Cholinesterase Structure: Identification of Residues and Domains Affecting Organophosphate Inhibition and Catalysis

1998 ◽  
Author(s):  
Palmer W. Taylor
Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3913
Author(s):  
Rui-Jie He ◽  
Jun Li ◽  
Yong-Lin Huang ◽  
Ya-Feng Wang ◽  
Bing-Yuan Yang ◽  
...  

Polyphenols, widely distributed in the genus Melastoma plants, possess extensive cellular protective effects such as anti-inflammatory, anti-tyrosinase, and anti-obesity, which makes it a potential anti-inflammatory drug or enzyme inhibitor. Therefore, the aim of this study is to screen for the anti-inflammatory and enzyme inhibitory activities of compounds from title plant. Using silica gel, MCI, ODS C18, and Sephadex LH-20 column chromatography, as well as semipreparative HPLC, the extract of Melastoma normale roots was separated. Four new ellagitannins, Whiskey tannin C (1), 1-O-(4-methoxygalloyl)-6-O-galloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (2), 1-O-galloyl-6-O-(3-methoxygalloyl)-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (3), and 1-O-galloyl-6-O-vanilloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (4), along with eight known polyphenols were firstly obtained from this plant. The structures of all isolates were elucidated by HRMS, NMR, and CD analyses. Using lipopolysaccharide (LPS)-stimulated RAW2 64.7 cells, we investigated the anti-inflammatory activities of compounds 1–4, unfortunately, none of them exhibit inhibit nitric oxide (NO) production, their IC50 values are all > 50 μM. Anti-tyrosinase activity assays was done by tyrosinase inhibition activity screening model. Compound 1 showed weak tyrosinase inhibitory activity with IC50 values of 426.02 ± 11.31 μM. Compounds 2–4 displayed moderate tyrosinase inhibitory activities with IC50 values in the range of 124.74 ± 3.12–241.41 ± 6.23 μM. The structure–activity relationships indicate that hydroxylation at C-3′, C-4′, and C-3 in the flavones were key to their anti-tyrosinase activities. The successful isolation and structure identification of ellagitannin provide materials for the screening of anti-inflammatory drugs and enzyme inhibitors, and also contribute to the development and utilization of M. normale.


Author(s):  
Eko Hadi Sujiono ◽  
Vicran Zharvan ◽  
Sultra Ade Poetra ◽  
Muthmainnah Muchtar ◽  
Abdi Manab Idris ◽  
...  

2021 ◽  
Vol 920 ◽  
Author(s):  
Mohamed Frihat ◽  
Bérengère Podvin ◽  
Lionel Mathelin ◽  
Yann Fraigneau ◽  
François Yvon

Abstract


2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
G Armstrong ◽  
G Toogood ◽  
DG Jayne ◽  
AM Smith

Abstract Introduction This study explored near-infrared fluorescent cholangiography (NIRFC) with Indocyanine Green (ICG) during laparoscopic cholecystectomy (LC) surgery in a tertiary referral hepatobiliary unit. ICG binds to albumin and is excreted in bile. NIRFC utilises the fluorescent and excretory properties of ICG to provide dynamic extrahepatic bile duct mapping during LC. Method Non-randomised single centre feasibility study. Twenty-two participants were sequentially allocated to four dosing subgroups prior to NIRFC assisted LC. Each received a single intravenous dose of ICG prior to LC with the Stryker Novadaq NIR laparoscope. The biliary anatomy was assessed with NIRFC at three time-points, detection was compared to radiological cholangiogram where available and surgeon satisfaction was assessed. Result Eight participants received 2.5mg ICG 20-40min before surgery, four 0.25mg/kg 20-40min, five 90min – 180min and five 12 – 36 hour pre-operatively. Average age 50 years (S.D±15), BMI 27.5m2 (S.D±3.6), 6/22 were acute LC procedures. The prolonged dosing interval produced increased extrahepatic biliary structure identification (p = 0.016), reduced noise to signal ratio and was consistently preferred by the operating surgeon. NIRFC was inferior to radiological cholangiogram (n = 10) (p = 0.014) for bile duct mapping. We observed iatrogenic bile spillage saturating the field and obscuring structure differentiation and peri-hilar inflammation impeding fluorescent detection in acute LC. Conclusion The dosing regimen 0.25mg/kg ICG 12 to 36 hours prior to surgery provides optimum NIRFC structure visualisation. Fluorescent tissue penetrance is limited in acute peri-hilar inflammation. More research in to the efficiency of NIRFC in emergency LC is required. Take-home message An intravenous dose of 0.25mg/kg of Indocyanine Green 12 to 36 hours before surgery is the optimum dosing regimen for increased extra-hepatic bile duct structures with near infrared fluorescent cholangiography. The role of NIRFC in acute laparoscopic cholecystectomy surgery remains ill-defined.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1996
Author(s):  
 Oluwafemi Adeleke Ojo ◽  
Adebola Busola Ojo ◽  
Charles Okolie ◽  
Mary-Ann Chinyere Nwakama ◽  
Matthew Iyobhebhe ◽  
...  

Neurodegenerative diseases, for example Alzheimer’s, are perceived as driven by hereditary, cellular, and multifaceted biochemical actions. Numerous plant products, for example flavonoids, are documented in studies for having the ability to pass the blood-brain barrier and moderate the development of such illnesses. Computer-aided drug design (CADD) has achieved importance in the drug discovery world; innovative developments in the aspects of structure identification and characterization, bio-computational science, and molecular biology have added to the preparation of new medications towards these ailments. In this study we evaluated nine flavonoid compounds identified from three medicinal plants, namely T. diversifolia, B. sapida, and I. gabonensis for their inhibitory role on acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO) activity, using pharmacophore modeling, auto-QSAR prediction, and molecular studies, in comparison with standard drugs. The results indicated that the pharmacophore models produced from structures of AChE, BChE and MAO could identify the active compounds, with a recuperation rate of the actives found near 100% in the complete ranked decoy database. Moreso, the robustness of the virtual screening method was accessed by well-established methods including enrichment factor (EF), receiver operating characteristic curve (ROC), Boltzmann-enhanced discrimination of receiver operating characteristic (BEDROC), and area under accumulation curve (AUAC). Most notably, the compounds’ pIC50 values were predicted by a machine learning-based model generated by the AutoQSAR algorithm. The generated model was validated to affirm its predictive model. The best models achieved for AChE, BChE and MAO were models kpls_radial_17 (R2 = 0.86 and Q2 = 0.73), pls_38 (R2 = 0.77 and Q2 = 0.72), kpls_desc_44 (R2 = 0.81 and Q2 = 0.81) and these externally validated models were utilized to predict the bioactivities of the lead compounds. The binding affinity results of the ligands against the three selected targets revealed that luteolin displayed the highest affinity score of −9.60 kcal/mol, closely followed by apigenin and ellagic acid with docking scores of −9.60 and −9.53 kcal/mol, respectively. The least binding affinity was attained by gallic acid (−6.30 kcal/mol). The docking scores of our standards were −10.40 and −7.93 kcal/mol for donepezil and galanthamine, respectively. The toxicity prediction revealed that none of the flavonoids presented toxicity and they all had good absorption parameters for the analyzed targets. Hence, these compounds can be considered as likely leads for drug improvement against the same.


Sign in / Sign up

Export Citation Format

Share Document