scholarly journals Active-site-directed irreversible inhibition of rat brain 4-aminobutyrate aminotransferase by ethanolamine O-sulphate in vitro and in vivo

1972 ◽  
Vol 130 (2) ◽  
pp. 569-573 ◽  
Author(s):  
L. J. Fowler ◽  
R. A. John
Keyword(s):  
Rat Brain ◽  
Dependent Manner ◽  
Aminobutyrate Aminotransferase ◽  
First Order ◽  
Irreversible Inhibition ◽  
First Order Kinetics ◽  
Intracisternal Injection ◽  
Pseudo First Order

1. Partially purified preparations of rat brain 4-aminobutyrate aminotransferase were inhibited in a time-dependent manner by ethanolamine O-sulphate. The inhibition was not reversed by dialysis. 2. The inhibitor formed an initial reversible complex with the enzyme (Ki=4.4×10−4m) and the rate of inactivation followed pseudo-first-order kinetics (k=7.15×10−4s−1). The inclusion of 4-aminobutyrate markedly slowed the rate of inactivation. 3. Ethanolamine O-sulphate did not inhibit glutamate decarboxylase, alanine aminotransferase or aspartate aminotransferase. 4. Intracisternal injection of ethanolamine O-sulphate into rats led to rapid inactivation of 4-aminobutyrate aminotransferase in vivo.

In-vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

2020 ◽  
Vol 16 ◽  
Author(s):  
M. Alarjah
Keyword(s):  
Half Life ◽  
Hplc Method ◽  
Hydrolysis Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Rp Hplc ◽  
Pharmacokinetic Properties ◽  
Pseudo First Order ◽  
Kinetic Hydrolysis

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

scholarly journals CATION EXCHANGE BETWEEN CELLS AND PLASMA OF MAMMALIAN BLOOD

1950 ◽  
Vol 33 (6) ◽  
pp. 703-722 ◽  
Author(s):  
C. W. Sheppard ◽  
W. R. Martin
Keyword(s):  
Exchange Rate ◽  
Radioactive Isotope ◽  
Specific Activity ◽  
Compartment System ◽  
First Order ◽  
First Order Kinetics ◽  
Mammalian Blood ◽  
The Mean ◽  
Pseudo First Order

The exchange of potassium between cells and plasma of heparinized human blood has been studied in vitro using the radioactive isotope K42. The changes in cell and plasma specific activity are characteristic of a simple two-compartment system. The mean of seven determinations of the exchange rate at 38°C. is 1.8 per cent of the cellular potassium per hour. The results indicate that at 38°C. the rate is relatively insensitive to oxygenation or reduction of the hemoglobin, and to 1200 r of gamma radiation. With varying temperature the rate follows pseudo first order kinetics with a Q10 of 2.35. Below 15°C. the rate of loss of potassium exceeds the rate of uptake.

scholarly journals The synthesis of ribonucleic acid in vivo in the nuclei of rat brain fractionated by zonal centrifugation

1973 ◽  
Vol 132 (4) ◽  
pp. 813-819 ◽  
Author(s):  
J. Austoker ◽  
D. Cox ◽  
A. P. Mathias
Keyword(s):  
Rat Brain ◽  
Ribonucleic Acid ◽  
Orotic Acid ◽  
Specific Radioactivity ◽  
Brain Nuclei ◽  
Neuronal Nuclei ◽  
Intracisternal Injection ◽  
Zone Ii

1. Radioactive orotic acid, uridine and adenosine were administered to rats by intracisternal injection. The effects of the size of the dose, the specific radioactivity and time on the incorporation into the RNA of unfractionated nuclei of brain tissue were examined to establish appropriate conditions for studies of the relative activities in vivo of the various sorts of brain nuclei fractionated by zonal centrifugation. Uridine is incorporated more efficiently than either orotic acid or adenosine. 2. With [3H]uridine as precursor the astrocytes in zone (II) contain the highest radioactivity except at the beginning of the experiment when the neuronal nuclei of zone (I) are more highly labelled. This fraction utilizes [14C]orotic acid more readily than the nuclei of zone (II). The astrocytic nuclei of zone (III) show a general resemblance to those of zone (II). Considerable differences between the incorporations into the two types of oligodendrocyte nuclei in zones (IV) and (V) are observed. 3. The relative synthetic activities of the major types of brain nuclei in vitro and in vivo are discussed.

