Disposition of quercetin and kaempferol in human following an oral administration of Ginkgo biloba extract tablets
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Ten adult volunteers with an average age 28 years were given a single oral dose of six tablets of Ginkgo biloba extract. Quercetin and kaempferol in different period of human urine were determined by using RP-HPLC.
The results showed the elimination rate constantk and the absorption rate constantk a of quercetin were slightly more than that of kaempferol; and the absorption half-life (t1/2a), the elimination half-life (t1/2) and tmax of qurcetin were less than that of kaempferol, the differences were, however, not statistically significant.
The mean values ofk a were 0.61 h−1 and 0.55 h−1, t1/2a 1.51h and 1.56h,k 0.37 h−1 and 0.30 h−1, t1/2 2.17h and 2.76h, Tmax 2.30h and 2.68h for quercetin and kaempferol, respectively, which mean absorption and elimination of quercetin and kaemperferol are 0.17% and 0.22%, respectively.
Quercetin and kaemferol are excreted in the human urine mainly as glucuronides.
KeywordsGinkgo biloba extract kaempferul quercetin Disposition Glucuronide Excretion
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