Presence Of Isatin Research Articles

Protective effects of isatin and its synthetic derivatives against iron, copper and lead toxicity

IntroductionWhile some metals are required for physiological functions in the form of essential trace elements, they can cause toxicity in the excessive concentrations. Chelation therapy was used to reduce the adverse effects of acute and chronic poisoning by metals. Isatin derivatives form complexes with copper ions indicating that they may have protective activity against metal overload. MethodIn this study, four compounds (isatin and three isatin-derivatives Mj1, TR and Mk1) were evaluated for drug-likeliness. Then their potency inhibiting cell proliferation was determined in HEK293 cell culture assay. Finally, IC50 values for lead, copper, and iron was evaluated in the absence and also the presence of isatin and its derivatives. ResultsIsatin and its derivatives used in this study complied with the Lipinski criteria for drug-likeliness. The greatest difference between the IC50 values and the non-toxic dose was obtained for TR and Mj1, respectively. Pretreatment with the Mj1 increased the IC50 values for lead, iron, and copper, by 2.1, 1.7 and 1.7 times, respectively. At non-toxic dose, TR has only increased the IC50 values for lead and copper by 1.4 and 1.3 times without affecting iron cytotoxicity. Mk1 increased the IC50 values for lead, copper, and iron by 1.3, 1.8 and 1.7 times, respectively. ConclusionsMj1 is suggested as a lead compound for developing therapeutic agents for lead (Pb) toxicity and Mk1 for copper and iron.

Direct Molecular Fishing of New Protein Partners for Human Thromboxane Synthase

Thromboxane synthase (TBXAS1) catalyzes the isomerization reaction of prostaglandin H2 producing thromboxane A2, the autocrine and paracrine factor in many cell types. A high activity and metastability by these arachidonic acid derivatives suggests the existence of supramolecular structures that are involved in the regulation of the biosynthesis and directed translocation of thromboxane to the receptor. The objective of this study was to identify TBXAS1 protein partners from human liver tissue lysate using a complex approach based on the direct molecular fishing technique, LC-MS/MS protein identification, and protein-protein interaction validation by surface plasmon resonance (SPR). As a result, 12 potential TBXAS1 protein partners were identified, including the components regulating cytoskeleton organization (BBIP1 and ANKMY1), components of the coagulation cascade of human blood (SERPINA1, SERPINA3, APOH, FGA, and FN1), and the enzyme involved in the metabolism of xenobiotics and endogenous bioregulators (CYP2E1). SPR validation on the Biacore 3000 biosensor confirmed the effectiveness of the interaction between CYP2E1 (the enzyme that converts prostaglandin H2 to 12-HHT/thromboxane A2 proantagonist) and TBXAS1 (Kd = (4.3 0.4) 10-7 M). Importantly, the TBXAS1CYP2E1 complex formation increases fivefold in the presence of isatin (indole-2,3-dione, a low-molecular nonpeptide endogenous bioregulator, a product of CYP2E1). These results suggest that the interaction between these hemoproteins is important in the regulation of the biosynthesis of eicosanoids.

Прямой молекулярный фишинг новых белков-партнеров тромбоксансинтазы человека

Thromboxane synthase (TBXAS1) catalyzes the isomerization reaction of prostaglandin H2 producing thromboxane A2, the autocrine and paracrine factor in many cell types. A high activity and metastability by these arachidonic acid derivatives suggests the existence of supramolecular structures that are involved in the regulation of the biosynthesis and directed translocation of thromboxane to the receptor. The objective of this study was to identify TBXAS1 protein partners from human liver tissue lysate using a complex approach based on the direct molecular fishing technique, LC-MS/MS protein identification, and protein-protein interaction validation by surface plasmon resonance (SPR). As a result, 12 potential TBXAS1 protein partners were identified, including the components regulating cytoskeleton organization (BBIP1 and ANKMY1), components of the coagulation cascade of human blood (SERPINA1, SERPINA3, APOH, FGA, and FN1), and the enzyme involved in the metabolism of xenobiotics and endogenous bioregulators (CYP2E1). SPR validation on the Biacore 3000 biosensor confirmed the effectiveness of the interaction between CYP2E1 (the enzyme that converts prostaglandin H2 to 12-HHT/thromboxane A2 proantagonist) and TBXAS1 (Kd = (4.3 ± 0.4) × 10-7 M). Importantly, the TBXAS1•CYP2E1 complex formation increases fivefold in the presence of isatin (indole-2,3-dione, a low-molecular nonpeptide endogenous bioregulator, a product of CYP2E1). These results suggest that the interaction between these hemoproteins is important in the regulation of the biosynthesis of eicosanoids.

