Showing papers in "Current Medicinal Chemistry in 2016"

Alzheimer's disease: A review from the pathophysiology to diagnosis, new perspectives for pharmacological treatment.

Abstract: Dementia is characterized by the impairment of cognition and behavior of people over 65 years. Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder in the world, as approximately 47 million people are affected by this disease and the tendency is that this number will increase to 62% by 2030. Two microscopic features assist in the characterization of the disease, the amyloid plaques and neurofibrillary agglomerates. All these factors are responsible for the slow and gradual deterioration of memory that affect language, personality or cognitive control. For the AD diagnosis, neuropsychological tests are performed in different spheres of cognitive functions but since not all cognitive functions may be affected, cerebrospinal fluid biomarkers are used along with these tests. To date, cholinesterase inhibitors are used as treatment, they are the only drugs that have shown significant improvements in the cognitive functions of AD patients. Despite the proven effectiveness of cholinesterase inhibitors, an AD carrier, even while being treated, is continually subjected to progressive degeneration of the neuronal tissue. For this reason, other biochemical pathways associated with the pathophysiology of AD have been explored as alternatives to the treatment of this condition such as inhibition of β-secretase and glycogen synthase kinase-3β. The present study aims to conduct a review of the epidemiology, pathophysiology, symptoms, diagnosis and treatment of Alzheimer's disease, emphasizing the research and development of new therapeutic approaches.

Structure and Expression of Different Serum Amyloid A (SAA) Variants and their Concentration-Dependent Functions During Host Insults.

Abstract: Serum amyloid A (SAA) is, like C-reactive protein (CRP), an acute phase protein and can be used as a diagnostic, prognostic or therapy follow-up marker for many diseases. Increases in serum levels of SAA are triggered by physical insults to the host, including infection, trauma, inflammatory reactions and cancer. The order of magnitude of increase in SAA levels varies considerably, from a 10- to 100- fold during limited inflammatory events to a 1000-fold increase during severe bacterial infections and acute exacerbations of chronic inflammatory diseases. This broad response range is reflected by SAA gene duplications resulting in a cluster encoding several SAA variants and by multiple biological functions of SAA. SAA variants are single-domain proteins with simple structures and few post-translational modifications. SAA1 and SAA2 are inducible by inflammatory cytokines, whereas SAA4 is constitutively produced. We review here the regulated expression of SAA in normal and transformed cells and compare its serum levels in various disease states. At low concentrations (10-100 ng/ml), early in an inflammatory response, SAA induces chemokines or matrix degrading enzymes via Toll-like receptors and functions as an activator and chemoattractant through a G protein-coupled receptor. When an infectious or inflammatory stimulus persists, the liver continues to produce more SAA (≥ 1000 ng/ml) to become an antimicrobial agent by functioning as a direct opsonin of bacteria or by interference with virus infection of host cells. Thus, SAA regulates innate and adaptive immunity and this information may help to design better drugs to treat specific diseases.

Morin: A Promising Natural Drug.

Abstract: Morin is a natural polyphenol, originally isolated from members of the Moraceae family that can be extracted from leaves, fruits, stems and branches of numerous plants. Several evidence have demonstrated that Morin could have a beneficial effect on several human diseases. In fact, Morin exerts antioxidant, antidiabetic, anti-inflammatory, antitumoral, antihypertensive, antibacterial, hypouricemic, and neuroprotective effects, by modulating the activity of many enzymes. In some cases, Morin shows a systemic protective action, reducing negative side effects of several drugs, without interfering with their functions. In addition, in vitro and in vivo studies demonstrated that Morin exhibits very low toxicity levels and its chronic administration is well tolerated. All these findings suggest that Morin could be used, either alone or in combination with other drugs, to prevent many human pathologies.

Targeting the Microglial Signaling Pathways: New Insights in the Modulation of Neuropathic Pain.

Abstract: The microglia, once thought only to be supporting cells of the central nervous system (CNS), are now recognized to play essential roles in many pathologies. Many studies within the last decades indicated that the neuro-immune interaction underlies the generation and maintenance of neuropathic pain. Through a large number of receptors and signaling pathways, the microglial cells communicate with neurons, astrocytes and other cells, including those of the immune system. A disturbance or loss of CNS homeostasis causes rapid responses of the microglia, which undergo a multistage activation process. The activated microglia change their cell shapes and gene expression profiles, which induce proliferation, migration, and the production of pro- or antinociceptive factors. The cells release a large number of mediators that can act in a manner detrimental or beneficial to the surrounding cells and can indirectly alter the nociceptive signals. This review discusses the most important microglial intracellular signaling cascades (MAPKs, NF-kB, JAK/STAT, PI3K/Akt) that are essential for neuropathic pain development and maintenance. Our objective was to identify new molecular targets that may result in the development of powerful tools to control the signaling associated with neuropathic pain.

