Evaluation of the effect of Cyperus rotundus L. in scopolamine-induced learning defi cit in mice

Cyperus rotundus L. was used in traditional Iranian medicine to treat memory and cognition disorders. The present study was aimed at investigating the effect of the extract and essential oil of C. rotundus on memory dysfunction.

Cognition was evaluated using the object recognition task that was composed of a square wooden open field box with different shape objects. The test was consisted of three sections: 15 min exploration, first trial for 12 min and second one for 5 min. In the second trial the difference in exploration between a previously seen object and novel one, was considered as an index of memory performance (recognition index). Memory deficit was induced by scopolamine (0.5 mg/kg) before injection of plant extracts and essential oil.

Rivastigmine at 0.6 mg/kg reversed the scopolamine induced memory dysfunction in mice (P < 0.05). On the contrary, neither the hydroalcholic extracts (100, 200, 400 mg/kg) nor the polyphenolic extract (50, 100, 200 mg/kg) and essential oil (10, 20, 40 mg/kg) of C. rotundus produced significant improvement of memory dysfunction. The fact that rivastigmine reversed the scopolamine-induced memory dysfunction confirms the validity of this memory paradigm.

Using the current method of the memory evaluation, none of the tested doses of the plant extract or essential oil changed the memory status of the animals, indicating either a lack of effective ingredient or unsuitable method for evaluation.