The influence of biologically active compounds of medicinal plants on the central nervous system receptors – basis of potential interaction with synthetic drugs mechanisms. Part I.
Advances in understanding of molecular mechanisms in phytotherapy allow the better identification of neurochemical mechanisms leading to interactions between herbal medicines and synthetic drugs on the receptors level in the central nervous system (CNS). We have summarised the possible interactions between selected medicinal plants: Ginkgo biloba (Ginkgo), Hypericum perforatum (St. John’s Worth) (part I of series), Valeriana officinalis (Valerian) oraz Panax ginseng (Ginseng) (part II ) and synthetic drugs, i.e. benzodiazepin and barbiturate derivatives as well as opioids – on the receptors of CNS (i.e. alfa-aminobutyric acid, glutamate, dopamine, muscarinic, adenosine receptors) from in vitro and animal model studies. The analysis of bibliographical data has shown that ginkgolides and bilobalid bind to GABA receptors (as noncompetitive antagonist) and shortened the time of sleep induced by hexobarbital and urethane. Other studies showed that hyperforin, hypericine and amenthoflawon influence on the activity of different receptors of the central nervous system (NMDA , DA , GABA, 5-HT). Several studies showed binding of valerenic acid to GABA receptors. These results confirmed that valerian may cause a valerian-anesthetic, anxiolytics and sedative drugs interactions and may potentiate the sedative effects of these drugs. Moreover it was shown that ginsenosides may interact with morphine and apomorphine on the dopamine receptor level. In conclusion, imore detailed neurochemical and pharmacological studies are needed to explain the mechanisms of interactions between herbal and synthetic drugs in CNS.