Memory-enhancing potentials of hydroalcoholic extract of Eragrostis tremula Hochst. exSteud. (Poaceae) in Mice

Background & Aim:Cognitive impairment is one of the age-related mental problems and a typical indicator of neurodegeneration. Eragrostis tremula Hochst. ex Steud. is a commonly used medicinal plant in Nigeria for memory enhancement. This study, therefore, aimed at evaluating the memory-enhancing potential of aqueous ethanolic extract of E. tremula in mice. Experimental: Classes of phytochemicals present in the extract were determined using standard protocol while its oral median lethal dose (LD50) in mice was estimated. The effect of E. tremula extract (125, 250 and 500 mg/kg) on learning and memory was evaluated in mice using behavioural paradigms: elevated plus maze (EPM), novel object recognition and Barnes maze. Open field and hole-board tests were also carried out to evaluate locomotion. Results: The phytochemical constituents of E. tremula were alkaloids, cardiac glycosides, flavonoids, tannins, saponins, steroids and triterpenes. Oral LD50 was estimated to be >5000 mg/kg. E. tremula extract significantly (P<0.05) decreased the transfer latency of mice during the retention phase of EPM test. In the novel object recognition test, it significantly (P<0.05) increased the discrimination index. In Barnes maze test, the extract significantly (P<0.05) decreased the mean primary errors during the acquisition trials. It also significantly (P<0.05) decreased the primary latency, primary error and increased the time spent in the target quadrant during the probe trial. E. tremula extract significantly (P<0.05) decreased the immobility time of mice in an open field at 250 mg/kg, while in the hole-board test, it significantly (P<0.05) increased the mean head-dip of mice at 125 mg/kg when compared to the negative control. Recommended applications/industries: The ethanol extract of E. tremula possesses memory enhancing properties which can be utilized in the management of amnesia and cognitive deficit.