Evaluating the Effect of Foeniculum Vulgar on Scopolamin-Induced Memory Impairment in Male Mice

Estrogen is a steroid that regardless of its obvious effects on females’ reproductive functions shows beneficial effects on cognition. Foeniculum vulgar (fennel) has phytoestrogen compounds that might be beneficial in memory performance. This research was performed to understand if this plant can improve memory. To evaluate memory, novel object recognition task was used in male Balb-c mice, which comprised of three sections: habituation, learning trial (T1) and the test trial (T2). In this method, the difference in the exploration time between a familial (F) and a novel (N) object is taken as an index of memory performance [recognition index (RI) = (N – F)/(N + F) × 100]. Memory was harmed using 0.5 mg/kg subcutaneous scopolamine [RI (%) = -16.0 ± 3.0]. 50 mg/kg intraperitoneal fennel considerably prevented memory impairment of scopolamine [RI (%) = 35.0 ± 7.1] and this was parallel with the memory index in normal animals [RI (%) = 50.0 ± 5.8]. In addition, 0.2 mg/kg intraperitoneal 17-β estradiol showed similar results as fennel on memory protection [RI (%) = 36.0 ± 6.6]. However, the beneficial effects of fennel were impaired by prior intraperitoneal injection of 1 mg/kg tamoxifen [RI (%) = -29.0 ± 7.1]. The beneficial effect of fennel on memory is achieved by estrogenic receptors present in the brain; by stimulating these receptors, they could cause an increase in acetylcholine release. Therefore, it can competitively prevent the antagonizing effect of scopolamine on cholinergic receptors.