Catechol-based matrix metalloproteinase inhibitors with additional antioxidative activity

New Hybrid Compounds Incorporating Natural Products as Multifunctional Agents against Alzheimer's Disease

A series of new hybrid derivatives 1a-c, 2a-c, 3a-c, 4a-c, 5a-c, inspired by nature, were synthesized and studied as multifunctional agents for the treatment of Alzheimer's disease (AD). These compounds were designed to merge together the trifluoromethyl benzyloxyaminic bioactive moiety, previously identified, with different acids available in nature. The ability of the synthesized compounds to chelate biometals, such as Cu2+, Zn2+ and Fe2+, was studied by UV-Vis spectrometer, and through a preliminary screening their antioxidant activity was evaluated by DPPH. Then, selected compounds were tested by in vitro ABTS free radical method and ex vivo rat brain TBARS assay. Compounds 2a-c, combining the strongest antioxidant and biometal chelators activities, were studied for their ability to contrast Aβ1-40 fibrillization process. Finally, starting from the promising profile obtained for compound 2a, we evaluated if it could be able to induce a positive cross-interaction between transthyretin (TTR) and Aβ in presence and in absence of Cu2+.

Synthesis and biological evaluation of resveratrol amide derivatives as selective COX-2 inhibitors

Selective COX-2 inhibitors have been considered to be reliable alternatives to tNSAIDs, but most of them were withdrawn from the market due to their risk of heart attack and stroke. Therefore, it is urgent to develop a new type of selective COX-2 inhibitor with high efficiency and low toxicity. Inspired by the cardiovascular protection, and anti-inflammatory activity of resveratrol, we synthesized 38 resveratrol amide derivatives and evaluated their COX-1/COX-2 inhibitory activities. Compounds 8a, 6a, 8c and 13c showed important inhibitory activity against COX-2 (IC₅₀ = 0.42-2.54 μM) with definite selectivity (SI = 48-83). Molecular docking study demonstrated that these compounds partially entered the 2°-pocket of the COX-2 active site and interacted with the amino acid residues responsible for the COX-2 selectivity, which was in a similar orientation and binding interactions to rofecoxib. Further anti-inflammatory activity evaluation in vivo of these active compounds revealed that compound 8a showed no gastric ulcer toxicity, and displayed evident anti-inflammatory effect (45.95% inhibition of edema) with three oral doses of 50 mg/kg, which is worthy of further study. Moreover, compounds 6a and 8c also exhibited superior gastric safety profiles compared to the reference drugs celecoxib and indomethacin.

Utilizing genetic code expansion to modify N-TIMP2 specificity towards MMP-2, MMP-9, and MMP-14

Matrix metalloproteinases (MMPs) regulate the degradation of extracellular matrix (ECM) components in biological processes. MMP activity is controlled by natural tissue inhibitors of metalloproteinases (TIMPs) that non-selectively inhibit the function of multiple MMPs via interaction with the MMPs' Zn2+-containing catalytic pocket. Recent studies suggest that TIMPs engineered to confer MMP specificity could be exploited for therapeutic purposes, but obtaining specific TIMP-2 inhibitors has proved to be challenging. Here, in an effort to improve MMP specificity, we incorporated the metal-binding non-canonical amino acids (NCAAs), 3,4-dihydroxyphenylalanine (L-DOPA) and (8-hydroxyquinolin-3-yl)alanine (HqAla), into the MMP-inhibitory N-terminal domain of TIMP2 (N-TIMP2) at selected positions that interact with the catalytic Zn2+ ion (S2, S69, A70, L100) or with a structural Ca2+ ion (Y36). Evaluation of the inhibitory potency of the NCAA-containing variants towards MMP-2, MMP-9 and MMP-14 in vitro revealed that most showed a significant loss of inhibitory activity towards MMP-14, but not towards MMP-2 and MMP-9, resulting in increased specificity towards the latter proteases. Substitutions at S69 conferred the best improvement in selectivity for both L-DOPA and HqAla variants. Molecular modeling provided an indication of how MMP-2 and MMP-9 are better able to accommodate the bulky NCAA substituents at the intermolecular interface with N-TIMP2. The models also showed that, rather than coordinating to Zn2+, the NCAA side chains formed stabilizing polar interactions at the intermolecular interface with MMP-2 and MMP-9. Our findings illustrate how incorporation of NCAAs can be used to probe-and possibly exploit-differential tolerance for substitution within closely related protein-protein complexes as a means to improve specificity.

