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The involvement of human carbonic anhydrase (hCA) IX/XII in the pathogenesis and progression of many types of cancer is well acknowledged, and more recently human monoamine oxidases (hMAOs) A and B have been found important contributors to tumor development and aggressiveness. With a view of an enzymatic dual-blockade approach, in this investigation, new coumarin-based amino acyl and ( pseudo )-dipeptidyl derivatives were synthesized and firstly evaluated in vitro for inhibitory activity and selectivity against membrane-bound and cytosolic hCAs (hCA IX/XII over hCA I/II), as well as the hMAOs, to estimate their potential as anticancer agents. De novo design of peptide-coumarin conjugates was subsequently carried out and involved the combination of the widely explored coumarin nucleus with the unique biophysical and structural properties of native or modified peptides. All compounds displayed nanomolar inhibitory activities towards membrane-anchored hCAs, whilst they were unable to block the ubiquitous CA I and II isoforms. Structural features pertinent to potent and selective CA inhibitory activity are discussed, and modeling studies were found to support the biological data. Lower potency inhibition of the hMAOs was observed, with most compounds showing preferential inhibition of hMAO-A. The binding of the most potent ligands ( 6 and 16 ) to the hydrophobic active site of hMAO-A was investigated in an attempt to explain selectivity on the molecular level. Calculated Ligand Efficiency values indicate that compound 6 has the potential to serve as a lead compound for developing innovative anticancer agents based on the dual inhibition strategy. This information may help design new coumarin-based peptide molecules with diverse bioactivities.

Non-ST-segment elevation acute coronary syndromes (NSTE-ACSs) are a group of clinical conditions characterized by acute myocardial ischemia. Conventional echocardiography is generally used to evaluate cardiac function using wall motion analysis and left ventricular ejection fraction but may be insufficient to explore all the complex features of NSTE-ACSs, which may vary substantially from patient to patient in terms of severity of ischemia and extent of involved myocardium. In the last years, speckle tracking echocardiography (STE) has become a widely available technique for the non-invasive assessment of cardiac function and has been repeatedly applied in the setting of NSTE-ACSs. In this review we summarize current evidence about the use of STE in patients with NSTE-ACSs, trying to underline advantages and limitations in comparison with conventional echocardiography for: diagnosis of NSTE-ACS, differential diagnosis, identification of high-risk patients, and prediction of outcome., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Biofilm is a complex aggregation of microorganisms characterized by the presence of a dynamic, adhesive and protective extracellular matrix composed of polysaccharides, proteins and nucleic acids. It is estimated that the vast majority of human infections are related to the biofilm in which the microorganisms reside and communicate with each other (Quorum Sensing), surviving in hostile environmental conditions., Areas Covered: This review provides a comprehensive focus on the development state of promising strategies against biofilm production and eradication describing chemical structures, results, administration routes, pharmaceutical compositions, and SARs as well as their shortcomings within the 2019-2020 range., Expert Opinion: New pharmacological targets have been explored in the past years, allowing a broader therapeutic arsenal against biofilm-related pathologies. The Quorum Sensing system was targeted as well in order to avoid the development of intrinsically antibiotic-resistant bacteria and to enhance a proper host defense.

Matrix metalloproteinases (MMPs) are a large family of zinc-dependent endoproteases known to exert multiple regulatory roles in tumor progression and invasiveness. This encouraged over the years the approach of MMP, and particularly MMP-2, targeting for anticancer treatment. Early generations of MMP inhibitors, based on aspecific zinc binding groups (ZBGs) assembled on (pseudo)peptide scaffolds, have been discontinued due to the clinical emergence of toxicity and further drawbacks, giving the way to inhibitors with alternative zinc-chelator moieties or not binding the catalytic zinc ion. In the present paper, we continue the search for new non-zinc binding MMP-2 inhibitors: exploiting previously identified compounds, a virtual screening (VS) campaign was carried out and led to the identification of a new class of ligands. The structure-activity relationship (SAR) of the benzimidazole scaffold was explored by synthesis of several analogues whose inhibition activity was tested with enzyme inhibition assays. By performing the molecular simplification approach, we disclosed different sets of single-digit micromolar inhibitors of MMP-2, with up to a ten-fold increase in inhibitory activity and ameliorated selectivity towards off-target MMP-8, compared to selected lead compound. Molecular dynamics calculations conducted on complexes of MMP-2 with docked privileged structures confirmed that analyzed inhibitors avoid targeting the zinc ion and dip inside the S1' pocket. Present results provide a further enrichment of our insights for the design of novel MMP-2 selective inhibitors., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In this work we report the application of the ring-closing metathesis (RCM) to the preparation of two cyclic olefin-bridged analogues of biphalin (Tyr-d-Ala-Gly-Phe-NH-NH ← Phe ← Gly ← d-Ala ← Tyr), using the second generation Grubbs' catalyst. The resulting cis - and trans -cyclic isomers were identified, fully characterized, and tested in vitro at μ (ΜΟR), δ (DOR), and κ (KOR) opioid receptors and in vivo for antinociceptive activity. Both were shown to be full agonists at MOR and potential partial antagonists at DOR, with low potency KOR agonism. They also share a strong antinociceptive effect after intracerebroventricular (i.c.v.) and intravenous (i.v.) administration, higher than that of the cyclic biphalin analogues containing a disulfide bridge between the side chains of two d-Cys or d-Pen residues, previously described by our group., Competing Interests: The authors declare no competing financial interest.

