Pharmacological basis for sedative and hypnotic like effects of Pyrus pashia using in vivo experimental models.

OBJECTIVE: Pyrus pashia has traditionally been used as a therapeutic agent including sedative. In this regard, hydroethanolic extract of Pyrus pashia (HEPP) was screened for phytochemical investigation, acute toxicity, and sedative-hypnotic activity to provide a scientific rationale to its ethno-medicinal uses.

METHODS: Mice were used in acute toxicity test; sedative potential was observed in open field test while thiopental-induced sleeping time and barbiturate-induced sleeping time tests were used for the assessment of hypnotic like effects of HEPP. Various phytochemical groups were detected in preliminary phytochemical tests.

RESULTS: In acute toxicity study, the extract was found safe up to 1g/kg while the extract caused 50% death at 1500 mg/kg. In all animal models, the extract had shown sedative and hypnotic effects but the most significant effect observed at increased dose in comparison with standard diazepam-treated group. In open field test, the extract at doses of 200 and 400 mg/kg, there is mild decrease in number of lines crossed by tested animals (mice) while significant reduction shown at 600 mg/kg compared with diazepam-treated group at dose 0.5 mg/kg. In phytochemical investigation HEPP subjected to different phytochemical tests. From the thoroughly study, it is revealed that these constituents mainly participating in sedation and hypnosis.

CONCLUSIONS: The results of the present study showed significant sedative-hypnotic effects of the HEPP in mice and that the central benzodiazepine receptors are involved in the sedative-hypnotic effects of this plant.