• YAKHAK HOEJI
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• v.46 no.3
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• pp.185-191
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• 2002

Alzheimer's disease (AD) involves neuronal degeneration with impaired cholinergic transmission, particularly in areas of the brain associated with learning and memory. Several cholinesterase inhibitors are widely prescribed to ameliorate the cognitive deficits in AD patients. In an attempt to examine if tacrine and donepezil, two well-known cholinesterase inhibitors, exhibit additional pharmacological actions in primary cultured rat cortical cells, we investigated the effects on neuronal injuries induced by glutamate or N-methyl-D-aspartate (NMDA), $\beta$-amyloid fragment ( $A_{{beta}25-35)}$), and various oxidative insults. Both tacrine and donepezil did not significantly inhibit the excitotoxic neuronal damage induced by glutamate. However, tacrine inhibited the toxicity induced by NMDA in a concentration-dependent fashion. In addition, tacrine significantly inhibited the $A_{{beta}25-35)}$-induced neuronal injury at the concentration of 50 $\mu$M. In contrast, donepezil did not reduce the NMDA- nor $A_{{beta}25-35)}$-induced neuronal injury. Tacrine and donepezil had no effects on oxidative neuronal injuries in cultures nor on lipid peroxidation in vitro. These results suggest that, in addition to its anticholinesterase activity, the neuroprotective effects by tacrine against the NMDA- and $A_{{beta}25-35)$-induced toxicity may be beneficial for the treatment of AD. In contrast, the potent and selective inhibition of central acetylcholinesterase appears to be the major action mechanism of donepezil.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.438-443
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• 1991

This study was designed to examine the effects of diphenhydramine and papaverine on the toxic manifestations of cholinesterase inhibitors. It was found that papaverine increase acetylcholinesterase activity in cerebral cortex of mice. Papaverine pretreatment tended to increase acetylcholinesterase activity against the actions of neostigmine and physostigmine. When diphenhydramine (20~30 mg/kg, s.c.) was treated 20 min before the administration of cholinesterase inhibitor, it significantly extended the onset latency in the signs of toxicosis which were characteristically produced by physostigmine (0.25~1.5 mg/kg, s.c.) or neostigmine (0.125~0.5 mg/kg, s.c.), and it also prevented lethality in all of the animals.

• Dementia and Neurocognitive Disorders
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• v.21 no.4
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• pp.107-116
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• 2022

Attention is being paid to diagnosis and treatment of mild cognitive impairment (MCI) because early diagnosis and preventive management can slow down the progression of Alzheimer's disease. In particular, in the present era, the use of biomarkers for predicting conversion into dementia is permitted in medical practice. Therefore, authors aimed to propose additional considerations when updating guidelines for the management of MCI, including predictable biomarkers, revising treatment option after additional clinical trials for cholinesterase inhibitors, and detailed regimes for lifestyle interventions. After reviewing 3 patients with MCI by detailed evaluation, we realized that cholinesterase inhibitors were not recommended. In addition, regular exercise and cognitive training were only possible recommendations for patients according to current guidelines, although all 3 patients had evidence of β-amyloid accumulation and related neurodegeneration. Furthermore, caregivers for all 3 patients were worried whether patients could keep doing regular exercise and cognitive training by themselves and asked about the economic training system which monitors patients so that they can keep training. Therefore, we propose that guidelines for managing MCI need to be updated in the present era when the use of biomarkers for predicting conversion into dementia is permitted in medical practice.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.225-228
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• 2007

Lipoic acid (LA) is a multifunctional antioxidant against a variety of ROS. Nitrone acts as free radical spin trap and exhibits neuroprotective activity. Thus, LA-nitrone derivatives (6, 7, 8, and 9) were synthesized and screened as an antioxidant and inhibitors for cholinesterases. Even though the antioxidant effect of LA-nitrone derivatives was not improved, they turned out to be effective inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in μM range.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.289-293
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• 2011

The antioxidant and cholinesterase inhibitory activities of methanol, pretanol, and acetone extracts of Eupausia superba were investigated and their bioactivities compared. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] ($ABTS^+$) radical-scavenging activities and reducing power assays were used to determine antioxidant activities, and Ellman's colorimetric methods were applied to evaluate cholinesterase inhibitory activity. Although all extracts were positive, Acetone extract of E. superba showed the highest activities. However, these showed moderate or no inhibitory activity against butyrylcholinesterase. Moreover, the total carotenoid contents of the organic solvent extracts followed the same order as their antioxidant and acetylcholinesterase inhibitory activities. These results suggest that E. superba is a potential source of natural antioxidants and cholinesterase inhibitors.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.190.2-191
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• 2001

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1681-1686
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• 2014

