Synthesis, Sensing Performance and DFT Studies of a Novel Coumarin-based Schiff Base As a Turn-on Fluorescence Probe for Zinc Ion Detection.

The design and development of novel efficient fluorescent chemical sensors for the selective detection of ions is currently of significant importance in supramolecular chemistry. Since zinc is a ubiquitous, indispensable and the second most abundant metal ion in the human body, developing chemosensors that can accurately discriminate between Zn2+ and Cd2+ ions has been a challenge due to their similar properties as they are in the same group of the periodic table. Therefore, a technique to trace and visualize free zinc ions is demanded. In this study, an innovative coumarin-based Schiff base (L) was synthesized and characterized by 1H NMR, 13C NMR and mass spectroscopy. A novel "Turn On" fluorescence chemosensor platform was developed for trace amounts of Zn2+ ions. The fluorescence Job's plot measurement was used to determine the complexation ratio between the probe and Zn2+ ion, which showed a maximum point indicating the formation of a ML2 adduct. Additionally, the geometrical parameters calculated using DFT and TD-DFT calculations were in close agreement with the experimentally observed values.

Conversion of antibacterial quinolone drug levofloxacin to potent cytotoxic agents.

Levofloxacin, the optical S-(-) isomer of ofloxacin, is a broad-spectrum antibacterial agent widely used to control various infections caused by Gram-positive and Gram-negative bacteria. While the COOH group is necessary for antibacterial activity, its modification can offer anticancer activity to the fluoroquinolone framework. Therefore, several levofloxacin carboxamides 11a-j and 12 containing 5-substituted-1,3,4-thiadiazole residue were synthesized and screened in vitro for their anticancer activity. The in vitro MTT viability assay revealed that the most compounds had significant activity against cancer cells MCF-7, A549, and SKOV3. In particular, the 3-chloro- and 4-fluoro- benzyl derivatives (11b and 11h), with IC50 values of 1.69-4.76 µM were as potent as or better than doxorubicin. It should be noted that the mother quinolone levofloxacin showed no activity on the tested cancer cell lines. The SAR analysis demonstrated that the 3-chloro or 4-fluoro substituent on the S-benzyl moiety had positive effect on the activity. Further in vitro evaluations of the most promising compounds 11b and 11h by flow cytometric analysis and comet test revealed the ability of compounds in the induction of apoptosis and blockage of the cell proliferation at the G1-phase by nuclear fragmentation and DNA degradation in cancer cells. The obtained results demonstrated that the alteration of 6-COOH functional group in the levofloxacin structure and conjugation with a proper heterocyclic pharmacophore is a good strategy to obtain new anticancer agents.

Evaluation of anti-parasitic activities of new quinolones containing nitrofuran moiety against Toxoplasma gondii.

Toxoplasmosis is a disease with a worldwide prevalence that is caused by Toxoplasma gondii. Pyrimethamine and sulfadiazine are two pharmacological agents commonly used to treat of this infection. However, they are accompanied by some side effects. Therefore, the identifying of new drugs with low toxocytosis seems to be a matter of vital importance. Quinolones are DNA replication inhibitors, exerting inhibitory effects against many pathogens, including bacteria, mycoplasma, and protozoa. Given the importance of quinolones and their efficacy, the present in vitro study was conducted to investigate the antiparasitic activities of new quinolones (NFQ-2, NFQ-5, and NFQ-6) containing nitrofuran moiety against T. gondii. To this end, Vero cells were incubated with various concentrations of new quinolones and pyrimethamine (positive control) to determine their viability. Subsequently, they were infected with T. gondii (RH strain) and then subjected to drug treatment. The obtained IC50 values were 3.60, 4.84, 5.59, 3.44 and 2.75 µg/mL for NFQ-2, NFQ-5, NFQ-6, ciprofloxacin and pyrimethamine, respectively. The CC50 values for the NFQ-2, NFQ-5, and NFQ-6 were 25.20, 29.89, and 28.43 µg/mL, indicating the selectivity indexes more than 5 for these compounds. The anti-Toxoplasma efficiency was determined by evaluating infection index, number and size of plaques, and T. gondii intracellular proliferation. As the results indicated, the administration of new quinolone derivatives resulted in the reduction of intracellular proliferation, infection index, and the number and size of plaques in comparison to uninfected treated cells (P < 0.05). The results were indicative of a considerable synergetic effect when each of the derivatives was used in combination with pyrimethamine, compared to when used alone. Based on our results, the nitrofuran-derived quinolones can be considered as new leads for the design of new anti-Toxoplasma agents.

