Chromone-lipoic acid conjugate: Neuroprotective agent having acceptable butyrylcholinesterase inhibition, antioxidant and copper-chelation activities

Lipoic acid-plumbagin conjugate protects pancreatic beta cells against high glucose-induced toxicity

Pancreatic β cells that produce insulin play a significant role in maintaining glucose homeostasis. However, high glucose (HG) causes oxidative stress, which leads to pancreatic β cell dysfunction. The synthesis of lipoic acid (LA) and plumbagin (PLU) conjugate (LA-PLU) was done and characterized using (1H) NMR, (13C) NMR, LC-ESI-MS/MS, and UV-visible spectroscopy techniques. ADME analysis confirmed the drug-like properties of LA-PLU. The present study revealed the protective effect of LA-PLU conjugate against HG (25 mM)-induced oxidative stress on pancreatic β cells. Cell viability was performed on RIN-5F cells and found that LA-PLU exhibits non-toxic up to 91.23 ± 2.61% of cell viability at 12.5 µM concentration. At 12.5 µM, LA-PLU protected pancreatic β cells up to 73.45 ± 3.72% under HG conditions. LA-PLU showed a protective effect on RIN-5F cells against HG-induced DNA damage, followed by preserving mitochondrial membrane potential and decreasing reactive oxygen species formation. Further, LA-PLU showed an anti-apoptotic effect by increasing the Bcl-2 (B cell lymphoma-2) level and decreasing the apoptotic proteins [Bcl-2 associated x (Bax), and cleaved caspase-3). Hence, the overall study concludes that LA-PLU could act as a potent antioxidant that protects the RIN-5F cells under HG conditions, resulting in the maintenance of glucose homeostasis.

Lipoic acid scaffold applications in the design of multitarget-directed ligands against Alzheimer's disease

Alzheimer's disease (AD) is becoming a fast-growing public health problem which can result in psychological problems as well as loss of speech, language, short-term memory, and motor coordination. Many medications were developed and produced to treat AD, however due to the complexity of the pathology involved in the illness, many of these medications often failed in clinical or preclinical studies. The main issue with the current anti-AD medications is their low efficacy since they use a single target. Multi-target-directed ligands (MTDLs) based on "one molecule; multiple targets" have been introduced to address these two fundamental issues. MTDLs have demonstrated improved efficacy and safety since they regulate many biological targets simultaneously. Alpha-lipoic acid (LA), a natural molecule with distinct properties, is a viable scaffold for developing new MTDLs in treating many neurodegenerative diseases, particularly AD. It is a key mitochondrial enzymes' cofactor and an organic molecule with disulfide functionality. It also has potent antioxidant characteristics that enhance mitochondrial activity. Considering the neuroprotective and anti-inflammatory effects of LA, various hybrids of LA with tacrine, rivastigmine, coumarin and chromone, ibuprofen, melatonin, niacin have been synthesized and biologically evaluated as the MTDLs. In this article, we review the design of LA-based hybrids or conjugates, their biological activities, and structure-activity relationship studies, to develop new MTDLs in the field of AD pharmacotherapy.

Analysis of skeletal diversity of multi-target directed ligands (MTDLs) targeting Alzheimer's disease

Alzheimer's disease (AD) remains a significant healthcare challenge, necessitating innovative therapeutic approaches to address its complex and multifactorial nature. Traditional drug discovery strategies targeting single molecular targets are not sufficient for the effective treatment of AD. In recent years, MTDLs have emerged as promising candidates for AD therapy, aiming to simultaneously modulate multiple pathological targets. Among the various strategies employed in MTDL design, pharmacophore hybridization offers a versatile approach to integrate diverse pharmacophoric features within a single molecular scaffold. This strategy provides access to a wide array of chemical space for the design and development of novel therapeutic agents. This review, therefore, provides a comprehensive overview of skeletal diversity exhibited by MTDLs designed recently for AD therapy based on pharmacophore hybridization approach. A diverse range of pharmacophoric elements and core scaffolds hybridized to construct MTDLs that has the potential to target multiple pathological features of AD including amyloid-beta aggregation, tau protein hyperphosphorylation, cholinergic dysfunction, oxidative stress, and neuroinflammation are discussed. Through the comprehensive analysis and integration of structural insights of key biomolecular targets, this review aims to enhance optimization efforts in MTDL design, ultimately striving towards a comprehensive cure for the multifaceted pathophysiology of the disease.

