Effect of ethanolic extract of leaves of Solanum trilobatum on scopolamine-induced memory impairment in Sprague Dawley rats

Abstract

Objective: The objective of the study is to determine the effect of ethanolic extract of leaves of Solanum trilobatum (EEST) on scopolamine-induced memory impairment in Sprague Dawley (SD) rats. Materials and Methods: The leaves of S. trilobatum were extracted with ethanol and used for the study. The SD rats were divided into six groups each consist of six animals, namely normal control; scopolamine control; donepezil treated 3 mg/kg; and EEST treated 100, 200, and 400 mg/kg, respectively. Except normal control, all other animals were administered with intraperitoneal injection of scopolamine (1 mg/kg body weight) for 21 days to induce memory impairment. Donepezil and EEST were administered once daily through oral gavage for 21 consecutive days. On prestudy, 7th, 14th, and 21st days of the experiment, the animals' locomotor activity, muscle grip strength and escape latency time (ELT) were measured. At the end of the study, blood samples were collected from all the animals and they were sacrificed; the organs such as brain, liver, lung, heart, kidney, and stomach were harvested, and absolute organ weight was measured. Blood samples were used for the biochemical analysis. Results: The rats treated with EEST 100, 200, and 400 mg/kg did not show any change in locomotor activity and grip strength and significantly reduced motor resistance. The animals treated with donepezil showed a significant reduction in ELT. The animals treated with EEST 100 and 200 mg/kg showed significant increases in ELT, whereas animals treated with EEST 400 mg/kg did not show significant changes in ELT compared with that of prestudy. At the end of the study, EEST-treated animals did not show significant changes in biochemical parameters, whereas donepezil-treated animals showed a significant increase in cholesterol level compared with control animals. Furthermore, EEST did not affect regular body weight gain, absolute and relative organ weight. Conclusion: EEST did not show neuroprotective effect at lower doses in rats, but the high dose (400 mg/kg) prevented scopolamine-induced memory impairment, and this effect is not significant when compared with standard donepezil.