Avenanthramides Are Bioavailable and Have Antioxidant Activity in Humans after Acute Consumption of an Enriched Mixture from Oats

Abstract

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.

Chronic consumption of a low calorie, high polyphenol cranberry beverage attenuates inflammation and improves glucoregulation and HDL cholesterol in healthy overweight humans: a randomized controlled trial

“…However, we did not find the same effect after the 8 week CEB consumption. These results are consistent with a temporal effect of polyphenols on elevated GSH concentrations reported by Chen et al [37]. In addition to GSH:GSSG ratio, we noted that SOD activity but not GPx was greater after chronic CEB consumption.…”

“…The final anthocyanin concentrations were adjusted with creatinine to account for urine volume differences. Urinary flavanols, flavonols, and phenolic acids were quantified by HPLC with electrochemical detection [31,37]. Concentrations of individual polyphenols were determined using calibration curves constructed with authenticated standards.…”

Protective effect of oat bran extracts on human dermal fibroblast injury induced by hydrogen peroxide

“…It is well known that SOD serves as the first gatekeeper in the antioxidant defense system designed to scavenge superoxide anions (Reiter et al, 2000), while GSH-Px is a catalyzer that activates the reaction of lipid hydroperoxides with reduced glutathione to form glutathione disulfide (Venukumar and Latha, 2002). An avenanthramides (AVE)-enriched mixture extracted from oat was reported to increase human plasma GSH-Px activity by 30%-35% (Chen et al, 2007). In this study, both SOD and GSH-Px activities were significantly downregulated in H 2 O 2 -treated groups.…”

Phenolic amides (avenanthramides) in oats - a review

“…Both animal studies and human clinical trials confirmed that oats antioxidants have the potential of reducing cardiovascular risks by lowering serum cholesterol, inhibiting LDL cholesterol oxidation and peroxidation (Cook & Samman 1996;Ji et al 2003;Inglett & Chen 2012). Therefore, it is emphasised that the consumption of oats and oats products is extremely important to reduce the risk of cardiovascular disease (Bazzano et al 2003;Chen et al 2004Chen et al , 2007Singh et al 2013). Another study has indicated that the consumption of oats and oats bran may reduce the risk of colon cancer not only because of their high fiber contents but also due to AVAs (Guo et al 2010).…”