Revalidation of the neuroprotective effects of a United States patented polyherbal formulation on scopolamine induced learning and memory impairment in rats

Objective: Alzheimer's disease (AD) is the most common cause of dementia yet treatment options are extremely limited. The disease is associated with cognitive impairment as well as structural irregularities, accumulation of plaques and neurofibrillary tangles, diminished levels of acetylcholine, oxidative stress, and inflammation in the brain. We have previously reported on the positive effects of a united states patented (US 7,273,626 B2) poly herbal test formulation, consisting of Bacopa monnieri, Hippophae rhamnoides and Dioscorea bulbifera extracts, on cognitive deficits in AD patients. The present study was conducted to investigate the mechanism(s) of action of the formulation using scopolamine treated rats as an AD model. Method: The formulation was administered daily along with scopolamine for a period of 14 days following which the elevated plus maze, passive avoidance, and Morris water maze tests were performed to assess learning and memory. Rats treated with scopolamine or vehicle only were also included in the experiment. Acetylcholine levels and activities of acetylcholinesterase (AChE) and anti-oxidant enzymes in the brain were also measured at the end of the treatment period. Results: The study demonstrate that scopolamine treatment resulted in learning and memory deficits which were partially and significantly ameliorated by the formulation. The formulation also counteracted scopolamine-induced decreases in acetylcholine levels, increases in AChE activity, and decreases in activities of the antioxidant enzymes. Conclusion: The study demonstrates the ability of the test formulation to reverse scopolamine-induced learning and memory deficits in rats which may at least partially be explained by the reversal of scopolamine-induced reductions in brain acetylcholine levels and antioxidant activities by the test formulation.