Document Detail


Antidepressant-like components of Hypericum perforatum extracts: an overview of their pharmacokinetics and metabolism.
MedLine Citation:
PMID:  16379667     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Extracts of Hypericum perforatum are becoming increasingly popular for the treatment of mild to moderate depression, despite the lack of consensus on their efficacy. Although the mechanism(s) of this action are still debated, several components, including the naphthodianthrones hypericin and pseudohypericin, the acylphloroglucinol hyperforin and some flavonols, are believed to play major roles in the antidepressant-like effects. Some of these also increase the expression of the P-glycoprotein transporter and others the expression of cytochrome P450 enzymes, possibly contributing to the interactions involving the extracts and conventional drugs. However, few pharmacokinetic studies of naphthodianthrones and hyperforin have appeared and none has yet evaluated the exposure to unchanged quercetin and its glycosides after intake of extracts. There are no formal pharmacokinetic studies in special populations. Bioavailability appears low, giving variable steady-state plasma concentrations, whose prediction may be complicated by non-linearity for hypericin and hyperforin. Data on tissue distribution are scarce, and it appears that hypericin and hyperforin do not reach the central nervous system in appreciable concentrations in animals. Clearance is low-intermediate, with little or no unchanged compounds excreted with urine. Although some potentially active conjugated metabolites have been identified for quercetin and its glycosides after intake of authentic compounds or flavonol-rich foods, these too have been characterised little with regard to their pharmacokinetics and central activities. Thus, further pharmacokinetic and pharmacodynamic studies of the main components and their metabolites are urgently needed to clarify the role of each constituent and provide more rational and safe regimens for people preferring "natural" drugs.
Authors:
Silvio Caccia
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Current drug metabolism     Volume:  6     ISSN:  1389-2002     ISO Abbreviation:  Curr. Drug Metab.     Publication Date:  2005 Dec 
Date Detail:
Created Date:  2005-12-28     Completed Date:  2006-02-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100960533     Medline TA:  Curr Drug Metab     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  531-43     Citation Subset:  IM    
Affiliation:
Istituto di Ricerche Farmacologiche "Mario Negri", via Eritrea 62, 20157 Milan, Italy. caccia@ marionegri.it
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MeSH Terms
Descriptor/Qualifier:
Animals
Antidepressive Agents / chemistry,  metabolism*,  pharmacokinetics*
Area Under Curve
Humans
Hypericum / chemistry*
Plant Extracts / chemistry,  metabolism,  pharmacokinetics
Chemical
Reg. No./Substance:
0/Antidepressive Agents; 0/Plant Extracts

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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