scholarly journals Local salt substitutes “Obu-otoyo” activate acetylcholinesterase and butyrylcholinesterase and induce lipid peroxidation in rat brain

2015 ◽  
Vol 8 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Ayodele J. Akinyemi ◽  
Ganiyu Oboh ◽  
Adedayo O. Ademiluyi
Keyword(s):  
Heavy Metals ◽  
Lipid Peroxidation ◽  
Rat Brain ◽  
Palm Kernel ◽  
Dependent Manner ◽  
Toxic Heavy Metals ◽  
Induce Lipid Peroxidation ◽  
Mda Content

Abstract Evidence has shown that ingestion of heavy metals can lead to neurodegenerative diseases. This study aimed to investigate the neurotoxic potential of salt substitutes (Obu-Otoyo); salt A (made by burning palm kernel shaft then soaked in water overnight and the extract from the resulting residue is used as the salt substitute) and salt B (an unrefined salt mined from a local site at Ilobu town, Osun-State, Nigeria) by assessing their effect on some key enzymes linked with neurodegenerative disease [acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities] as well as on malondialdehyde (MDA) content of the rat brain. Salt substitutes were fed to normal rats as dietary inclusion at doses of 0.5 and 1.0% for 30 days. Thereafter, the effect of the salt substitutes on AChE and BChE activities as well as on MDA level in the rat brain was determined. The results revealed that the salt substitutes caused a significant (p<0.05) increase in both AChE and BChE activity and also induced lipid peroxidation in the brain of rats in vivo as well as under in vitro condition in a dose-dependent manner. The effect of the salt substitutes on AChE and BChE activities could be attributed to the presence of some toxic heavy metals. Therefore, the ability of the salt substitutes to induce lipid peroxidation and activate AChE and BChE activities could provide some possible mechanism for their neurotoxic effect.

In Vitro and In Vivo Inhibition of Rat Brain Nitric Oxide Synthase Activity by Phencyclidine

1999 ◽  
Vol 18 (4) ◽  
pp. 245-250 ◽  
Author(s):  
D. Desaiah ◽  
M. Pande ◽  
P. J. S. Vig ◽  
J. A. Cameron ◽  
S. F. Ali
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Rat Brain ◽  
Control Group ◽  
Dependent Manner ◽  
Kinetic Evaluation ◽  
Oxide Synthase ◽  
Brain Nitric Oxide

Phencyclidine (PCP) is a widely abused psychoactive drug that perturbs many neurotransmitter systems studied to date. Nitric oxide (NO) has been established as a neuronal messenger and its rapid diffusibility across cell membranes makes NO an extensive and versatile messenger in brain development and functioning. The present study was initiated to investigate the effect of PCP on rat brain nitric oxide synthase (NOS) activity both in vitro and in vivo. Brain cytosolic fractions from normal rats were used for in vitro and in vivo studies. The rats were treated with a single dose of PCP (10 mg/kg, intraperitoneally); the brains were removed at 0, 1, 2, 6, and 12 hours after PCP treatment and the cytosolic fractions were prepared by homogenization and centrifugation. NOS activity was assessed by quantifying the release of [3H]-citrulline from [3H]-arginine. PCP significantly inhibited rat brain NOS in vitro in a concentration (0.05–2 mM)-dependent manner. The kinetic evaluation of arginine, NADPH, and Ca2+ activation of NOS revealed that PCP (0.5 mM) inhibited NOS activity competitively with respect to arginine and NADPH and noncompetitively inhibited with respect to Ca2+. PCP also caused a time-dependent reduction of brain NOS activity in vivo as early as 1 hour after treatment. Even after 12 hours of PCP treatment, NOS activity did not reverse to its normal level as compared to the control group, suggesting sequestration and persistence of the drug in the central nervous system. These results suggest that inhibition of brain NOS by PCP might be one of the mechanisms through which PCP causes neurotoxicity.

scholarly journals Catalytic irreversible inhibition of bacterial and plant arginine decarboxylase activities by novel substrate and product analogues

1987 ◽  
Vol 242 (1) ◽  
pp. 69-74 ◽  
Author(s):  
A J Bitonti ◽  
P J Casara ◽  
P P McCann ◽  
P Bey
Keyword(s):  
Arginine Decarboxylase ◽  
Irreversible Inhibitor ◽  
Polyamine Biosynthesis ◽  
E Coli ◽  
First Order ◽  
Irreversible Inhibition ◽  
First Order Kinetics ◽  
Low Concentrations ◽  
Pseudo First Order