A series of hybrid molecules between (${\alpha}$)-lipoic acid (ALA) and 4-amino-1-benzyl piperidines were synthesized and their in vitro cholinesterase (acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)) inhibitory activities were evaluated. Even though the parent compounds did not exhibit any inhibitory activity against cholinesterase (ChE) with the exception of compound 14 ($IC_{50}=255.26{\pm}4.41$ against BuChE), all hybrid molecules demonstrated BuChE inhibitory activity. Some hybrid compounds also displayed AChE inhibitory activity. Specifically, compound 17 was shown to be an effective inhibitor against both AChE ($IC_{50}=1.75{\pm}0.30{\mu}M$) and BuChE ($IC_{50}=5.61{\pm}1.25{\mu}M$) comparable to galantamine ($IC_{50}=1.7{\pm}0.9{\mu}M$ against AChE and $IC_{50}=9.4{\pm}2.5{\mu}M$ against BuChE). Inhibition kinetic studies using compound 17 indicated a mixed inhibition type for AChE and a noncompetitive inhibition type for BuChE. Its binding affinity ($K_i$) values to AChE and BuChE were $3.8{\pm}0.005{\mu}M$ and $7.0{\pm}0.04{\mu}M$, respectively.

• Korean Journal of Biological Psychiatry
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• v.23 no.2
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• pp.48-56
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• 2016

Alzheimer's disease (AD) is a neurodegenerative disorder in which neuronal loss causes cognitive decline and other neuropsychiatric problems. It can be diagnosed based on history, examination, and appropriate objective assessments, using standard criteria such as the Diagnostic and Statistical Manual of Mental Disorders or the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA). Brain imaging and biomarkers are making progress in the differential diagnoses among the different disorders. The cholinesterase inhibitors, donepezil, rivastigmine and galantamine and N-methyl-D-aspartate receptors antagonist memantine are approved by the US Food and Drug Administration for AD. Recently some acetylcholinesterase inhibitors gained approval for the treatment of severe AD and became available in a higher dose formulation or a patch formulation. Optimal care in AD is multifactorial and it should include early diagnosis and multidisciplinary care with pharmacological and nonpharmacological interventions including exercise interventions, cognitive interventions and maintenance of social networks.

• Journal of Pharmacopuncture
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• v.22 no.4
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• pp.231-238
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• 2019

Objectives: Alzheimer's disease (AD), an overwhelming neurodegenerative disease, has deleterious effects on the brain that consequently causes memory loss and language impairment. This study was intended to investigate the neuroprotective activity of the two essential oils (EOs) from Iranian Pistacia khinjuk (PK) leaves and Allium sativum (AS) cloves against β-Amyloid 25-35 (Aβ25-35) induced elevation of cholinesterase enzymes in AD. Methods: The EOs of PK (PKEO) and AS (ASEO) were prepared and analyzed in terms of extraction yield, phenolic content, and cholinergic markers in vitro. Moreover, both were administered orally to adult male Wistar rats at concentrations of 1, 2, and 3%. The inhibitory potential of PKEO and ASEO was compared with Donepezil (0.75 mg/kg) against the high activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Results: PKEO reached an inhibition rate of 83.6% and 81.4% against AChE and BChE, respectively. ASEO had lower anti-cholinesterase activity (65.4% and 31.5% for the inhibition AChE and BChE). PKEO was found to have more phenolic content than ASEO. A significantly positive correlation was observed between the total phenolics and anti-cholinesterase potential. In rats, both EOs decreased the enzyme activity in a concentration-dependent manner. As compared with Donepezil, the significant difference in the AChE and BChE inhibition occurred as rats were treated with PKEO 3% (p < 0.05). Conclusion: It could be concluded that PKEO and ASEO are potent inhibitors of AChE and BChE in rats that hold promise to be used for the treatment of AD.

• Journal of the Korean Chemical Society
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• v.60 no.2
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• pp.125-130
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• 2016

With the goal of developing Alzheimer’s disease therapeutics, we have designed and synthesized new triazole linked decursinol derivatives having potency inhibitory activities against cholinesterase [acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)]. Since inhibition of cholinesterase (ChE) is still considered to be one of the most effective targets to treat AD patients, many new classes of ChE inhibitors have been synthesized. In an effort of identifying new type of cholinergic drug, decursinol derivatives 11-17 have been synthesized between decursinol and other biological interesting compounds such as lipoic acid, polyphenols, etc by using the click reaction and then evaluated their biological activities. Compound 12 (IC₅₀ = 5.89 ± 0.31 mM against BuChE) showed more effective inhibitory activity against BuChE than galantamine (IC₅₀ = 9.4 ± 2.5 mM). Decursinol derivatives can be considered a new class inhibitor for BuChE and can be applied to be a novel drug candidate to treat AD patients.