Flavonoids as Natural Anti-Inflammatory Agents in the Atopic Dermatitis Treatment

Eczema is a complex autoimmune condition characterised mainly by inflammation and skin lesions along with physical and psychological comorbidities. Although there have been significant advances in understanding the mechanisms behind atopic dermatitis, conventionally available treatments yield inconsistent results and have some unintended consequences. In today's digital age, where knowledge is just a click away, natural-based supplements have been on the rise for a more "natural" treatment towards any type of disease. Natural compounds, particularly derived from medicinal plants, have piqued significant interest in the development of herbal remedies for chronic inflammatory skin conditions. Among many compounds, flavonoids have shown promise in treating eczema due to their strong anti-inflammatory, antioxidant, and anti-allergic properties, making them helpful in preventing allergic reactions, inflammation, and skin irritation. This review highlights the therapeutic potential of flavonoid-based bioactive compounds to manage eczema, emphasising the mechanisms of action. Additionally, providing a comprehensive analysis of the potential of emerging and established compounds, while bridging a gap between traditional and modern medicine. Flavonoids offer a variety of opportunities for further research and innovative formulations that can maximise its full benefits. Further combination of flavonoids with various approaches such as nanoencapsulation for enhanced bioavailability, hydrogel-based delivery systems for a controlled release, and additive manufacturing for personalised topical formulations, could align with future precision medicine needs.

Homeostasis and metabolism of iron and other metal ions in neurodegenerative diseases

As essential micronutrients, metal ions such as iron, manganese, copper, and zinc, are required for a wide range of physiological processes in the brain. However, an imbalance in metal ions, whether excessive or insufficient, is detrimental and can contribute to neuronal death through oxidative stress, ferroptosis, cuproptosis, cell senescence, or neuroinflammation. These processes have been found to be involved in the pathological mechanisms of neurodegenerative diseases. In this review, the research history and milestone events of studying metal ions, including iron, manganese, copper, and zinc in neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD), will be introduced. Then, the upstream regulators, downstream effector, and crosstalk of mental ions under both physiologic and pathologic conditions will be summarized. Finally, the therapeutic effects of metal ion chelators, such as clioquinol, quercetin, curcumin, coumarin, and their derivatives for the treatment of neurodegenerative diseases will be discussed. Additionally, the promising results and limitations observed in clinical trials of these metal ion chelators will also be addressed. This review will not only provide a comprehensive understanding of the role of metal ions in disease development but also offer perspectives on their modulation for the prevention or treatment of neurodegenerative diseases.

Evaluation of hydrazone and N-acylhydrazone derivatives of vitamin B6 and pyridine-4-carbaldehyde as potential drugs against Alzheimer's disease

The growing prevalence of Alzheimer's disease calls for a drug that can simultaneously act towards several targets involved in the pathophysiology of the disease. In our study, we evaluated the potential of hydrazone and N-acylhydrazone derivatives of vitamin B6 and pyridine-4-carbaldehyde to be used as multi-target directed ligands targeting cholinergic system by inhibiting acetyl- and butyrylcholinesterase, lowering the accumulation of β-amyloid plaques by inhibiting both the β-secretase activity and amyloid self-aggregation, and maintaining the biometal balance by chelating certain biometals. Our results showed that all of the tested hydrazones were potent inhibitors of human cholinesterases with inhibition constants (Ki) in micromolar range able to lower the activity of β-secretase, inhibit amyloid aggregation, chelate biometals and act as antioxidants. Also, most of them were estimated to be able to cross the blood-brain barrier by passive transport and to be absorbed in human intestines as well as with moderate metabolic stability in liver microsomes.

