Onion (bulbs of Allium cepa L.) is the richest source of polyphenols among vegetables and fruits. The major polyphenols in onion are quercetin glycosides and onion skin has the highest content. This study investigated the pharmacokinetics of onion skin and onion soup in rats. Our results indicated that after oral administration of onion skin and onion soup, no free form of quercetin was detected, whereas quercetin sulfates were found predominantly in the blood. Onion soup showed faster absorption of quercetin glycosides than onion skin, which is like a sustained-released dosage from.
Methotrexate (MTX), a dicarboxylic acid, is an important immunosuppressant with narrow therapeutic index. Rats were orally given MTX with and without onion skin and onion soup. The results showed that coadministration of onion skin significantly increased AUC0-t of MTX by 140 % and increased MRT by 90 %. In addition, unexpectedly, coadministration with onion skin resulted in a mortality of 5/5 (100%). Coadministration of onion soup significantly increased the AUC0-t of MTX by 99 %, but didn’t affect MRT and all rats survived well throughout the study.
Intramuscular administration of 50 % glycerol induced acute renal failure of rats. Our results showed that oral administration of 500 mg/kg of rutin significantly reduced serum creatinine and BUN, indicating that rutin exerted kidney protection effect.
