Discovery of novel 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives as multifunctional MAO-B inhibitors for the treatment of Parkinson's disease.

To discover novel multifunctional agents for the treatment of Parkinson's disease, a series of 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives was designed, synthesized and evaluated. The results revealed that representative compound 3h possessed potent and selective MAO-B inhibitory activity (IC50 = 0.062 µM), and its inhibitory mode was competitive and reversible. Additionally, 3h also displayed excellent anti-oxidative effect (ORAC = 2.27 Trolox equivalent), significant metal chelating ability and appropriate BBB permeability. Moreover, 3h exhibited good neuroprotective effect and anti-neuroinflammtory ability. These results indicated that compound 3h was a promising candidate for further development against PD.

2-Hydroxy-4-benzyloxylimine Resveratrol Derivatives as Potential Multifunctional Agents for the Treatment of Parkinson's Disease.

A series of 2-hydroxy-4-benzyloxylimine resveratrol derivatives was designed, synthesized and evaluated as multifunctional agents for the treatment of Parkinson's disease. The results revealed that most derivatives possessed good multifunctional activities. Among them, representative compound (E)-5-[(4-fluorobenzyl)oxy]-2-{[(4-hydroxyphenyl)imino]methyl}phenol (7 h) exhibited excellent MAO-B inhibition (IC50 =8.43×10-3  µM) and high antioxidant activity (ORAC=3.45 Trolox equivalent). Additionally, 7 h displayed good metal chelating ability, appropriate blood-brain barrier (BBB) permeability, significant neuroprotective effect, and great anti-neuroinflammatory activity. Furthermore, 7 h can also ameliorate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease symptoms in mice. Therefore, compound 7 h was found to be a promising candidate for further development against PD.

Discovery of novel 2-hydroxyl-4-benzyloxybenzyl aniline derivatives as potential multifunctional agents for the treatment of Parkinson's disease.

To discover novel multifunctional agents for the treatment of Parkinson's disease, a series of 2-hydroxyl-4-benzyloxybenzyl aniline derivatives was designed, synthesized and evaluated. The biological screening indicated that representative compound 6h possessed excellent MAO-B inhibition (IC50 = 0.014 µM), high antioxidant activity (ORAC = 2.14 Trolox equivalent), good metal chelating ability, appropriate BBB permeability and significant neuroprotective effect. Additionally, 6h exhibited great ability to alleviate the neuroinflammtion by suppressing the activation of NF-κB pathway in vitro. Furthermore, 6h can also ameliorate MPTP induced Parkinson's disease symptoms in mice by improving the dopamine level and repressing oxidative damage. These results indicated that compound 6h was a promising candidate for further development against PD.

Design, synthesis, and evaluation of chalcone-Vitamin E-donepezil hybrids as multi-target-directed ligands for the treatment of Alzheimer's disease.

A novel series of chalcone-Vitamin E-donepezil hybrids was designed and developed based on multitarget-directed ligands (MTDLs) strategy for treating Alzheimer's disease (AD). The biological results revealed that compound 17f showed good AChE inhibitory potency (ratAChE IC50 = 0.41 µM; eeAChE IC50 = 1.88 µM). Both the kinetic analysis and docking study revealed that 17f was a mixed type AChE inhibitor. 17f was also a good antioxidant (ORAC = 3.3 eq), selective metal chelator and huMAO-B inhibitor (IC50 = 8.8 µM). Moreover, it showed remarkable inhibition of self- and Cu2+-induced Aß1-42 aggregation with a 78.0 and 93.5% percentage rate at 25 µM, respectively, and disassembled self-induced and Cu2+-induced aggregation of the accumulated Aß1-42 fibrils with 72.3 and 84.5% disaggregation rate, respectively. More importantly, 17f exhibited a good neuroprotective effect on H2O2-induced PC12 cell injury and presented good blood-brain barrier permeability in vitro. Thus, 17f was a promising multi-target-directed ligand for treating AD.

Phthalimide-(N-alkylbenzylamine) cysteamide hybrids as multifunctional agents against Alzheimer's disease: Design, synthesis, and biological evaluation.

