Bergenia ciliata ameliorates streptozotocin-induced spatial memory deficits through dual cholinesterase inhibition and attenuation of oxidative stress in rats

Bergenia ciliata (Haw.) Sternb. rhizomes, family Saxifragaceae, are claimed to possess an array of beneficial effects like antioxidant, anti-inflammatory, immunomodulatory, antibacterial and anticancer activities. The plant has also been reported to be used by Nepalese folk to alleviate symptoms related to Parkinson's disease. Oxidative stress is one of the major reasons for cognitive decline observed in sporadic Alzheimer's disease (AD). Bergenia ciliata rhizomes have depicted potent antioxidant properties, but their role in the treatment of Alzheimer's disease is yet unexplored. Therefore, the present study was intended to explore the beneficial effects of methanolic extracts of rhizomes of B. ciliata (BM) in a streptozotocin-induced model of Alzheimer's disease in Wistar rats. Streptozotocin (STZ) was injected intracerebroventricularly (ICV) on day 1 (3 mg/kg, unilaterally) in Wistar rats. BM was thereafter administered (125, 250 and 500 mg/kg b.w./day p.o.), daily for 28 days. Morris water maze and Y maze test were used to evaluate learning and memory in rats on 7th, 14th, 21st and 28th days following initiation of dosing. Terminally, acetylcholinesterase activity, butyrylcholinesterase, and levels of oxidative stress markers were assessed in the serum as well as in brain homogenates of rats. Additionally, histopathological studies were carried out to observe effects in brain tissues at the cellular level. STZ produced significant (p < 0.001) learning and memory impairment, oxidative stress as well as a cholinergic deficit in rats. Whereas, BM treatment at various dose levels was able to significantly and dose-dependently diminish STZ induced behavioral deficits and biochemical anomalies in rats. The observed cognitive improvement following BM administration in STZ injected rats may be accredited to its antioxidant activity and refurbishment of cholinergic functions. The results of the study are indicative of the therapeutic potential of Bergenia ciliata in cognitive disorders such as AD as well as other such neurodegenerative disorders.