A combined in vitro and in silico study of the inhibitory mechanism of angiotensin-converting enzyme with peanut peptides.

Food-derived peptides with low molecular weight, high bioavailability, and good absorptivity have been exploited as angiotensin-converting enzyme (ACE) inhibitors. In the present study, in-vitro inhibition kinetics of peanut peptides, in silico screening, validation of ACE inhibitory activity, molecular dynamics (MD) simulations, and HUVEC cells were performed to systematically identify the inhibitory mechanism of ACE interacting with peanut peptides. The results indicate that FPHPP, FPHY, and FPHFD peptides have good thermal, pH, and digestive stability. MD trajectories elucidate the dynamic correlation between peptides and ACE and verify the specific binding interaction. Noteworthily, FPHPP is the best inhibitor with a strongest binding affinity and significantly increases NO, SOD production, and AT2R expression, and decreases ROS, MDA, ET-1 levels, ACE, and AT1R accumulation in Ang II-injury HUVEC cells.

Synergistic Effect of Combined Walnut Peptide and Ginseng Extracts on Memory Improvement in C57BL/6 Mice and Potential Mechanism Exploration.

This work aimed to investigate whether there are synergistic effects between walnut peptide (WNP) and ginseng extracts (GSE) treatments to ameliorate the memory impairment caused by scopolamine (SCOP). The Morris water maze trial, hippocampal neuron morphology, neurotransmitters, and synaptic ultrastructure were examined, along with brain-derived neurotrophic factor (BDNF)-related signaling pathway proteins. The results of the Morris water maze trial demonstrated that the combined administration of WNP and GSE effectively alleviated memory impairment in C57BL/6 rats caused by SCOP. Improvement in the morphology of hippocampal neurons, dendritic spines, and synaptic plasticity and upregulation of neurotransmitters AChE, ACh, ChAT, Glu, DA, and 5-HT supported the memory improvement effects of WNP + GSE. In addition, compared with the model group, WNP + GSE significantly enhanced the protein levels of VAChT, Trx-1, and the CREB/BDNF/TrkB pathway in hippocampal and PC12 cells induced by SCOP (p < 0.05). Notably, WNP + GSE boosted memory via multiple pathways, not only the BDNF/TrkB/CREB target.

Improving ACE inhibitory activity of hazelnut peptide modified by plastein: Physicochemical properties and action mechanism.

The plastein reaction can increase the activity of angiotensin-converting enzyme (ACE) inhibitory peptides, but the underlying mechanism is unknown. Hence, hazelnut protein hydrolysate and hazelnut peptide YLVR were used as substrate to explore the effect of plastein on physicochemical properties and the mechanism of structural change. The increase in turbidity and particle size and the decrease in free amino groups indicated that the reaction occurred via condensation. The modified products of YLVR were identified by NANO-HPLC-MS/MS, indicating that the N-terminal homologous amino acid aggregates in the plastein. Novel ACE inhibitory peptide YYLVR, YLLVR, and YYLLVR were synthesized and their inhibition rates were 66.35, 72.61, and 89.10 %, respectively, which were higher than that of YLVR (52.58 %). MD simulation showed that YYLLVR exhibited the lowest binding energies of -35.98 ± 2.30 kcal/mol to ACE. Taken together, plastein reaction is a promising strategy for inducing structural modifications to improve the activity of peptide.