Identification of Gingko biloba flavonol metabolites after oral administration to humans.
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 Urine samples were collected for 3 days, and blood samples were withdrawn every 30 min for 5 h. The samples were purified through SPE C18 cartridges and analyzed by reversed-phase LC-diode array detection for the presence of EGb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.
Pietta
P G
PG
CNR-ITBA, Milan, Italy.
Gardana
C
C
Mauri
P L
PL
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
D001565:Benzoates; D005419:Flavonoids; D010936:Plant Extracts