Current Medicinal Chemistry - Volume 25, Issue 42, 2018

The development of isozyme-selective heme oxygenase (HO) inhibitors promises powerful pharmacological tools to elucidate the regulatory characteristics of the HO system. It is already known that HO has cytoprotective properties with a role in several disease states; thus, it is an enticing therapeutic target. Historically, the metalloporphyrins have been used as competitive HO inhibitors based on their structural similarity to the substrate, heme. However, heme’s important role in several other proteins (e.g. cytochromes P450, nitric oxide synthase), results in non-selectivity being an unfortunate side effect. Reports that azalanstat and other non-porphyrin molecules inhibited HO led to a multi-faceted effort over a decade ago to develop novel compounds as potent, selective inhibitors of HO. The result was the creation of the first generation of non-porphyrin based, non-competitive inhibitors with selectivity for HO, including a subset with isozyme selectivity for HO-1. Using X-ray crystallography, the structures of several complexes of HO-1 with novel inhibitors have been elucidated and provided insightful information regarding the salient features required for inhibitor binding. This included the structural basis for non-competitive inhibition, flexibility and adaptability of the inhibitor binding pocket, and multiple, potential interaction subsites, all of which can be exploited in future drug-design strategies. Notably, HO-1 inhibitors are of particular interest for the treatment of hyperbilirubinemia and certain types of cancer. Key features based on this initial study have already been used by others to discover additional potential HO-1 inhibitors. Moreover, studies have begun to use selected compounds and determine their effects in some disease models.

Tocainide is an antiarrhythmic agent belonging to class IB that was primarily used for suppression of symptomatic ventricular arrhythmias. Tocainide was also reported to relieve pain such as tic douloureux, trigemina neuralgia in humans and tinnitus. Significant antinociception, as assayed on the hot-plate test, was observed after intraperitoneal injection of tocainide, too. By the mid-1980s tocainide was emerging as a more consistently effective treatment for myotonic disorders. Numerous reports of serious adverse reactions led to the use of tocainide being discontinued, even though research on tocainide and its analogues, endowed with a better pharmacological profile, is still in progress for their potential usefulness in the treatment of myotonias. This review is focused on the description of the different synthetic routes to racemic and optically active tocainide developed in the last decades, as well as analytical studies regarding enantioseparation methods. Finally, some analogues of tocainide reported in the literature, most of which with pharmacological studies, have been mentioned.

Adverse drug reactions (ADRs) represent an important cause of morbidity and mortality worldwide. Statins are a class of drugs whose main adverse effects are drug-induced liver injury (DILI) and myopathy. Some of these may be predictable, due to their pharmacokinetic and pharmacodynamic properties, while others, unfortunately, are idiosyncratic. Genetic factors may also influence patient susceptibility to DILI and myopathy in the case of statins. This review will first discuss the role of statins in cardiovascular disease treatment and prevention and the underlying mechanisms of action. Furthermore, to explore the susceptibility of statin-induced adverse events such as myopathy and hepatotoxicity, it will then focus on the recent Genome-Wide Association Studies (GWAS) concerning the transporter genes, Cytochrome P450 (CYP), organic anion-transporting polypeptide (OATP) and ABCB1 and ABCC1, which seem to play a role in the development of clinically relevant adverse events. Finally, we appraise the evidence for and against the use of statins in metabolic syndrome and in HCV-infected patients, in terms of their safety and efficacy in cardiovascular events.

Rheumatoid Arthritis (RA) is a chronic autoimmune disease and becomes one of the major causes of disability and work force loss. The presence of abnormal B cell and autoantibodies produced by most RA patients, primarily ACPA and RF, indicate that the function of B cell was involved in the development of RA disease. Accordingly, the drug targeting B cell has become a hot spot in the treatment of RA. Studies have shown that Bruton's tyrosine kinase (BTK) is involved in the regulation of B cell proliferation and activation process. Some small molecule BTK inhibitors have shown excellent inhibition in biological activity analysis and animal models. Therefore, this review will briefly introduce BTK and its role in cell signaling and overview recent progress of BTK inhibitors for RA treatment.