The complex pathogenesis of Alzheimer's disease (AD) calls for multi-target approach for disease treatment. Herein, based on the MTDLs strategy, a series of phthalimide-(N-alkylbenzylamine) cysteamide hybrids were designed, synthesized, and investigated in vitro for the purpose. Most of the target compounds were found to be potential multi-target agents. In vitro results showed that compound 9e was the representative compound in this series, endowed with high EeAChE and HuAChE inhibitory potency (IC50  = 1.55 µm and 2.23 µm, respectively), good inhibitory activity against self-induced Aß1-42 aggregation (36.08% at 25 µm), and moderate antioxidant capacity (ORAC-FL value was 0.68 Trolox equivalents). Molecular docking studies rationalized the binding mode of 9e in both PAS and CAS of AChE. Moreover, 9e displayed excellent ability to against H2 O2 -induced PC12 cell injury and penetrate BBB. Overall, these results highlighted that compound 9e was an effective and promising multi-target agent for further anti-AD drug development.

Design, synthesis, and in vitro evaluation of 4-aminoalkyl-1(2H)-phthalazinones as potential multifunctional anti-Alzheimer's disease agents.

A series of 4-aminoalkyl-1(2H)-phthalazinone derivatives was designed and synthesized as potential multifunctional agents for Alzheimer's disease (AD) treatment. In vitro biological assay results demonstrated that most synthesized compounds exhibited significant AChE inhibition, moderate to high MAOs inhibitory potencies and good anti-platelet aggregation abilities. Among them, compound 15b exhibited the highest inhibitory potencies towards MAO-B and MAO-A (IC50 = 0.7 µM and 6.4 µM respectively), moderate inhibition towards AChE (IC50 = 8.2 µM), and good activities against self- and Cu2+-induced Aß1-42 aggregation and platelet aggregation. Moreover, 15b also displayed antioxidant capacity, neuroprotective potency, anti-neuroinflammation and BBB permeability. These excellent results indicated that compound 15b could be worthy of further studies to be considered as a promising multifunctional candidate for the treatment of AD.

Design, synthesis and evaluation of novel dimethylamino chalcone-O-alkylamines derivatives as potential multifunctional agents against Alzheimer's disease.

A novel series of dimethylamino chalcone-O-alkylamines derivatives was designed and synthesized as multifunctional agents for the treatment of AD. All the target compounds exhibited significant abilities to inhibit and disaggregate Aß aggregation, and acted as potential selective AChE inhibitors, biometal chelators and selective MAO-B inhibitors. Among these compounds, compound TM-6 showed the greatest inhibitory activity against self-induced Aß aggregation (IC50 = 0.88 µM) and well disaggregation ability toward self-induced Aß aggregation (95.1%, 25 µM), the TEM images, molecular docking study and molecular dynamics simulations provided reasonable explanation for its high efficiency, and it was also found to be a remarkable antioxidant (ORAC-FL values of 2.1eq.), the best AChE inhibitor (IC50 = 0.13 µM) and MAO-B inhibitor (IC50 = 1.0 µM), as well as a good neuroprotectant. UV-visual spectrometry and ThT fluorescence assay revealed that compound TM-6 was not only a good biometal chelator by inhibiting Cu2+-induced Aß aggregation (95.3%, 25 µM) but also could disassemble the well-structured Aß fibrils (88.1%, 25 µM). Further, TM-6 could cross the blood-brain barrier (BBB) in vitro. More importantly, compound TM-6 did not show any acute toxicity in mice at doses of up to 1000 mg/kg and improved scopolamine-induced memory impairment. Taken together, these data indicated that TM-6, an excellent balanced multifunctional inhibitor, was a potential lead compound for the treatment of AD.

Novel 3-benzylidene/benzylphthalide Mannich base derivatives as potential multifunctional agents for the treatment of Alzheimer's disease.

To discover novel multifunctional agents for the treatment of Alzheimer's disease, a series of 3-benzylidene/benzylphthalide Mannich base derivatives were designed, synthesized and evaluated. The biological screening results indicated that most of these derivatives exhibited good multifunctional activities. Among them, compound (Z)-13c raised particular interest because of its excellent multifunctional bioactivities. It displayed excellent EeAChE and HuAChE inhibition (IC50 = 9.18 × 10-5 and 6.16 × 10-4 µM, respectively), good MAO-B inhibitory activity (IC50 = 5.88 µM) and high antioxidant activity (ORAC = 2.05 Trolox equivalents). Additionally, it also exhibited good antiplatelet aggregation activity, moderate self- and Cu2+-induced Aß1-42 aggregation inhibitory potency, disaggregation ability on Aß1-42 fibrils, biometal chelating ability, appropriate BBB permeability and significant neuroprotective effect. Furthermore, (Z)-13c can also ameliorate the learning and memory impairment induced by scopolamine in mice. These multifunctional properties highlight compound (Z)-13c as a promising candidate for further development of multifunctional drug against AD.

