No abstract

Background: ␤-Amyloid aggregates are at the basis of Alzheimer disease development. Short synthetic peptides are seen to inhibit polymerization. Results: Various synthetic peptides have been studied by MD simulations and tested experimentally. Conclusion:Combined results indicate Ac-LPFFN-NH 2 as an effective lead compound able to slow down A␤ 1-40 aggregation. Significance: Designing potential A␤ aggregation inhibitors will help fight Alzheimer disease.

β-Amyloid peptide (Aβ) aberrant production and aggregation are major factors implicated in the pathogenesis of Alzheimer's disease (AD), causing neuronal death via oxidative stress. Several studies have highlighted the importance of polyphenolic antioxidant compounds in the treatment of AD, but complex food matrices, characterized by a different relative content of these phytochemicals, have been neglected. In the present study, we analyzed the protective effect on SH-SY5Y cells treated with the fragment Aβ 25–35 by two crude juices of broccoli sprouts containing different amounts of phenolic compounds as a result of different growth conditions. Both juices protected against Aβ-induced cytotoxicity and apoptotic cell death as evidenced by cell viability, nuclear chromatin condensation, and apoptotic body formation measurements. These effects were mediated by the modulation of the mitochondrial function and of the HSP70 gene transcription and expression. Furthermore, the juices upregulated the intracellular glutathione content and mRNA levels or activity of antioxidant enzymes such as heme oxygenase-1, thioredoxin, thioredoxin reductase, and NAD(P)H:quinone oxidoreductase 1 via activation of NF-E2-related factor 2 (Nrf2). Although the effects of the two juices were similar, the juice enriched in phenolic compounds showed a greater efficacy in inducing the activation of the Nrf2 signalling pathway.

Previously, we identified a potent antimicrobial analogue of temporin L (TL), [Pro3]TL, in which glutamine at position 3 was substituted with proline. In this study, a series of analogues in which position 3 is substituted with non‐natural proline derivatives, was investigated for correlations between the conformational properties of the compounds and their antibacterial, cytotoxic, and hemolytic activities. Non‐natural proline analogues with substituents at position 4 of the pyrrolidine ring were considered. Structure–activity relationship (SAR) studies of these analogues were performed by means of antimicrobial and cytotoxicity assays along with circular dichroism (CD) and NMR spectroscopic analyses for selected compounds. The most promising peptides were additionally evaluated for their activity against some representative veterinary microbial strains to compare with those from human strains. We identified novel analogues with interesting properties that make them attractive lead compounds.

The opioid agonists endomorphins (Tyr–Pro–Trp–Phe–NH2; EM1 and Tyr–Pro–Phe–Phe–NH2; EM2) and morphiceptin (Tyr–Pro–Phe–Pro–NH2) exhibit an extremely high selectivity for μ-opioid receptor. Here a series of novel EM2 and morphiceptin analogues containing in place of the proline at position 2 the S and R residues of β-homologues of proline (HPro), of 2-pyrrolidinemethanesulphonic acid (HPrs) and of 3-pyrrolidinesulphonic acid (βPrs) have been synthesized and their binding affinity and functional activity have been investigated. The highest μ-receptor affinity is shown by [(S)βPrs2]EM2 analogue (6e) which represents the first example of a β-sulphonamido analogue in the field of opioid peptides.