Amelioration of walnut-derived novel peptides against d-galactose-induced cognitive impairment by modulating the gut microbiota composition

Abstract

In our present work, RLWPF (Arg-Leu-Trp-Pro-Phe) and VLRLF (Val-Leu-Arg-Leu-Phe), were investigated the effects against D-galactose (D-gal) induced cognitive impairment via microbiota-gut-brain axis. The two novel peptides derived from walnut protein...

Peripheral inflammation and neurocognitive impairment: correlations, underlying mechanisms, and therapeutic implications

“…In addition to intervening and removing factors that induce peripheral inflammation, drugs such as ulinastatin ( Kim et al, 2023 ), α2-AR agonists Dex ( Oxlund et al, 2022 ) and guanfacine ( Arnsten et al, 2023 ), cyclooxygenase (Cox) inhibitors ( Weng et al, 2021 ), and lidocaine ( Geng et al, 2023 ) all exert anti-inflammatory or neuroprotective effects to attenuate cognitive impairment through various pathways. Peptides consisting of arginine, valine, leucine, and phenylalanine ( Li T. et al, 2023 ) and proline-rich peptides ( Banasiak-Cieslar et al, 2023 ), as well as neutralizing antibodies, such as anti-IL-17 ( Cristiano et al, 2019 ) and anti-IL-6 ( Hisaoka-Nakashima et al, 2022 ), have also been shown to have a positive effect in limiting inflammation and thus improving cognition.…”

Isolation, Identification, Activity Evaluation, and Mechanism of Action of Neuroprotective Peptides from Walnuts: A Review

“…Various enzymes, including neutralase, alkaline protease, protamex, pepsin, trypsin, and viscozyme L, have been reported to produce peptides from walnut proteins with memory-improving properties. For instance, alkaline proteases can hydrolyse walnut protein to produce peptides (RLWPF, VLRLF) that inhibit oxidative stress and neuroinflammation, modulate the intestinal microflora and metabolites, and improve learning ability in mice [ 33 ]. Walnut-derived peptides (GGW, VYY, LLPF) can also be produced by plant hydrolase and pancreatin complexes to improve learning ability and alleviate memory loss in sleep-deprived rats [ 34 ].…”

“…This treatment also significantly increases the activity of the AChE enzyme and reverses cholinergic dysfunction [ 22 ]. Wang et al [ 33 ] found that administering walnut protein hydrolysate orally to mice significantly improved their behavioural performance. This also helped in restoring the cholinergic system disorder and oxidative stress in the mouse brain.…”

“…According to 16S rRNA sequencing analysis, the treatment of RLWPF and VLRLF was found to improve cognitive impairment by altering the composition of gut microbiota and reducing the abundance of harmful bacteria such as the Firmicutes -to- Bacteroidetes ratio, Helicobacter , Allobaculum , Alistipes , Mucispirillum , and Odoribacter . Along with this regulation, both RLWPF and VLRLF have their own distinct markers and regulatory flora [ 33 ]. In addition, walnut protein hydrolysate had a significant impact on reducing Aβ plaque accumulation in the brain of a APP/PS1 transgenic mouse model.…”

Effects of an Akt-activating peptide obtained from walnut protein degradation on the prevention of memory impairment in mice

“…14 To date, several walnut peptides with neuroprotective properties have been identified, e.g., RLWPF, VLRLF, LPF, GVYY and APTLW. 15,16 Among them, RLWPF and VLRLF can regulate the intestinal flora of AD model mice, and LPF, GVYY and APTLW have been shown to alleviate neuroinflammation. Nevertheless, walnut peptides as Akt activators have not been properly investigated, and more data are still needed on walnut peptides as modulators of intestinal flora.…”