scholarly journals Synthesis and Evaluation of the Acetylcholinesterase Inhibitory Activities of Some Flavonoids Derived from Naringenin

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
The-Huan Tran ◽  
Thi-Thu-Hien Vo ◽  
Thi-Quynh-Nhi Vo ◽  
Thi-Cam-Nhung Cao ◽  
Thai-Son Tran
Keyword(s):  
Inhibitory Activity ◽  
Biological Activities ◽  
Developed Countries ◽  
Catalytic Triad ◽  
Peripheral Region ◽  
Strong Interactions ◽  
Research Approach ◽  
Aging Populations ◽  
Ache Inhibitory Activity ◽  
Long Time

Alzheimer’s disease (AD) is an irreversible neurodegenerative disease that affects many older people adversely. AD has been putting a huge socioeconomic burden on the healthcare systems of many developed countries with aging populations. The need for new therapies that can halt or reverse the progression of the disease is now extremely great. A research approach in the finding new treatment for AD that has attracted much interest from scientists for a long time is the reestablishment of cholinergic transmission through inhibition of acetylcholinesterase (AChE). Naringenin is a flavonoid with the potential inhibitory activity against AChE. From naringenin, many other flavonoid derivatives, such as flavanones and chalcones, can be synthesized. In this study, by applying the Williamson method, nine flavonoid derivatives were synthesized, including four flavanones and five chalcones. The evaluation of AChE inhibitory activity by the Ellman method showed that there were four substances (2, 4, 5, and 7) with relatively good biological activities (IC50 < 100 μM), and these biological activities were better than that of naringenin. The molecular docking revealed that strong interactions with amino acid residue Ser200 of the catalytic triad and those of the peripheral region of the enzyme were crucial for strong effects against AChE. Compound 7 had the strongest AChE inhibitory activity (IC50 13.0 ± 1.9 μM). This substance could be used for further studies.

scholarly journals Volatile terpenoids as potential drug leads in Alzheimer’s disease

2017 ◽  
Vol 15 (1) ◽  
pp. 332-343 ◽  
Author(s):  
Karolina A. Wojtunik-Kulesza ◽  
Katarzyna Targowska-Duda ◽  
Katarzyna Klimek ◽  
Grażyna Ginalska ◽  
Krzysztof Jóźwiak ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mtt Assay ◽  
Inhibitory Activity ◽  
Biological Activities ◽  
Plant Metabolites ◽  
Secondary Plant Metabolites ◽  
Docking Simulations ◽  
Ache Inhibitory Activity ◽  
Volatile Terpenoids

AbstractAlzheimer’s disease (AD) is by far the most prevalent of all known forms of dementia. Despite wide-spread research, the main causes of emergence and development of AD have not been fully recognized. Natural, low-molecular, lipophilic terpenoids constitute an interesting group of secondary plant metabolites, that exert biological activities of possible use in the prevention and treatment of AD. In order to identify secondary metabolites possessing both antioxidant activity and the potential to increase the level of acetylcholine, selected terpenoids have been screened for possible acetylcholinesterase inhibitory activity by use of two methods, namely Marston (chromatographic assay) and Ellman (spectrophotometric assay). In order to describe the interaction between terpenes and AChE active gorge, molecular docking simulations were performed. Additionally, all analyzed terpenes were also evaluated for their cytotoxic properties against two normal cell lines using MTT assay. The obtained results show that: carvone (6), pulegone (8) and γ-terpinene (7) possess desirable AChE inhibitory activity. MTT assay revealed low or lack of cytotoxicity of these metabolites. Thus, among the investigated terpenes, carvone (6), pulegone (8) and y-terpinene (7) can be recognized as compounds with most promising activities in the development of multi-target directed ligands.