Juvenile Idiopathic Arthritis (JIA) is one of the most common chronic diseases in children. Recently, the management of JIA has substantially changed, thanks to the availability of new treatment options, represented by biological drugs or biologics. These drugs modulate the specific mechanisms of the immune systems, such as TNF-α, IL-1 and IL-6 signaling, or lymphocyte activation and/or functioning. In this review, we provide a comprehensive discussion on the current recommendations and clinical evidence regarding the use of the available biologics in the treatment of JIA; moreover, the main pharmacokinetic and pharmacodynamic aspects of any specific biologic drug have been summarized.

The blood-brain barrier (BBB) is a complex system controlling two-way substances traffic between circulatory (cardiovascular) system and central nervous system (CNS). It is almost perfectly crafted to regulate brain homeostasis and to permit selective transport of molecules that are essential for brain function. For potential drug candidates, the CNSoriented neuropharmaceuticals as well as for those of primary targets in the periphery, the extent to which a substance in the circulation gains access to the CNS seems crucial. With the advent of nanopharmacology, the problem of the BBB permeability for drug nano-carriers gains new significance. Compared to some other fields of medicinal chemistry, the computational science of nano-delivery is still premature to offer the black-box type solutions, especially for the BBB-case. However, even its enormous complexity can spell out the physical principles, and as such subjected to computation. The basic understanding of various physicochemical parameters describing the brain uptake is required to take advantage of their usage for the BBB-nano delivery. This mini-review provides a sketchy introduction of essential concepts allowing application of computational simulation to the BBB-nano delivery design.

Background: The understanding of the action mechanism of the nanoparticles systems consisting of metallic nanoparticles and dyes or cytostatic molecule is crucial for searching and designing the ideal, novel drugs. In this review, we have considered moleculefunctionalized metallic nanoparticle systems for phototherapy. Methods: We performed a thorough search of the high-quality peer-reviewed literature on metallic nanoparticles systems in phototherapy, focusing on their biological importance and the action mechanism. Results: 138 papers were included in the mini-review. The majority of them discussed the way of metallic nanoparticles functionalization and its impact on the biological activity of a hybrid system. Conclusion: In this work, we show numerous medically and chemically important development strategies of hybrid types of drugs which can be used in phototherapy. These systems have a high affinity to the tumor cells surface proteins which transport the nanoparticles directly into a cell. The application of functionalized metallic nanoparticles in phototherapy improved photophysical properties lowered cytotoxicity of commonly used photosensitizers and facilitated the development of the third generation photosensitizers. Furthermore, this type of nanoparticles could also be used as a cytostatic drug carrier in the chemo or combined anticancer therapies.

Background: ATP-binding cassette (ABC) transporters-mediated multidrug resistance (MDR) remains the major obstacle for effective cancer therapy. Nanoparticles (NPs)-based delivery systems are promising to overcome MDR, but only a few of them have been accepted for clinical treatment, which should be due to their insufficient transportation and potential toxicity. In this respect, more and more attentions are being attracted on the interactions between NPs and ABC transporters, which hold a key role in the treatment of MDR cancer and the toxicity of NPs. However, there are no systematic reviews about such interactions, especially about their corresponding mechanism. Methods: We undertook extensive search of PubMed databases for peer-reviewed literatures using focused review questions. The retrieved papers were mostly published within the 5 years (84 of 104) and all with an impact factor above 2. First, this review focused on the current knowledge of ABC transporters involved in MDR and their inhibitors. Then, we reviewed the most recent literature about the inhibitory effects of organic NPs' excipients on ABC transporters and the direct interactions of inorganic NPs with ABC transporters. The major elements of obtained papers were described and classified depending on the structure of NPs. Results: Both organic and inorganic NPs can inhibit the function of ABC transporters, but based on different mechanisms. The effects of organic NPs are caused by several excipients like surfactants, polymers, lipids and cyclodextrin. Meanwhile, inorganic NPs usually act as the substrates of ABC transporters and competitively inhibit the efflux of drugs. These phenomena are interesting and worth investigating. Conclusion: The finding of this review confirmed the potential interactions between NPs and ABC transporters. These phenomena are interesting and worth investigating, and a knowledge of related mechanism would not only be important for the clinical therapies toward overcoming cancer MDR, but also help the treatment of other diseases like tuberculosis, AIDS, and central nervous system disorders, whose drugresistance was also related to ABC transporter-mediated efflux.

