Disposition of quercetin and kaempferol in human following an oral administration of Ginkgo biloba extract tablets.
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 constant k and the absorption rate constant ka of quercetin were slightly more than that of kaempferol; and the absorption half-life (t(1/2a)), the elimination half-life (t(1/2)) and t(max) of quercetin were less than that of kaempferol, the differences were, however, not statistically significant. The mean values of ka were 0.61 h(-1) and 0.55 h(-1), t(1/2a) 1.51 h and 1.56 h, k 0.37 h(-1) and 0.30 h(-1), t(1/2) 2.17 h and 2.76 h, T(max) 2.30 h and 2.68 h for quercetin and kaempferol, respectively, which mean absorption and elimination of quercetin and kaempferol are 0.17% and 0.22%, respectively. Quercetin and kaempferol are excreted in the human urine mainly as glucuronides.
Wang
F M
FM
Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
Yao
T W
TW
Zeng
S
S
D000284:Administration, Oral; D000328:Adult; D020441:Ginkgo biloba; D006801:Humans; D044949:Kaempferols / Q000008:administration & dosage* / Q000652:urine*; D016018:Least-Squares Analysis; D010936:Plant Extracts / Q000008:administration & dosage / Q000652:urine; D011794:Quercetin / Q000008:administration & dosage* / Q000652:urine*; D013607:Tablets
D044949:Kaempferols; D010936:Plant Extracts; D013607:Tablets; C006552:kaempferol; D011794:Quercetin