A critical appraisal of geroprotective activities of flavonoids in terms of their bio-accessibility and polypharmacology

Flavonoids, a commonly consumed natural product, elicit health-benefits such as antioxidant, anti-inflammatory, antiviral, anti-allergic, hepatoprotective, anti-carcinogenic and neuroprotective activities. Several studies have reported the beneficial role of flavonoids in improving memory, learning, and cognition in clinical settings. Their mechanism of action is mediated through the modulation of multiple signalling cascades. This polypharmacology makes them an attractive natural scaffold for designing and developing new effective therapeutics for complex neurological disorders like Alzheimer's disease and Parkinson's disease. Flavonoids are shown to inhibit crucial targets related to neurodegenerative disorders (NDDs), including acetylcholinesterase, butyrylcholinesterase, β-secretase, γ-secretase, α-synuclein, Aβ protein aggregation and neurofibrillary tangles formation. Conserved neuro-signalling pathways related to neurotransmitter biogenesis and inactivation, ease of genetic manipulation and tractability, cost-effectiveness, and their short lifespan make Caenorhabditis elegans one of the most frequently used models in neuroscience research and high-throughput drug screening for neurodegenerative disorders. Here, we critically appraise the neuroprotective activities of different flavonoids based on clinical trials and epidemiological data. This review provides critical insights into the absorption, metabolism, and tissue distribution of various classes of flavonoids, as well as detailed mechanisms of the observed neuroprotective activities at the molecular level, to rationalize the clinical data. We further extend the review to critically evaluate the scope of flavonoids in the disease management of neurodegenerative disorders and review the suitability of C. elegans as a model organism to study the neuroprotective efficacy of flavonoids and natural products.

α-Lipoic acid: a potential regulator of copper metabolism in Alzheimer's disease

Alzheimer's disease (AD) is characterized by classic hallmarks such as amyloid plaques and neurofibrillary tangles, however, intensive research has broadened its scope to explore additional underlying mechanisms. Notably, disruptions in metal homeostasis, particularly involving copper, have gained significant attention. In AD pathology, an imbalance is evident: there is an excess of extracellular copper alongside a deficiency in intracellular copper in brain tissue. Our previous work demonstrated that α-lipoic acid (LA) can effectively shift copper from the extracellular space to the intracellular environment in a neuronal cell model. However, the precise mechanism of action and role of LA in copper metabolism remained elusive. In this study, we compared the cellular effects of LA with those of different synthetic copper-binding ligands: diethyldithiocarbamate (DETC), clioquinol (CQ), D-penicillamine (D-PA) and elesclomol (ES). Using differentiated SH-SY5Y cell culture as a neuronal model, we found that, unlike other synthetic compounds, natural ligand LA is not toxic in the presence of extracellular copper, even at high doses. LA gradually increased intracellular copper levels over 24 h. In contrast, DETC, CQ, and ES acted as fast copper ionophores, potentially explaining their higher toxicity compared to LA. D-PA did not facilitate copper uptake into cells. We demonstrated that a slow increase of LA inside the cells is enhanced in the presence of copper. Furthermore, the ability of LA to modulate the equilibrium of extra- and intracellular copper was evident when we added copper isotope 65Cu. The ratio of copper isotopes changed rapidly, reflecting the impact of LA on the equilibrium of copper distribution without affecting the copper transport network. Our results provide compelling evidence that α-lipoic acid holds promise as a non-toxic agent capable of normalizing copper metabolism in Alzheimer's disease.

Synthesis, bioactivity assessment, molecular docking and ADMET studies of new chromone congeners exhibiting potent anticancer activity

In consideration of the chromones' therapeutic potential and anticancer activity, a new series of chromanone derivatives have been synthesized through a straightforward reaction between 6-formyl-7-hydroxy-5-methoxy-2-methylchromone (2) and various organic active compounds. The cytotoxic activity of the newly synthesized congeners was investigated against MCF-7 (human breast cancer), HCT-116 (colon cancer), HepG2 (liver cancer), and normal skin fibroblast cells (BJ1). The obtained data indicated that compounds 14b, 17, and 19 induce cytotoxic activity in the breast MCF7, while compounds 6a, 6b, 11 and 14c showed highly potent activity in the colon cancer cell lines. Overall, the results demonstrate that the potential cytotoxic effects of the studied compounds may be based on their ability to induce DNA fragmentation in cancer cell lines, down-regulate the expression level of CDK4 as well as the anti-apoptotic gene Bcl-2 and up-regulate the expression of the pro-apoptotic genes P53 and Bax. Furthermore, compounds 14b and 14c showed a dual mechanism of action by inducing apoptosis and cell cycle arrest. The docking studies showed that the binding affinity of the most active cytotoxic compounds within the active pocket of the CDK4 enzyme is stronger due to hydrophobic and H-bonding interactions. These results were found to be consistent with the experimental results.