Silver‐Induced Cα(sp3)–H Activation of Benzylamines Followed by [1,5]‐ versus [1,3]‐Rearrangement: A Strategy towards the Regioselective Synthesis of Spiro‐Dihydropyrroles

For the first time in pyrrole chemistry, silver‐mediated Cα(sp3)–H bond activation of benzylamines followed by [1,5]‐ versus [1,3]‐rearrangement towards the regioselective synthesis of spiro‐dihydropyrrole derivatives has been achieved. The reaction proceeds through cleavage of the benzylamine C–N bond promoted by the crucial silver carbonate followed by a regioselective [1,5]‐rearrangement with dialkyl but‐2‐ynedioate in the presence of isatin or N‐methylisatin. Equally, N‐substituted isatin with benzyl, allyl, ethyl, propyl, and n‐butyl substituents proceeds through an alternate [1,3]‐rearrangement strategy. The study highlights the recycling of silver species and for selective use in oxidative C–N and C–C coupling reactions.

Structural effects on kinetics and a mechanistic investigation of the reaction between DMAD and N\u2013H heterocyclic compound in the presence of triphenylarsine: spectrophotometry approach

Kinetics and a mechanistic investigation of the reaction between dimethyl acetylenedicarboxcylate (DMAD) and saccharin (N–H heterocyclic compound) has been spectrally studied in methanol environment in the presence of triphenylarsine (TPA) as a catalyst. Previously, in a similar reaction, triphenylphosphine (TTP) (instead of triphenylarsine) has been employed as a third reactant (not catalyst) for the generation of an ylide (final product) while, in the present work the titled reaction in the presence of TPA leaded to the especial N-vinyl heterocyclic compound with different kinetics and mechanism. The reaction followed second order kinetics. In the kinetic study, activation energy and parameters (Ea, ΔH‡, ΔS‡ and ΔG‡) were determined. Also, the structural effect of the N–H heterocyclic compound was investigated on the reaction rate. The result showed that reaction rate increases in the presence of isatin (N–H compound) that participates in the second step (step2), compared to saccharin (another N–H compound). This was a good demonstration for the second step (step2) of the reaction that could be considered as the rate- determining step (RDS). As a significant result, not only a change in the structure of the reactant (TPA instead of TPP) creates a different product, but also kinetics and the reaction mechanism have been changed.

The effect of isatin on protein-protein interactions between cytochrome b5 and cytochromes P450

Cytochromes P450 (CYP) are involved in numerous biochemical processes including metabolism of xenobiotics, biosynthesis of cholesterol, steroid hormones etc. Since some CYP catalyze indol oxidation to isatin, we have hypothesized that isatin can regulate protein-protein interactions (PPI) between components of the CYP system thus representing a (negative?) feedback mechanism. The aim of this study was to investigate a possible effect of isatin on interaction of human CYP with cytochrome b5 (CYB5A). Using the optical biosensor test system employing surface plasmon resonance (SPR) we have investigated interaction of immobilized CYB5A with various CYP in the absence and in the presence of isatin. The SPR-based experiments have shown that a high concentration of isatin (270 mM) increases Kd values for complexes CYB5A/CYP3А5 and CYB5A/CYP3A4 (twofold and threefold, respectively), but has no influence on complex formation between CYB5A and other CYP (including indol-metabolizing CYP2C19 and CYP2E1). Isatin injection to the optical biosensor chip with the preformed molecular complex CYB5A/CYP3A4 caused a 30%-increase in its dissociation rate. Molecular docking manipulations have shown that isatin can influence interaction of CYP3А5 or CYP3A4 with CYB5A acting at the contact region of CYB5A/CYP.