Development of Anticancer Agents from Plant-Derived Sesquiterpene Lactones

Abstract: Sesquiterpene lactones are of considerable interest due to their potent bioactivities, including cancer cell cytotoxicity and antineoplastic efficacy in in vivo studies. Among these compounds, artesunate, dimethylaminoparthenolide, and L12ADT peptide prodrug, a derivative of thapsigargin, are being evaluated in the current cancer clinical or preclinical trials. Based on the structures of several antitumor sesquiterpene lactones, a number of analogues showing greater potency have been either isolated as natural products or partially synthesized, and some potential anticancer agents that have emerged from this group of lead compounds have been investigated extensively. The present review focuses on artemisinin, parthenolide, thapsigargin, and their naturally occurring or synthetic analogues showing potential anticancer activity. This provides an overview of the advances in the development of these types of sesquiterpene lactones as potential anticancer agents, including their structural characterization, synthesis and synthetic modification, and antitumor potential, with the mechanism of action and structure-activity relationships also discussed. It is hoped that this will be helpful in stimulating the further interest in developing sesquiterpene lactones and their derivatives as new anticancer agents.

Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging.

Abstract: The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets.

Adamantane – A Lead Structure for Drugs in Clinical Practice

Abstract: The adamantane moiety is the structural backbone of numerous compounds and its discovery launched a new field of chemistry studying the approaches to the synthesis as well as the physicochemical and biological properties of organic polyhedral compounds with practical application in the pharmaceutical industry. Adamantane derivatives have proven to be very potent compounds in a wide range of applications from systemic to topical therapy. This review summarizes the currently available adamantane derivatives in clinical practice (amantadine, memantine, rimantadine, tromantadine, adapalene, saxagliptin, vildagliptin), focusing on mechanisms of action, pharmacokinetics, pharmacodynamics and clinical trials. The adamantane-based compounds presented in this manuscript have been approved for a wide spectrum of indications (antivirals, antidiabetics and against Alzheimer's and Parkinson's disease). Each of the compounds proved to be of vital importance in their therapeutic indication for numerous patients worldwide. This review also considers the mechanisms of side effects to deliver a complete perspective on current treatment options.

Eosinophils in Cancer: Favourable or Unfavourable?

Abstract: Eosinophils are granulocytic leukocytes residing in blood and tissues in the lung, breast, gastrointestinal and reproductive systems. Eosinophilia is uncommon in healthy individuals, however, it is associated with allergies, helminth infections and some inflammatory states. Eosinophilia has also been observed in cancer, including colorectal, breast, ovarian, cervical, oral squamous, Hodgkin's lymphoma and prostate cancer. Whether an increase in eosinophils leading to a favourable or unfavourable prognosis still remains controversial and depends on many factors including the type of cancer. Eosinophil infiltration is considered unfavourable in Hodgkin's lymphoma, conversely it has also been linked to a favourable prognosis in colorectal, breast and prostate cancers. Eosinophils secrete a variety of cytokines and factors including eosinophil cationic protein, eosinophil-derived neurotoxin, peroxidase and major basic protein which have either anti-tumor effects or stimulate tumor progression. Herein, we discuss the role of eosinophils in tumor immunity and propose mechanisms accounting for their functional differences in tumorigenesis.

Overview of Systems Biology and Omics Technologies

Abstract: Traditional technologies using reductionist approach are relatively insufficient to solve problems in a biological system. Rather than a reductionist approach, systems biology uses a holistic and integrative approach to better figure out the whole process. Both qualitatively and quantitatively of biological system provide information about diseases, toxicities, therapies etc. Omics technologies, which systems biology brings, are valuable tools for comprehensive analyses. Automated DNA sequencers enabled the sequencing of genomes; microarray and mass spectrometry analysis permit global transcriptional profiling and lead to large-scale proteomic and metabolomics analysis. These high-throughput data need to be interpreted by bioinformatics. So far there has been no concrete published paper that compiles omics technologies according to PubMed database. In the present review, it was aimed to give brief description of systems biology and information on the advantages and disadvantages of omics technologies.

