Improving Effect of the Policosanol from Ericerus pela Wax on Learning and Memory Impairment Caused by Scopolamine in Mice

Abstract

Policosanol (PC) is a mixture of long-chain fatty alcohols that exhibits multiple biological activities, such as reducing blood lipid and cholesterol levels, lowering blood pressure, and extenuating liver inflammation. To assess PC’s impact on cognitive behavior and function, PC was prepared from Ericerus pela wax using a reduction method and analyzed using gas chromatography (GC). A total of 60 mice were randomly divided into six groups of 10 animals each: control (0.5% CMC-Na solution, i.g.), model (0.5% CMC-Na solution, i.g.), donepezil (3 mg/kg, i.g.), PC low- (2 g/kg, i.g.), medium (4 g/kg, i.g.), and high- (6 g/kg, i.g.) dose groups. All the groups were administered daily for 28 consecutive days. There were four parameters—escape latency, crossings of platform, swimming distance, and time spent in the target quadrant—that were recorded to evaluate the cognitive performance of mice in the Morris Water Maze (MWM). After MWM testing, the levels of acetylcholine (ACh), acetylcholinesterase (AChE), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) that were present in brain tissue were determined using assay kits. The GC data showed that PC consisted of four major components: tetracosanol (14.40%), hexacosanol (48.97%), octacosanol (25.40%), and triacontanol (4.80%). In the MWM test, PC significantly decreased the escape latency (p < 0.05) and increased the crossings of the platform (p < 0.05) and swimming distance (p < 0.05) and time in the target quadrant (p < 0.05) in rodents compared to that in the model group. Moreover, PC increased the levels of ACh, SOD, and GSH; inhibited AChE; and reduced MDA in the brain tissue of the tested animals. This is the first report to evaluate the efficacy of PC for cognitive behavior and function in animals. Our findings demonstrate that PC from E. pela wax is likely to exert an enhancing effect on learning and memory by promoting the cholinergic system and attenuating oxidative stress, which will provide a new insight into the efficacy of PC and expand its application in the food, nutraceutical, and beverage industries.