Click chemistry-aided drug discovery: A retrospective and prospective outlook

Click chemistry has emerged as a valuable tool for rapid compound synthesis, presenting notable advantages and convenience in the exploration of potential drug candidates. In particular, in situ click chemistry capitalizes on enzymes as reaction templates, leveraging their favorable conformation to selectively link individual building blocks and generate novel hits. This review comprehensively outlines and introduces the extensive use of click chemistry in compound library construction, and hit and lead discovery, supported by specific research examples. Additionally, it discusses the limitations and precautions associated with the application of click chemistry in drug discovery. Our intention for this review is to contribute to the development of a modular synthetic approach for the rapid identification of drug candidates.

Chromone Containing Hybrid Analogs: Synthesis and Applications in Medicinal Chemistry

The use of privileged scaffolds has proven beneficial for generating novel bioactive scaffolds in drug discovery program. Chromone is one such privileged scaffold that has been exploited for designing pharmacologically active analogs. The molecular hybridization technique combines the pharmacophoric features of two or more bioactive compounds to avail a better pharmacological activity in the resultant hybrid analogs. The current review summarizes the rationale and techniques involved in developing hybrid analogs of chromone, which show potential in fields of obesity, diabetes, cancer, Alzheimer's disease and microbial infections. Here the molecular hybrids of chromone with various pharmacologically active analogs or fragments (donepezil, tacrine, pyrimidines, azoles, furanchalcones, hydrazones, quinolines, etc.) are discussed with their structure-activity relationship against above-mentioned diseases. Detailed methodologies for the synthesis of corresponding hybrid analogs have also been described, with suitable synthetic schemes. The current review will shed light on various strategies utilized for the design of hybrid analogs in the field of drug discovery. The importance of hybrid analogs in various disease conditions is also illustrated.

Synthesis, Antioxidant, Cytotoxicity, Induce Apoptosis Investigation and Docking Study of New Halogenated Dihydropyrano[3,2-b]Chromene-3-Carbonitrile Derivatives on MCF-7 Breast Cancer Cell Line

Background

Chromene derivatives showed numerous biological activities. In the current study, the antioxidant, cytotoxicity, and apoptosis properties of halogenated dihydropyrano[3,2-b]chromene-3-carbonitrile derivatives (HDCCD) on MCF-7 cell line have been examined.

Objectives

This study's principal point was synthesizing new halogenated pyranochromene derivatives and assessing their cytotoxic effects and apoptosis potential on MCF-7 breast cancer cell line by flow cytometry.

Methods

Initially, 6-chloro- and 6-bromo-3-hydroxychromone compounds were prepared. In the next step, a series of HDCCD were synthesized by a one-pot three-component reaction of these two compounds, aromatic aldehydes, and malononitrile, in the presence of triethylamine in EtOH at reflux conditions. These compounds were fully characterized by standard spectroscopic techniques (IR, 1H, and 13C NMR) and elemental analyses. The potential of the antioxidant activity was determined by using ferric reducing antioxidant power assay (FRAP). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) were used to evaluate metabolic activity. The nitric oxide (NO) and malondialdehyde (MDA) biomarkers of the exposed cells were evaluated on the cells and their supernatant. To quantify apoptotic death of MCF-7 breast cancer cells treated by the compounds at their IC50 concentrations, Annexin V-FITC apoptosis detection kit was utilized. Molecular docking of compounds (6a-j) into the Cyclin-dependent kinase 6 (PDB code: 4EZ5) was carried out, and the probable binding mode of compounds 6e and 6j was determined.