Circulating microRNAs as Potential Diagnostic Biomarkers and Therapeutic Targets in Gastric Cancer: Current Status and Future Perspectives

Abstract: Gastric cancer is among the leading causes of cancer related death worldwide. Patients with gastric cancer are typically asymptomatic, and diagnosed at late stages, supporting the need for the identification of novel prognostic and diagnostic biomarkers. Recently, microRNAs have emerged as molecular regulators that can play key roles in pathogenesis and progression of different malignancies, including gastric cancer. There is a growing body of evidence showing the aberrant activation of some known circulating miRNAs, e.g. let-7a, miR-21, miR-16, miR-93, miR- 103, miR-192a s well as tissue specific-miRNAs, e.g. miR-18a, miR-10b, miR-544, miR-195, miR-378, miR-34a, miR-145 in patients affected by gastric cancer, which involved with modulation of gastric-cancer-associated genes. In addition, there are mounting evidences on the value of miRNAs which are detected to be associated with drug-resistance mechanisms; suggesting their modulation as a potential approach to overcome chemo-resistance. Attuned with these facts, in this review we highlight several recent preclinical and clinical studies performed on circulating and tissue-specific miRNAs as promising biomarkers for detection of patients at early stages, prediction of prognosis, and monitoring of the patients in response to therapy.

The Effects of Vitamin B in Depression

Abstract: Vitamins are dietary components which are necessary for life. They play a major role in health and their deficiency may be linked to symptoms of psychiatric disorders. B vitamins are required for proper functioning of the methylation cycle, monoamine oxidase production, DNA synthesis and the repair and maintenance of phospholipids. Vitamin B deficiency could influence memory function, cognitive impairment and dementia. In particular, vitamins B1, B3, B6, B9 and B12 are essential for neuronal function and deficiencies have been linked to depression. We discuss the causes of depression and the neurochemical pathways in depression. In particular, we provide evidence that vitamin B contributes to the complexity of depressive symptoms.

Rutin as a Natural Therapy for Alzheimer's Disease: Insights into its Mechanisms of Action

Abstract: Rutin (quercetin-3-O-rutinoside) is a multifunctional natural flavonoid glycoside with profound effects on the various cellular functions under pathological conditions. Due to the ability of rutin and/or its metabolites to cross the blood brain barrier, it has also been shown to modify the cognitive and various behavioral symptoms of neurodegenerative diseases. In this review, its therapeutic potential for Alzheimer's disease (AD) is evaluated through appraisal of current literatures relevant to the various cellular and molecular targets of the disease. Among the most relevant mechanisms involved are effect on amyloid beta (Aβ) processing, aggregation and action; alteration of the oxidant-antioxidant balance associated with neuronal cell loss; removing the inflammatory component of neurodegeneration, etc. The effect of rutin resulting from its physicochemical features related to effects like metal chelation and bioavailability are also discussed.

A Compendium of Volatile Organic Compounds (VOCs) Released By Human Cell Lines

Abstract: Volatile organic compounds (VOCs) offer unique insights into ongoing biochemical processes in healthy and diseased humans. Yet, their diagnostic use is hampered by the limited understanding of their biochemical or cellular origin and their frequently unclear link to the underlying diseases. Major advancements are expected from the analyses of human primary cells, cell lines and cultures of microorganisms. In this review, a database of 125 reliably identified VOCs previously reported for human healthy and diseased cells was assembled and their potential origin is discussed. The majority of them have also been observed in studies with other human matrices (breath, urine, saliva, feces, blood, skin emanations). Moreover, continuing improvements of qualitative and quantitative analyses, based on the recommendations of the ISO-11843 guidelines, are suggested for the necessary standardization of analytical procedures and better comparability of results. The data provided contribute to arriving at a more complete human volatilome and suggest potential volatile biomarkers for future validation. Dedication:This review is dedicated to the memory of Prof. Dr. Anton Amann, who sadly passed away on January 6, 2015. He was motivator and motor for the field of breath research.

Current Advances in Developing Inhibitors of Bacterial Multidrug Efflux Pumps

Abstract: Antimicrobial resistance represents a significant challenge to future healthcare provision. An acronym ESKAPEE has been derived from the names of the organisms recognised as the major threats although there are a number of other organisms, notably Neisseria gonorrhoeae, that have become equally challenging to treat in the clinic. These pathogens are characterised by the ability to rapidly develop and/or acquire resistance mechanisms in response to exposure to different antimicrobial agents. A key part of the armoury of these pathogens is a series of efflux pumps, which effectively exclude or reduce the intracellular concentration of a large number of antibiotics, making the pathogens significantly more resistant. These efflux pumps are the topic of considerable interest, both from the perspective of basic understanding of efflux pump function, and its role in drug resistance but also as targets for the development of novel adjunct therapies. The necessity to overcome antimicrobial resistance has encouraged investigations into the characterisation of resistance-modifying efflux pump inhibitors to block the mechanisms of drug extrusion, thereby restoring antibacterial susceptibility and returning existing antibiotics into the clinic. A greater understanding of drug recognition and transport by multidrug efflux pumps is needed to develop clinically useful inhibitors, given the breadth of molecules that can be effluxed by these systems. This review discusses different bacterial EPIs originating from both natural source and chemical synthesis and examines the challenges to designing successful EPIs that can be useful against multidrug resistant bacteria.

