Diketoacid chelating ligands as dual inhibitors of HIV-1 integration process

Liquid-assisted mechanochemical synthesis, crystallographic, theoretical and molecular docking study on HIV instasome of novel copper complexes: (µ-acetato)-bis(2,2'-bipyridine)-copper and bromidotetrakis(2-methyl-1H-imidazole)-copper bromide

In the present work the two new Cu(II) complexes, (µ-acetato)-bis(2,2'-bipyridine)-copper [Cu(bpy)2(CH3CO2)] and bromidotetrakis(2-methyl-1H-imidazole)-copper bromide [Cu(2-methylimid)4Br]Br have been synthesized by liquid assisted mechanochemical method. The [Cu(bpy)2(CH3CO2)] complex (1) and [Cu(2-methylimid)4Br]Br complex (2) characterised by IR and UV-visible spectroscopy and the structure are confirmed by XRD diffraction studies. Complex (1) crystallized in the Monoclinic with the space group of C2/c where a = 24.312(5) Å, b = 8.5892(18) Å, c = 14.559(3) Å, α = 90°, β = 106.177(7)° and γ = 90° and Complex (2) crystallized in the Tetragonal with the space group of P4nc, a = 9.9259(2) Å, b = 9.9259(2) Å, c = 10.9357(2) Å, α = 90°, β = 90° and γ = 90°. The complex (1) has distorted octahedral geometry where the acetate ligand showed bidentate bridging with the central metal ion and complex (2) has slightly deformed square pyramidal geometry. The HOMO-LUMO energy gap value and the low chemical potential showed that the complex (2) is stable and difficult to polarize compare to complex (1). The molecular docking study of complexes with the HIV instasome nucleoprotein showed the binding energy values - 7.1 and - 5.3 kcal/mol for complex (1) and complex (2) respectively. The negative binding energy values showed the complexes have affinity to bind with HIV instasome nucleoproteins. The in-silico pharmacokinetic study of the complex (1) and complex (2) showed non AMES toxicity, non-carcinogens and low honey Bee toxicity but weakly inhibit Human Ether-a-go-go-related gene.

The Integrase: An Overview of a Key Player Enzyme in the Antiviral Scenario

Integration of a desossiribonucleic acid (DNA) copy of the viral ribonucleic acid (RNA) into host genomes is a fundamental step in the replication cycle of all retroviruses. The highly conserved virus-encoded Integrase enzyme (IN; EC 2.7.7.49) catalyzes such a process by means of two consecutive reactions named 3'-processing (3-P) and strand transfer (ST). The Authors report and discuss the major discoveries and advances which mainly contributed to the development of Human Immunodeficiency Virus (HIV) -IN targeted inhibitors for therapeutic applications. All the knowledge accumulated over the years continues to serve as a valuable resource for the design and development of effective antiretroviral drugs.

Targeting Metalloenzymes: The "Achilles' Heel" of Viruses and Parasites

Metalloenzymes are central to the regulation of a wide range of essential viral and parasitic functions, including protein degradation, nucleic acid modification, and many others. Given the impact of infectious diseases on human health, inhibiting metalloenzymes offers an attractive approach to disease therapy. Metal-chelating agents have been expansively studied as antivirals and antiparasitics, resulting in important classes of metal-dependent enzyme inhibitors. This review provides the recent advances in targeting the metalloenzymes of viruses and parasites that impose a significant burden on global public health, including influenza A and B, hepatitis B and C, and human immunodeficiency viruses as well as Trypanosoma brucei and Trypanosoma cruzi.

Structural Comparison of Diverse HIV-1 Subtypes using Molecular Modelling and Docking Analyses of Integrase Inhibitors

The process of viral integration into the host genome is an essential step of the HIV-1 life cycle. The viral integrase (IN) enzyme catalyzes integration. IN is an ideal therapeutic enzyme targeted by several drugs; raltegravir (RAL), elvitegravir (EVG), dolutegravir (DTG), and bictegravir (BIC) having been approved by the USA Food and Drug Administration (FDA). Due to high HIV-1 diversity, it is not well understood how specific naturally occurring polymorphisms (NOPs) in IN may affect the structure/function and binding affinity of integrase strand transfer inhibitors (INSTIs). We applied computational methods of molecular modelling and docking to analyze the effect of NOPs on the full-length IN structure and INSTI binding. We identified 13 NOPs within the Cameroonian-derived CRF02_AG IN sequences and further identified 17 NOPs within HIV-1C South African sequences. The NOPs in the IN structures did not show any differences in INSTI binding affinity. However, linear regression analysis revealed a positive correlation between the Ki and EC50 values for DTG and BIC as strong inhibitors of HIV-1 IN subtypes. All INSTIs are clinically effective against diverse HIV-1 strains from INSTI treatment-naïve populations. This study supports the use of second-generation INSTIs such as DTG and BIC as part of first-line combination antiretroviral therapy (cART) regimens, due to a stronger genetic barrier to the emergence of drug resistance.

