Identification of Ginkgo biloba flavonol metabolites after oral administration to humans

• Published in: Journal of chromatography. Biomedical applications Vol. 693; no. 1; pp. 249 - 255
• Main Authors: Pietta, P.G, Gardana, C, Mauri, P.L
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 23.05.1997
• Subjects: 3,4-Dihydroxybenzoic acid; 3-Methoxy-4-hydroxybenzoic acid; 3-Methoxy-4-hydroxyhippuric acid; 4-Hydroxybenzoic acid; 4-Hydroxybenzoic acid conjugate; 4-Hydroxyhippuric acid; Flavonols; Hippuric acid; Vanillic acid; Ginkgo biloba; Flavonols; 4-Hydroxybenzoic acid conjugate; Hippuric acid; 3-Methoxy-4-hydroxybenzoic acid; 4-Hydroxyhippuric acid; 4-Hydroxybenzoic acid; Vanillic acid; 3-Methoxy-4-hydroxyhippuric acid; 3,4-Dihydroxybenzoic acid
• ISSN: 0378-4347
• DOI: 10.1016/S0378-4347(96)00513-0

An extract of Ginkgo biloba leaves (EGb) was given to healthy volunteers. Urine samples were collected for 3 days, and blood samples were withdrawn every 30 min for 5 h. The samples were purified through SPE C 18 cartridges and analyzed by reversed-phase LC–diode array detection for the presence of EGb metabolites. Only urine samples contained detectable amounts of substituted benzoic acids, i.e., 4-hydroxybenzoic acid conjugate, 4-hydroxyhippuric acid, 3-methoxy-4-hydroxyhippuric acid, 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, hippuric acid and 3-methoxy-4-hydroxybenzoic acid (vanillic acid). In contrast to rats no phenylacetic acid or phenylpropionic acid derivatives were found in urine, thus indicating that in humans a more extensive metabolism takes place. As for rats the metabolites found in human urines accounted for less than 30% of the flavonoids given. The same procedure was applied to blood samples, and no metabolites could be detected.