Application of Mesenchymal Stem Cells in Melanoma: A Potential Therapeutic Strategy for Delivery of Targeted Agents.

Abstract: Melanoma is a leading cause of mortality from skin cancer and has a poor prognosis. Despite rapid advances in the treatment of this tumor type, the efficacy of current chemo-/targeted-therapies is still limited owing to the lack of sufficient drug accumulation in the tumor tissue and development of chemo-resistance. Recently, the application of mesenchymal stem cells (MSCs) in cancer therapy has gained substantial attention, suggesting their potential roles as an intriguing vehicle in improving the delivery of targeted agents. MSCs are genetically modified with suicide tumor suppressor genes to inhibit cell signaling pathways associated with the progression and metastatic features of melanoma. Here we describe the clinical application of MSCs in melanoma with a particular emphasis on recent findings on the role of MSC expressing a distinct set of biologically functional chemokines and tumor suppressing agents. Accumulating data has shown the tumor- oriented homing capacity of MSCs and their applications as a vehicle (e.g., adipose derived mesenchymal stem cells expressing TRAIL, interferon-α/γ, pigment epithelium-derived factor and cytosine deaminase). Several questions regarding possible potential and intrinsic mechanisms that might induce tumorigenesis and drug resistance are yet to be addressed for tailoring MSC-nbased treatment of melanoma.

MicroRNAs: Key Players in Microglia and Astrocyte Mediated Inflammation in CNS Pathologies

Abstract: The significance of microglia and astrocytes in neural development, in maintaining synaptic connections and homeostasis in the healthy brain is well established. Microglia are dynamic immune cells of the brain that elicit an immune response during brain damage and also participate in tissue repair and regeneration, while astrocytes contribute to the local inflammatory response by producing proinflammatory cytokines and resolving neuronal damage through production of anti-inflammatory cytokines and neurotrophic factors. Recent efforts have focused on elucidating the epigenetic mechanisms which regulate glial cell behavior in normal and pathologic states. An important class of epigenetic regulators is microRNAs (miRNAs) which are small non-coding RNA molecules that regulate gene expression posttranscriptionally. Certain dysregulated miRNAs contribute to chronic microglial inflammation in the brain, thereby leading to progression of neurological diseases like Alzheimer's disease, traumatic injury, amyotrophic lateral sclerosis and stroke. Further, several miRNAs are differentially expressed in astrocytes after ischemia and spinal cord injury. Despite knowledge about miRNAs in neuroinflammation, little is known about effective delivery routes and pharmacokinetic data for miRNA based therapeutics. This review summarizes the current research on the role of miRNAs in promoting and inhibiting inflammatory response of microglia and astrocytes in a disease-specific manner. In addition, miRNA delivery as a therapeutic strategy to treat neuroinflammation is discussed.

Action of Nanoparticles on Platelet Activation and Plasmatic Coagulation.

Abstract: Nanomaterials can get into the blood circulation after injection or by release from implants but also by permeation of the epithelium after oral, respiratory or dermal exposure. Once in the blood, they can affect hemostasis, which is usually not intended. This review addresses effects of biological particles and engineered nanomaterials on hemostasis. The role of platelets and coagulation in normal clotting and the interaction with the immune system are described. Methods to identify effects of nanomaterials on clotting and results from in vitro and in vivo studies are summarized and the role of particle size and surface properties discussed. The literature overview showed that mainly pro-coagulative effects of nanomaterials have been described. In vitro studies suggested stronger effects of smaller than of larger NPs on coagulation and a greater importance of material than of surface charge. For instance, carbon nanotubes, polystyrene particles, and dendrimers inferred with clotting independent from their surface charge. Coating of particles with polyethylene glycol was able to prevent interaction with clotting by some particles, while it had no effect on others and the more recently developed bio-inspired surfaces might help to design coatings for more biocompatible particles. The mainly pro-coagulative action of nanoparticles could present a particular risk for individuals affected by common diseases such as diabetes, cancer, and cardiovascular diseases. Under standardized conditions, in vitro assays using human blood appear to be a suitable tool to study mechanisms of interference with hemostasis and to optimize hemocompatibility of nanomaterials.

