Effects of oral administration of Silexan on behavioural parameters in rats and mice

Silexan is a new phytochemical preparation which is under development for the treatment of mild affective disorders. It contains essential oil obtained from the flowers of Lavendula angustifolia. Native preparations of lavender essential oil, are traditionally used in aromatherapy and in the flavouring industries. Since the 1980s, a considerable number of studies have been carried out, and a wide range of biological activities were found for lavender oil or its main constituents linalool and linalyl acetate (1,2). For example, linalool shows anticonvulsant and antiphlogistic properties and modifies nicotine receptor function at neuromuscular junctions.(3,4,5,6,7). The aim of the present investigation was to determine potential central nervous effects of Silexan in animal models of depression, sleeping time and anxiety. For this purpose, the effect of oral administration of Silexan was investigated in rats and mice. Repeated oral administration of Silexan in a dose range between 3 and 30mg/kg caused a statistically significant inhibition of the immobility time in the forced swimming test. Anxiolytic effects were tested in mice using the „light-dark-box“ and the „elevated-plus-maze“ models. Statistically significant effects were found in both models after single oral administration in doses of 3 to 30mg/kg b.w. Influence on pentobarbital-induced sleeping time was investigated in mice after single and repeated oral administration of the test compound. The sleeping time was significant prolonged after oral administration of 3, 10 or 30mg/kg Silexan. These results suggest that Silexan has anxiolytic and antidepressant properties and could modify the sleeping profile, which is frequently disturbed in affective disorders.

References: [1] Cavanagh, H.M.A. et al. (2002) Phytotherapy Research 16: 301–308; [2] Heuberger, E. et al. (2004) Neuropharmacology 29 1925–1932; [3] Elisabetsky, E. et al. (1999) Phytomedicine 6 (2): 107–113; [4] Peana, A. et al. (2004) Eur. J. Pharmacol. 497: 279–284; [5] Re, L et al. (2000) Pharmacol. Res. 42 (2): 177–181; [6] Ghelardini, C. et al. (1999) Planta Med. 65: 700–703; [7] Ballabeni, V. et al. (2004) Phytomedicine 11: 596–601