Synthesis of 4-Hydroxycoumarin-Based Triazoles/Oxadiazoles as Novel Anticancer Agents.

A series of novel 3-substituted-4-hydroxycoumarins 7 and 8 containing (5-aryl-1,3,4-oxadiazol-2-yl)thio or (4-amino-5-aryl-4H-1,2,4-triazol-3-yl)thio moieties have been synthesized and evaluated as anticancer agents. The in vitro MTT assay of compounds against hepatocellular carcinoma (HepG2), breast cancer (MCF7) cells, and a human colorectal adenocarcinoma cell line with epithelial morphology (HT29) indicated that the HepG2 cells had more susceptibility to the tested compounds. Indeed, all compounds (with the exception of 7b, 7c, 7g, and 8g) were more potent than the standard drug doxorubicin against HepG2 cells (IC50 values=1.65-3.83 µM). Although, the better result was obtained with the oxadiazole analog 7h against HepG2 (IC50 =1.65 µM), the N-amino-triazole derivatives 8c, 8e, 8f and, 8h with IC50 values of 1.78-6.34 µM showed potent activity against all tested cell lines. The good drug-like properties and in vitro potency and selectivity of 4-hydroxycoumarins 8 make them as good leads for the development of new anticancer agents.

Papaverine, a promising therapeutic agent for the treatment of COVID-19 patients with underlying cardiovascular diseases (CVDs).

The causative agent of coronavirus disease-2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), enters the host cells via an angiotensin-converting enzyme 2 (ACE2)-mediated endocytosis-dependent manner. Because ACE2 is highly expressed in the heart, SARS-CoV-2 can severely infect heart tissue and arteries, causing acute and chronic damage to the cardiovascular system. Therefore, special attention should be paid to finding appropriate agents to protect this vital system during COVID-19 treatment. Papaverine is a unique vasodilator alkaloid that is clinically used in the treatment of vasospasm. Interestingly, this compound has potent and direct effects on a wide range of viruses, and could also prevent viral exploitation mechanisms of the host cell facilities by inhibiting some cellular signaling pathways such as p38 MAPK. This pathway was recently introduced as a promising target for the treatment of COVID-19. Papaverine also has anti-inflammatory effects which is useful in combating the hyper-inflammatory phase of the COVID-19. Unlike some medications that have severe dosage-restrictions in the treatment of COVID-19 due to cardiac side effects, papaverine is recommended for use in many heart disorders. The ability of papaverine to treat COVID-19 has become more promising when the results of some extensive screenings showed the strong ability of this compound to inhibit the cytopathic effects of SARS-CoV-2 with EC50 of 1.1 µM. Having several therapeutic effects along with desired safety profile raises this hypothesis that papaverine could be a promising compound for the suppression of SARS-CoV-2 and prevention of ischemia/vasoconstriction-related complications in COVID-19 disease, especially in patients with underlying cardiovascular diseases (CVDs).

Synthesis and Biological Evaluation of 99mTc-Labeled Phenylpiperazine Derivatives as Selective Serotonin-7 Receptor Ligands for Brain Tumor Imaging.

With a poor prognosis, glioblastoma multiforme is the most aggressive tumor of the central nervous system in humans. The aim of this study was to develop novel tracers for the tumor targeting and imaging of overexpressed serotonin-7 receptors (5-HT7Rs) in U-87 MG glioma xenografted nude mice. Two phenylpiperazine derivatives named as PHH and MPHH were designed, and the corresponding radiotracers 99mTc-PHH and 99mTc-MPHH were synthesized in high radiochemical purity (>95%). 99mTc-MPHH showed a higher affinity to 5-HT7Rs on U-87 MG cells compared to 99mTc-PHH. In biodistribution studies, the radiocomplexes showed good brain uptake at 15 min combined with good radioactivity retention in the brain for 240 min. Regional rabbit brain studies indicated a higher radioactivity concentration in the hippocampus and diencephalon than in the cerebellum. Compared to 99mTc-MPHH, the 99mTc-PHH exhibited a significantly increased tumor uptake at 15 and 60 min, but the rapid blood clearance of 99mTc-MPHH led to enhanced tumor-to-muscle ratios at 240 min. A significant reduction in tumor uptake 60 min after an injection of pimozide (5-HT7 receptor antagonist) confirms the tumor uptake was receptor-mediated specifically. The tumor-to-contralateral muscle tissue ratio of 99mTc-PHH and 99mTc-MPHH in nude mice with U-87 MG xenograft was measured (5.25 and 4.65) at 60 min as well as (6.25 and 6.76) at 240 min, respectively.