Glycyrrhetinic Acid and Its Derivatives: Anti-Cancer and Cancer Chemopreventive Properties, Mechanisms of Action and Structure- Cytotoxic Activity Relationship.

Abstract: The anti-cancer properties of liquorice have been attributed, at least in part, to glycyrrhizin (GL). However, GL is not directly absorbed through the gastrointestinal tract. It is hydrolyzed to 18-β-glycyrrhetinic acid (GA), the pharmacologically active metabolite, by human intestinal microflora. GA exhibits remarkable cytotoxic and anti-tumor properties. The pro-apoptotic targets and mechanisms of action of GA have been extensively studied over the past decade. In addition, GA is an inexpensive and available triterpene with functional groups (COOH and OH) in its structure, which make it an attractive lead compound for medicinal chemists to prepare a large number of analogues. To date, more than 400 cytotoxic derivatives have been prepared on the basis of GA scaffold, including 128 cytotoxic derivatives with IC50 values less than 30 µM. Researchers have also succeeded in synthesizing very potent cytotoxic derivatives with IC50s ≤ 1 µM. Studies have shown that the introduction of a double bound at the C1-C2 position combined with an electronegative functional group, such as CN, CF3 or iodine at C2 position, and the oxidation of the hydroxyl group of C3 to the carbonyl group, significantly increased cytotoxicity. This review describes the cytotoxic and anti-tumor properties of GA and its derivatives, targets and mechanisms of action and provides insight into the structure-activity relationship of GA derivatives.

Osteoimmunology and Beyond

Abstract: Objective Osteoimmunology investigates interactions between skeleton and immune system. In the light of recent discoveries in this field, a new reading register of osteoporosis is actually emerging, in which bone and immune cells are strictly interconnected. Osteoporosis could therefore be considered a chronic immune mediated disease which shares with other age related disorders a common inflammatory background. Here, we highlight these recent discoveries and the new landscape that is emerging. Method Extensive literature search in PubMed central. Results While the inflammatory nature of osteoporosis has been clearly recognized, other interesting aspects of osteoimmunology are currently emerging. In addition, mounting evidence indicates that the immunoskeletal interface is involved in the regulation of important body functions beyond bone remodeling. Bone cells take part with cells of the immune system in various immunological functions, configuring a real expanded immune system, and are therefore variously involved not only as target but also as main actors in various pathological conditions affecting primarily the immune system, such as autoimmunity and immune deficiencies, as well as in aging, menopause and other diseases sharing an inflammatory background. Conclusion The review highlights the complexity of interwoven pathways and shared mechanisms of the crosstalk between the immune and bone systems. More interestingly, the interdisciplinary field of osteoimmunology is now expanding beyond bone and immune cells, defining new homeostatic networks in which other organs and systems are functionally interconnected. Therefore, the correct skeletal integrity maintenance may be also relevant to other functions outside its involvement in bone mineral homeostasis, hemopoiesis and immunity.

Non-Photoinduced Biological Properties of Verteporfin.

Abstract: Background: Verteporfin is a porphyrinic photosensitizer clinically used for the photodynamic treatment of age-related macular degeneration. It has been identified almost simultaneously as a YAP/TEAD and an autophagosome inhibitor. Over the last few years, YAP (TAZ), the downstream effectors of the Hippo pathway, have emerged as promising anticancer targets, as shown by several experimental lines of evidence, showing the overproduction of YAP in several cancers. However, YAP was also found to be closely connected to autophagy, mitochondria and reactive oxygen/nitrogen species. We herein, review the recent studies where VP was used without photoactivation as a YAP/TEAD inhibitor or protein oligomerization promoter, focusing on its effects on the YAP/TEAD gene targets and other biomarkers related to autophagy. Results: Since the identification of VP as YAP/TEAD inhibitor, several in vitro and in vivo studies have revealed the new potential of this molecule in different cancers, where YAP is overexpressed. However, detailed structural information about its interaction with YAP is still lacking. Concomitantly, VP was identified as autophagosome inhibitor by promoting oligomerization of p62. Moreover, VP proves to be tumor-selective proteotoxic (by oligomerization of p62, STAT3) in colorectal cancer. Knowledge on the biological properties of the only YAP inhibitor available to date is vital for its pharmacological use on cellular and animal models. Conclusion: VP is a multi-target drug interacting with several proteins implicated in major cellular processes. Although this does not impact its clinical use, VP does not seem to be the ideal drug for pharmacological inhibitions of YAP/TEAD.

