Bioavailability of dietary antioxidants in Acanthopanax sieboldianus Makino leaves

We have investigated the intestinal absorption and metabolism of the polyphenols contained in Acanthopanax sieboldianus Makino (Ukogi in Japanese) in rat plasma using a liquid chromatography/mass spectrometry (LC/MS). Ukogi mainly contained chlorogenic acid, rutin, and kaempferol 3-O-rutinoside. These polyphenols were detected in non-hydrolyzed rat plasma 0.5 hour after oral administration, and the concentration of rutin was 13.6 ± 3.65 nM. The metabolized compounds of kaempferol sulfoglucuronide and 3'-O-methylquercetin sulfoglucuronide were identified by exact mass determination and exact mass mass spectrometry/mass spectrometry (MS/MS) in the plasma of rats fed a 5 % Ukogi diet for 8-24 days. Antioxidant potential of the metabolized compounds is discussed concerning a beneficial effect in the body via antioxidation caused by not only scavenging superoxide but also blocking superoxide generation.