Design, Synthesis, Docking Studies and Biological Activities Novel 2,3- Diaryl-4-Quinazolinone Derivatives as Anti-HIV-1 Agents

BACKGROUND

Although major efforts have been devoted to the effective treatment of HIV-1 infection, it has remained one of the leading causes of deaths around the world. So, development of anti-HIV-1 agents featuring novel structure is essential.

OBJECTIVE

To synthesize novel quinazolinone derivatives and evaluate their anti-HIV-1 activity.

METHOD

In this study, we designed and synthesized a series of novel 2,3-diaryl-4-quinazolinone derivatives using a one-pot multicomponent reaction. Then, the resulting derivatives were evaluated for anti-HIV-1 activity using Hela cell-based single-cycle replication assay.

RESULTS

Most of the compounds showed efficacy against HIV-1 replication and the compound 9c exhibited the highest activity with EC50 value of 37 μM. Docking studies indicated that synthesized compounds can interact with the key residues of the HIV-1 integrase active site. Binding of the most active compound was consistent with the HIV-1 integrase inhibitors.

CONCLUSION

Based on our results, these derivatives represent novel lead compounds for the development of new promising anti-HIV-1 agents.

Recent Advances in the Development of Integrase Inhibitors for HIV Treatment

PURPOSE OF THE REVIEW

The complex multistep life cycle of HIV allows it to proliferate within the host and integrate its genome in to the host chromosomal DNA. This provirus can remain dormant for an indefinite period. The process of integration, governed by integrase (IN), is highly conserved across the Retroviridae family. Hence, targeting integration is not only expected to block HIV replication but may also reveal new therapeutic strategies to treat HIV as well as other retrovirus infections.

RECENT FINDINGS

HIV integrase (IN) has gained attention as the most promising therapeutic target as there are no equivalent homologues of IN that has been discovered in humans. Although current nano-formulated long-acting IN inhibitors have demonstrated the phenomenal ability to block HIV integration and replication with extraordinary half-life, they also have certain limitations. In this review, we have summarized the current literature on clinically established IN inhibitors, their mechanism of action, the advantages and disadvantages associated with their therapeutic application, and finally current HIV cure strategies using these inhibitors.

Recent advances in the discovery of small-molecule inhibitors of HIV-1 integrase

AIDS caused by the infection of HIV is a prevalent problem today. Rapid development of drug resistance to existing drug classes has called for the discovery of new targets. Within the three major enzymes (i.e., HIV-1 protease, HIV-1 reverse transcriptase and HIV-1 integrase [IN]) of the viral replication cycle, HIV-1 IN has been of particular interest due to the absence of human cellular homolog. HIV-1 IN catalyzes the integration of viral genetic material with the host genome, a key step in the viral replication process. Several novel classes of HIV IN inhibitors have been explored by targeting different sites on the enzyme. This review strives to provide readers with updates on the recent developments of HIV-1 IN inhibitors.

AIDS is an epidemic disease that endangers the lives of millions of people across the world. The AIDS virus, also known as HIV, has developed resistance to the majority of available drugs on the market, thus requiring the need for new drugs. HIV integrase is one of the key viral enzymes required for viral cell proliferation. Since there is no similar enzyme in the human body, major emphasis is being made to develop therapeutics for this novel target. The drugs that are at various stages of development for this target are reviewed here.

Antiviral activity and metal ion-binding properties of some 2-hydroxy-3-methoxyphenyl acylhydrazones

Here we report on the results obtained from an antiviral screening, including herpes simplex virus, vaccinia virus, vesicular stomatitis virus, Coxsackie B4 virus or respiratory syncytial virus, parainfluenza-3 virus, reovirus-1 and Punta Toro virus, of three 2-hydroxy-3-methoxyphenyl acylhydrazone compounds in three cell lines (i.e. human embryonic lung fibroblast cells, human cervix carcinoma cells, and African Green monkey kidney cells). Interesting antiviral EC₅₀ values are obtained against herpes simplex virus-1 and vaccinia virus. The biological activity of acylhydrazones is often attributed to their metal coordinating abilities, so potentiometric and microcalorimetric studies are here discussed to unravel the behavior of the three 2-hydroxy-3-methoxyphenyl compounds in solution. It is worth of note that the acylhydrazone with the higher affinity for Cu(II) ions shows the best antiviral activity against herpes simplex and vaccinia virus (EC₅₀ ~ 1.5 µM, minimal cytotoxic concentration = 60 µM, selectivity index = 40).