Omega-3 Fatty Acids and their Role in Central Nervous System - A Review

Abstract: Polyunsaturated fatty acids (PUFAs) are crucial for our health and wellbeing; therefore, they have been widely investigated for their roles in maintaining human health and in disease treatment. Most Western diets include significant amount of saturated and omega-6 fatty acids and insufficient quantity of omega-3; however, the balance between omega-6 and omega-3 PUFA, in particular, is essential for the formation of pro- and anti-inflammatory lipids to promote health and prevent disease. As our daily diet affects our health, this paper draws attention to unique representatives of the omega-3 fatty acid group: alpha-linolenic acid and its derivatives. Recently, this has been shown to be effective in treating and preventing various diseases. It has been confirmed that omega-3 PUFAs may act as therapeutic agents as well and their significant role against inflammatory diseases, such as cardiovascular and neurodegenerative diseases, has been described. Some of nutritional factors have been described as a significant modifiers, which can influence brain elasticity and thus, effect on central nervous system functioning. Therefore, appropriate dietary management appears to be a non-invasive and effective approach to counteract neurological and cognitive disorders.

Why Antidiabetic Vanadium Complexes are Not in the Pipeline of “Big Pharma” Drug Research? A Critical Review

Abstract: Public academic research sites, private institutions as well as small companies have made substantial contributions to the ongoing development of antidiabetic vanadium compounds. But why is this endeavor not echoed by the globally operating pharmaceutical companies, also known as "Big Pharma"? Intriguingly, today's clinical practice is in great need to improve or replace insulin treatment against Diabetes Mellitus (DM). Insulin is the mainstay therapeutically and economically. So, why do those companies develop potential antidiabetic drug candidates without vanadium (vanadium- free)? We gathered information about physicochemical and pharmacological properties of known vanadium-containing antidiabetic compounds from the specialized literature, and converted the data into explanations (arguments, the "pros and cons") about the underpinnings of antidiabetic vanadium. Some discoveries were embedded in chronological order while seminal reviews of the last decade about the Medicinal chemistry of vanadium and its history were also listed for further understanding. In particular, the concepts of so-called "noncomplexed or free" vanadium species (i.e. inorganic oxido-coordinated species) and "biogenic speciation" of antidiabetic vanadium complexes were found critical and subsequently documented in more details to answer the question.

Berberine: New Insights from Pharmacological Aspects to Clinical Evidences in the Management of Metabolic Disorders.

Abstract: Berberine is a quaternary ammonium salt from the protoberberine group of isoquinoline alkaloids found in such plants as gender Berberis. Berberine is recognised to improve glucose and lipid metabolism disorders and preliminary clinical evidences suggest the ability of berberine to reduce endothelial inflammation improving vascular health, even in patients already affected by cardiovascular diseases, suggesting a possible interesting role of berberine and its metabolites in clinical practice. However, its physicochemical properties, pharmacokinetic, and metabolism are not fully elucidated and contradictory data have been reported. This review provides a summary regarding the pharmacological and biological features of berberine, with a focus on berberine as well as their pharmacologically active metabolites and the different mechanisms underlying their activities in order to clarify the correct use of berberine supplementation, alone or in association with other nutraceuticals, for the management of metabolic disorders associated to increased cardiovascular disease risk. A particular attention has also been given to the available clinical trials assessing its short- and middle- term use tolerability, safety and efficacy in various conditions, such as dyslipidaemia, impaired fasting glucose, metabolic syndrome and type 2 diabetes.

A Comprehensive Review of N-Heterocycles as Cytotoxic Agents

Abstract: Scientific community is striving to understand the role of heterocycles and fused heterocycles in drug discovery programme due to its impact on multi-drug resistance (MDR) of anticancer drugs. Architecting of various scaffolds for cancer treatment has become gradually increased in many years. Till now there is no treatment which is so proficient that it can cure the cancer from the roots. Hence, it is very necessary to design novel anticancer agents with minimum side effects. Synthesis of hybrids from natural leads is one of the rationale approaches in medicinal chemistry. It remains a big challenge to invent new efficient drugs to beat cancer. The design and synthesis of fused molecules as anticancer agents is one of the great innovations of modern era. In drug discovery archetype, a variety of heterocycles have been considered for the development of novel lead compounds. This article presents some recent advancements in the field of anticancer heterocyclic agents all around the world and also attracted the structure activity relationship along with the structure of the most promising molecules along with IC50 values against various human cancer cell lines.