Synergistic Effect of Sophora japonica and Glycyrrhiza glabra Flavonoid-Rich Fractions on Wound Healing: In Vivo and Molecular Docking Studies

Glycyrrhiza glabra and Sophora japonica (Fabaceae) are well-known medicinal plants with valuable secondary metabolites and pharmacological properties. The flavonoid-rich fractions of G. glabra roots and S. japonica leaves were prepared using Diaion column chromatography, and the confirmation of flavonoid richness was confirmed using UPLC-ESI-MS profiling and total phenolics and flavonoids assays. UPLC-ESI-MS profiling of the flavonoid-rich fraction of G. glabra roots and S. japonica leaves resulted in the tentative identification of 32 and 23 compounds, respectively. Additionally, the wound healing potential of topical preparations of each fraction, individually and in combination (1:1) ointment and gel preparations, were investigated in vivo, supported by histopathological examinations and biomarker evaluations, as well as molecular docking studies for the major constituents. The topical application of G. glabra ointment and gel, S. japonica ointment and gel and combination preparations significantly increase the wound healing rate and the reduction of oxidative stress in the wound area via MDA reduction and the elevation of reduced GSH and SOD levels as compared to the wound and Nolaver®-treated groups. The molecular docking study revealed that that major compounds in G. glabra and S. japonica can efficiently bind to the active sites of three proteins related to wound healing: glycogen synthase kinase 3-β (GSK3-β), matrix metalloproteinases-8 (MMP-8) and nitric oxide synthase (iNOS). Consequently, G. glabra roots and S. japonica leaves may be a rich source of bioactive metabolites with antioxidant, anti-inflammatory and wound healing properties.

Comparative Metabolic Study of Tamarindus indica L.'s Various Organs Based on GC/MS Analysis, In Silico and In Vitro Anti-Inflammatory and Wound Healing Activities

The chemical composition of the n-hexane extract of Tamarindus indica's various organs-bark, leaves, seeds, and fruits (TIB, TIL, TIS, TIF)-was investigated using gas chromatography-mass spectrometry (GC/MS) analysis. A total of 113 metabolites were identified, accounting for 93.07, 83.17, 84.05, and 85.08 % of the total identified components in TIB, TIL, TIS, and TIF, respectively. Lupeol was the most predominant component in TIB and TIL, accounting for 23.61 and 22.78%, respectively. However, n-Docosanoic acid (10.49%) and methyl tricosanoate (7.09%) were present in a high percentage in TIS. However, α-terpinyl acetate (7.36%) and α-muurolene (7.52%) were the major components of TIF n-hexane extract. By applying a principal component analysis (PCA) and hierarchal cluster analysis (HCA) to GC/MS-based metabolites, a clear differentiation of Tamarindus indica organs was achieved. The anti-inflammatory activity was evaluated in vitro on lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. In addition, the wound healing potential for the n-hexane extract of various plant organs was assessed using the in-vitro wound scratch assay using Human Skin Fibroblast cells. The tested extracts showed considerable anti-inflammatory and wound-healing activities. At a concentration of 10 µg/mL, TIL showed the highest nitric oxide (NO) inhibition by 53.97 ± 5.89%. Regarding the wound healing potential, after 24 h, TIB, TIL, TIS, and TIF n-hexane extracts at 10 g/mL reduced the wound width to 1.09 ± 0.04, 1.12 ± 0.18, 1.09 ± 0.28, and 1.41 ± 0.35 mm, respectively, as compared to the control cells (1.37 ± 0.15 mm). These findings showed that the n-hexane extract of T. indica enhanced wound healing by promoting fibroblast migration. Additionally, a docking study was conducted to assess the major identified phytoconstituents' affinity for binding to glycogen synthase kinase 3-β (GSK3-β), matrix metalloproteinases-8 (MMP-8), and nitric oxide synthase (iNOS). Lupeol showed the most favourable binding affinity to GSK3-β and iNOS, equal to -12.5 and -13.7 Kcal/mol, respectively, while methyl tricosanoate showed the highest binding affinity with MMP-8 equal to -13.1 Kcal/mol. Accordingly, the n-hexane extract of T. indica's various organs can be considered a good candidate for the management of wound healing and inflammatory conditions.