Current development of sigma-2 receptor radioligands as potential tumor imaging agents.

Sigma receptors are transmembrane proteins with two different subtypes: σ1 and σ2. Because of its overexpression in tumors, the σ2 receptor (σ2R) is a well-known biomarker for cancer cells. A large number of small-molecule ligands for the σ2Rs have been identified and tested for imaging the proliferative status of tumors using single photon emission computed tomography (SPECT) and positron emission tomography (PET). These small molecules include derivatives of bicyclic amines, indoles, cyclohexylpiperazines and tetrahydroisoquinolines. This review discusses various aspects of small molecule ligands, such as chemical composition, labeling strategy, affinity for σ2Rs, and in vitro/in vivo investigations. The recent studies described here could be useful for the development of σ2R radioligands as potential tumor imaging agents.

Synthesis, in silico, in vitro and in vivo evaluations of isatin aroylhydrazones as highly potent anticonvulsant agents.

In this study, a series of new isatin aroylhydrazones (5a-e and 6a-e) was synthesized and evaluated for their anticonvulsant activities. The (Z)-configuration of compounds was confirmed by 1H NMR. In vivo studies using maximal electroshock (MES) and pentylenetetrazole (PTZ) models of epilepsy in mice revealed that while most of compounds had no effect on chemically-induced seizures at the higher dose of 100 mg/kg but showed significant protection against electrically-induced seizures at the lower dose of 5 mg/kg. Certainly, N-methyl analogs 6a and 6e were found to be the most effective compounds, displaying 100% protection at the dose of 5 mg/kg. Protein binding and lipophilicity(logP) of the selected compounds (6a and 6e) were also determined experimentally. In silico evaluations of title compounds showed acceptable ADME parameters, and drug-likeness properties. Distance mapping and docking of the selected compounds with different targets proposed the possible action of them on VGSCs and GABAA receptors. The cytotoxicity evaluation of 6a and 6e against SH-SY5Y and Hep-G2 cell lines indicated safety profile of compounds on the neuronal and hepatic cells.

Synthesis, computational study and cytotoxicity of 4-hydroxycoumarin-derived imines/enamines.

In this study, we applied a direct condensation between 3-acetyl-4-hydroxy-2H-chromen-2-one and different amines (anilines and benzyl amines) in order to synthesize some coumarin-based imines/enamines (3a-o) as cytotoxic agents. All the compounds were characterized by means of FT-IR, NMR, mass spectroscopy and elemental analyses. Since the title compounds can exist as different forms including (s-cis)-imine and (s-trans)-imine or (E and Z)-enamines, their conformational and geometrical aspects were investigated computationally by DFT method. The optimized geometry parameters, ΔE, ΔG, ΔH, Mulliken atomic charge, HOMO and LUMO energy, and NBO analysis suggested that these compounds can exist predominantly in (E)-enamine form. All the synthesized compounds (3a-o) were evaluated in vitro for their cytotoxic activities against cancer cell lines (MCF-7 and A549) and normal cell line (BEAS-2B) using the MTT assay. The 4-hydroxybenzyl derivative 3k was found to be the most potent cytotoxic agent with no selectivity, similar to doxorubicin. However, the 4-chlorobenzyl analog 3o could be considered as an equipotent compound respect to doxorubicin with higher selectivity.

Synthesis and biological assessment of ciprofloxacin-derived 1,3,4-thiadiazoles as anticancer agents.

