Pharmaceutical Chemistry

Ischemic heart diseases are the leading cause of morbidity and mortality worldwide. Reperfusion of an ischemic heart is necessary to regain the normal functioning of the heart. However, abrupt reperfusion of an ischemic heart elicits a cascade of adverse events that leads to injury of the myocardium, i.e., ischemia-reperfusion injury. An endogenous powerful strategy to protect the ischemic heart is ischemic preconditioning, in which the myocardium is subjected to short periods of sublethal ischemia and reperfusion before the prolonged ischemic insult. However, it should be noted that the cardioprotective effect of preconditioning is attenuated in some pathological conditions. The aim of this article is to review present knowledge on how menopause and some metabolic disorders such as diabetes and hyperlipidemia affect myocardial ischemic preconditioning and the mechanisms involved.

Monoamine oxidase (MAO) enzymes are one of the most promising targets for the treatment of neurological disorders. A series of phenylisoxazole carbohydrazides was designed, synthesized and screened for both MAO-A and MAO-B inhibition using Amplex Red assays. None of the compounds inhibited the MAO-A activity while most of them significantly inhibited MAO-B in the micromolar to nanomolar range. Among them, the compound N'-(4-methylbenzylidene)-5-phenylisoxazole-3-carbohydrazide (6c) exhibited the most potent inhibitory activity towards MAO-B. Enzyme kinetic studies revealed the reversible and competitive nature of compound 6c towards MAO-B inhibition. The results of the enzyme inhibition assay were in agreement with molecular docking study, in which compound 6c displayed a strong binding affinity for MAO-B with a docking score of -10.98 Kcal/mol. In order to explore the neuroprotective effect of compound 6c, MPTP-induced mouse model for Parkinson's disease was used, and motor behavioural assessment of experimental animals was carried out. The compound 6c was able to significantly prevent the MPTP-induced neurotoxicity as revealed by improvement in gait behaviour in footprint test and increase in grip strength score in horizontal wire test. Thus, phenylisoxazole carbohydrazides can be promising leads in the development of potent, selective and reversible MAO-B inhibitors for the treatment of Parkinson's disease.

Selective monoamine oxidase B inhibitors are potential drug candidates for the treatment of Parkinson’s disease. A series of phenyl substituted isoxazole carbohydrazides was designed by structural modification of isocarboxazid, a nonselective MAO inhibitor and evaluated as inhibitors of MAO-A and MAO-B. The compounds were not able to inhibit MAO-A significantly, but most of the compounds exhibited potent inhibitory activity against MAO-B. The enzyme kinetic study of the most active compounds 5d, 5-phenyl-N′-(1-(p-tolyl)ethylidene)isoxazole-3-carbohydrazide and 5g, N′-(1-(3,4-dimethoxyphenyl)ethylidene)-5-phenylisoxazole-3-carbohydrazide displayed reversible and competitive MAO-B inhibition. In molecular modeling studies, compounds 5d and 5g exhibited strong binding affinity on MAO-B active site. The administration of compounds 5d and 5g exhibited prevention of MPTP-induced Parkinsonism as indicated by footprint analysis and horizontal wire tests. Further optimization studies are essential to exploit their potential for MAO-B associated neurodegenerative pathologies.

Past researches on 4-thiazolidinone nucleus have revealed the prominent potential of derivatives containing this nucleus to be developed as a potent therapeutic agent. Because of these biological activities, their structure-activity relationship has created an interest for medicinal chemists leading to the discovery of a number of lead molecules. This review highlights the routes for its synthesis and summarizes the past and recent studies on its biological activities to guide the medicinal chemists working on this nucleus in the development of clinically viable drugs.

: Due to the extremely contagious nature of SARS-COV-2, it presents a significant threat to humans worldwide. A plethora of studies are going on all over the world to discover the drug to fight SARS-COV-2. One of the most promising targets is RNA-dependent RNA polymerase (RdRp), responsible for viral RNA replication in host cells. Since RdRp is a viral enzyme with no host cell homologs, it allows the development of selective SARS-COV-2 RdRp inhibitors. A variety of studies used in silico approaches for virtual screening, molecular docking, and repurposing of already existing drugs and phytochemicals against SARS-COV-2 RdRp. This review focuses on collating compounds possessing the potential to inhibit SARS-COV-2 RdRp based on in silico studies to give medicinal chemists food for thought so that the existing drugs can be repurposed for the control and treatment of ongoing COVID-19 pandemic after performing in vitro and in vivo experiments.

: The entire world has been in a battle against the COVID-19 pandemic since its first appearance in December 2019. Thus researchers are desperately working to find an effective and safe therapeutic agent for its treatment. The multifunctional coronavirus enzyme papain-like protease (PLpro) is a potential target for drug discovery to combat the ongoing pandemic responsible for cleavage of the polypeptide, deISGylation, and suppression of host immune response. The present review collates the in silico studies performed on various FDA-approved drugs, chemical compounds, and phytochemicals from various drug databases and represents the compounds possessing the potential to inhibit PLpro. Thus this review can provide quick access to a potential candidate to medicinal chemists to perform in vitro and in vivo experiments who are thriving to find the effective agents for the treatment of COVID-19.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive damage of mesencephalic dopaminergic neurons of the substantia nigra and the striatal projections. Recent studies suggest that estrogen and estrogen-like chemicals have beneficial effects on neurodegenerative diseases, particularly PD. Animal studies demonstrate that estrogen influences dopamine's synthesis, release, and metabolism. In vivo studies have also shown the significant beneficial effects of estrogen in shielding the brain from neurodegenerative processes like PD. Moreover, the expression and function of dopamine receptors can be modified by estrogen. Phytoestrogens are non-steroidal compounds derived from plants present in a large spectrum of foods, most specifically soy, and in numerous dietary supplements. Phytoestrogens share structural and functional similarities with 17β-estradiol and can be used as an alternative treatment for PD because of estrogen's undesirable effect...

The UWB-MIMO system is the combined technology of ultra wide-band (UWB) and multiple input and output(MIMO) technology that provide higher data rate (more than 3 Gb/sec)and greater channel capacity [1] in modern wireless communication system. The design challenges for MIMO antenna are mutual coupling and size of antenna. The mutual coupling increases, when antenna elements are placed close together with separation less than a quarter wavelength. Furthermore, various isolation method have been introduced by researchers to reduce interference among antennas and also enhance isolation. An efficient and excellent UWB-MIMO antenna can be obtained by introducing improve isolation techniques that will suppress the interfering band with UWB frequency band. Therefore, this paper presented a state-of-the-art of various isolation improvement techniques.

A robust pharmacophore model was developed and the structure-activity relationship was analyzed using 71 pyrimidine derivatives reported for covalent Janus Kinase 3 (JAK3) inhibition. Pharmacophore modeling developed a five featured pharmacophore: one H-bond acceptor, two H-bond donors, one hydrophobic, and one aromatic ring features. The atom-based three-dimensional QSAR models with statistical significance were generated using the training set of 52 compounds. The excellent predictive correlation coefficients were obtained for 3D models determined using a test set of 19 molecules. The generated QSAR model implies that the hydrophobic character is important for the JAK3 inhibitory activity of these compounds. Additionally, electron-withdrawing and hydrogen bond donor groups at specific positions positively contribute to the JAK3 inhibition potency. These results provided essential three-dimensional structural requirements and the crucial binding features of 2,4-disubstituted pyrimi...

: The battle against the novel coronavirus disease (COVID-19) emerged in December 2019. It is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is still existent all over the world. Researchers worldwide are continuously conducting in silico studies or virtual screening on various phytochemicals and reporting potential candidates that can be developed against COVID-19 after in vitro and in vivo validation. Antiviral effects of several phytochemicals have been demonstrated against different kinds of coronavirus, including SARS-CoV. Using drug repurposing techniques, a number of phytochemicals have shown substantial antiviral efficacy against COVID 19. This article reviews the efficacy of lead phytochemicals in computational studies on different important targets of SARS-CoV-2 like main protease, ACE-2, papain-like protease, spike protein, nsp-1, nsp-15, RdRp, MTase, helicase, cathepsin, TMPRSS-2. This review carries vision for the potential application of these phytochemicals, which can guide medicinal chemists to choose phytochemicals to proceed with further in vitro and in vivo testing for SARS-CoV-2, which may eventually lead to an effective therapeutic agent and thus can be used to control the current ongoing pandemic.