LC-MS/MS metabolomics profiling of Glechoma hederacea L. methanolic extract; in vitro antimicrobial and in vivo with in silico wound healing studies on Staphylococcus aureus infected rat skin wound

LC-MS/MS analysis of Glechoma hederacea L. methanolic extract (GHME), revealed the identification of 25 metabolites. Ursolic acid (1), 2α-hydroxyursolic acid or corosolic acid (2), 2β-hydroxyursolic acid or epi-corosolic (3), luteolin 7-O-β-D-glucopyranoside (4) and rosmarinic acid (5) were isolated and identified using spectroscopy. Antibacterial activity of GHME against multi drug resistance Staphylococcus aureus clinical isolates was measured. Minimum inhibitory concentrations (MICs) were ranged from 62.5 to 500 µg/ml. In vivo wound healing potential of 2%, and 5% GHME prepared hydrogels were criticized on Staphylococcus aureus infected wound rat model. 5% GHME prepared hydrogel treated group showed significant (p < 0.05) shrinkage of their colony forming unit/ml (CFU/ml) values in comparison with standard Fucidin. Meanwhile, wound closure associated with full re-epithelization and hair follicles proliferation was noticed after ten days of treatment. Finally, among the GHME isolated compounds, luteolin 7-O-β-D-glucopyranoside (4) exhibited the highest molecular docking score (-9.6 kcal/mol) against matrix metalloproteinase-8 target (MMP-8).

Enhancing resin-dentin bond durability using a novel mussel-inspired monomer

Numerous approaches have been developed to improve the resin-dentin bond performance, among which the bio-application of mussel-derived compounds have drawn great attention recently. To assess the performance of N-(3,4-dihydroxyphenethyl)methacrylamide (DMA), a mussel-derived compound, as a functional monomer in dental adhesive, its potential property to cross-link with dentin collagen and polymerize with adhesive will first be evaluated by transmission electron microscopy (TEM), attenuated total reflectance technique of Fourier transform infrared (ATR-FTIR), and atomic force microscopy (AFM) via Peakforce QNM mode. After validating the influence of DMA on collagen and adhesive separately, the overall performance of DMA/ethanol solution as a primer in dentin bonding was examined using micro-tensile bond strength (μTBS) testing, fracture pattern observation, and nanoleakage evaluation both immediately and after 10,000 times thermocycling aging. The inhibitory effect of DMA on endogenous metalloproteinases (MMPs) was evaluated by in situ zymography using confocal laser scanning microscopy (CLSM) and the cytotoxicity of DMA was evaluated using cell counting kit-8. Results demonstrated that DMA successfully cross-linked with dentin collagen via non-covalent bonds and had no influence on the polymerization and mechanical properties of the adhesive. Furthermore, even after 10,000 times thermocycling aging, the μTBS and nanoleakage expression of the DMA-treated groups showed no significant change compared with their immediate values. In situ zymography revealed reduced endogenous proteolytic activities after the application of DMA, and no cytotoxicity effect was observed for DMA concentration up to 25 ​μmol/L. Thus, DMA could be used as a novel, biocompatible functional monomer in dentin bonding.

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DMA acts as a functional monomer in dentin bonding system with high biocompatibility.

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DMA connects the adhesive and collagen network to resist various external attacks.

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DMA/ethanol inhibits the activity of MMPs and improve resin-dentin bond durability.

Molecular docking analysis of Plasmodium falciparum dihydroorotate dehydrogenase towards the design of effective inhibitors

Malaria remains a global public health burden with significant mortality and morbidity. Despite the several approved drugs available for its management, the parasite has developed resistance to virtually all known antimalarial drugs. The development of a new drug that can combat resistant to Artemisinin based Combination Therapies (ACTs) for malaria is imperative. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH), a flavin-dependent mitochondrial enzyme is vital in the parasite's pyrimidine biosynthesis is a well-known drug target. Therefore, it is of interest to document the MOLECULAR DOCKING analysis (using Maestro, Schrodinger) data of DIHYDROOROTATE DEHYDROGENASE PfDHODH from P. falciparum towards the design of effective inhibitors. The molecular docking features of 10 compounds with reference to chloroquine with PfDHODH are documented in this report for further consideration.

