African Journal of
Pharmacy and Pharmacology

  • Abbreviation: Afr. J. Pharm. Pharmacol.
  • Language: English
  • ISSN: 1996-0816
  • DOI: 10.5897/AJPP
  • Start Year: 2007
  • Published Articles: 2285

Full Length Research Paper

Effect of Viola tricolor on pentobarbital-induced sleep in mice

Ahmad Ghorbani1, Naimeh Javadi Youssofabad2 and Hassan Rakhshandeh1, 3*
1Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. 2School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Iran. 3Department of Pharmacology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Email: [email protected]

  •  Accepted: 17 August 2012
  •  Published: 22 September 2012


Traditionally, Viola tricolor has been recommended for its sedative property. However, no pharmacological studies have yet evaluated the effect of this plant on sleep. The hydro-alcoholic extract (HAE) was prepared by the extraction of the aerial parts of V. tricolor in 70% ethanol using a Soxhalet apparatus. Also, with solvent-solvent extraction, the HAE was further fractionated to water fraction (WF), ethyl acetate fraction (EAF) and N-butanol fraction (NBF). The extract (50, 75, 100, 150, 200, 300 mg/kg, ip) and its fractions (200 mg/kg, ip) were administrated to mice, 30 min before pentobarbital (30 mg/kg, ip) injection. Furthermore, the possible neurotoxicity of the plant was assessed using PC12 neuron cell line. The HAE, at 300 mg/kg, significantly prolonged (34%) duration of pentobarbital-induced sleep. Similarly, theEAF significantly increased (51%) the sleep duration. None of the HAE doses or the fractionscould significantly change the sleep latency time. The sedative effect of V. tricoloraccompanied with no neuron toxicity, except for very high concentrations of EAF. The results suggest that V. tricolor potentiates pentobarbital hypnosis and the main component(s) responsible for this effect is most likely found in EAF. Isolation and purification of the active compound(s) may yield novel sleep-prolonging agents.


Key words: Viola, sleep, pentobarbital, mice.