Memory Enhancement of the New Tryptamine-Like Components in the Walnut Kernel

Abstract

Walnut kernel has been applied in daily diets for thousands of years with its effect of memory enhancement. For further observing the effect of memory enhancement, the walnut kernel was extracted and separated for active parts, with the evaluation in mice. It showed the memory enhancement of 30% ethanol elution through the Morris and step-down tests. After further separation and purification, four compounds were acquired with tryptamine-like structures firstly found in the walnut kernel. And compounds III and IV were new ones. Compound III showed strengthened memory enhancement through the behavior test. Compound III also alleviated acetylcholinesterase activity and promoted acetylcholine transferase activity. In silico docking and molecular dynamic studies displayed the solid binding abilities of compound III on 5-hydroxytryptamine receptor 4 (5-HTR4), and anti-degeneration effect to monoamine oxidase A (MAO-A). These results illustrated the memory enhancement of compound III, as well as the walnut kernel.

Keywords: Walnut kernel, Mice, Evaluation, Tryptamine