Development of Phthalimide-Donepezil Hybrids as Potent Multitarget- Directed Ligands for the Treatment of Alzheimer’s Disease

2020 ◽  
Vol 17 (9) ◽  
pp. 1155-1163
Author(s):  
Lintao Yu ◽  
Jian Shi ◽  
Xinfeng Cheng ◽  
Keren Wang ◽  
Shuang Liu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Inhibitory Activity ◽  
Biological Activities ◽  
Docking Study ◽  
Binding Mode ◽  
Mao B ◽  
Ic50 Value ◽  
Ache Inhibitory Activity

Background: Due to the complex etiology of AD, multi-target-directed ligands (MTDLs), combining two or more distinct pharmacological moieties, have been developed in both symptomatic and disease-modifying efficiencies and are considered as an effective way for the treatment of AD. Methods: To test their biological activities, including AChE/BChE inhibitory activity and MAOA/ MAO-B inhibitory activity. In addition, molecular modeling studies were performed to afford insight into the binding mode. Results: The results displayed that compound 4c showed the best AChE inhibitory activity with an IC50 value of 4.2 μM, which was supported by the kinetic study and docking study. Compound 4c was also a selective MAO-B inhibitor (IC50 = 8.2 μM). Moreover, compound 4c could cross the blood-brain barrier in vitro. Conclusion: Compound 4c deserved to further study as a potential multifunctional agent for the treatment of Alzheimer’s disease.

scholarly journals MANAGERS’ PROPENSITY FOR PARTICIPATIVE DECISION MAKING IN BANGLADESH AND MALAYSIA: A COMPARATIVE STUDY

2020 ◽  
pp. 294-302
Author(s):  
Lt Col Md Enamul Islam ◽  
Barrister Shahrina Razzaque Juhi ◽  
Dr. Valliappan Raju
Keyword(s):  
Decision Making ◽  
Developed Countries ◽  
Organisational Culture ◽  
Business Leaders ◽  
Power Sharing ◽  
Decision Making Process ◽  
Research Approach ◽  
Four Dimensions ◽  
Organisational Effectiveness ◽  
Long Time

Subordinate participation in the decision-making process has been practised extensively in developed countries for a long time. Less is known about developing and least developing nations. This study assesses the propensity for participative decision making among the managers of Bangladesh and Malaysia. The hypotheses test propensity scale among the managers of both the countries and if mangers of Malaysian Industries demonstrate more propensity than Bangladeshi managers. In the process, the study assesses the similarities and differences of opinion concerning four dimensions of the participative decision-making process, i.e. organisational effectiveness, organisational culture, perceived power-sharing and mutual trust. The quantitative survey research approach found that individual differences significantly determine one’s propensity for the participative decision-making process. In an independent samples t-test, Malaysian managers have shown a more significant level propensity for participative decision making than Bangladeshi managers. The study also shows that there is a significant relationship between trust and organisational culture as two important dimensions of PDM. The results of this study arise a case for managers of both countries to question their expectations about employees and disparagingly examine whether their predispositions influence their decision-making practices. The findings may provide business leaders of both the courtiers in these contexts with an understanding of the possible adaptation of the concept of the participative decision-making process. KEYWORDS: Propensity for Participative Decision-Making Process, Productivity, Managing People at Work, Power Sharing, Bangladesh, Malaysia

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

Effect of alkaloid extracted from Huperzia phlegmaria on cognitive deficits scopolamine-induced in mice

2020 ◽  
Vol 16 ◽  
Author(s):  
Dang Kim Thu ◽  
Dao Thi Vui ◽  
Nguyen Thi Ngoc Huyen ◽  
Nguyen Thi Thanh Binh ◽  
Nguyen Thi Huyen ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mouse Brain ◽  
Cognitive Deficits ◽  
Inhibitory Activity ◽  
Water Maze ◽  
Ache Activity ◽  
Y Maze ◽  
Ache Inhibitory Activity ◽  
Kinetic Inhibition ◽  
Brain Tissues

