Investigating the Effect of Amygdalin Encapsulated in Nano-Chitosan on the Passive Avoidance Memory in Male NMRI Mice

Abstract

Background and purpose: Various studies have been conducted to treat memory and learning disorders using medicinal plants and other compounds. Amygdalin, as the main compound of the seeds of Rosaceae plants, has multiple beneficial properties but can release cyanide compounds in the body. On the other hand, local drug delivery using nanoparticles has created the ability to release the drug with fewer side effects. Chitosan is one of the compounds whose nanoparticles are used in drug delivery systems. In the present study, the impact of non-capsulated and encapsulated amygdalin in chitosan nano-particles on passive avoidance memory has been studied. Materials and methods: In this experimental research, 150 male NMRI mice aged 5-6 weeks weighing 25-30 gr were used. All injections were done intraperitoneally. This study was conducted in three separate phases. In the first stage, different doses of ethanol were injected (0.25, 0.5, 0.75, and 1 gram per kilogram of body weight) to obtain the appropriate dose for passive avoidance memory impairment. In the second phase, after memory impairment using ethanol, the effect of different doses (6.25, 12.5, 25, and 50 mg/kg) of uncoated amygdalin on passive avoidance memory was evaluated. In the third phase, the effect of the same doses of amygdalin in the previous phase but encapsulated in chitosan nanoparticles was evaluated. The process of investigating passive avoidance memory was carried out on two consecutive days, including the training day and the test day, using the shuttle box device. Data mean and standard deviation was analyzed in GraphPad Prism software via one-way analysis of variance (ANOVA) and Tukey's test in a P< 0.05 significant level. Results: The results of the first phase showed that ethanol by doses of 0.75 and 1 gram per kilogram body weight at P<0.001 and by dose of 0.5 grams per kilogram body weight at P<0.01 significantly caused amnesia. The results of the second phase showed that all doses of uncoated amygdalin not only did not cause memory impairment but also significantly (P<0.0001) improved ethanol-induced amnesia. In the third phase, the results showed that although all doses of amygdalin encapsulated in chitosan nanoparticles significantly(P<0.01) cause amnesia in doses of 25 and 50 mg/kg, they can improve amnesia in a state-dependent pattern. Comprising the effect of match doses of non-capsulated and encapsulated amygdalin on the passive avoidance memory revealed no significant difference between any of the matched doses so both of them can improve the impaired memory caused by ethanol. Conclusion: In this study, amygdalin received by the intraperitoneal method was able to improve the impaired avoidance memory and encapsulated in nano chitosan showed a state-dependent learning pattern, probably because cyanide was not released under the influence of the microbial flora of the digestive tract. Therefore, it seems necessary to investigate the effect of oral consumption of amygdalin on avoidance memory, spatial memory, or other cognitive activities.

Keywords

• amygdalin
• amnesia
• chitosan
• memory
• nano-particle