Molecular Dissection of Renal Ischemia-Reperfusion: Oxidative Stress and Cellular Events.

Abstract: Ischemic reperfusion kidney injury (IRKI) is a complex pathophysiological event, which is the most common cause of the acute kidney injury. The key characteristic of IRKI is a reduction in glomerular filtration rate, which implies an underlying impairment in hemodynamic regulation. In recent decades, convincing evidence illuminated the molecular and pathological events in the acute kidney injury, revealing the role of ischemia/reperfusion, oxidative stress, apoptosis, inflammation, fibrosis and changes in gene expression which activate different signaling pathways. The cascade of inflammation events is a key mediator of IRKI, which includes the inflammation process, complement activation and mobilization of innate immunity. Oxidative stress represents the increased presence of various free radicals that cannot be buffered by the antioxidant capacity which comprises of enzymatic and non-enzymatic components. Renal tissue injury during ischemia/reperfusion comes as a result of membrane lipids peroxidation, oxidative damage of proteins and DNA and results in apoptosis and necrosis. It is evident from many studies that augmentation of the antioxidant defense mechanisms has a protective role on kidney tissue. In recent years, the importance of heat-shock proteins and MicroRNAs in the pathogenesis of IRKI has been revealed and there are promising indications that in future they could serve as diagnostic biomarkers or therapeutic targets. Striking changes in global gene expression were shown, providing a great potential for fundamental understanding and clinical management of IRKI. The clinical outcome among patients with kidney transplantation will have the furthermost advance from the better understanding of the underlying molecular pathology of IRKI.

Xanthine Oxidoreductase in Drug Metabolism: Beyond a Role as a Detoxifying Enzyme.

Abstract: The enzyme xanthine oxidoreductase (XOR) catalyzes the last two steps of purine catabolism in the highest uricotelic primates. XOR is an enzyme with dehydrogenase activity that, in mammals, may be converted into oxidase activity under a variety of pathophysiologic conditions. XOR activity is highly regulated at the transcriptional and post-translational levels and may generate reactive oxygen and nitrogen species, which trigger different consequences, ranging from cytotoxicity to inflammation. The low specificity for substrates allows XOR to metabolize a number of endogenous metabolites and a variety of exogenous compounds, including drugs. The present review focuses on the role of XOR as a drug-metabolizing enzyme, specifically for drugs with anticancer, antimicrobial, antiviral, immunosuppressive or vasodilator activities, as well as drugs acting on metabolism or inducing XOR expression. XOR has an activating role that is essential to the pharmacological action of quinone drugs, cyadox, antiviral nucleoside analogues, allopurinol, nitrate and nitrite. XOR activity has a degradation function toward thiopurine nucleotides, pyrazinoic acid, methylxanthines and tolbutamide, whose half-life may be prolonged by the use of XOR inhibitors. In conclusion, to avoid potential drug interaction risks, such as a toxic excess of drug bioavailability or a loss of drug efficacy, caution is suggested in the use of XOR inhibitors, as in the case of hyperuricemic patients affected by gout or tumor lysis syndrome, when it is necessary to simultaneously administer therapeutic substances that are activated or degraded by the drug-metabolizing activity of XOR.

Resveratrol and Lifespan in Model Organisms

Abstract: Background: Resveratrol may possess life-prolonging and health-benefitting properties, some of which may resemble the effect of caloric restriction (CR) CR appears to prolong the lifespan of model organisms in some studies and may benefit human health However, for humans, restricting food intake for an extended period of time seems impracticable and substances imitating the beneficial effects of CR without having to reduce food intake could improve health in an aging and overweight population Methods: We have reviewed the literature studying the influence of resveratrol on the lifespan of model organisms including yeast, flies, worms, and rodents We summarize the in vivo findings, describe modulations of molecular targets and gene expression observed in vivo and in vitro, and discuss how these changes may contribute to lifespan extension Data from clinical studies are summarized to provide an insight about the potential of resveratrol supplementation in humans Results: Resveratrol supplementation has been shown to prolong lifespan in approximately 60% of the studies conducted in model organisms However, current literature is contradictory, indicating that the lifespan effects of resveratrol vary strongly depending on the model organism While worms and killifish seemed very responsive to resveratrol, resveratrol failed to affect lifespan in the majority of the studies conducted in flies and mice Furthermore, factors such as dose, gender, genetic background and diet composition may contribute to the high variance in the observed effects Conclusion: It remains inconclusive whether resveratrol is indeed a CR mimetic and possesses life-prolonging properties The limited bioavailability of resveratrol may further impede its potential effects

