title: Identification of Gingko biloba flavonol metabolites after oral administration to humans.
abstract: 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 Urine samples were collected for 3 days, and blood samples were withdrawn every 30 min for 5 h. The samples were purified through SPE C18 cartridges and analyzed by reversed-phase LC-diode array detection for the presence of EGb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.
authors.affiliation: CNR-ITBA, Milan, Italy.
authors.forename: P G
authors.initials: PG
authors.lastname: Pietta
authors.forename: C
authors.initials: C
authors.lastname: Gardana
authors.forename: P L
authors.initials: PL
authors.lastname: Mauri
mesh_terms: D001565:Benzoates / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001565:Benzoates; D005419:Flavonoids; D010936:Plant Extracts