The endogenous ligand nociceptin (N/OFQ) and a positively charged synthetic peptide RYYRIK are both selective for the nociceptin opioid receptor (NOPr). Despite their structural dissimilarity, N/OFQ and RYYRIK compete for the same binding site of NOP receptor possessing full and partial agonistic character, respectively. In the view of the message-address concept, hybrid peptide constructs were probed for the NOP receptor combining different regions of N/OFQ and RYYRIK related peptide sequences. Nine novel nociceptin- or Ac-RYYRIK-NH 2 peptide variants or hybrid peptides were synthesized and characterized. Peptides P2 and P8 contain fragments of native N/OFQ. The other seven analogues (P1, P3-7, P9) are composed of Ac-RYYRIK-NH 2 fragments and parts of the original nociceptin sequence. The analogues were characterized in receptor binding assays and G-protein activation experiments on rat brain membranes, as well as by electrically stimulated mouse vas deferens bioassay. In receptor binding assays ligands P2, P4, P6 (K i 0.37 nM) and P7 showed higher affinity (K i 0.65 nM, 0.6 nM, 0.37 nM and 0.44 nM, respectively) for NOP receptor than their parent compounds N/OFQ (K i 2.8 nM) or Ac-RYYRIK-NH 2 (K i 4.2 nM). In [ 35 S]GTPγS binding experiments P2 and P3 behaved as full agonists. The other variants exhibited partial agonist properties characterized by submaximal stimulatory effects. In mouse vas deferens bioassay only P2 showed agonist activity. P4, P5, P6 inhibited the biological activity of N/OFQ more effectively than the NOP receptor selective antagonist JTC-801. In summary, hybrid peptides P4, P5 and P6 proved to be NOP receptor partial agonists even antagonists, while P2 peptide retained the full agonist property., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Aim: The inhibition of pancreatic lipase (PL) represents one of the most promising strategies in the search for novel antiobesity drugs. We propose here a pioneering course by exploring tripeptide scaffolds in the way to selective PL inhibitors., Methodology/results: The peptide series exhibited good PL inhibitory properties in vitro, with all the strongest inhibitors sharing a central arginine, shown in silico to be relevant for the active site-directed activity. The compounds were found devoid of inhibitory properties on acetylcholinesterase., Conclusion: Present results disclosed that basic tripeptides are able to interact efficiently with the PL-binding pocket, where they adopt a binding pose suitable for functional-to-inhibition interactions with key amino acids. Main inhibitor MALA4 may be selected as lead for further optimization.

Oxidative damage is among the factors associated with the onset of chronic pathologies, such as neurodegenerative and metabolic diseases. Several classes of anti-oxidant compounds have been suggested as having a protective role against cellular stressors, but, in this perspective, peptides' world represents a poorly explored source. In the present study, the free radical scavenging properties, the metal ion reducing power, and the metal chelating activity of a series of sulfurated amino acids and tripeptides were determined in vitro through canonical assays (DPPH, ABTS, CUPRAC, FRAP, PM, and EECC) and estimated in comparison with the corresponding activities of synthetic peptide semicarbazones, incorporating the peculiar non-proteinogenic amino acid, tert -leucine ( t Leu). The compounds exhibited remarkable anti-oxidant properties. As expected, sulfurated compounds 1 ⁻ 5 were found to be the most efficient radical scavengers and strongest reductants. Nevertheless, t Leu-containing peptides 7 and 8 disclosed notable metal reducing and chelating activities. These unprecedented results indicate that t Leu-featuring di- and tripeptide backbones, bearing the semicarbazone chelating moiety, are compatible with the emergence of an anti-oxidant potential. Additionally, when tested against a panel of enzymes usually targeted for therapeutic purposes in neurodegenerative and metabolic disorders, all samples were found to be good inhibitors of tyrosinase.