The quinolone-3-carboxylic acid scaffold is essential structure for antibacterial activity of fluoroquinolones such as ciprofloxacin. Modification of 3-carboxylic functionality in this structure can be used for switching its activity from antibacterial to anticancer. Accordingly, a series of C-3 modified ciprofloxacin derivatives containing N-(5-(benzylthio)-1,3,4-thiadiazol-2-yl)-carboxamide moiety was synthesized as novel anticancer agents. Most of compounds showed significant activity against MCF-7, A549 and SKOV-3 cancer cells in the MTT assay. In particular, compounds 13a-e and 13g were found to be as potent as standard drug doxorubicin against MCF-7 cell line (IC50s = 3.26-3.90 µM). Furthermore, the 4-fluorobenzyl derivatives 13h and 14b with IC50 values of 3.58 and 2.79 µM exhibited the highest activity against SKOV-3 and A549 cells, being as potent as doxorubicin. Two promising compounds 13e and 13g were further tested for their apoptosis inducing activity and cell cycle arrest. Both compounds could significantly induce apoptosis in MCF-7 cells, while compound 13e was more potent apoptosis inducer resulting in an 18-fold increase in the proportion of apoptotic cells at the IC50 concentration in MCF-7 cells. The cell cycle analysis revealed that compounds 13e and 13g could increase cell portions in the sub-G1 phase, inducing oligonucleosomal DNA fragmentation and apoptosis confirmed by comet assay.

Synthesis and in vitro anti-Toxoplasma gondii activity of a new series of aryloxyacetophenone thiosemicarbazones.

A new series of aryloxyacetophenone thiosemicarbazones 4a-q have been synthesized as anti-Toxoplasma gondii agents. All compounds showed significant inhibitory activity against T. gondii-infected cells (IC50 values 1.09-25.19 µg/mL). The 4-fluorophenoxy derivative (4l) was the most potent compound with the highest selectivity toward host cells (SI = 19), being better than standard drug pyrimethamine. SAR study indicated that the concurrence of proper substituents on both aryl ring of phenoxyacetophenone is important for potency and safety profile. Further in vitro experiments with the representative compounds 4l and 4p revealed that these compounds at the concentration of 5 µg/mL can significantly reduce the viability of T. gondii tachyzoites, as well as their infectivity rate and intracellular proliferation, comparable to those of pyrimethamine.

Tropolone alkaloids from Colchicum kurdicum (Bornm.) Stef. (Colchicaceae) as the potent novel antileishmanial compounds; purification, structure elucidation, antileishmanial activities and molecular docking studies.

Natural compounds played an important role for prevention and treatment of the disease as well as are the important compounds for the design of the new bioactive compounds. In this study, eight tropolone alkaloids were isolated from Colchicum kurdicum including colchicoside, 2-demethyl colchicine, 3-demethyl colchicine, demecolcine, colchifoline, N-deacetyl-N-formyl colchicine, colchicine and cornigerine by column and preparative thin layer chromatography. The chemical structures were identified by 1H NMR and 13C NMR spectroscopy. Moreover, the antileishmanial activity on Leishmania major, anti-inflammatory activity, iron chelating activity and toxicity studies including hemolytic activity, brine shrimp toxicity, cytotoxicity and acute toxicity and docking study of all isolated bioactive compounds were evaluated. As result, colchicoside and colchicine had potent leishmanicidal effects and N-deacetyl-N-formyl colchicine and cornigerine had the highest anti-inflammatory effects. All compounds had the significant iron chelating activity. According to toxicity studies, isolated compounds showed the low hemolytic activity and cytotoxicity, high LC50, LC90 and LD50. In the molecular docking study, colchicoside had the high dockscore. According to the study, with future studies all isolated compounds could be used for design the novel antileishmanial drugs.

The effect of edelfosine on GRA1 and MIC3 expressions in acute toxoplasmosis.

Phosphoinositide-dependent phospholipase-C (PI-PLC) triggers the calcium signaling pathway which plays an important role in dense granule and microneme secretion and pathogenesis of Toxoplasma gondii (T. gondii). There are limited data about the effects of phospholipid analogues against T. gondii. The current study assessed the effect of edelfosine, as a phospholipid analogue, on GRA1 and MIC3 expressions using in vitro and in vivo models of acute toxoplasmosis. Infected Vero cells were treated by edelfosine in two subgroups: 24 h following the cell infection and treatment at the same time of cell infection. Animal study was performed on forty mice in four groups including non-infected, infected untreated, infected edelfosine-treated, and infected pyrimethamine-treated. Gene and protein expression analyses were done using quantitative real-time PCR and western blot, respectively. Edelfosine significantly reduced the GRA1 (P < 0.01) and MIC3 (P < 0.01) mRNA and protein expressions in 24 h following the cell infection and at the same time of cell infection groups. In vivo study showed that the edelfosine significantly reduced the GRA1 expression in eye, and MIC3 expression in brain and liver. Moreover, the edelfosine-treated infected mice had significant higher survival rate compared with uninfected mice. The reducing effect of edelfosine on GRA1 and MIC3 mRNA and protein levels 24 h following the cell infection was more than treatment at the same time of cell infection group. Moreover, the effect of edelfosine on GRA1 and MIC3 expression in animal tissues was variable. These data showed that the edelfosine may decrease the T. gondii excretory/secretory antigens through inhibition of PI-PLC.