Design, synthesis and evaluation of phthalide alkyl tertiary amine derivatives as promising acetylcholinesterase inhibitors with high potency and selectivity against Alzheimer's disease.

A series of phthalide alkyl tertiary amine derivatives were designed, synthesized and evaluated as potential multi-target agents against Alzheimer's disease (AD). The results indicated that almost all the compounds displayed significant AChE inhibitory and selective activities. Besides, most of the derivatives exhibited increased self-induced Aß1-42 aggregation inhibitory activity compared to the lead compound dl-NBP, and some compounds also exerted good antioxidant activity. Specifically, compound I-8 showed the highest inhibitory potency toward AChE (IC50 = 2.66 nM), which was significantly better than Donepezil (IC50 = 26.4 nM). Moreover, molecular docking studies revealed that compound I-8 could bind to both the catalytic active site and peripheral anionic site of AChE. Furthermore, compound I-8 displayed excellent BBB permeability in vitro. Importantly, the step-down passive avoidance test indicated that I-8 significantly reversed scopolamine-induced memory deficit in mice. Collectively, these results suggested that I-8 might be a potent and selective AChE inhibitor for further anti-AD drug development.

Pyridoxine-resveratrol hybrids as novel inhibitors of MAO-B with antioxidant and neuroprotective activities for the treatment of Parkinson's disease.

A series of pyridoxine-resveratrol hybrids were designed and synthesized as monoamine oxidase B inhibitors for the treatment of Parkinson's disease. Most of them exhibited potent inhibitory activities on MAO-B with high selectivity. Specifically, compounds 12a, 12g and 12l showed the most excellent inhibition to hMAO-B with the IC50 values of 0.01 µM, 0.01 µM and 0.02 µM, respectively. Further reversibility study demonstrated that 12a and 12l were reversible and 12g was irreversible MAO-B inhibitors. Molecular docking studies of MAO revealed the binding mode and high selectivity of these compounds with MAO-B. In addition, these three representative compounds also exhibited low cytotoxicity and excellent neuroprotective effect in the test on H2O2-induced PC-12 cell injury. Moreover, 12a, 12g and 12l showed good antioxidant activities and high blood-brain barrier permeability. Overall, all of these results highlighted 12a, 12g and 12l were potential and excellent MAO-B inhibitors for PD treatment.

Design, synthesis and evaluation of flurbiprofen-clioquinol hybrids as multitarget-directed ligands against Alzheimer's disease.

A series of novel flurbiprofen-clioquinol hybrids were designed and synthesized as multifunctional agents for Alzheimer's disease therapy, and their potential was evaluated through various biological experiments. In vitro studies showed that most target compounds exhibited significant ability to inhibit self- and Cu2+-induced ß-amyloid aggregation. Furthermore, some target compounds, especially 7i and 7r, also showed biometal chelating abilities, antioxidant activity, anti-neuroinflammatory activity and appropriate BBB permeability. These biological activities indicated that the representative compound 7i and 7r might be promising multifunctional agents for AD treatment.

Flurbiprofen-chalcone hybrid Mannich base derivatives as balanced multifunctional agents against Alzheimer's disease: Design, synthesis and biological evaluation.

The complex pathogenesis of Alzheimer's disease (AD) calls for multitarget approach for disease management. Herein, a series of novel flurbiprofen-chalcone hybrid Mannich base derivatives were designed and synthesized. The biological screening results indicated that most of the derivatives exhibited potent multi-target effects involved in AD. In particular, compound 6c bearing a pyrrolidine group showed the highest activities against self- and Cu2+-induced Aß1-42 aggregation (70.65% and 54.89% at 25.0 µM, respectively), highly selective inhibition towards AChE and MAO-B (IC50 = 7.15 µM and 0.43 µM respectively), good antioxidant ability and metal-chelating property. Moreover, 6c displayed excellent anti-neuroinflammatory activity and appropriate BBB permeability in vitro. These outstanding results qualified compound 6c as a promising multifunctional agent for further development of disease-modifying treatment of AD.

Design, synthesis and evaluation of chalcone Mannich base derivatives as multifunctional agents for the potential treatment of Alzheimer's disease.