Inhibition of bacterial and human zinc-metalloproteases by bisphosphonate- and catechol-containing compounds

Compounds containg catechol or bisphosphonate were tested as inhibitors of the zinc metalloproteases, thermolysin (TLN), pseudolysin (PLN) and aureolysin (ALN) which are bacterial virulence factors, and the human matrix metalloproteases MMP-9 and -14. Inhibition of virulence is a putative strategy in the development of antibacterial drugs, but the inhibitors should not interfere with human enzymes. Docking indicated that the inhibitors bound MMP-9 and MMP-14 with the phenyl, biphenyl, chlorophenyl, nitrophenyl or methoxyphenyl ringsystem in the S₁'-subpocket, while these ringsystems entered the S₂'- or S₁ -subpockets or a region involving amino acids in the S₁'- and S₂'-subpockets of the bacterial enzymes. An arginine conserved among the bacterial enzymes seemed to hinder entrance deeply into the S₁'-subpocket. Only the bisphosphonate containing compound RC2 bound stronger to PLN and TLN than to MMP-9 and MMP-14. Docking indicated that the reason was that the conserved arginine (R203 in TLN and R198 in PLN) interacts with phosphate groups of RC2.

The application of novel mussel-inspired compounds in dentistry

OBJECTIVE

To give a current review of the mechanism of mussel adhesion, the application of mussel-inspired compounds in dentistry and the challenges associated with clinical application.

METHODS

Inspired by the wet adhesion property of 3,4-dihydroxyphenol-l-alanine (Dopa) in mussel plaques, various chemical compounds have been synthesized to mimic the mussel as an adhesion model for medical applications. Similar to mussels in the marine environment, dental materials in the oral environment have to endure long-term water hydrolysis, mechanical stress and other chemical challenges. These challenges have influenced an increasing number of studies that are exploring the translation of mussel-inspired adhesion to clinical applications. Therefore, this review discusses the mussel adhesion chemistry and its related application in dentistry.

RESULTS

Mussel-inspired compounds have achieved relatively acceptable performances in various dental fields, including surface coating, metal ions chelation, dentin bonding and mucosal adhesion. However, two practical problems remain to be comprehensively addressed, namely the protection of catechol groups from oxidation, and the feasibility for clinical application.

SIGNIFICANCE

The mussel's wet adhesion ability has attracted much research interest in the dental field because of its properties of moisture-resistant adhesion and surface coating. Despite the emergence of several mussel-inspired compounds in recent years, a comprehensive and timely review of their applications in dentistry is lacking. Therefore, the current review hopes to provide valuable information around the application of mussel-inspired compounds in dentistry with their pros and cons discussed.

(2-Aminobenzothiazole)-Methyl-1,1-Bisphosphonic Acids: Targeting Matrix Metalloproteinase 13 Inhibition to the Bone

Matrix Metalloproteinases (MMPs) are a family of secreted and membrane-bound enzymes, of which 24 isoforms are known in humans. These enzymes degrade the proteins of the extracellular matrix and play a role of utmost importance in the physiological remodeling of all tissues. However, certain MMPs, such as MMP-2, -9, and -13, can be overexpressed in pathological states, including cancer and metastasis. Consequently, the development of MMP inhibitors (MMPIs) has been explored for a long time as a strategy to prevent and hinder metastatic growth, but the important side effects linked to promiscuous inhibition of MMPs prevented the clinical use of MMPIs. Therefore, several strategies were proposed to improve the therapeutic profile of this pharmaceutical class, including improved selectivity toward specific MMP isoforms and targeting of specific organs and tissues. Combining both approaches, we conducted the synthesis and preliminary biological evaluation of a series of (2-aminobenzothiazole)-methyl-1,1-bisphosphonic acids active as selective inhibitors of MMP-13 via in vitro and in silico studies, which could prove useful for the treatment of bone metastases thanks to the bone-targeting capabilities granted by the bisphosphonic acid group.