1,2,3-Triazole-based kojic acid analogs as potent tyrosinase inhibitors: Design, synthesis and biological evaluation.

A series of kojic acid-derived compounds 6a-p bearing aryloxymethyl-1H-1,2,3-triazol-1-yl moiety were designed by modifying primary alcoholic group of kojic acid as tyrosinase inhibitors. The target compounds 6a-p were synthesized via click reaction. All compounds showed very potent anti-tyrosinase activity (IC50s = 0.06-6.80 µM), being superior to reference drug, kojic acid. In particular, the naphthyloxy analogs 6o and 6p were found to be 31-155 times more potent than kojic acid. The metal-binding study of selected compound 6o revealed that the prototype compound possesses metal-chelating ability, particularly with Cu2+ ions. The promising compounds 6o and 6p had acceptable safety profile as demonstrated by cytotoxicity assay against melanoma (B16) cell line and Human Foreskin Fibroblast (HFF) cells.

Design, synthesis and biological evaluation of flexible and rigid analogs of 4H-1,2,4-triazoles bearing 3,4,5-trimethoxyphenyl moiety as new antiproliferative agents.

Several flexible and rigid analogs of 4H-1,2,4-triazoles (compounds 8a-g and 9a-g) bearing trimethoxyphenyl pharmacophoric unit, were designed and synthesized as potential anticancer agents. The in vitro cytotoxic assay indicated that both flexible and rigid analogs (8 and 9, respectively) can potentially inhibit the growth of cancerous cells (A549, MCF7, and SKOV3), with IC50 values less than 5.0 µM. Furthermore, compounds 10a-l as regional isomers of compounds 9 exhibited remarkable cytotoxic activity with IC50 values ranging from 0.30 to 5.0 µM. The rigid analogs 9a, 10h and 10k were significantly more potent than etoposide against MCF7, SKOV3 and A549 cells, respectively. These compounds showed high selectivity towards cancer cells over normal cells, as they had no significant cytotoxicity against L929 cells. In addition, the representative compounds 9a and 10h could inhibit the tubulin polymerization at micro-molar levels. By determining changes in the colchicine-tubulin fluorescence, it was suggested that compound 10h could bind to the tubulin at the colchicine pocket. The molecular docking study further confirmed the inhibitory activity of promising compounds 9a, 10h and 10k on tubulin polymerization through binding to the colchicine-binding site.

New potent antifungal triazole alcohols containing N-benzylpiperazine carbodithioate moiety: Synthesis, in vitro evaluation and in silico study.

A number of 1H-1,2,4-triazole alcohols containing N-(halobenzyl)piperazine carbodithioate moiety have been designed and synthesized as potent antifungal agents. In vitro bioassays against different Candida species including C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis revealed that the N-(4-chlorobenzyl) derivative (6b) with MIC values of 0.063-0.5 µg/mL had the best profile of activity, being 4-32 times more potent than fluconazole. Docking simulation studies confirmed the better fitting of compound 6b in the active site of lanosterol 14α-demethylase (CYP51) enzyme, the main target of azole antifungals. Particularly, the potential of compound 6b against fluconazole-resistant isolates along with its minimal toxicity against human erythrocytes and HepG2 cells make this prototype compound as a good lead for discovery of potent and safe antifungal agents.

Synthesis and biological evaluation of new N-benzylpyridinium-based benzoheterocycles as potential anti-Alzheimer's agents.

