Commercial valerian interactions with [3H]flunitrazepam and [3H]MK-801 binding to rat synaptic membranes

Valeriana officinalis extracts are used in folkloric medicine for their sedative, hypnotic and tranquilizer effects. Using [H-3]flunitrazepam binding as an indicator, the interactions of commercial Valerian extracts with GABA(A) receptors were examined. There was considerable fluctuation among the different extracts, some mildly enhanced [H-3]flunitrazepam binding, others had no effect and others had inhibitory effects, independent of standardization by valerenic acid. Central depression can also be accomplished by a reduction of excitatory transmission. Valerian extracts had modest inhibitory effects on [H-3]MK-801 binding, an indicator of NMDA-Valerian interactions. Spectral analyses (UV region) did not show marked differences among the different extracts. The inhibitory effects of one of the extracts on [H-3]flunitrazepam binding was somewhat stable, while on [H-3]MK-801 binding the inhibitory effects were lost within months. These results suggest that particular care should be taken in analysing and interpreting results from commercial Valerian preparations. Copyright (c) 2006 John Wiley & Sons, Ltd.