Computational analysis of the metal selectivity of matrix metalloproteinase 8

Matrix metalloproteinase (MMP) is a class of metalloenzyme that cleaves peptide bonds in extracellular matrices. Their functions are important in both health and disease of animals. Here using quantum mechanics simulations of the MMP8 protein, the coordination chemistry of different metal cofactors is examined. Structural comparisons reveal that Jhan-Teller effects induced by Cu(II) coordination distorts the wild-type MMP8 active site corresponding to a significant reduction in activity observed in previous experiments. In addition, further analysis suggests that a histidine to glutamine mutation at residue number 197 can potentially allow the MMP8 protein to utilize Cu(II) in reactions. Simulations also demonstrates the requirement of a conformational change in the ligand before enzymatic cleavage. The insights provided here will assist future protein engineering efforts utilizing the MMP8 protein.

A Series of Ferulic Acid Amides Reveals Unexpected Peroxiredoxin 1 Inhibitory Activity with in vivo Antidiabetic and Hypolipidemic Effects

Insulin resistance is a major pathophysiological feature in the development of type 2 diabetes (T2DM). Ferulic acid is known for attenuating the insulin resistance and reducing the blood glucose in T2DM rats. In this work, we designed and synthesized a library of new ferulic acid amides (FAA), which could be considered as ring opening derivatives of the antidiabetic PPARγ agonists Thiazolidinediones (TZDs). However, since these compounds displayed weak PPAR transactivation capacity, we employed a proteomics approach to unravel their molecular target(s) and identified the peroxiredoxin 1 (PRDX1) as a direct binding target of FAAs. Interestingly, PRDX1, a protein with antioxidant and chaperone activity, has been implied in the development of T2DM by inducing hepatic insulin resistance. SPR, mass spectrometry-based studies, docking experiments and in vitro inhibition assay confirmed that compounds VIe and VIf bound PRDX1 and induced a dose-dependent inhibition. Furthermore, VIe and VIf significantly improved hyperglycemia and hyperlipidemia in streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats as confirmed by histopathological examinations. These results provide guidance for developing the current FAAs as new potential antidiabetic agents.

Synthesis of Novel Sulfamethaoxazole 4-Thiazolidinone Hybrids and Their Biological Evaluation

A search for potent antitubercular agents prompted us to design and synthesize sulfamethaoxazole incorporated 4-thiazolidinone hybrids (7a–l) by using a cyclocondensation reaction between 4-amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide (4), aryl aldehyde (5a–l), and mercapto acetic acid (6) resulting in good to excellent yields. All the newly synthesized 4-thiazolidinone derivatives were screened for their in vitro antitubercular activity against M. Bovis BCG and M. tuberculosis H37Ra (MTB) strains. The compounds 7d, 7g, 7i, 7k, and 7l revealed promising antimycobacterial activity against M. Bovis and MTB strains with IC₉₀ values in the range of 0.058–0.22 and 0.43–5.31 µg/mL, respectively. The most active compounds were also evaluated for their cytotoxicity against MCF-7, HCT 116, and A549 cell lines and were found to be non-cytotoxic. Moreover, the synthesized compounds were also analyzed for ADME (absorption, distribution, metabolism, and excretion) properties and showed potential as good oral drug candidates.

Importance of Biometals as Targets in Medicinal Chemistry: An Overview about the Role of Zinc (II) Chelating Agents

Zinc (II) is an important biometal in human physiology. Moreover, in the last two decades, it was deeply studied for its involvement in several pathological states. In particular, the regulation of its concentration in synaptic clefts can be fundamental for the treatment of neurodegenerative diseases, such as Alzheimer’s disease (AD). Zinc (II) is also a constituent of metalloenzymes (i.e., matrix metalloproteinases, MMPs, and carbonic anhydrases, CAs) with catalytic function; therefore, it can be an important target for the inhibition of these proteins, frequently involved in cancer onset. This review is focused on the significance of zinc (II) chelating agents in past and future medicinal chemistry research, and on the importance of selectivity in order to revamp the possibility of their use in therapy, often hindered by possible side effects.