1,5-Diphenylpenta-2,4-dien-1-ones as potent and selective monoamine oxidase-B inhibitors

A series of (2E,4E)-1-(2-hydroxyphenyl)-5-phenylpenta-2,4-dien-1-ones (3a–r) and (2Z,4E)-3-hydroxy-1-(2-hydroxyphenyl)-5-phenylpenta-2,4-dien-1-ones (6a–l) were synthesized and evaluated in vitro as inhibitors of the two human Monoamine oxidase (hMAO) isoforms, MAO-A and MAO-B. Most of the compounds showed a selective MAO-B inhibitory activity in the nanomolar or low micromolar range. (2E,4E)-5-(4-Chlorophenyl)-1-(2-hydroxy-4-methoxyphenyl)penta-2,4-dien-1-one (3g) and (2E,4E)-5-(4-chlorophenyl)-1-(2,4-dihydroxyphenyl)penta-2,4-dien-1-one (3h) were the most potent hMAO-B inhibitors exhibiting IC50 of 4.51 nM and 11.35 nM, respectively, coupled with high selectivity. Moreover, partial recovery of MAO-B activity was observed after repeated washing in the presence of isatin (reversible inhibitor) and compounds 3g and 3h suggesting a reversible inhibition of the enzyme. Molecular mechanics and quantum chemistry methods were used to elucidate the MAO recognition of the most active inhibitors 3g and 3h.

B-type natriuretic peptide at early reperfusion limits infarct size in the rat isolated heart

Natriuretic peptides are regulatory autacoids in the mammalian myocardium whose functions, mediated via particulate guanylyl cyclase/cGMP, may include cytoprotection against ischaemia-reperfusion injury. Previous work has identified that B-type natriuretic peptide (BNP) limits infarct size when administered prior to and during coronary occlusion through a K(ATP) channel-dependent mechanism. The present study examined the hypothesis that the protection afforded by BNP is mediated specifically at reperfusion in a postconditioning-like manner. Langendorff-perfused rat hearts were subjected to 35 min coronary artery occlusion and 120 min reperfusion, and infarct size was determined by tetrazolium staining. Postconditioning was effected by applying six 10-second periods of global ischaemia at the onset of reperfusion.Treatment with either BNP 10 nM or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) 1-10 microM was commenced 5 min prior to reperfusion and continued until 10 min after reperfusion. Control infarct size (% of ischaemic risk zone) was 40.8 +/- 3.7%.BNP at reperfusion induced a significant limitation of infarct size (BNP 22.9 +/- 4.1% P<0.05 vs. control). Co-treatment at reperfusion with BNP and the K(ATP) channel blockers 5-hydroxydecanote (5HD, 100 microM), glibenclamide (Glib; 10 microM) or HMR1098 (10 microM) abolished the infarct-limiting effect of BNP (BNP + 5HD 41.0 +/- 3.9%, BNP + Glib 39.8 +/- 5.6%, BNP + HMR 1098 46.0 +/- 7.1%,P < 0.05 vs. BNP). BNP given together with L-NAME (100 microM) at reperfusion resulted in a marked loss of protection (BNP + L-NAME 53.1 +/- 3.8% P < 0.001 vs. BNP). In a second series of experiments, SNAP (1-10 microM) given at reperfusion was found not to be protective (SNAP 1 microM 30.2 +/- 4.9%, SNAP 2 microM 27.5 +/- 9.5%, SNAP 5 microM 39.2 +/- 5.7%, SNAP 10 microM 33.7 +/- 6.4%, not significant vs. control). In a third series of experiments, postconditioning significantly limited infarct size (14.9 +/- 3.6 % vs. control 34.5 +/- 4.9%, P < 0.01) and this effect of postconditioning was abolished in the presence of isatin (100 microM), a non-specific blocker of particulate guanylyl cyclases (35.1 +/- 6%, P < 0.05 vs. postconditioning). In conclusion, pharmacological activation of pGC by BNP can effectively induce protection against reperfusion injury, by mechanisms involving K(ATP) channel opening and endogenous NO synthase activation. Furthermore, endogenous activation of pGC could play a role in the mechanism of postconditioning.

