Web Release Date: July 31,
Antioxidant Effects of Phenolic Rye (Secale cereale L.) Extracts, Monomeric Hydroxycinnamates, and Ferulic Acid Dehydrodimers on Human Low-Density Lipoproteins
and
Department of Horticulture, Danish Institute of Agricultural Sciences, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark; BioCentrum-DTU, Technical University of Denmark, DK-2800 Lyngby, Denmark; and Department of Dairy and Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark
Received for review February 13, 2001. Revised manuscript received June 11, 2001. Accepted June 12, 2001.
Abstract:
Dietary antioxidants that protect low-density lipoprotein (LDL) from oxidation may help to prevent
atherosclerosis and coronary heart disease. The antioxidant activities of purified monomeric and
dimeric hydroxycinnamates and of phenolic extracts from rye (whole grain, bran, and flour) were
investigated using an in vitro copper-catalyzed human LDL oxidation assay. The most abundant
ferulic acid dehydrodimer (diFA) found in rye, 8-O-4-diFA, was a slightly better antioxidant than
ferulic acid and p-coumaric acid. The antioxidant activity of the 8-5-diFA was comparable to that
of ferulic acid, but neither 5-5-diFA nor 8-5-benzofuran-diFA inhibited LDL oxidation when added
at 10-40 
M. The antioxidant activity of the monomeric hydroxycinnamates decreased in the
following order: caffeic acid > sinapic acid > ferulic acid > p-coumaric acid. The antioxidant activity
of rye extracts was significantly correlated with their total content of monomeric and dimeric
hydroxycinnamates, and the rye bran extract was the most potent. The data suggest that especially
rye bran provides a source of dietary phenolic antioxidants that may have potential health effects.
Keywords: Antioxidant; LDL; ferulic acid; ferulic acid dehydrodimers; hydroxycinnamates; phenolic extracts; rye; Secale cereale L.
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