Six tripeptides incorporating acidic amino acid residues were prepared for investigation as activators of β- and γ-carbonic anhydrases (CAs, EC 4.2.1.1) from the pathogenic bacteria Vibrio cholerae, Mycobacterium tuberculosis, and Burkholderia pseudomallei. The primary amino acid residues that are involved in the catalytic mechanisms of these CA classes are poorly understood, although glutamic acid residues near the active site appear to be involved. The tripeptides that contain Glu or Asp residues can effectively activate VchCAβ and VchCAγ (enzymes from V. cholerae), Rv3273 CA (mtCA3, a β-CA from M. tuberculosis) and BpsCAγ (γ-CA from B. pseudomallei) at 0.21-18.1 µM levels. The position of the acidic residues in the peptide sequences can significantly affect bioactivity. For three of the enzymes, tripeptides were identified that are more effective activators than both l-Glu and l-Asp. The tripeptides are also relatively selective because they do not activate prototypical α-CAs (human carbonic anhydrases I and II). Because the role of CA activators in the pathogenicity and life cycles of these infectious bacteria are poorly understood, this study provides new molecular probes to explore such processes.

Propafenone is an antiarrhythmic drug applied to ventricular arrhythmias, initially recognized as a sodium channel blocker. This study aims to evaluate the bioequivalence of two propafenone formulations (300 mg tablet) in healthy subjects under non-fasting conditions. The study was conducted as an open, randomized, 2-period design with a 2-sequence (RT, TR) with a 1-week washout interval. The subjects were selected for the study after having their health status previously assessed by a clinical evaluation and laboratory tests (biochemical and hematological parameters, and urinalysis). Debrisoquine phenotype of healthy subjects was determined by analysis of urinary excretion of debrisoquine and its major metabolite, 4-hydroxydebrisoquine. A single propafenone tablet (300 mg) was given in each occasion. Plasma propafenone concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (HPLC/MS/MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM). The geometric mean and 90% confidence intervals (CI) of propafenone/Ritmonorm ® (T/R) percent ratio were 100.44% (88.39 - 114.13%) for AUC last , 99.84% (90.31 - 110.36%) for AUC inf , and 99.30% (90.08 - 109.47%) for C max . Since the 90% CI for C max , AUC last , and AUC inf ratios were all inside the 80 - 125% interval proposed by the US Food and Drug Administration Agency, it was concluded that the propafenone formulation elaborated by Biolab Sanus Farmacêutica Ltda. is bioequivalent to Ritmonorm ® formulation for both the rate and the extent of absorption. The drug was well tolerated by the subjects, indicating that it is safe to perform propafenone bioequivalence studies in healthy subjects with intermediate/extensive metabolism.
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A series of nanomolar phosphonate matrix metalloproteinase (MPP) inhibitors was tested for inhibitory activity against a panel of selected human carbonic anhydrase (CA, EC 4.2.1.1) isozymes, covering the cancer-associated CA IX and XII. None of the reported sulfonyl and sulfonylamino-derivatives sensitively affected the catalytic activity of the cytosolic isoforms CA I and II, which are considered off-target isoforms in view of their physiological role. The most active inhibitors were in the series of chiral N-(sulfonyl)phosphovaline derivatives, which showed good to excellent inhibitory activity over target CAs, with compound 15 presenting the best isoform-selectivity toward CA IX. We suggest here that the phosphonates have the potential as dual inhibitors of MMPs and CAs, both involved in tumor formation, invasion and metastasis.

Aim: The conjugation of fluorescent labels to opioid peptides is an extremely challenging task, which needs to be overcome to create new classes of probes for biological assays., Materials & Methods: Three opioid peptide analogs of biphalin and [D-Pen2,5]-Enkephalin (DPDPE) containing a fluorescein-maleimide motif were synthesized., Results & Discussion: The biphalin analog 17 binds to opioid receptors with K i μ = 69.8 ± 16.4 nM. We then tested the ability of the compounds to stimulate G-protein-coupling, 17 activated μ-receptor expressing cells (EC i δ = 69.8 ± 16.4 nM. We then tested the ability of the compounds to stimulate G-protein-coupling, 17 activated μ-receptor expressing cells (EC 50 = 16.7 ± 6.7 nM, E Max = 76 ± 4%) as well as δ-receptor expressing cells (EC 50 = 42 ± 10 nM, E Max = 34 ± 8%). However, 17 was not able to fluorescently label receptor in live or fixed cells., Conclusion: Our data suggest that the biphalin scaffold could be employed to develop fluorescent ligands with the appropriate fluorescent motif, and suggest a means for further probe development.

