a shorter time. These results indicated that bioavailability of FA and its sugar esters is dependent on the absence or presence of the saccharide moiety and, in the latter case, its structure. This is the first study to show that FA-sulfoglucuronide is the main metabolite (60 -70% of the total) in the plasma of rats administered FA or its sugar esters. Thus, the physiological functions of FA and its sugar esters found in vitro might require reconsideration in vivo. J. Nutr. 133: 1355Nutr. 133: -1361Nutr. 133: , 2003. KEY WORDS: • bioavailability • excretion • ferulic acid ester • metabolism • rat . 2 Abbreviations used: DW, distilled water; FA, ferulic acid; FAA, 5-O-feruloyl-L-arabinofuranose; FAXn, feruloyl-arabinoxylan; total FA, all forms of FA, containing free FA and all its derivatives.
doi:10.1093/jn/133.5.1355 pmid:12730422 fatcat:gc7dqwspgvbctf3ckkfl54uuai