Current Medicinal Chemistry - Volume 28, Issue 22, 2021

Background: Major Depressive Disorder(MDD) and its frequent partial response to antidepressants are a major health concern and therefore an important focus of research. Despite the efforts, MDD pathogenesis and the mechanisms of antidepressant action are only partially understood. In the last few years, the need of rethinking the classification of depressive disorders and psychiatric disorders, in general, has been suggested, in order to provide a nosology that reflects more closely the biological background associated with disease pathogenesis and its role/significance in treatment. The classification proposed by the National Institute of Mental Health (NIMH), namely the research domain criteria (RDoC), may represent a key framework to guide research in this direction. Methods: A literature search was performed on PubMed and Google Scholar databases in order to retrieve data regarding Antidepressants effects on specific RDoC constructs. Further, the targets of drugs of interest were identified through the Drug bank database, and their possible function within RDoC constructs was discussed. Discussion: In this review, we summarize and discuss the significance of the results of pre-clinical and clinical studies investigating specific RDoC paradigms relevant to depressive phenotypes and antidepressant effects. Conclusion: The RDoC framework may facilitate a more specific use of antidepressants based on the individual’s spectrum of symptoms and the development of new compounds that target specific depressive symptoms.

Cancer stem cells (CSCs) constitute a subpopulation of tumor cells that possess self-renewal and tumor initiation capacity, and the ability to give rise to the heterogeneous lineages of cancer cells that comprise the tumor. CSCs exhibit intrinsic mechanisms of resistance to virtually all conventional cancer therapeutics, allowing them to survive current cancer therapies and to initiate tumor recurrence and metastasis. Different pathways and mechanisms that confer resistance and survival of CSCs, including activation of the Wnt/β- catenin, Sonic Hedgehog, Notch, PI3K/Akt/mTOR and STAT3 signaling pathways, expression of aldehyde dehydrogenase 1 (ALDH1) and oncogenic microRNAs, and acquisition of epithelial-mesenchymal transition (EMT), have been identified recently. Certain phytochemicals, in particular curcumin, epigallocatechin-3-gallate (EGCG), sulforaphane, resveratrol and genistein have been shown to interfere with these intrinsic CSC pathways in vitro and in human xenograft mice, leading to elimination of CSCs. Moreover, recent clinical trials have demonstrated the therapeutic efficacy of five phytochemicals, alone or in combination with modern cancer therapeutics, and in various types of cancer. Since current cancer therapies fail to eradicate CSCs, leading to cancer recurrence and progression, targeting of CSCs with phytochemicals such as curcumin, EGCG, sulforaphane, resveratrol and genistein, combined with each other and/or in combination with conventional cytotoxic drugs and novel cancer therapeutics, may offer a novel therapeutic strategy against cancer.

Cancer is the world’s leading cause of death after heart diseases and involves abnormal cell growth at a primary site and the potential to spread to other parts of the body. Tumors are highly heterogeneous and consist of subgroups of cells with distinct characteristics. Of these, the cancer stem cells (CSC) niche plays a crucial role in driving the spread of the tumor and are thought to provide treatment resistance. CSC is a rare special population of cancer cells exhibiting high tumorigenic properties together with self-renewal and differentiation capability. CSC is not only linked with high tumor-initiating activity, but is also implicated in chemotherapeutic resistance, metastasis, epithelial to mesenchymal transition, and recurrence. Thereafter, novel therapeutic strategies targeting CSC are in need to improve long-term clinical outcomes. The literature supports the evidence that marine natural compounds can exhibit antioxidant, antimitotic, anti-inflammatory, antibiotic as well as anticancer activity. In this review, we will provide an insight into the relevance of selected marine natural products as a source of bioactive compounds with anti-cancer properties to target CSC, which may benefit the development of novel anti-cancer therapeutic strategies.

Background: Vaginal drug delivery offers an opportunity for effective microbicide treatments. However, the physiological characteristics of the vagina represent a challenge when preparing microbicide formulations for local delivery that avoid systemic effects. Objective: To review recent advances in vaginal microbicides placing special emphasis on nanocarriers that encapsulate peptide microbicides. The review includes an overview of local treatment and prevention strategies for bactericidal, fungal, protozoal and viral vaginal infections that use peptide microbicides. Methods: Scientific literature and clinical trials published in the PubMed database since 2015 are analyzed. Result: Peptide microbicides are used for vaginal drug delivery as a means of prevention and treatment of several infectious diseases, especially sexually transmitted infections, and it is clear that such peptide-based microbicides constitute a suitable strategy. Their combination with nanotechnological drug delivery systems improves local peptide administration while avoiding their degradation and adverse effects. To date, only a few polymeric and lipid-based nanocarriers have been used for peptide microbicide vaginal delivery. Conclusion: The combination of nanotechnology and peptide microbicides has emerged over recent years, and different platforms are being used for vaginal peptide delivery. Nanostructured systems for peptide delivery via vaginal rings or hydrogels are increasingly used as platforms capable of providing suitable drug delivery. However, there is still a lack of knowledge about nanocarriers aimed at encapsulating peptides for local microbicide delivery.

