Avenanthramides are bioavailable and have antioxidant activity in humans after acute consumption of an enriched mixture from oats.
The consumption of polyphenols is associated with a decreased risk of cardiovascular disease. Avenanthramides (AV), alkaloids occurring only in oats, may have anti-atherosclerotic activity, but there is no information concerning their bioavailability and bioactivity in humans. We characterized the pharmacokinetics and antioxidant action of avenanthramide A, B, and C in healthy older adults in a randomized, placebo-controlled, 3-way crossover trial with 1-wk washout periods. Six free-living subjects (3 mol/L, 3 F; 60.8 +/- 3.6 y) consumed 360 mL skim milk alone (placebo) or containing 0.5 or 1 g avenanthramide-enriched mixture (AEM) extracted from oats. Plasma samples were collected over a 10-h period. Concentrations of AV-A, AV-B, and AV-C in the AEM were 154, 109, and 111 micromol/g, respectively. Maximum plasma concentrations of AV (free + conjugated) after consumption of 0.5 and 1 g AEM were 112.9 and 374.6 nmol/L for AV-A, 13.2 and 96.0 nmol/L for AV-B, and 41.4 and 89.0 nmol/L for AV-C, respectively. Times to reach the C(max) for both doses were 2.30, 1.75, and 2.15 h for AV-A, AV-B, and AV-C and half times for elimination were 1.75, 3.75, and 3.00 h, respectively. The elimination kinetics of plasma AV appeared to follow first-order kinetics. The bioavailability of AV-A was 4-fold larger than that of AV-B at the 0.5 g AEM dose. After consumption of 1 g AEM, plasma reduced glutathione was elevated by 21% at 15 min (P < or = 0.005) and by 14% at 10 h (P < or = 0.05). Thus, oat AV are bioavailable and increase antioxidant capacity in healthy older adults.
Chen
C-Y Oliver
CY
Antioxidants Research Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA. oliver.chen@tufts.edu
Milbury
Paul E
PE
Collins
F William
FW
Blumberg
Jeffrey B
JB
D000975:Antioxidants / Q000493:pharmacokinetics* / Q000494:pharmacology; D019540:Area Under Curve; D018554:Avena; D001682:Biological Availability; D018592:Cross-Over Studies; D005260:Female; D005978:Glutathione / Q000097:blood; D006207:Half-Life; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D062367:ortho-Aminobenzoates / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology
D000975:Antioxidants; D062367:ortho-Aminobenzoates; D008315:Malondialdehyde; C514463:avenanthramide-2C; D005978:Glutathione