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

Abstract

The purpose of this study was to determine the neuroprotective effect and mechanism of walnut protein hydrolysates (WPH) against memory deficits induced by scopolamine in mice and further to validate the potent neuroprotective peptides identified by integrated approaches of in silico analysis and peptidomics in scopolamine-induced zebrafish. Results showed that a remarkable amelioration on behavioral performance was observed for oral administration of WPH, and disorders of cholinergic system and oxidative stress were normalized in the brains of mice also. Unfortunately, no obvious inflammatory response and antiinflammatory effect were observed. Additionally, WPH significantly upregulated the expressions of antioxidant defense-related protein (Nrf2) and neurotrophic-related protein (BDNF and CREB). Furthermore, 20 peptides with relatively higher abundance and PeptideRanker scores were predicted by docking to AchE and Keap1. Among them, FY and SGFDAE with the highest binding affinities, −9.8 and −8.0 kcal/mol, were considered as the promising AchE and Keap1 inhibitors, respectively. They were further validated to have neuroprotective capacity in scopolamine-induced zebrafish, indicating that peptidomics and in silico prediction might be the effective approaches to screen neuroprotective peptides.

Protective effects of bioactive peptides in foxtail millet protein hydrolysates against experimental colitis in mice

“…Moreover, it is widely agreed that the amino acid composition and MW distribution are key factors affecting the bioactivities of peptides. 28 Low MW peptides (<3 kDa) have been found to be the most potential bioactive peptides in many studies, and polypeptides with higher hydrophobicity have been shown to penetrate the cell membrane more easily to reach the target location. 29 In our study, 60.7% of the peptides in FMPH had a molecular weight less than 3 kDa, and over 50% of the amino acids were hydrophobic, suggesting their potential biological activities.…”

Exogenous Bioactive Peptides Have a Potential Therapeutic Role in Delaying Aging in Rodent Models

“…Moreover, many studies on active peptides mainly focus on the direct effects of these exogenous active peptides but ignore their indirect effects through regulating endogenous antioxidants in vivo. For example, exogenous active peptides can enhance endogenous antioxidative activity by increasing the levels of glutathione (GSH), superoxide dismutase (SOD), and bone-derived neurotrophic factor (BDNF) [14][15][16].…”

Quantitative In Silico Evaluation of Allergenic Proteins from Anacardium occidentale, Carya illinoinensis, Juglans regia and Pistacia vera and Their Epitopes as Precursors of Bioactive Peptides

“…Tree nut proteins are also sources of peptides with bioactive potential. For example, proteins from walnut ( Juglans regia ) are known as precursors of angiotensin-converting enzyme (ACE) inhibitors [ 11 , 12 , 13 ], dipeptidyl peptidase IV inhibitors [ 14 ], peptides with antioxidant activity [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ], peptides with anticancer activity [ 16 ], tyrosinase (EC 1.14.18.1) inhibitor [ 22 ], and anti-fatigue peptides [ 23 ]. Peptides with sequences YEP [ 11 ] and YVPHWEL [ 12 ] may serve as examples of ACE inhibitors from walnut.…”

“…Peptide with sequence ADAF is an example of antioxidative peptide from walnut. Liu et al [ 19 ] and Wang et al [ 20 , 21 ] highlighted neuroprotective and anti-inflammatory effects of antioxidative peptides. The peptide with sequence FPY has been found as tyrosinase inhibitor [ 22 ].…”