Results

A dose-response relationship was seen in all the compounds. Most of them induced cytotoxic effects on the cells. Nitrite concentration of the culture media of the cells was decreased compared to the control. Malondialdehyde levels of the cells were below the range of the control by the addition of 6b, 6d, 6e, 6f, and 6g compounds on the cells, while the addition of the 6a, 6c, 6h, 6i, and 6j compounds increased the MDA level compared to the control. Flow cytometric analysis showed that most of the exposed cells were in the early and late apoptotic stage, and a few of them were in the necrotic stage.

Conclusions

It could be concluded that HDCCD (6a-j) was toxic and caused death in the cells by apoptosis. The compounds have lipophilic characteristics, so they can easily pass the cell membrane. As confirmed by LDH results, it can be concluded that the cytotoxicity is connected with apoptosis rather than necrosis, endorsed by flowcytometry analysis afterward.

Resveratrol–Maltol and Resveratrol–Thiophene Hybrids as Cholinesterase Inhibitors and Antioxidants: Synthesis, Biometal Chelating Capability and Crystal Structure

New resveratrol–thiophene and resveratrol–maltol hybrids were synthesized as cholinesterase inhibitors and antioxidants. As with photostability experiments, biological tests also found remarkable differences in the properties and behavior of thiophene and maltol hybrids. While resveratrol–thiophene hybrids have excellent inhibitory and antioxidant properties (similar to the activity of reference drug galantamine), maltols have been proven to be weaker inhibitors and antioxidants. The molecular docking of selected active ligands gave insight into the structures of docked enzymes. It enabled the identification of interactions between the ligand and the active site of both cholinesterases. The maltols that proved to be active cholinesterase inhibitors were able to coordinate Fe³⁺ ion, forming complexes of 1:1 composition. Their formation constants, determined by spectrophotometry, are very similar, lgK = 11.6–12.6, suggesting that Fe³⁺ binds to the common hydroxy-pyranone moiety and is hardly affected by the other aromatic part of the ligand. Accordingly, the characteristic bands in their individual absorption spectra are uniformly red-shifted relative to those of the free ligands. The crystal structures of two new resveratrol–maltol hybrids were recorded, giving additional information on the molecules’ intermolecular hydrogen bonds and packing. In this way, several functionalities of these new resveratrol hybrids were examined as a necessary approach to finding more effective drugs for complicated neurodegenerative diseases.

Recent advance on pleiotropic cholinesterase inhibitors bearing amyloid modulation efficacy

Due to the hugely important roles of neurotransmitter acetylcholine (ACh) and amyloid-β (Aβ) in the pathogenesis of Alzheimer's disease (AD), the development of multi-target directed ligands (MTDLs) focused on cholinesterase (ChE) and Aβ becomes one of the most attractive strategies for combating AD. To date, numerous preclinical studies toward multifunctional conjugates bearing ChE inhibition and anti-Aβ aggregation have been reported. Noteworthily, most of the reported multifunctional cholinesterase inhibitors are carbamate-based compounds due to the initial properties of carbamate moiety. However, because their easy hydrolysis in vivo and the instability of the compound-enzyme conjugate, the mechanism of action of these compounds is rare. Thus, non-carbamate compounds are of great need for developing novel cholinesterase inhibitors. Besides, given that Aβ accumulation begins to occur 10-15 years before AD onset, modulating Aβ is ineffective only in inhibiting its aggregation but not eliminate the already accumulated Aβ if treatment is started when the patient has been diagnosed as AD. Considering the limitation of current Aβ accumulation modulators in ameliorating cognitive deficits and ineffectiveness of ChE inhibitors in blocking disease progression, the development of a practically valuable strategy with multiple pharmaceutical properties including ChE inhibition and Aβ modulation for treating AD is indispensable. In this review, we focus on summarizing the scaffold characteristics of reported non-carbamate cholinesterase inhibitors with Aβ modulation since 2020, and understanding the ingenious multifunctional drug design ideas to accelerate the pace of obtaining more efficient anti-AD drugs in the future.