Context: The inhibition of glutathione S-transferase P1-1 (GSTP1-1) is a sound strategy to overcome drug resistance in oncology practice., Objective: The nitrobenzoxadiazolyl (NBD) S-conjugate of glutathione and the corresponding γ-oxa-glutamyl isostere (compounds 1 and 5, respectively) have been disclosed as GST inhibitors. The rationale of their design is discussed in juxtaposition to non-peptide NBD thioethers., Materials and Methods: Synthesis of derivatives 1 and 5 and in vitro evaluation on human GSTP1-1 and M2-2 are reported., Results: Conjugates 1 and 5 were found to be low micromolar inhibitors of both isoforms. Furthermore, they display a threefold reduction in selectivity for GSTM2-2 over the P1-1 isozyme in comparison with the potent non-peptide inhibitor nitrobenzoxadiazolyl-thiohexanol (NBDHEX)., Discussion and Conclusions: Spectroscopic data are congruent with the formation of a stable sigma-complex between GSH and the inhibitors in the protein active site. Conjugate 5 is suitable for in vivo modulation of GST activity in cancer treatment.

Crocus sativus L. is known in herbal medicine for the various pharmacological effects of its components, but no data are found in literature about its biological properties toward Helicobacter pylori, Plasmodium spp. and Leishmania spp. In this work, the potential anti-bacterial and anti-parasitic effects of crocin and safranal, two important bioactive components in C. sativus, were explored, and also some semi-synthetic derivatives of safranal were tested in order to establish which modifications in the chemical structure could improve the biological activity. According to our promising results, we virtually screened our compounds by means of molecular modeling studies against the main H. pylori enzymes in order to unravel their putative mechanism of action.

Different winemaking products (ascorbic acid, glutathione, yeast lees and a yeast autolysate) were tested in comparison with sulphur dioxide, concerning radical scavenging activity (measured by DPPH assay), oxygen consumption capacity and ability to reduce wine colour and predisposition to browning. Trials were performed in white wines and model solution. SO2 was the most active in reducing wine colour development. Fresh lees and ascorbic acid were very effective in oxygen and free radical scavenging, but they both induced browning during wine storage, the former, by releasing phenolic compounds. Glutathione was also able to scavenge DPPH in wine, but less effective against oxygen, and it induced browning during storage. Surprisingly, the yeast derivative preparation was the treatment that behave more similarly to sulphiting; it was very active in scavenging DPPH, and, even without modifying oxygen consumption rate, it protected quite well wine colour over an 8months storage time., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Caspase-3 displays a pivotal role as an executioner of apoptosis, hydrolyzing several proteins including the nuclear enzyme poly(ADP-ribose)polymerase (PARP). Ac-Asp-Glu-Val-Asp-H (K i° = 2.3 × 10(-10) M at pH 7.5 and 25.0 °C), designed on the basis of the cleavage site of PARP, has been reported as a highly specific human caspase-3 inhibitor. Here, di- and tri-peptidyl aldehydes 11-13 and 27-29 have been synthesized to overcome the susceptibility to proteolysis, the intrinsic instability, and the scarce membrane permeability of the current inhibitors. Compounds 11-13, 27-29 inhibit in vitro human caspase-3 competitively, values of K i° ranging between 6.5 (±0.82) × 10(-9) M and 1.1 (±0.04) × 10(-7) M (at pH 7.4 and 25.0 °C). Moreover, the most effective caspase-3 inhibitor 11 impairs apoptosis in human DLD-1 colon adenocarcinoma cells. Furthermore, the binding mode of 11-13 and 27-29 to human caspase-3 has been investigated in silico. The comparative analysis of human caspase-3 inhibitors indicates that (1) aldehyde 11 is the minimal highly effective inhibitor, (2) the tLeu-Asp sequence is pivotal for satisfactory enzyme inhibition, and (3) the occurrence of the tLeu residue at the inhibitor P2 position is fundamental for enzyme/inhibitor recognition. Moreover, calculations suggest that the tLeu residue reduces the conformational flexibility of the inhibitor that binds to the enzyme with a lower energetic penalty.

Endomorphin-2 [Tyr-Pro-Phe-Phe-NH2] and DAMGO [Tyr-D-Ala-Gly-(N-Me)Phe-Gly-ol] are natural (EM2) and synthetic (DAMGO) opioid peptides both selective for μ opioid receptor with high analgesic activity. In this work we report synthesis, in vitro and in vivo biological evaluation of five new hybrid EM2/DAMGO analogues, with the aim to obtain compounds with high affinity at μ-opioid receptor, high activity in animal nociception tests (hot plate and tail flick) and improved enzymatic stability. Double N-methylation on both Phe residues and C-terminal ethanolamide led to analogue 6e, which possesses a good in vitro μ affinity (Kiμ=34 nM), combined with a remarkable in vivo antinociceptive activity., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)