A series of chalcone Mannich base derivatives were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer's disease based on the multi-target directed ligands design strategy. In vitro assays demonstrated that most of the derivatives exerted potent selective inhibitory potency on AChE with good multifunctional properties. Among them, representative compound 7c exhibited moderate inhibitory potency for EeAChE (IC50 = 0.44 µM) and MAO-B inhibition (IC50 = 1.21 µM), good inhibitory effect on self-induced Aß1-42 aggregation (55.0%, at 25 µM), biometal chelating property, moderate antioxidant activity with a value 1.93-fold of Trolox. Moreover, both kinetic analysis of AChE inhibition and molecular modeling study revealed that 7c showed a mixed-type inhibition, binding simultaneously to CAS and PAS of AChE. In addition, 7c also displayed high BBB permeability. These properties indicated 7c may be a promising multifunctional agent for the treatment of AD.

Novel salicylamide derivatives as potent multifunctional agents for the treatment of Alzheimer's disease: Design, synthesis and biological evaluation.

A series of salicylamide derivatives were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer's disease. In vitro assays demonstrated that most of the derivatives were selective AChE inhibitors. They showed good inhibitory activities of self- and Cu2+-induced Aß1-42 aggregation, and significant antioxidant activities. Among them, compound 15b exhibited good inhibitory activity toward RatAChE and EeAChE with IC50 value of 10.4 µM and 15.2 µM, respectively. Moreover, 15b displayed high antioxidant activity (2.46 Trolox equivalents), good self- and Cu2+-induced Aß1-42 aggregation inhibitory potency (42.5% and 31.4% at 25.0 µM, respectively) and moderate disaggregation ability to self- and Cu2+-induced Aß1-42 aggregation fibrils (23.4% and 27.0% at 25 µM, respectively). Furthermore, 15b also showed biometal chelating abilities, anti-neuroinflammatory ability and BBB permeability. These multifunctional properties indicated compound 15b was worthy of being chosen for further pharmacokinetics, toxicity and behavioral researches to test its potential for AD treatment.

Discovery of novel 2,5-dihydroxyterephthalamide derivatives as multifunctional agents for the treatment of Alzheimer's disease.

A series of 2,5-dihydroxyterephthalamide derivatives were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer's disease. In vitro assays demonstrated that most of the derivatives exhibited good multifunctional activities. Among them, compound 9d showed the best inhibitory activity against both RatAChE and EeAChE (IC50 = 0.56 µM and 5.12 µM, respectively). Moreover, 9d exhibited excellent inhibitory effects on self-induced Aß1-42 aggregation (IC50 = 3.05 µM) and Cu2+-induced Aß1-42 aggregation (71.7% at 25.0 µM), and displayed significant disaggregation ability to self- and Cu2+-induced Aß1-42 aggregation fibrils (75.2% and 77.2% at 25.0 µM, respectively). Furthermore, 9d also showed biometal chelating abilities, antioxidant activity, anti-neuroinflammatory activities and appropriate BBB permeability. These multifunctional properties highlight 9d as promising candidate for further studies directed to the development of novel drugs against AD.

Design, synthesis and evaluation of 4'-OH-flurbiprofen-chalcone hybrids as potential multifunctional agents for Alzheimer's disease treatment.

A series of 4'-OH-flurbiprofen-chalcone hybrids were designed, synthesized and evaluated as potential multifunctional agents for the treatment of Alzheimer's disease. The biological screening results indicated that most of these hybrids exhibited good multifunctional activities. Among them, compounds 7k and 7m demonstrated the best inhibitory effects on self-induced Aß1-42 aggregation (60.0% and 78.2%, respectively) and Cu2+-induced Aß1-42 aggregation (52.4% and 95.0%, respectively). Moreover, these two representative compounds also exhibited good antioxidant activities, MAO inhibitions, biometal chelating abilities and anti-neuroinflammatory activities in vitro. Furthermore, compound 7m displayed appropriate blood-brain barrier permeability. These multifunctional properties highlight compound 7k and 7m as promising candidates for further development of multi-functional drugs against AD.

Design, synthesis and evaluation of scutellarein-O-acetamidoalkylbenzylamines as potential multifunctional agents for the treatment of Alzheimer's disease.