Silver-catalysed three-component reactions of alkynyl aryl ketones, element selenium, and boronic acids leading to 3-organoselenylchromones

An Ag-catalysed three-component reaction of alkynyl aryl ketones bearing an ortho-methoxy group, element selenium, and arylboronic acid, providing a facile route to selenofunctionalized chromone products has been developed. This protocol features high efficiency and high regioselectivity, and the use of selenium powder as the selenium source. Mechanistic experiments indicated that the combined oxidative effect of (bis(trifluoroacetoxy)iodo)benzene and oxygen in the air pushes the catalytic redox cycle of the Ag catalyst and the phenylselenium trifluoroacetate formed in situ is the key intermediate of the PIFA-mediated 6-endo-electrophilic cyclization and selenofunctionalization reaction of alkynyl aryl ketones.

4-Aminoquinoline-Based Adamantanes as Potential Anticholinesterase Agents in Symptomatic Treatment of Alzheimer's Disease

Considering that acetylcholinesterase (AChE) inhibition is the most important mode of action expected of a potential drug used for the treatment of symptoms of Alzheimer's disease (AD), our previous pilot study of 4-aminoquinolines as potential human cholinesterase inhibitors was extended to twenty-two new structurally distinct 4-aminoquinolines bearing an adamantane moiety. Inhibition studies revealed that all of the compounds were very potent inhibitors of AChE and butyrylcholinesterase (BChE), with inhibition constants (Ki) ranging between 0.075 and 25 µM. The tested compounds exhibited a modest selectivity between the two cholinesterases; the most selective for BChE was compound 14, which displayed a 10 times higher preference, while compound 19 was a 5.8 times more potent inhibitor of AChE. Most of the compounds were estimated to be able to cross the blood-brain barrier (BBB) by passive transport. Evaluation of druglikeness singled out fourteen compounds with possible oral route of administration. The tested compounds displayed modest but generally higher antioxidant activity than the structurally similar AD drug tacrine. Compound 19 showed the highest reducing power, comparable to those of standard antioxidants. Considering their simple structure, high inhibition of AChE and BChE, and ability to cross the BBB, 4-aminoquinoline-based adamantanes show promise as structural scaffolds for further design of novel central nervous system drugs. Among them, two compounds stand out: compound 5 as the most potent inhibitor of both cholinesterases with a Ki constant in low nano molar range and the potential to cross the BBB, and compound 8, which met all our requirements, including high cholinesterase inhibition, good oral bioavailability, and antioxidative effect. The QSAR model revealed that AChE and BChE inhibition was mainly influenced by the ring and topological descriptors MCD, Nnum, RP, and RSIpw3, which defined the shape, conformational flexibility, and surface properties of the molecules.

Recent advancements in chromone as a privileged scaffold towards the development of small molecules for neurodegenerative therapeutics

Neurodegenerative disorders, i.e., Alzheimer's or Parkinson's disease, involve progressive degeneration of the central nervous system, resulting in memory loss and cognitive impairment. The intensification of neurodegenerative research in recent years put some molecules into clinical trials, but still there is an urgent need to develop effective therapeutic molecules to combat these diseases. Chromone is a well-identified privileged structure for the design of well-diversified therapeutic molecules of potential pharmacological interest, particularly in the field of neurodegeneration. In this short review, we focused on the recent advancements and developments of chromones for neurodegenerative therapeutics. Different small molecules were reviewed as multi-target-directed ligands (MTDLs) with potential inhibition of AChE, BuChE, MAO-A, MAO-B, Aβ plaque formation and aggregation. Recently developed MTDLs emphasized that the chromone scaffold has the potential to develop new molecules for the treatment of neurodegenerative diseases.

