title: In vivo striatal measurement of hydroxytyrosol, and its metabolite (homovanillic alcohol), compared with its derivative nitrohydroxytyrosol.
abstract: Phenolic compounds were measured by in vivo brain microdialysis in rat striatum. Basal extracellular levels of hydroxytyrosol, homovanillic alcohol and nitro-hydroxytyrosol were not detectable by HPLC with electrochemical detection. However, systemic administration of hydroxytyrosol (20 and 40mg/kg, i.p.) showed a clear increase in the extracellular level of this compound. This increase was accompanied by an increase in the extracellular level of homovanillic alcohol, a metabolite of hydroxytyrosol formed by catechol-O-methyltransferase activity. Perfusion of hydroxytyrosol (20μM) through the microdialysis cannula also produced an increase in the extracellular level of homovanillic alcohol. Systemic administration of nitro-hydroxytyrosol (20 and 40mg/kg, i.p.) produced a small increase in the extracellular level of this compound. Our data show that hydroxytyrosol is a more brain penetrant phenolic compound than nitro-hydroxytyrosol. Accordingly, there is high cerebral metabolism of hydroxytyrosol to produce homovanillic alcohol by catechol-O-methyltransferase activity, that is saturated at the higher administered dose of hydroxytyrosol.
authors: Departamento de Química Orgánica y Farmacéutica. Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain.
authors: Elena
authors: E
authors: Gallardo
authors: Departamento de Química Orgánica y Farmacéutica. Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain.
authors: Rocío
authors: R
authors: Palma-Valdés
authors: Departamento de Química Orgánica y Farmacéutica. Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain.
authors: José Luis
authors: JL
authors: Espartero
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain. Electronic address: msantiago@us.es.
authors: Marti
authors: M
authors: Santiago
mesh_terms: D000818:Animals; D001711:Biotransformation; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D006719:Homovanillic Acid / Q000378:metabolism*; D008297:Male; D017072:Neostriatum / Q000378:metabolism*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: C532664:homovanillic alcohol; C005975:3,4-dihydroxyphenylethanol; D002394:Catechol O-Methyltransferase; D010626:Phenylethyl Alcohol; D006719:Homovanillic Acid
keywords: HPLC; Homovanillic alcohol; Hydroxytyrosol; Microdialysis; Nitro-hydroxytyrosol; Rat's striatum