Effect of Sanguisorba Minor on Scopolamine-induced Memory Loss in Rat: Involvement of Oxidative Stress and Acetylcholinesterase

Abstract Sanguisorba minor (S. minor) has neuroprotective and antioxidant activities; nevertheless, its potential benefits in ameliorating learning and memory functions have not been explored yet. So, in this study, rats were treated with S. minor hydro-ethanolic extract (50, 100, and 200 mg/kg, intraperitoneal (i.p.)) as well as rivastigmine (0.5 mg/kg, i.p.) for 21 consecutive days. Thereafter, their behavioral performance was assessed using Morris water maze (MWM) and passive avoidance (PA) tasks. Scopolamine was also injected 30 min before conducting the tasks. Finally, oxidative stress biomarkers and acetyl cholinesterase (AChE) activity were determined in the brain. The extract characterization was presented using liquid chromatography-mass spectrometry (LC-MS), which confirmed the presence of quercetin, myricetin, kaempferol, catechin, ellagic acid, and gallic acid derivatives. According to the results, the extract at all doses could significantly recover the impairment of cognitive performance of the scopolamine-treated rats. In the MWM test, the extract and rivastigmine reduced escape latency and travelled distance, compared to the scopolamine group. Moreover, in the PA test, the latency to enter the dark chamber was significantly increased by the extract and rivastigmine, compared to the scopolamine group (p<0.05-p<0.001). Similar to rivastigmine, the extract attenuated both AChE activity and oxidative injury in the brain as evidenced by the increased antioxidant enzymes and total thiol content, but it decreased malondialdehyde level (p<0.05-p<0.001). In conclusion, the results suggested the effectiveness of S. minor on preventing cognitive dysfunction induced by scopolamine. Accordingly, these protective effects might be produced through the regulation of cholinergic activity and oxidative stress.