Bone-Seeking Matrix Metalloproteinase Inhibitors for the Treatment of Skeletal Malignancy

Matrix metalloproteinases (MMPs) are a family of enzymes involved at different stages of cancer progression and metastasis. We previously identified a novel class of bisphosphonic inhibitors, selective for MMPs crucial for bone remodeling, such as MMP-2. Due to the increasing relevance of specific MMPs at various stages of tumor malignancy, we focused on improving potency towards certain isoforms. Here, we tackled MMP-9 because of its confirmed role in tumor invasion, metastasis, angiogenesis, and immuno-response, making it an ideal target for cancer therapy. Using a computational analysis, we designed and characterized potent MMP-2/MMP-9 inhibitors. This is a promising approach to develop and clinically translate inhibitors that could be used in combination with standard care therapy for the treatment of skeletal malignancies.

Substituted N-(Pyrazin-2-yl)benzenesulfonamides; Synthesis, Anti-Infective Evaluation, Cytotoxicity, and In Silico Studies

We prepared a series of substituted N-(pyrazin-2-yl)benzenesulfonamides as an attempt to investigate the effect of different linkers connecting pyrazine to benzene cores on antimicrobial activity when compared to our previous compounds of amide or retro-amide linker type. Only two compounds, 4-amino-N-(pyrazin-2-yl)benzenesulfonamide (MIC = 6.25 μg/mL, 25 μM) and 4-amino-N-(6-chloropyrazin-2-yl)benzenesulfonamide (MIC = 6.25 μg/mL, 22 μM) exerted good antitubercular activity against M. tuberculosis H37Rv. However, they were excluded from the comparison as they-unlike the other compounds-possessed the pharmacophore for the inhibition of folate pathway, which was proven by docking studies. We performed target fishing, where we identified matrix metalloproteinase-8 as a promising target for our title compounds that is worth future exploration.

Natural Scaffolds with Multi-Target Activity for the Potential Treatment of Alzheimer's Disease

A few symptomatic drugs are currently available for Alzheimer’s Disease (AD) therapy, but these molecules are only able to temporary improve the cognitive capacity of the patients if administered in the first stages of the pathology. Recently, important advances have been achieved about the knowledge of this complex condition, which is now considered a multi-factorial disease. Researchers are, thus, more oriented toward the preparation of molecules being able to contemporaneously act on different pathological features. To date, the inhibition of acetylcholinesterase (AChE) and of β-amyloid (Aβ) aggregation as well as the antioxidant activity and the removal and/or redistribution of metal ions at the level of the nervous system are the most common investigated targets for the treatment of AD. Since many natural compounds show multiple biological properties, a series of secondary metabolites of plants or fungi with suitable structural characteristics have been selected and assayed in order to evaluate their potential role in the preparation of multi-target agents. Out of six compounds evaluated, 1 showed the best activity as an antioxidant (EC₅₀ = 2.6 ± 0.2 μmol/µmol of DPPH) while compound 2 proved to be effective in the inhibition of AChE (IC₅₀ = 6.86 ± 0.67 μM) and Aβ_1–40 aggregation (IC₅₀ = 74 ± 1 μM). Furthermore, compound 6 inhibited BChE (IC₅₀ = 1.75 ± 0.59 μM) with a good selectivity toward AChE (IC₅₀ = 86.0 ± 15.0 μM). Moreover, preliminary tests on metal chelation suggested a possible interaction between compounds 1, 3 and 4 and copper (II). Molecules with the best multi-target profiles will be used as starting hit compounds to appropriately address future studies of Structure-Activity Relationships (SARs).

Biomolecular basis of matrix metallo proteinase-9 activity

Matrix metalloproteinases (MMPs) are structurally related endopeptidases. They are also known as metzincins due to their interaction with zinc ion of the conserved methionine (Met) at the active site. MMPs play an important role in physiological and signaling processes of wound healing, bone resorption and angiogenesis. The structure of MMPs consists of signal peptide, propeptide, catalytic domain, hinge region and hemopexin-like domain. MMP-9 shares high structural and functional similarities with MMP-2, therefore designing selective MMP-9 inhibitors (MMPIs) is challenging. The selectivity can be achieved by targeting S2 subsite of MMP-9 that is having difference with MMP-2. Further, targeting its exosite and protein disulfide isomerase may also provide selective MMPIs. The review highlights the molecular features and basis of MMP-9 enzyme action. The MMPIs reported in the recent years have also been included.