A Synthesis of Dialkyl Phosphorylsuccinates from the Reaction of NH-Acids with Dialkyl Acetylenedicarboxylates in the Presence of Trialkyl(aryl) Phosphites

The reaction of dialkyl acetylenedicarboxylates with trialkyl(aryl) phosphites in the presence of isatin, phthalimide, indole, or pyrrole leads to stable dialkyl(aryl) phosphorylsuccinates in excellent yields.

Simple Synthesis of Dialkyl 2‐(3‐Oxo‐3H‐indol‐2‐yl)‐but‐2‐enedioates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Inhibition of glucose transport in human erythrocytes by 2,3-dioxoindole (isatin).

10 mM isatin (2,3-dioxoindole) inhibited glucose influx into human erythrocytes by over 30%. The inhibition is of the competitive type, where the affinity constant (Kt) was increased from 5.71 (control) to 11.11 mM in the presence of isatin with no change in Vmax (130 nmol/min/ml packed cells). The observed inhibition of sugar transport by isatin was not mediated through membrane -SH groups accessible to iodoacetate, iodoacetamide, DTNB, DNP or sodium arsenite. Isatin inhibited sugar transport in the presence of 2 mM harmaline, an alkaloid inhibitor of Na+, K(+)-ATPase activity. The inhibition was non additive which suggests that these two compounds interact with the same or a similar site on the erythrocyte membrane.

Isatin inhibition of rat testicular alkaline phosphatase. A non-allosteric phenomenon.

Isatin has been found to inhibit rat testicular alkaline phosphatase (EC 3.1.3.1) uncompetitively. The hyperbolic curve relating inhibition as a function of substrate concentration; the persistence of inhibition after the tertiary structure of the enzyme has been altered by heat denaturation, exposure to urea or papain digestion; the small changes in entropy, free energy and enthalpy in the presence of isatin, and the number of isatin molecules (n = 1.29) combining with one molecule of enzyme indicate the non-allosteric nature of inhibition.

Nature of inhibition of rat testicular alkaline phosphatase by isatin.

Isatin has been found to inhibit rat testicular alkaline phosphatase (EC 3.1.3.1). That the inhibition is non-competitive as well as non-allosteric is evident from a) the hyperbolic curve relating inhibition as a function of inhibitor concentration; b) the small change in enthalpy, free energy and entropy; c) the number of isatin molecules associating with 1 molecule of the enzyme (n=1.29); and, d) the decrease in the values of both Km and Vmax in the presence of isatin.

Polarographic behaviour of isatin and some of its derivatives in DMF

Summary The electrochemical behaviour of isatin and some of its derivatives has been examined in aprotic solution. N-Methylisatin is reduced in two one-electron waves, the first of which leads to the formation of a radical anion reducible, at more negative potential, to the dianion. Isatin is reduced in three steps; the first and the second, reversible, lead to the primary formation of the radicals of isatin and of that of its conjugated base, respectively. Both radicals are unstable when in presence of isatin in excess, owing to its acidic properties that affect the reduction mechanism. The third polarographic wave corresponds to a two-electron process; when proton donors such as phenol or acetic acid are added to the solution, isatin is reduced in two waves with formation of dioxindole and oxindole respectively.