A novel series of benzylpyridinium-based benzoheterocycles (benzimidazole, benzoxazole or benzothiazole) were designed as potent acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The title compounds 4a-q were conveniently synthesized via condensation reaction of 1,2-phenylenediamine, 2-aminophenol or 2-aminothiophenol with pyridin-4-carbalehyde, followed by N-benzylation using various benzyl halides. The results of in vitro biological assays revealed that most of them, especially 4c and 4g, had potent anticholinesterase activity comparable or more potent than reference drug, donepezil. The kinetic study demonstrated that the representative compound 4c inhibits AChE in competitive manner. According to the ligand-enzyme docking simulation, compound 4c occupied the active site at the vicinity of catalytic triad. The compounds 4c and 4g were found to be inhibitors of Aß self-aggregation as well as AChE-induced Aß aggregation. Meanwhile, these compounds could significantly protect PC12 cells against H2O2-induced injury and showed no toxicity against HepG2 cells. As multi-targeted structures, compounds 4c and 4g could be considered as promising candidate for further lead developments to treat Alzheimer's disease.

In vitro and in vivo evaluation of kojic acid against Toxoplasma gondii in experimental models of acute toxoplasmosis.

As current toxoplasmosis chemotherapies have many side effects along with toxicity on patients, we examined the anti-Toxoplasma effect of a biologically important natural antibiotic, kojic acid, in vitro and in vivo. Vero cells were incubated with different concentrations of kojic acid or pyrimethamine (positive control), and the cellular viability was determined. Next, Vero cells were infected with T. gondii (RH strain) and treated with drugs. Then, we calculated the infection index, T. gondii intracellular proliferation and the number and measure of plaque. Moreover, the effect of kojic acid on survival times, serum levels of IFN-γ and TNF-α and histopathological changes in the liver and spleen of Balb/c mice infected with T. gondii were determined. Kojic acid reduced the infection index, intracellular proliferation, the number and measure of plaque in vitro when compared to untreated infected cells. Kojic acid (100 mg/kg/day) also showed a better survival rate than infected untreated control mice (P < 0.05). IFN-γ and TNF-α secretions were significantly increased by kojic acid treatment in comparison to untreated groups (P < 0.05). In addition, its inhibitory effects on inflammatory alterations, apoptosis, and necrosis have been shown in sections of liver and spleen. We conclude that kojic acid exhibit potent anti-Toxoplasma activity with direct and indirect effects on the parasite, although further studies are needed before consideration of clinical trials.

Design, synthesis, in vivo and in silico evaluation of phenacyl triazole hydrazones as new anticonvulsant agents.

A series of phenacyl triazole hydrazones 3 have been designed based on the hybridization of (arylalkly)triazole and aroyl hydrazone scaffolds as new anticonvulsant agents. The target compounds 3 were easily synthesized from appropriate phenacyl triazoles and aryl acid hydrazides and characterized by IR, NMR and Mass spectroscopy. The in vivo anticonvulsant evaluation of synthesized compounds by using MES and PTZ tests revealed that they are more effective in MES model respect to PTZ test. All compounds showed 33-100% protection against MES-induced seizures at the dose of 100 mg/kg. However, the isonicotinic acid hydrazide derivative 3h showed the best profile of activity in both models. Molecular docking studies of compound 3h with different targets (NMDA, AMPA, GABAA and sodium channel), postulated that the compound acts mainly via GABAA receptors. In silico molecular properties predictions indicated that all compounds have favourable oral bioavailability and BBB permeability.

Novel 3-phenylcoumarin-lipoic acid conjugates as multi-functional agents for potential treatment of Alzheimer's disease.

New series of triazole-containing 3-phenylcoumarin-lipoic acid conjugates were designed as multi-functional agents for treatment of Alzheimer's disease. The target compounds 4a-o were synthesized via the azide-alkyne cycloaddition reaction and their biological activities were primarily evaluated in terms of neuroprotection against H2O2-induced cell death in PC12 cells and AChE/BuChE inhibition. The promising compounds 4j and 4i containing four carbons spacer were selected for further biological evaluations. Based on the obtained results, the benzocoumarin derivative 4j with IC50 value of 7.3 µM was the most potent AChE inhibitor and displayed good inhibition toward intracellular reactive oxygen species (ROS). This compound with antioxidant and metal chelating ability showed also protective effect on cell injury induced by Aß1-42 in SH-SY5Y cells. Although the 8-methoxycoumarin analog 4i was slightly less active than 4j against AChE, but displayed higher protection ability against H2O2-induced cell death in PC12 and could significantly block Aß-aggregation. The results suggested that the prototype compounds 4i and 4j might be promising multi-functional agents for the further development of the disease-modifying treatments of Alzheimer's disease.