A series of scutellarein-O-acetamidoalkylbenzylamines derivatives were designed based on a multitarget-directed ligands strategy for the treatment of Alzheimer's disease. Among these compounds, compound T-22 demonstrated excellent acetylcholinesterase inhibitory, moderate inhibitory effects on self-induced Aß1-42 aggregation, Cu2+-induced Aß1-42 aggregation, human AChE-induced Aß1-40 aggregation and disassembled Cu2+-induced aggregation of the well-structured Aß1-42 fibrils, and also acted as potential antioxidant and biometals chelator. Both kinetic analysis of AChE inhibition and molecular modeling study suggested that T-22 interacted with both the catalytic active site and peripheral anionic site of AChE. Moreover, compound T-22 showed a good neuroprotective effect against H2O2-induced PC12 cell injury and low toxicity in SH-SY5Y cells. Furthermore, the step-down passive avoidance test indicated T-22 significantly reversed scopolamine-induced memory deficit in mice. Taken together, the data showed that T-22 was an interesting multifunctional lead compound worthy of further study for AD.

Pyridoxine-resveratrol hybrids Mannich base derivatives as novel dual inhibitors of AChE and MAO-B with antioxidant and metal-chelating properties for the treatment of Alzheimer's disease.

A series of pyridoxine-resveratrol hybrids Mannich base derivatives as multifunctional agents have been designed, synthesized and evaluated for cholinesterase (ChE) and monoamine oxidase (MAO) inhibitory activity. To further explore the multifunctional properties of the new derivatives, their antioxidant activities and metal-chelating properties were also tested. The results showed that most of these compounds could selectively inhibit acetylcholinesterase (AChE) and MAO-B. Among them, compounds 7d and 8b exhibited the highest potency for AChE inhibition with IC50 values of 2.11µM and 1.56µM, respectively, and compound 7e exhibited the highest MAO-B inhibition with an IC50 value of 2.68µM. The inhibition kinetic analysis revealed that compound 7d showed a mixed-type inhibition, binding simultaneously to the CAS and PAS of AChE. Molecular modeling study was also performed to investigate the binding mode of these hybrids with MAO-B. In addition, all target compounds displayed good antioxidant and metal-chelating properties. Taken together, these preliminary findings can be a new starting point for further development of multifunctional agents for Alzheimer's disease.

Multifunctional thioxanthone derivatives with acetylcholinesterase, monoamine oxidases and ß-amyloid aggregation inhibitory activities as potential agents against Alzheimer's disease.

A series of 1-hydroxyl-3-aminoalkoxy-thioxanthone derivatives were designed, synthesized and evaluated as potential multifunctional agents against Alzheimer's disease (AD). The results indicated that most of these compounds exhibited good AChE and MAOs inhibitory activities, significant inhibition of self- and Cu2+-induced Aß1-42 aggregation, and moderate to good antioxidant activities. Specifically, compound 9e displayed high inhibitory potency toward AChE (IC50=0.59±0.02µM), MAO-A and MAO-B (IC50=1.01±0.02µM and 0.90±0.01µM respectively), excellent efficiency to block both self- and Cu2+-induced Aß1-42 aggregation (74.8±1.2% and 87.7±1.9% at 25µM, respectively), good metal-chelating property and a low toxicity in SH-SY5Y cells. Furthermore, kinetic and molecular modeling studies revealed that compound 9e binds simultaneously to the catalytic active site and peripheral anionic site of AChE, and could penetrate the BBB. Collectively, these results suggested that 9e might be a potential multifunctional agent for further development in the treatment of AD.

DL-3-n-butylphthalide-Edaravone hybrids as novel dual inhibitors of amyloid-ß aggregation and monoamine oxidases with high antioxidant potency for Alzheimer's therapy.

Considering the complex etiology of Alzheimer's disease (AD), multifunctional agents may be beneficial for the treatment of this disease. A series of DL-3-n-butylphthalide-Edaravone hybrids were designed, synthesized and evaluated as novel dual inhibitors of amyloid-ß aggregation and monoamine oxidases. Among them, compounds 9a-d exhibited good inhibition of self-induced Aß1-42 aggregation with inhibition ratio 57.7-71.5%. For MAO, these new hybrids exhibited good balance of inhibition for MAO-A and MAO-B. In addition, all target compounds retained the antioxidant activity of edaravone, showed equal or better antioxidant activity than edaravone. The results of the parallel artificial membrane permeability assay for blood-brain barrier indicated that compounds 9a-d would be able to cross the blood-brain barrier and reach their biological targets in the central nervous system. The promising results in all assays demonstrated that the strategy behind the designing of compounds was rational and favourable. Taken together, these preliminary findings suggested that the compounds with the strongest bioactivity deserves further investigated for pharmacological development in AD therapy.