Background: COVID-19 has brought the world to its knees, and there is an urgent need for new strategies to identify molecules capable of fighting the pandemic. During the last few decades, NMR (Nuclear Magnetic Resonance) spectroscopy has emerged as an intriguing structural biology instrument in the antiviral drug discovery field. Objective: The review highlights how a variety of NMR-based tools can be employed to better understand viral machineries, develop anti-viral agents and set-up diagnostic and therapeutic routes. Methods: Works summarized herein were searched through PubMed database and the Web. Results: The review focuses on a subset of human viruses that have been largely studied through NMR techniques. Indeed, NMR solid- or solution-state methodologies allow to gain structural information on viral proteins and viral genomes either in isolation or bound to diverse binding partners. NMR data can be employed to set up structure-based approaches to design efficient antiviral agents inhibiting crucial steps of viral life cycle. In addition, NMR-based metabolomics analyses of biofluids from virus-infected patients let identify metabolites biomarkers of the disease and follow changes in metabolic profiles associated with antiviral therapy thus paving the way for novel diagnostic and therapeutic approaches. Conclusion: Considering the NMR-based work conducted on different viruses, we believe that in the near future, much more NMR efforts will be devoted to discovering novel anti SARS-CoV-2 agents.

Severe acute respiratory syndrome (SARS) is a critical respiratory disease caused by coronaviruses (CoV). The available antiviral agents or host-specific antiinflammatory therapies are the principal treatment modalities, with drug-repurposing as the most viable approach to timely tackle the CoV pandemic. Though these approaches are successful to some extent in reducing the mortality rate, however, it is too far to see a complete escape from the current SARS CoV-2 pandemic. Plants are the primary source of diet, dietary supplements, botanical drugs, and natural products (NPs). It has been well accepted and proved via several scientific studies that plant-based therapies play a vital role in managing such infections. The faulty immune system (compromised innate immunity or aberrant immune activation) determines the severity of the respiratory distress in CoV-2 infected patients. Natural products intervene at various stages of the virus replication cycle, including inhibition of virus entry into the host cells, inhibition of serine/ cysteine proteases, RNA-dependent RNA polymerase (RdRp) or helicase. Besides, several natural products or plant-based dietary supplements have a unique ability to strengthen the immune system or alleviate the hyper-inflammatory condition. Many plant-based formulations, dietary supplements, and NPs are being investigated in clinical trials in CoV-2 infected patients, and few have already shown positive results. The review has unearthed several NP leads for medicinal chemistry programs as well as some having direct opportunity of repurposing in SARS CoV infections.

Background: The 2019 novel coronavirus (2019-nCoV), also known as coronavirus 2 (SARS-CoV-2) acute respiratory syndrome has recently emerged and continued to spread rapidly with high mortality and morbidity rates. Currently, no efficacious therapy is available to relieve coronavirus infections. As new drug design and development takes time, there is a possibility offindingan effective treatment from existing antiviral agents. Objective: The aim of this study is to find out the relationship between thepossible drug targets and themechanism of action of antiviral drugs. This review discusses the efforts indevelopingdrug from known or new molecules. Methods: Viruses usually have two structural integrities, proteins and nucleic acids, both of which can be possible drug targets. Herein, we systemically discuss the structural-functional relationships of the spike, 3-chymotrypsin-like protease (3CLpro), papain like protease (PLpro) and RNA-dependent RNA polymerase (RdRp), as these are prominent structural features of thecoronavirus. Certain antiviral drugs such as Remdesivir are RNA-dependent RNA polymerase inhibitorswiththe ability to terminate RNA replication by inhibiting ATP. Results: It is reported that ATP is involved in synthesis of coronavirus non-structural proteins from 3CLpro and PLpro. Similarly, mechanisms of action of many other antiviral agents havebeen discussed in this review. It will provide new insights into the mechanism of inhibition, and let us develop new therapeutic antiviral approaches against novel SARS-CoV-2 coronavirus. Conclusion: In conclusion, this review summarizes recent progress in developing protease inhibitors for SARS-CoV-2.