Ischemic stroke is one of the leading causes of mortality and permanent disability in developed countries. Stroke induces massive glutamate release, which in turn causes N-Methyl-D-aspartate (NMDA) receptor over-excitation and thus, calcium overload in neurons leading to cell death via apoptotic cascades. The kynurenine pathway is a complex enzymatic cascade of tryptophan catabolism, generating various neuroactive metabolites. One metabolite, kynurenic acid (KYNA), is a potent endogenous NMDA glutamate receptor antagonist, making it a possible therapeutic tool to decrease excitotoxicity and neuroinflammation. Recently, clinical investigations have shown that during the acute phase of ischemic stroke, kynurenine pathway is activated and peripheral levels of metabolites correlated with worse outcome. In this review, we set out to summarize the current literature on the connection of the kynurenine pathway and ischemic stroke and set a course for future investigations and potential drug development.

Background: Activated microglia play a pivotal role neurodegenerative diseases by producing a variety of proinflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin- 1beta (IL-1β) and nitric oxide (NO) that are toxic to neurons and oligodendrocytes. Methods: In view of the above, suppression of microglia mediated neuroinflammation is deemed a therapeutic strategy for neurodegenerative diseases. Several potential Chinese herbal extracts have been reported to exert neuroprotective effects against neurodegenerative diseases targeting specifically at the activated microglia. In this connection, the phenolic glucoside gastrodin, a main constituent of the Chinese herbal medicine Gastrodia rhizoma, produced widely in the local community exhibits potential neuroprotective effects through suppression of neurotoxic proinflammatory mediators. Results: Here, we first review the roles of activated microglia in different brain diseases. The effects of gastrodin on activated microglia are then considered. We have identified gastrodin as a putative therapeutic agent as it has been found to suppress microglial activation thus ameliorating neuroinflammation. More importantly, gastrodin downregulates the expression of renin angiotensin system (RAS) and production of proinflammatory mediators. Remarkably, gastrodin promotes Sirtuin 3 (Sirt3) up-regulation and nicotinamide adenine dinucleotide phosphate oxidase-2 (NOX-2) down-regulation after ischemichypoxia in activated microglia mediated by AT1 or AT2 receptors which are angiotensin II receptors subtypes, indicating a possible molecular link between RAS and Sirt3 survival genes. Conclusion: This review summarizes the beneficial effects of gastrodin acting on activated microglia along with other herbal compounds. Its efficacy in neuroprotection is consistent with some common herbal products in China.

Staphylococcus aureus is a notorious pathogenic bacterium causing a wide range of diseases from soft-tissue contamination, to more serious and deep-seated infections. This species is highlighted by its ability to express several kinds of virulence factors and to acquire genes related to drug resistance. Target this number of factors to design any drug is not an easy task. In this review, we discuss the importance of computational methods to impulse the development of new drugs against S. aureus. The application of docking methods to screen large libraries of natural or synthetic compounds and to provide insights into action mechanisms is demonstrated. Particularly, the studies that validated in silico results with biochemical and microbiological assays are highlighted. We also comment on the computer-aided design of new molecules using some known inhibitors. The confirmation of in silico results with biochemical and microbiological assays allowed the identification of lead molecules that could be used for drug design such as rhodomyrtone, quinuclidine, berberine (and their derivative compounds). The fast development of the computational methods is essential to improve our ability to discover new drugs, as well as to expand understanding about drug-target interactions.

Lectins are a group of proteins or glycoproteins with various potentially exploitable bioactivities and have been capturing more interest recently. They have been isolated and reported from various tissues of a diversity of plant species. Tubers are modified and enlarged plant structures derived from stems or roots that are used for nutrient storage and asexual reproduction. A number of plants such as yam, taro and potato are grown for their edible tubers, and lectins are found to be one of the major storage proteins. These lectins exhibit potent bioactivities encompassing mitogenic, antitumor, antimicrobial, immunomodulatory, antioxidative, hypoglycemic, insecticidal and nematicidal activities. They are potential resources for development into functional or healthy foods and targets for food protein researchers.