Quercetin: A Bioactive Compound Imparting Cardiovascular and Neuroprotective Benefits: Scope for Exploring Fresh Produce, Their Wastes, and By-Products

Quercetin, a bioactive secondary metabolite, holds incredible importance in terms of bioactivities, which has been proved by in vivo and in vitro studies. The treatment of cardiovascular and neurological diseases by quercetin has been extensively investigated over the past decade. Quercetin is present naturally in appreciable amounts in fresh produce (fruits and vegetables). However, today, corresponding to the growing population and global demand for fresh fruits and vegetables, a paradigm shift and focus is laid towards exploring industrial food wastes and/or byproducts as a new resource to obtain bioactive compounds such as quercetin. Based on the available research reports over the last decade, quercetin has been suggested as a reliable therapeutic candidate for either treating or alleviating health issues, mainly those of cardiovascular and neurological diseases. In the present review, we have summarized some of the critical findings and hypotheses of quercetin from the available databases foreseeing its future use as a potential therapeutic agent to treat cardiovascular and neurological diseases. It is anticipated that this review will be a potential reference material for future research activities to be undertaken on quercetin obtained from fresh produce as well as their respective processing wastes/byproducts that rely on the circular concept.

Protective effect of dexmedetomidine on neuronal hypoxic injury through inhibition of miR-134

OBJECTIVE

To explore the mechanism of dexmedetomidine (DEX)-mediated miR-134 inhibition in hypoxia-induced damage in PC12 cells.

METHODS

Hydrogen peroxide (H₂O₂)-stimulated PC12 cells were divided into control, H₂O₂, DEX + H₂O₂, miR-NC/inhibitor + H₂O₂, and miR-NC/ mimic + DEX + H₂O₂ groups. Cell viability and apoptosis were assessed by the 3-(4,5-dimethylthiazol(-2-y1)-2,5-diphenytetrazolium bromide (MTT) assay and Annexin V-FITC/PI staining, while gene and protein expression levels were detected by qRT-PCR and western blotting. Reactive oxygen species (ROS) levels were tested by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining, and malondialdehyde (MDA) content was determined with a detection kit.

RESULTS

DEX treatment decreased H₂O₂-elevated miR-134 expression. H₂O₂-induced PC12 cell damage was improved by DEX and miR-134 inhibitor; additionally, cell viability was increased, while cell apoptosis was reduced. In addition, both DEX and miR-134 inhibitor reduced the upregulated expression of cleaved caspase-3 and increased the downregulated expression of Bcl-2 in H₂O₂-induced PC12 cells. However, compared to that in the DEX + H₂O₂ group, cell viability in the mimic + DEX + H₂O₂ group was decreased, and the apoptotic rate was elevated with increased cleaved caspase-3 and decreased Bcl-2 expression. Inflammation and oxidative stress were increased in H₂O₂-induced PC12 cells but improved with DEX or miR-134 inhibitor treatment. However, this improvement of H₂O₂-induced inflammation and oxidative stress induced by DEX in PC12 cells could be reversed by the miR-134 mimic.

CONCLUSION

DEX exerts protective effects to promote viability and reduce cell apoptosis, inflammation, and oxidative stress in H₂O₂-induced PC12 cells by inhibiting the expression of miR-134.

Chromone derivatives bearing pyridinium moiety as multi-target-directed ligands against Alzheimer's disease

A new serise of 7-hydroxy-chromone derivatives bearing pyridine moiety were synthesized, and evaluated as multifunctional agents against Alzheimer's disease (AD). Most of the compounds were good AChE inhibitors (IC₅₀ = 9.8-0.71 µM) and showed remarkable BuChE inhibition activity (IC₅₀ = 1.9-0.006 µM) compared with donepezil as the standard drug (IC₅₀ = 0.023 and 3.4 µM). Compounds 14 and 10 showed the best inhibitory activity toward AChE (IC₅₀ = 0.71 µM) and BuChE (IC₅₀ = 0.006 µM), respectively. The ligand-protein docking simulations and kinetic studies revealed that compound 14 and 10 could bind effectively to the peripheral anionic binding site (PAS) of the AChE and BuChE through mixed-type inhibition. In addition, the most potent compounds showed acceptable neuroprotective activity on H₂O₂- and Aβ-induced .neurotoxicity in PC12 cells, more than standard drugs. The compounds could block effectively self- and AChE-induced Aβ aggregation. All the results suggest that compounds 14 and 10 could be considered as promising multi-target-directed ligands against AD.