Background: The identification of vulnerable subgroups and risk factors associated with the susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) infection and coronavirus disease 2019 (COVID-19) is of utmost importance in a pandemic scenario. Potential interactions between renin-angiotensin system (RAS), immune markers and COVID-19 play a role in disease outcome in specific groups of patients. Objective: This review aimed to describe the particularities of the RAS and the immune system profile of particular subgroups of patients. Methods: This non-systematic review summarizes evidence on SARS-CoV-2 infection in specific subgroups of patients and possible relationships between immune system, RAS and the pathophysiology of COVID-19. Results: The RAS and the immune system exert a role in the pathogenesis and prognosis of COVID-19, mainly in cases of hypertension, diabetes, obesity and other chronic diseases. The overactivation of the ACE/Ang II/AT1R axis and the enhancement of inflammation contribute to deleterious effects of COVID-19. Likewise, pregnant women and elderly patients usually display immune responses that are less effective in withstanding exposition to viruses, while children are relatively protected against severe complications of COVID-19. Women, conversely, exhibit stronger antiviral responses and are less sensitive to the effects of increased Ang II. Future Perspectives: The recognition of vulnerable subgroups and risk factors for disease severity is essential to better understand the pandemic. Precision medicine tools, including proteomics and metabolomics approaches, identified metabolic patterns of the severe form of disease and might be the alternative to diagnose, evaluate and predict the prognosis and the efficiency of therapies.

Background: The indole framework is considered as one of the privileged structures in the area of medicinal chemistry and drug discovery because compounds containing this framework have shown to possess a remarkable ability to bind with many receptors or proteins with high affinity. It is therefore not surprising that the indole nucleus is a frequently found moiety in many bioactive agents or drugs. Indole derivatives have also been explored or studied for their anti-tubercular properties for a long time. The growth inhibition of Mycobacterium tuberculosis (MTB) in vitro and in vivo by the gut microbiota metabolite indole propionic acid (IPA) is one of the recent examples. Notably, tuberculosis (TB), an intractable disease and a major cause of death worldwide, has caused an alarming rise in the number of TB cases recently because of two main reasons, i.e., a several-fold rise among HIV-infected patients and increased drug resistance by some bacterial strains. Thus, the identification of new agents or potential drugs against TB is urgently needed. Methods: While the specific pharmacological target or mechanism of action (MOA) for antitubercular activities has been reported for many indole derivatives, the MOA is not well defined or known for a number of indole derivatives though they were found to be active against MTB. In the current review article, we have focused on both types of indole derivatives that have shown activities against MTB. The indoles with known MOA are further segregated based on this pharmacological target reported or indicated whereas other indoles are classified based on the type of anti-TB properties shown by them. The literature for the last 20 years as well as related to up to date knowledge and information was searched on Pubmed, Google Scholar, MEDLINE, and various other databases until August 2020. Results: A diverse range of functionalized indole derivatives, such as indole-based alkaloids, simple indoles, fused indoles, amide/peptide derivatives of indole, isatin derivatives, etc., have been reported to possess anti-tubercular activities. The anti-tubercular activities, in silico studies (if reported) and the chemical syntheses (in most of the cases) of representative indole derivatives are presented briefly in the current article. The papers referenced by this review allow a deep analysis of the status of the indole-based anti-tubercular agents explored over the past two decades. Conclusion: This review aims at stimulating renewed interest and effort in the discovery and development of new indole-based agents or potential drugs for the treatment of TB. The emergence of modern methods, especially those based on transition metal-catalyzed reactions, has opened up tremendous opportunities in the area of indole synthesis. The desired goal would be to have utilized these modern methodologies for the identification of potent and promising agents to fight against MTB.

Brucellosis caused by bacteria of the genus of Brucella remains a major zoonosis in the wide world, which is an infectious disease with a severe economic impact on animal husbandry and public health. The genus of Brucella includes ten species and the most prevalent is Brucella melitensis. The diagnosis of Brucella melitensis ruminant brucellosis is based on bacteriological and immunological tests. The use of vaccines and the false-positive serological reactions (FPSR) caused by other cross-reacting bacteria represent the immunological contexts. This complex context results in the development of the large number of diagnosis of Brucella melitensis brucellosis. The aim of this article is to briefly review the detection methods and compare the superiorities of different tests.

COVID-19 is an emerging outbreak similar to previous pandemics caused by Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). Till date, SARS-CoV-2 infection is still spreading, representing a major threat to public health, where several control measures are being practiced in order to culminate its spread. The research and development of new drugs require a lot of funding in addition to being a slow and costly process. As a result, new techniques have been proposed to streamline this process. The repositioning or repurposing of drugs represents an attractive strategy, presenting a promising way to introduce new drugs. Currently, numerous reused drugs are already available in the market and are in practice. In this review, it was observed that the antiviral drugs Entricitabine and Tenofovir display potential therapeutic efficacy in preclinical studies. Therefore, in silico analyses were considered a potential tool for predicting the effectiveness of drugs, mainly as an effective approach to encourage a complementary in vitro and in vivo antiviral evaluation.

Cell-to-cell transmission of the unfolded protein response (UPR) is one of the most exciting observations recently made in cell biology. One of the most efficient tools to induce UPR response in cell culture is treatment with specific compounds leading to accumulation of misfolded proteins in endoplasmic reticulum. In this article we discussed opposite opinions regarding application of this approach and possible sources of experimental artefacts.