Background: Huperzia phlegmaria has been used for the treatment of neurological disorder. Alkaloids are main bioactive compounds found in Huperzia phlegmaria. We aimed to investigate the acetylcholinesterase (AChE) inhibitory activity in vitro of Huperzia phlegmaria alkaloid extract (HpAE) and protective effects on mice which were induced cognitive deficits by scopolamine. Methods: AChE inhibitory activity and kinetic inhibition mechanism was investigated by Ellman's assay. Mice were administrated orally HpAE (30 mg/kg and 60 mg/kg) for fourteen days, and injected scopolamine at a dose of 1 mg/kg intraperitoneally for four days to induce cognitive impairment. The Y-maze and the Morris water maze were used for evaluating the memory behaviors. Acetylcholine (ACh) levels and AChE activity were measured in brain tissue. Glutathione peroxidase (GPx), superoxide dismutase (SOD) activities, and malondialdehyde (MDA) groups were also evaluated in the mouse brain tissues. Results: Our data showed that HpAE had the strong AChE inhibitory activity with an IC50 value of 5.12 ± 0.48 μg/mL in a concentration-dependent manner. Kinetic inhibition analysis demonstrated that HpPAE inhibited AChE followed the mixed inhibition type with Ki (representing the affinity of the enzyme and inhibitor) was 4.37 ± 0.35 µg/mL. Scopolamine induced the cognitive impairment in Morris Water Maze and Y-maze test along with reduced brain levels of ACh and antioxidant enzyme and increased AChE activity in mouse brain tissues. Treatment with HpAE at both dose (30 mg/kg and 60 mg/kg) decreased the SCP-induced cognitive impairment in both behavioral tests along with decreased acetylcholinesterase activity and MDA level, and increased ACh level and antioxidant enzyme in mouse brain tissues. Conclusion: Our results suggested that the HpAE at both dose (30 mg/kg and 60 mg/kg) may be used for prevent and treatment of Alzheimer’s disease.

Nω-Hydroxy-L-arginine and Its Homologues. Chemical and Biological Properties. A Review

2004 ◽  
Vol 69 (3) ◽  
pp. 499-510 ◽  
Author(s):  
Petra Beranová ◽  
Karel Chalupský ◽  
Gustav Entlicher
Keyword(s):  
Inhibitory Activity ◽  
Biological Activities ◽  
Biological Effects ◽  
Biological Properties ◽  
No Synthase ◽  
Point Of View ◽  
No Donor ◽  
Good Substrate ◽  
No Formation ◽  
Vasorelaxant Activity

Nω-Hydroxy-L-arginine (NOHA) is a stable intermediate in NO formation from L-arginine catalyzed by NO synthase (NOS). Apparently, NOHA can be released and serve as a stable reserve NO donor (as a substrate of NOS) or transported and exert its own biological effects. It shows endothelium-dependent as well as endothelium-independent vasorelaxant activity. The latter case indicates that NOHA can be metabolized by pathways independent of NOS. These possibilities are discussed in detail. Of the available NOHA homologues homo-NOHA is a good substrate of NOS while nor-NOHA seems to be a very poor substrate of this enzyme. On the contrary, nor-NOHA exerts arginase inhibitory activity 20 times higher than NOHA whereas homo-NOHA is inactive. Detailed investigation of biological activities of NOHA and its homologues seems to be promising from the pharmacological point of view. A review with 43 references.

scholarly journals Mangiferin as New Potential Anti-Cancer Agent and Mangiferin-Integrated Polymer Systems—A Novel Research Direction

Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Svetlana N. Morozkina ◽  
Thi Hong Nhung Vu ◽  
Yuliya E. Generalova ◽  
Petr P. Snetkov ◽  
Mayya V. Uspenskaya
Keyword(s):  
Molecular Mechanisms ◽  
Biological Activities ◽  
Research Direction ◽  
Biological Action ◽  
The Body ◽  
Biologically Active ◽  
Polymer Systems ◽  
Anti Cancer ◽  
Long Time ◽  
Cancer Agent