Current Tools and Methods in Molecular Dynamics (MD) Simulations for Drug Design

Abstract: Molecular Dynamics (MD) simulations is a computational method that employs Newton’s laws to evaluate the motions of water, ions, small molecules, and macromolecules or more complex systems, for example, whole viruses, to reproduce the behavior of the biological environment, including water molecules and lipid membranes. Specifically, structural motions, such as those that are dependent of the temperature and solute/ solvent are very important to study the recognition pattern of ligandprotein or protein-protein complexes, in that sense, MD simulations are very useful because these motions can be modeled using this methodology. Furthermore, MD simulations for drug design provide insights into the structural cavities required to design novel structures with higher affinity to the target. Also, the employment of MD simulations to drug design can help to refine the three-dimensional (3D) structure of targets in order to obtain a better sampling of the binding poses and more reliable affinity values with better structural advantages, because they incorporate some biological conditions that include structural motions compared to traditional docking procedures. This work analyzes the concepts and applicability of MD simulations for drug design because molecular structural motions are considered, and these help to identify hot spots, decipher structural details in the reported protein sites, as well as to eliminate sites that could be structural artifacts which could be originated from the structural characterization conditions from MD. Moreover, better free energy values for protein ligand recognition can also be obtained, and these can be validated under experimental procedures due to the robustness of the MD simulation methods.

The Use of Stilbene Scaffold in Medicinal Chemistry and Multi- Target Drug Design

Abstract: The stilbene scaffold is a basic element for a number of biologically active natural and synthetic compounds, and it is considered as a privileged structure. Stilbenes exemplified by resveratrol, combretastatin A-4 and pterostilbene are of significant interest for drug research and development because of their potential in therapeutic and preventive application. Resveratrol, present in grapes and other food products, plays a role in the prevention of several human pathological processes and has been suggested as an anticancer agent. Moreover, recent evidence has revealed its potential effect on the aging process, diabetes and neurological dysfunction. Combretastatin A-4, from the bark of South African bush willow Combretum caffrum, also shows significant antitumor activity. Pterostilbene is closely related to resveratrol, sharing the same unique therapeutic potential as anti-inflammatory, antineoplastic and antioxidant agent. Therefore, research and development of stilbene-based medicinal chemistry have become rapidly evolving and increasingly active topics covering almost the whole range of therapeutic fields. In the present review, we provide an overview of the role of stilbenes in medicinal chemistry. In this context, we highlight the chemical methodologies adopted for the synthesis of stilbene derivatives, and outline the successful design of novel stilbene based hybrids in the field of cancer, Alzheimer’s and other relevant diseases. This information may be useful in further design of stilbene-based molecules as new leads for the development of novel agents with clinical potential or as effective chemical probes to dissect biological processes.

Peptide Therapeutics and the Pharmaceutical Industry: Barriers Encountered Translating from the Laboratory to Patients

Abstract: Peptides are receiving increasing interest as clinical therapeutics. These highly tunable molecules can be tailored to achieve desirable biocompatibility and biodegradability with simultaneously selective and potent therapeutic effects. Despite challenges regarding up-scaling and licensing of peptide products, their vast clinical potential is reflected in the 60 plus peptide-based therapeutics already on the market, and the further 500 derivatives currently in developmental stages. Peptides are proving effective for a multitude of disease states including: type 2 diabetes (controlled using the licensed glucagon-like peptide-1 receptor liraglutide); irritable bowel syndrome managed with linaclotide (currently at approval stages); acromegaly (treated with octapeptide somatostatin analogues lanreotide and octreotide); selective or broad spectrum microbicidal agents such as the Gram-positive selective PTP-7 and antifungal heliomicin; anticancer agents including goserelin used as either adjuvant or monotherapy for prostate and breast cancer, and the first marketed peptide derived vaccine against prostate cancer, sipuleucel-T. Research is also focusing on improving the biostability of peptides. This is achieved through a number of mechanisms ranging from replacement of naturally occurring L-amino acid enantiomers with D-amino acid forms, lipidation, peptidomimetics, N-methylation, cyclization and exploitation of carrier systems. The development of self-assembling peptides are paving the way for sustained release peptide formulations and already two such licensed examples exist, lanreotide and octreotide. The versatility and tunability of peptide-based products is resulting in increased translation of peptide therapies, however significant challenges remain with regard to their wider implementation. This review highlights some of the notable peptide therapeutics discovered to date and the difficulties encountered by the pharmaceutical industry in translating these molecules to the clinical setting for patient benefit, providing some possible solutions to the most challenging barriers.