Synthesis of Diketohexenoic Acid Derivatives by Alkenylation of Indoles and Pyrroles with 4-Pyrones

A new synthesis of functionalized (Z)-6-hetaryl-2,4-dioxo-5-hexenoic acids based on acid-catalyzed alkenylation of indoles and pyrroles with derivatives of 5-substituted 4-pyrone-2-carboxylic acid in 37-82% yields has been developed. Coupling between isochelidonic acid and indoles followed by decarboxylation afforded biologically important (E)-6-indolyl-2,4-dioxo-5-hexenoic acids. These ring-opening reactions proceed with high regioselectivity through nucleophilic attack at the C-6 position of the pyrone ring. Reactions of ethyl 6-indolyl-2,4-dioxo-5-hexenoate with nucleophiles are useful for the production of different β-(indolyl)vinyl-containing azaheterocycles.

Potential of Casiopeínas® Copper Complexes and Antituberculosis Drug Combination against Mycobacterium tuberculosis

New compounds with antituberculosis activity and their combination with classic drugs have been evaluated to determine possible interactions and antagonism. The aim of this study was to evaluate the in vitro activity of Casiopeínas® copper-based compounds (CasIIIia, CasIIIEa, and CasIIgly) alone and combined with isoniazid (INH), rifampicin, or ethambutol (EMB) against resistant and susceptible Mycobacterium tuberculosis. Seventeen clinical M. tuberculosis isolates (5 multi-drug resistant and 2 resistant to INH and/or EMB) were subjected to determination of the minimal inhibitory concentration (MIC) by the resazurin microtiter assay and combination assessment by the resazurin drug combination microtiter assay. The Casiopeínas® alone showed a remarkable effect against resistant isolates with MIC values from 0.78 to 12.50 μg/ml. Furthermore, a synergistic effect mainly with EMB is shown for both resistant and susceptible clinical isolates. Casiopeínas® are promising candidates for future investigation into the development of antituberculosis drugs, being one of the first examples of essential metal-based drugs used in this field.

A versatile salicyl hydrazonic ligand and its metal complexes as antiviral agents

Acylhydrazones are very versatile ligands and their coordination properties can be easily tuned, giving rise to metal complexes with different nuclearities. In the last few years, we have been looking for new pharmacophores able to coordinate simultaneously two metal ions, because many enzymes have two metal ions in the active site and their coordination can be a successful strategy to inhibit the activity of the metalloenzyme. As a part of this ongoing research, we synthesized the acylhydrazone H2L and its complexes with Mg(II), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Their characterization, both in solution--also by means of potentiometric studies--and in the solid state, evidenced the ability of the o-vanillin hydrazone scaffold to give rise to different types of metal complexes, depending on the metal and the reaction conditions. Furthermore, we evaluated both the free ligand and its metal complexes in in vitro studies against a panel of diverse DNA- and RNA-viruses. In particular, the Mg(II), Mn(II), Ni(II) and Zn(II) complexes had EC50 values in the low micromolar range, with a pronounced activity against vaccinia virus.

A review on recent developments of indole-containing antiviral agents

Indole represents one of the most important privileged scaffolds in drug discovery. Indole derivatives have the unique property of mimicking the structure of peptides and to bind reversibly to enzymes, which provide tremendous opportunities to discover novel drugs with different modes of action. There are seven indole-containing commercial drugs in the Top-200 Best Selling Drugs by US Retail Sales in 2012. There are also an amazing number of approved indole-containing drugs in the market as well as compounds currently going through different clinical phases or registration statuses. This review focused on the recent development of indole derivatives as antiviral agents with the following objectives: 1) To present one of the most comprehensive listings of indole antiviral agents, drugs on market or compounds in clinical trials; 2) To focus on recent developments of indole compounds (including natural products) and their antiviral activities, summarize the structure property, hoping to inspire new and even more creative approaches; 3) To offer perspectives on how indole scaffolds as a privileged structure might be exploited in the future.

Antiretroviral activity of metal-chelating HIV-1 integrase inhibitors

Data regarding the activity of metal complexes against HIV virus in cell are surprisingly scarce. In this study, we present the antiviral activity against HIV-infected cells of different types of chelating ligands and of their metal complexes. In particular, the carboxamide chelating scaffold and the corresponding coordination compounds demonstrated an interesting antiviral profile in the nanomolar range. These molecules inhibit not only HIV integrase catalytic activity, but they also interfere with the function of the RNase H component of the HIV reverse transcriptase. Here we also discuss the thermodynamic characterization in solution of the metal complexes of the most active ligands, affording to the best of our knowledge for the first time this type of data for complexes with anti-HIV activity.