Extracts of Valeriana officinalis L. s.l. show anxiolytic and antidepressant effects but neither sedative nor myorelaxant properties.

ABSTRACT

Extracts of Valeriana officinalis L. s.l. are used for treating mild sleep disorders and nervous tension. Despite intensive research efforts, the pharmacological actions accounting for the clinical efficacy of valerian remain unclear. Thus, it was the aim of this study to evaluate CNS-related effects of different valerian extracts using behavioral paradigms (mice and rats). Following oral administration two commercially available preparations (extraction solvents 45% methanol m/m and 70% ethanol v/v), a 35% ethanolic v/v extract and a refined extract derived from it (patented special extract phytofin Valerian 368) were tested for sedative (locomotor activity, ether-induced anaesthesia) and anxiolytic (elevated plus maze) activity. Using the forced swimming and the horizontal wire test the latter two extracts were additionally tested for antidepressant and myorelaxant properties. Up to maximum dosages of 500 or 1000 mg/kg bw none of the valerian extracts displayed sedative effects. Neither spontaneous activity was reduced nor the duration of ether-induced narcosis was prolonged. In contrast, results obtained in the elevated plus maze test revealed a pronounced anxiolytic effect of the 45% methanolic and 35% ethanolic extract as well as of phyotofin Valerian 368 in a dose range of 100-500 mg/kg bw. Additionally and different from its primary extract (35% ethanolic extract) phytofin Valerian 368 showed antidepressant activity in the forced swimming test after subacute treatment. Myorelaxant effects were not observed in dosages up to 1000 mg/kg bw. Due to these findings it is proposed that not sedative but anxiolytic and antidepressant activity, which was elaborated particularly in the special extract phytofin Valerian 368, considerably contribute to the sleep-enhancing properties of valerian.