Interactions of valerian extracts and a fixed valerian-hop extract combination with adenosine receptors.
Phytopharmaceuticals and dietary supplements containing valerian are used as mild sleep-inducing agents. An in vitro radioligand binding assay at A(1) and A(2A) adenosine receptors (ARs) was conducted with a fixed extract combination of valerian and hop (Ze 91019) to investigate a possible mechanism for the pharmacological activity of the extract. Component extracts of valerian and hop were also individually investigated. The fixed combination Ze 91019 as well as the valerian extracts therein exhibited selective affinity to A(1)ARs (K(i) = 0.15-0.37 mg/mL vs [(3)H]CCPA). The same extracts exhibited partial agonist activity at the A(1) adenosine receptor as indicated by a lower degree of stimulation of [35S]GTP gamma S binding in membrane preparations of CHO-hA(1) cells as compared to the full A(1) AR agonist N(6)-cyclopentyladenosine (CPA). In addition valerian extract inhibited cAMP accumulation in CHO-hA(1) cell membranes. The partial agonistic activity at A(1)ARs may thus play a role in the sleep inducing effect of Ze 91019 and the valerian extract therein.
Müller
Christa E
CE
Universität Bonn, Pharmazeutisches Institut, Pharmazeutische Chemie Poppelsdorf, Kreuzbergweg 26, D-53115 Bonn, Germany. christa.mueller@uni-bonn.de
Schumacher
Britta
B
Brattström
Axel
A
Abourashed
Ehab A
EA
Koetter
Uwe
U
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D041743:Herb-Drug Interactions; D027582:Humulus / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology; D058915:Purinergic P1 Receptor Antagonists; D011869:Radioligand Assay; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1 / Q000187:drug effects*; D014632:Valerian / Q000737:chemistry*
D010936:Plant Extracts; D058915:Purinergic P1 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D018047:Receptors, Purinergic P1; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP