Discovery of novel 2,3-dihydro-1H-inden-1-ones as dual PDE4/AChE inhibitors with more potency against neuroinflammation for the treatment of Alzheimer's disease

Innovative pathological network-based multitarget approaches for Alzheimer's disease treatment

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease and is a major health threat globally. Its prevalence is forecasted to exponentially increase during the next 30 years due to the global aging population. Currently, approved drugs are merely symptomatic, being ineffective in delaying or blocking the relentless disease advance. Intensive AD research describes this disease as a highly complex multifactorial disease. Disclosure of novel pathological pathways and their interconnections has had a major impact on medicinal chemistry drug development for AD over the last two decades. The complex network of pathological events involved in the onset of the disease has prompted the development of multitarget drugs. These chemical entities combine pharmacological activities toward two or more drug targets of interest. These multitarget-directed ligands are proposed to modify different nodes in the pathological network aiming to delay or even stop disease progression. Here, we review the multitarget drug development strategy for AD during the last decade.

A comprehensive review of multi-target directed ligands in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia affecting specifically older population. AD is an irreversible neurodegenerative CNS disorder associated with complex pathophysiology. Presently, the USFDA has approved only four drugs viz. Donepezil, Rivastigmine, Memantine, and Galantamine for the treatment of AD. These drugs exhibit their neuroprotective effects either by inhibiting cholinesterase enzyme (ChE) or N-methyl-d-aspartate (NMDA) receptor. However, the conventional therapy "one target, one molecule" has failed to provide promising therapeutic effects due to the multifactorial nature of AD. This triggered the development of a novel strategy called Multi-Target Directed Ligand (MTDL) which involved designing one molecule that acts on multiple targets simultaneously. The present review discusses the detailed pathology involved in AD and the various MTDL design strategies bearing different heterocycles, in vitro and in vivo activities of the compounds, and their corresponding structure-activity relationships. This knowledge will allow us to identify and design more effective MTDLs for the treatment of AD.

Discovery of 4-Ethoxy-6-chloro-5-azaindazoles as Novel PDE4 Inhibitors for the Treatment of Alcohol Use Disorder and Alcoholic Liver Diseases

Alcohol use disorder (AUD) results in numerous disabilities and approximately 3 million deaths annually, caused mainly by alcoholic liver disease (ALD). Phosphodiesterase IV (PDE4) has emerged as an attractive molecular target for a new treatment for AUD and ALD. In this study, we describe the identification of 5-azaindazole analogues as PDE4 inhibitors against AUD and ALD. System optimization studies led to the discovery of ZL40 (IC50 = 37.4 nM) with a remarkable oral bioavailability (F = 94%), satisfactory safety, and a lower emetogenic potency than the approved PDE4 inhibitors roflumilast and apremilast. Encouragingly, ZL40 exhibited AUD therapeutic effects by decreasing alcohol intake and improving acute alcohol-induced sedation and motor impairment. Meanwhile, ZL40 displayed the potential to alleviate alcoholic liver injury and attenuate inflammation in the NIAAA mice model. These results showed that ZL40 is a promising compound for future drug development to treat alcohol-related diseases.

Palladium-catalyzed synthesis and anti-AD biological activity evaluation of N-aryl-debenzeyldonepezil analogues

A series of novel N-aryl-debenzeyldonepezil derivatives (1-26) were designed and synthesized as cholinesterase inhibitors by the modification of anti-Alzheimer's disease drug donepezil, using Palladium catalyzed Buchwald-Hartwig cross-coupling reaction as a key chemical synthesis strategy. In vitro cholinesterase inhibition studies demonstrated that the majority of synthesized compounds exhibited high selective inhibition of AChE. Among them, analogue 13 possessing a quinoline functional group showed the most potent AChE inhibition effect and significant neuroprotective effect against H2O2-induced injury in SH-SY5Y cells. Furthermore, Compound 13 did not show significant cytotoxicity on SH-SY5Y. These results suggest that 13 is a potential multifunctional active molecule for treating Alzheimer's disease.

Advances in the development of phosphodiesterase-4 inhibitors

Phosphodiesterase 4 (PDE4) hydrolyzes cyclic adenosine monophosphate (cAMP) and plays a vital roles in many biological processes. PDE4 inhibitors have been widely studied as therapeutics for the treatment of various diseases, including asthma, chronic obstructive pulmonary disease (COPD) and psoriasis. Many PDE4 inhibitors have progressed to clinical trials and some have been approved as therapeutic drugs. Although many PDE4 inhibitors have been approved to enter clinical trials, however, the development of PDE4 inhibitors for the treatment of COPD or psoriasis has been hampered by their side effects of emesis. Herein, this review summarizes advances in the development of PDE4 inhibitors over the last ten years, focusing on PDE4 sub-family selectivity, dual target drugs, and therapeutic potential. Hopefully, this review will contribute to the development of novel PDE4 inhibitors as potential drugs.

Antioxidative Indenone and Benzophenone Derivatives from the Mangrove-Derived Fungus Cytospora heveae NSHSJ-2

Seven new polyketides, including four indenone derivatives, cytoindenones A–C (1, 3–4), 3′-methoxycytoindenone A (2), a benzophenone derivative, cytorhizophin J (6), and a pair of tetralone enantiomers, (±)-4,6-dihydroxy-5-methoxy-α-tetralone (7), together with a known compound (5) were obtained from the endophytic fungus Cytospora heveae NSHSJ-2 isolated from the fresh stem of the mangrove plant Sonneratia caseolaris. Compound 3 represented the first natural indenone monomer substituted by two benzene moieties at C-2 and C-3. Their structures were determined by the analysis of 1D and 2D NMR, as well as mass spectroscopic data, and the absolute configurations of (±)-7 were determined on the basis of the observed specific rotation value compared with those of the tetralone derivatives previously reported. In bioactivity assays, compounds 1, 4–6 showed potent DPPH· scavenging activities, with EC50 values ranging from 9.5 to 16.6 µM, better than the positive control ascorbic acid (21.9 µM); compounds 2–3 also exhibited DPPH· scavenging activities comparable to ascorbic acid.

Trends and hotspots for European Journal of Medicinal Chemistry: A bibliometric study

European Journal of Medicinal Chemistry (EJMC) has been around for a long time and has gained broad interest from the various individuals working in the field. However, there is no bibliometric analysis on the publications of EJMC to thoroughly assess the scientific output and current status systematically. Therefore, the study was conducted to analyze the various publications of EJMC from 1987 to 2022 to improve their quality. A total of 13,386 papers were retrieved, with the number of publications increasing yearly. Based on the multiple indicators of bibliometrics, the highest impact countries, institutions, authors and representative literature were identified, and visualization networks were constructed using VOSviewer. Keyword co-occurrence analysis reveals a gradual shift from phenotypic drug discovery to target-based drug discovery in the EJMC theme change. Moreover, further discussion of the keyword clustering results is provided to support researchers in defining the scope of their research topics and planning their research directions. At this stage, there is a greater focus on developing antitumor and oxidative stress-related drugs than on the earlier anti-infective activities. In future studies, the main research directions are tumor multidrug resistance, oxidative stress, and dual inhibitors.

Synthesis of novel thiosemicarbazone derivatives and investigation of their dual AChE and MAO-B inhibitor effects

In this study, 15 thiosemicarbazone derivatives were synthesized. Analysis of the obtained compounds was performed by means of ¹ H-NMR, ¹³ C-NMR and high resolution mass spectroscopy (HRMS) spectroscopic methods. The inhibition effect of the obtained compounds on cholinesterase and monoaminoxidase (MAO) enzymes were investigated with in vitro methods. None of the compounds showed significant activity on the butyrylcholinesterase enzyme. On the other hand, compounds 3b, 3c, 3e, 3k, 3l, 3m, 3n and 3o displayed significant activity on acetylcholinesterase (AChE) while compounds 3f, 3i, 3k, 3l, 3m, 3n, 3o also showed remarkable effects on monoamine oxidase-B (MAO-B) enzymes. For the selected compounds, docking studies were performed and the enzyme active site and binding modes were determined. It was revealed that the strongest interaction with AChE and MAO-B enzyme active sites was observed with the compound 3k. Another important factor in the treatment of diseases affecting the central nervous system such as Alzheimer's is the ability of the compounds to cross the blood-brain barrier (BBB). Additionally, the agents planned for the treatment of these diseases must also pass the blood-brain barrier. Therefore, in silico BBB penetration properties of active compounds were investigated.