Coadministration with Tea Polyphenols Enhances the Neuroprotective Effect of Defatted Walnut Meal Hydrolysate against Scopolamine-Induced Learning and Memory Deficits in Mice

Abstract

The present study aimed to investigate the combined effects of defatted walnut meal hydrolysate (DWMH) and tea polyphenols (TP) on learning improvement and to explain mechanistically why the combined treatments were more effective than either subject alone. In the step-down avoidance test and the Morris water maze test, codelivery of DWMH and TP was more effective than either individual supplement in reversing memory impairment in scopolamine-treated mice. Mixing with TP significantly facilitated the protective effects of DWMH or DWMH-derived peptides (cationic peptide P1 and anionic peptide P2) on H2O2-injured SH-SY5Y cells. Although combination treatment with TP and DWMH did not significantly alter systemic exposure to P1 or P2 in rats, it significantly increased the accumulation of the two peptides in the mouse brain. In addition, TP significantly improved cellular uptake of P1 and P2 by brain capillary endothelial cells, indicating that TP enhanced the blood–brain barrier permeation of DWMH-derived peptides. The proposed explanation for the advantage of combined treatment with TP and DWMH in reversing memory impairment was that TP enhanced both the protective effects of DWMH on nerve cells and the accumulation of DWMH in the brain. Our study can aid efforts to develop products and investigate the effects of nutrient combinations on brain disorders.

Walnut-Derived Peptide Activates PINK1 via the NRF2/KEAP1/HO-1 Pathway, Promotes Mitophagy, and Alleviates Learning and Memory Impairments in a Mice Model

“…Similarly, Li et al found that WPH significantly decreased latency, increased crossing and target times in the spatial probe test and escape latency, and decreased error times in the step-down avoidance test in the scopolamine-induced mice . Sheng et al also reported that defatted walnut meal hydrolysate together with tea polyphenols markedly decreased escape latency in scopolamine-treated mice and increased protection in SH-SY5Y cells damaged by H 2 O 2 . Accordingly, our results also revealed that mice exposed to scopolamine had a negative impact on learning and memory.…”

“…25 Sheng et al also reported that defatted walnut meal hydrolysate together with tea polyphenols markedly decreased escape latency in scopolaminetreated mice and increased protection in SH-SY5Y cells damaged by H 2 O 2 . 26 Accordingly, our results also revealed that mice exposed to scopolamine had a negative impact on learning and memory. However, pretreatment of mice with YVLLPSPK was shown to result in a marked improvement in the MWM test, mainly embodied in the large and regular pyramidal neurons, which were shown to be increased in the hippocampus.…”

Polyphenols as Caloric-Restriction Mimetics and Autophagy Inducers in Aging Research

“…In fact, the neuroprotective capacity of natural polyphenols has been extensively studied and reported during recent decades [137][138][139][140][141][142][143][144]. One of the most studied polyphenols in terms of its neuroprotective activity is resveratrol [145][146][147][148][149][150][151].…”

Characterization and Exploration of Potential Neuroprotective Peptides in Walnut (Juglans regia) Protein Hydrolysate against Cholinergic System Damage and Oxidative Stress in Scopolamine-Induced Cognitive and Memory Impairment Mice and Zebrafish

“…Notably, the neuroprotective effect of walnut peptides was widely reported. Walnut peptide administration was demonstrated to have a neuroprotective effect on scopolamine-induced mice . Simultaneously, walnut peptides could regulate the oxidative stress by activating autophagy in Aβ 25–35 -induced PC12 cells .…”