Background: Polymers have wide applications in medicine, including dentistry, i.e. in prosthetic dentistry. Aim: The following paper is aimed at demonstrating the applications of selected modern polymers in prosthetic dentistry based on the reported literature. Material and Methods: The study was conducted using the PubMed, SCOPUS and CINAHL databases in relation to documents published during 1999–2017. The following keywords were used: polymers with prosthetic dentistry, impression materials, denture base materials, bite registration materials, denture soft liners, occlusal splint materials and 3D printing. Original papers and reviews which were significant from the modern clinical viewpoint and practical validity in relation to the possibility of using polymeric materials in prosthetic dentistry were presented. Results: Denture base materials were the most commonly modified polymers. Modifications mainly concerned antimicrobial properties and reinforcement of the material structure by introducing additional fibers. Antimicrobial modifications were also common in case of relining materials. Conclusion: Polymeric materials have widely been used in prosthetic dentistry. Modifications of their composition allow achieving new, beneficial properties that affect the quality of patients' life. Progress in science allows for a more methodologically-advanced research on the synthesis of new polymeric materials and incorporation of new substances into already known polymeric materials, that will require systematization and appropriate classification.

The bacterial resistance to antibiotics constitutes more than ever a severe public health problem. The enzymes involved in bacterial peptidoglycan biosynthesis are pertinent targets for developing new antibiotics, notably the MraY transferase that is not targeted by any marketed drug. Many research groups are currently working on the study or the inhibition of this enzyme. After a concise overview of the role, mechanism and inhibition of MraY, the structure–activity relationships of 5’-triazole-containing aminoribosyluridine inhibitors, we previously synthetized, will be presented. The recently published MraY X-ray structures allowed us to achieve a molecular virtual high-throughput screening of commercial databases and our in-house library resulting in the identification of promising compounds for the further development of new antibiotics.

Antibiotic resistance is one of the most pressing health issues of our days. It can arise due to a multiplicity of factors, such as target modification, decrease in the drug uptake, changes in the metabolic pathways and activation of efflux pumps. The overexpression of efflux pumps is responsible for the extrusion of drugs, making antibiotic therapy fail, as the quantity of intracellular antibiotic is not enough to provide the desired therapeutic effect. Efflux pumps can be included in five families according to their composition, nature of substrates, energy source, and number of transmembrane spanning regions. The ABC superfamily is mainly found in Gram-positive bacteria, use ATP as an energy source, and only a limited number of ABC pumps confer multidrug resistance (MDR). On the other hand, the MFS family, most present in Gram-positive bacteria, and the RND family, characteristic of Gram-negative bacteria, are most associated with antibiotic resistance. A wide variety of inhibitors have been disclosed for both families, from either natural or synthetic sources, or even drugs that are currently in therapy for other diseases. The other two families are the SMR, which are the smallest drug efflux proteins known, and the MATE family, whose pumps can also resort to the sodium gradient as an energy source. In this review, it is intended to present a comprehensive review of the classes of efflux pump inhibitors from the various sources, highlighting their structure-activity relationships, which can be useful for medicinal chemists in the pursuit of novel efflux pump inhibitors.

Background: Vaccines are very effective medical tools for disease prevention and life span increase. Controversies have raised concern about their safety, from autism to polio vaccine contamination with simian virus 40 (SV-40). Hysteria surrounding vaccine-associated risks has resulted in a declining number of vaccinations in developed countries. Outbreaks of vaccine-preventable diseases (e.g. measles) have occurred in Europe and North America, causing also some causalities. Objectives: In this review, data on safety and efficacy of vaccines are discussed, showing that the benefits of vaccines far outweigh the risks and that it is important to comply with vaccination protocols, to avoid spreading of severe, preventable diseases. Methods: Those opposed to vaccinations suggest that scientific literature supporting vaccines is influenced by pharmaceutical companies. In this review, studies on influenza produced by independent scientists and those authored by those who received some kind of benefit from the industry are discussed separately. All the chosen papers were selected through a MEDLINE research. Results: Vaccination rates are decreasing, even though they are effective public health tools. Influenza, for example, is responsible for 250,000–500,000 deaths each year, according to the WHO. Yet, campaigns to extend influenza vaccine to all elderly subjects report little success, because of the vaccine scare and because not all patients develop immunity following vaccination. Conclusions: This review proves that vaccine hysteria is detrimental because: 1) it causes an increased morbidity and mortality from preventable diseases; 2) it jeopardizes research for new vaccines; 3) patients are reluctant to accept any form of immune-therapy, commonly referred to as “vaccination”.