For a long time, the pharmaceutical industry focused on natural biologically active molecules due to their unique properties, availability and significantly less side-effects. Mangiferin is a naturally occurring C-glucosylxantone that has substantial potential for the treatment of various diseases thanks to its numerous biological activities. Many research studies have proven that mangiferin possesses antioxidant, anti-infection, anti-cancer, anti-diabetic, cardiovascular, neuroprotective properties and it also increases immunity. It is especially important that it has no toxicity. However, mangiferin is not being currently applied to clinical use because its oral bioavailability as well as its absorption in the body are too low. To improve the solubility, enhance the biological action and bioavailability, mangiferin integrated polymer systems have been developed. In this paper, we review molecular mechanisms of anti-cancer action as well as a number of designed polymer-mangiferin systems. Taking together, mangiferin is a very promising anti-cancer molecule with excellent properties and the absence of toxicity.

scholarly journals The validity of world class business criteria across developed and developing countries

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Andre J. Parker ◽  
Theo H. Veldsman
Keyword(s):  
Developing Countries ◽  
Developed Countries ◽  
General Assumption ◽  
Research Approach ◽  
Class Standing ◽  
Managerial Implications ◽  
World Class ◽  
Value Add ◽  
Business Challenges ◽  
Developing And Developed Countries

Orientation: World class implies being able to respond effectively to the prevailing business challenges in a manner that surpasses competitors and to compete effectively in the global economy.Research purpose: To assess the validity of the general assumption in the literature that world class criteria are equally applicable worldwide.Motivation for research: The possibility exists that developing countries require an adjusted mix of world class criteria and practices to become globally competitive.Research design, approach and method: A quantitative field survey research approach was adopted. A web-enabled questionnaire was designed, covering 35 world class practices grouped under 7 world class criteria. A cross-section of the senior management from 14 developing and 20 developed country’s organisations partook in the study.Main findings: It was empirically confirmed that the majority of world class practices posited in the literature are used by participating organisations; that world class criteria do not apply equally across developed and developing countries; and that more important than country location, is the deliberate choice by an organisation’s leadership to become world class. An empirically based model of ascending to world class was proposed.Practical/managerial implications: Regardless of country location, the leadership of an organisation can make their organisation world class by applying the proposed world class model.Contribution/value add: A reliable web enabled instrument was designed that can be used to assess an organisation’s world class standing; the assumption that world class criteria are equally valid across developing and developed countries was proven partially incorrect; since becoming or being world class is also a leadership choice regardless of location.

Marked differences in genetic diversity and differentiation between the centre and edge of the geographical range of Megaleranthis saniculifolia (Ranunculaceae), a Korean endemic species

2012 ◽  
Vol 60 (7) ◽  
pp. 582
Author(s):  
Ji Hee Jeong ◽  
Zin-Suh Kim
Keyword(s):  
Genetic Diversity ◽  
Peripheral Region ◽  
Issr Markers ◽  
Ex Situ ◽  
Allele Frequency Distribution ◽  
Low Genetic Diversity ◽  
Long Time ◽  
Megaleranthis Saniculifolia ◽  
Degree Of Differentiation ◽  
Substantial Degree

The amount and distribution of genetic diversity within and between Megaleranthis saniculifolia Ohwi populations were compared between the central and peripheral regions of the species distribution. Allozyme and ISSR markers were used for genetic analysis of six populations from the central region (DY) and five populations from the peripheral region (MJ). Genetic diversity was substantially higher in the DY region than in the MJ region. Relatively uniform homozygote excess at many loci in most populations indicated that M. saniculifolia was influenced by a substantial degree of inbreeding in both regions. The degree of differentiation between populations was remarkably higher in the MJ region than in the DY region. Cluster analysis showed a trend towards separation between regions, although populations in the MJ region exhibited a slightly different trend according to the markers. We conclude that genetic drift has been affecting the populations in the MJ region for a long time, on the basis of their low genetic diversity, high differentiation, U-shaped allele-frequency distribution, and fixation of alleles towards opposing frequencies (1 or 0) among populations. In contrast, the DY region maintained relatively stable populations, although evidence of a recent bottleneck was found in one population. Along with some practical measures for genetic conservation, we present an optimal sample size for ex situ conservation to secure as many common alleles as possible.

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