Arginine decarboxylase (ADC) activity from Escherichia coli and two plant species (oats and barley) was inhibited by five new substrate (arginine) and product (agmatine) analogues. The five compounds, (E)-alpha-monofluoromethyldehydroarginine (delta-MFMA), alpha-monofluoromethylarginine (MFMA), alpha-monofluoromethylagatine (FMA), alpha-ethynylagmatine (EA) and alpha-allenylagmatine (AA), were all more potent inhibitors of ADC activity than was alpha-difluoromethylarginine (DFMA), the only irreversible inhibitor of this enzyme described previously. The inhibition caused by the five compounds was apparently enzyme-activated and irreversible, since the loss of enzyme activity followed pseudo-first-order kinetics, was time-dependent, the natural substrate of ADC (arginine) blocked the effects of the inhibitors, and the inhibition remained after chromatography of inhibited ADC on Sephadex G-25 or on overnight dialysis of the enzyme. DFMA, FMA, delta-MFMA and MFMA were effective at very low concentrations (10 nM-10 microM) at inhibiting ADC activity in growing E. coli. FMA was also shown to deplete putrescine effectively in E. coli, particularly when combined with an inhibitor of ornithine decarboxylase, alpha-monofluoromethyl-putrescine. The potential uses of the compounds for the study of the role of polyamine biosynthesis in bacteria and plants is discussed.

Chickpea (Cicer arietinum L.) Lectin Exhibit Inhibition of ACE-I, α-amylase and α-glucosidase Activity

2019 ◽  
Vol 26 (7) ◽  
pp. 494-501 ◽  
Author(s):  
Sameer Suresh Bhagyawant ◽  
Dakshita Tanaji Narvekar ◽  
Neha Gupta ◽  
Amita Bhadkaria ◽  
Ajay Kumar Gautam ◽  
...  
Keyword(s):  
Biological Effects ◽  
Exchange Chromatography ◽  
Health Concern ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ic50 Values ◽  
Chickpea Lectin

Background: Diabetes and hypertension are the major health concern and alleged to be of epidemic proportions. This has made it a numero uno subject at various levels of investigation. Glucosidase inhibitor provides the reasonable option in treatment of Diabetes Mellitus (DM) as it specifically targets post prandial hyperglycemia. The Angiotensin Converting Enzyme (ACE) plays an important role in hypertension. Therefore, inhibition of ACE in treatment of elevated blood pressure attracts special interest of the scientific community. Chickpea is a food legume and seeds contain carbohydrate binding protein- a lectin. Some of the biological properties of this lectin hitherto been elucidated. Methods: Purified by ion exchange chromatography, chickpea lectin was tested for its in vitro antioxidant, ACE-I inhibitory and anti-diabetic characteristic. Results: Lectin shows a characteristic improvement over the synthetic drugs like acarbose (oral anti-diabetic drug) and captopril (standard antihypertensive drug) when, their IC50 values are compared. Lectin significantly inhibited α-glucosidase and α-amylase in a concentration dependent manner with IC50 values of 85.41 ± 1.21 ҝg/ml and 65.05 ± 1.2 µg/ml compared to acarbose having IC50 70.20 ± 0.47 value of µg/ml and 50.52 ± 1.01 µg/ml respectively. β-Carotene bleaching assay showed antioxidant activity of lectin (72.3%) to be as active as Butylated Hydroxylanisole (BHA). In addition, lectin demonstrated inhibition against ACE-I with IC50 value of 57.43 ± 1.20 µg/ml compared to captopril. Conclusion: Lectin demonstrated its antioxidant character, ACE-I inhibition and significantly inhibitory for α-glucosidase and α-amylase seems to qualify as an anti-hyperglycemic therapeutic molecule. The biological effects of chickpea lectin display potential for reducing the parameters of medically debilitating conditions. These characteristics however needs to be established under in vivo systems too viz. animals through to humans.

scholarly journals Exploration of in vitro thrombolytic, anthelminthic, cytotoxic and in vivo anxiolytic potentials with phytochemical screening of flowers of Brassica nigra

