Identification of a novel oligopeptide from defatted walnut meal hydrolysate as a potential neuroprotective agent

Free radical damage and oxidative stress are thought to play a crucial role in the development of neurodegenerative diseases. Walnut peptides, especially walnut oligopeptides, have been shown to protect nerve cells from oxidative stress and inflammatory damage, as well as improve memory function. In this study, walnut peptides were obtained from walnut meal through enzymatic hydrolysis, ultrafiltration, and gel filtration chromatography. A novel oligopeptide called AQ was successfully isolated and its chemical structure was identified as AASCDQ using ESI-MS/MS. AQ demonstrated remarkable scavenging activity against O2- free radicals (81.00%), DPPH free radicals (79.40%), and ABTS free radicals (67.09%) at a concentration of 1 mg mL-1. Furthermore, AQ exhibited strong neuroprotective effects against hydrogen peroxide-induced damage in SH-SY5Y cells, reducing cell injury and apoptosis. AQ also effectively inhibited the secretion of pro-inflammatory factors NO (IC50 = 46.03 ± 0.32 μM) and suppressed the expression of IL-6 and TNF-α in RAW264.7 cells stimulated by LPS. In vivo experiments demonstrated that AQ promoted angiogenesis in the quail chick chorioallantoic membrane assay and reduced ROS accumulation in Caenorhabditis elegans, thereby extending its lifespan. The anti-inflammatory mechanism of AQ was further confirmed by western blotting. In summary, the novel oligopeptide AQ possesses potential neuroprotective effects, including antioxidant, anti-inflammatory, angiogenic, and anti-aging properties, making it a promising candidate for the development of functional foods and pharmaceutical products.

How Healthy Are Non-Traditional Dietary Proteins? The Effect of Diverse Protein Foods on Biomarkers of Human Health

Future food security for healthy populations requires the development of safe, sustainably-produced protein foods to complement traditional dietary protein sources. To meet this need, a broad range of non-traditional protein foods are under active investigation. The aim of this review was to evaluate their potential effects on human health and to identify knowledge gaps, potential risks, and research opportunities. Non-traditional protein sources included are algae, cereals/grains, fresh fruit and vegetables, insects, mycoprotein, nuts, oil seeds, and legumes. Human, animal, and in vitro data suggest that non-traditional protein foods have compelling beneficial effects on human health, complementing traditional proteins (meat/poultry, soy, eggs, dairy). Improvements in cardiovascular health, lipid metabolism, muscle synthesis, and glycaemic control were the most frequently reported improvements in health-related endpoints. The mechanisms of benefit may arise from their diverse range of minerals, macro- and micronutrients, dietary fibre, and bioactive factors. Many were also reported to have anti-inflammatory, antihypertensive, and antioxidant activity. Across all protein sources examined, there is a strong need for quality human data from randomized controlled intervention studies. Opportunity lies in further understanding the potential effects of non-traditional proteins on the gut microbiome, immunity, inflammatory conditions, DNA damage, cognition, and cellular ageing. Safety, sustainability, and evidence-based health research will be vital to the development of high-quality complementary protein foods that enhance human health at all life stages.

Neuroprotective Effect Of Peptide Fractions from Chia (Salvia hispanica) on H2O2-Induced Oxidative Stress-Mediated Neuronal Damage on N1E-115 Cell Line

Neurodegenerative diseases (ND) affect around a billion people worldwide. Oxidative stress plays a critical role in the activation of neuronal death mechanisms, implicated in the ND etiology. In the present research, the neuroprotective effect of the S. hispanica protein derivatives is evaluated, on neuronal cells N1E-115, after the damage induction with H₂O₂. From the protein-rich fraction of S. hispanica, three peptide fractions were obtained (3-5, 1-3 y < 1 kDa) and its neuroprotective effect on neuronal cells N1E-115 was evaluated, through the antioxidant pathway. In the toxicity assay, the peptide fractions showed viability greater than 90%. When N1E-115 cells were incubated with 100 µM H₂O₂, fractions 1-3 and < 1 kDa, presented cell viability of 66.64% ± 3.2 and 67.32% ± 2.8, respectively. Fractions 1-3 and < 1 kDa reduced by 41.73% ± 3.2 and 40.87% ± 2.8, respectively, the ROS production compared to the control, without significant statistical difference between both fractions (p < 0.05), while F3-5 kDa, only reduced the ROS production by 21.95% ± 2.4. The protective effect observed in the < 3 kDa fractions could be associated with its antioxidant activity, which represents an important study target.