In many European countries common valerian, Valerianu officinalis L., is a popular herbal remedy considered to exert sedative effects. However, the evidence that valerian is sedative in man has been equivocal for many decades. In recent years, valerian root extracts have been shown in man to improve sleep quality (Leathwood et al., 1982), to reduce latency to fall asleep (Leathwood and Chauffard, 1985) and to diminish feelings of somatic arousal during a social stress situation (Kohnen and Oswald, 1988, 1992).
Only a few papers on animal experimentation with valerian have appeared during the past 20 years. In mice, sedation has been observed after administration of a tincture (Torrent et af., 1972), certain extract components (Petkov and Manolov, 1974) or essential oil (Hendricks et af., 1981) of Valerianu oficinalis L; furthermore, anticonvulsant effects were found by Petkov and Manolov (1974). Ammelounx et al. (1978) and Holm et af. (1980) evaluated the EEG and evoked potentials in cats but observed thymoleptic-like rather than sedative or tranquillizing effects of a valerian extract and a mixture of three valepotriates.
By means of the [C] deoxyglucose method central effects of valerian in rats have been postulated. Certain extracts of Valerianu oficinafis L. (but not valepotriates, valerenic acid, valeranone or the essential oil) diminished the local glucose utilization in many, albeit not all, brain parts (Grusla er al., 1986; Krieglstein and Grusla, 1988). Recently, an aqueous alkaline dried extract was shown to decrease motility and to increase barbiturate anaesthesia in female mice (Leuschner et al., 1993); from this finding the authors claimed sedative properties of the particular extract.
The aim of the present study was to find out whether neuropharmacological effects in mice would be exerted by fresh valerian root extracts and some of its isolated fractions.