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammad Sarowar Uddin ◽  
Md. Shalahuddin Millat ◽  
Mohammad Safiqul Islam ◽  
Md. Saddam Hussain ◽  
Md. Giash Uddin ◽  
...  
Keyword(s):  
Brassica Nigra ◽  
Anxiolytic Activity ◽  
Clot Lysis ◽  
Dependent Manner ◽  
Standard Drug ◽  
Lead Compounds ◽  
Lysis Activity ◽  
Test Models

Abstract Background Brassica nigra is a plant of Brassicaceae family, which possesses numerous medicinal values. Our present study is intended to assess the potential in vitro thrombolytic, anthelminthic, cytotoxic and in vivo anxiolytic properties of MCE of B. nigra flowers. MCE was fractioned for separating the compound on the basis of polarity by using chloroform, n-hexane and ethyl acetate solvent. Thrombolytic and anthelminthic activities were explained by collecting human erythrocytes and earthworms as test models, respectively. Anxiolytic activity was evaluated by elevated plus maze and hole board models while cytotoxic test was conducted through brine shrimp lethality bioassay. Results MCE revealed the presence of alkaloids, flavonoids, tannin, diterpenes, glycosides, carbohydrates, phenols, fixed oils and fat. In case of thrombolytic test, the MCE, CSF, ASF and n-HSF had produced maximum clot lysis activity at 5 and 10 mg/ml dose conditions. Two different concentrations (10 and 20 mg/ml) of MCE and its fractions showed significant (p < 0.05) anthelminthic activities in a dose-dependent manner. Significant anxiolytic activity was observed for all fractions which was comparable to the standard drug diazepam (p < 0.05). Again, the cytotoxic screening also presented good potentials for all fractions. Conclusion From the findings of present study, we can conclude that MCE of B. nigra flowers and its fraction possess significant anxiolytic, anthelmintic, anticancer and thrombolytic properties which may be a good candidate for treating these diseases through the determination of bio-active lead compounds.

scholarly journals Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xuxing Shen ◽  
Chao Wu ◽  
Meng Lei ◽  
Qing Yan ◽  
Haoyang Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Proteasome Inhibitor ◽  
Osteoclast Differentiation ◽  
Dependent Manner ◽  
Serum Enzyme ◽  
Herg Channels ◽  
Anti Tumor Activity ◽  
Dose Dependent

AbstractCarfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

scholarly journals Secreted KIAA1199 promotes the progression of rheumatoid arthritis by mediating hyaluronic acid degradation in an ANXA1-dependent manner

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Zhang ◽  
Guoyu Yin ◽  
Heping Zhao ◽  
Hanzhi Ling ◽  
Zhen Xie ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Hyaluronic Acid ◽  
Dependent Manner ◽  
Collagen Induced Arthritis ◽  
Intracellular Degradation ◽  
Main Pathway ◽  
First Time

AbstractIn inflamed joints, enhanced hyaluronic acid (HA) degradation is closely related to the pathogenesis of rheumatoid arthritis (RA). KIAA1199 has been identified as a hyaladherin that mediates the intracellular degradation of HA, but its extracellular function remains unclear. In this study, we found that the serum and synovial levels of secreted KIAA1199 (sKIAA1199) and low-molecular-weight HA (LMW-HA, MW < 100 kDa) in RA patients were significantly increased, and the positive correlation between them was shown for the first time. Of note, treatment with anti-KIAA1199 mAb effectively alleviated the severity of arthritis and reduced serum LMW-HA levels and cytokine secretion in collagen-induced arthritis (CIA) mice. In vitro, sKIAA1199 was shown to mediate exogenous HA degradation by attaching to the cell membrane of RA fibroblast-like synoviosytes (RA FLS). Furthermore, the HA-degrading activity of sKIAA1199 depended largely on its adhesion to the membrane, which was achieved by its G8 domain binding to ANXA1. In vivo, kiaa1199-KO mice exhibited greater resistance to collagen-induced arthritis. Interestingly, this resistance could be partially reversed by intra-articular injection of vectors encoding full-length KIAA1199 instead of G8-deleted KIAA119 mutant, which further confirmed the indispensable role of G8 domain in KIAA1199 involvement in RA pathological processes. Mechanically, the activation of NF-κB by interleukin-6 (IL-6) through PI3K/Akt signaling is suggested to be the main pathway to induce KIAA1199 expression in RA FLS. In conclusion, our study supported the contribution of sKIAA1199 to RA pathogenesis, providing a new therapeutic target for RA by blocking sKIAA1199-mediated HA degradation.

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