scholarly journals Synthesis, Characterization and Solution Chemistry of trans-Indazoliumtetrachlorobis(Indazole)Ruthenate(III), a New Anticancer Ruthenium Complex. IR, UV, NMR, HPLC Investigations and Antitumor Activity. Crystal Structures of trans-1-Methyl-Indazoliumtetrachlorobis-(1-Methylindazole)Ruthenate(III) and its Hydrolysis Product trans-Monoaquatrichlorobis-(1-Methylindazole)-Ruthenate(III)

1996 ◽  
Vol 3 (5) ◽  
pp. 243-260 ◽  
Author(s):  
Kari-Georg Lipponer ◽  
Ellen Vogel ◽  
Bernhard K. Keppler
Keyword(s):  
Antitumor Agents ◽  
Ruthenium Complex ◽  
Hydrolysis Product ◽  
Order Rate Constant ◽  
Solution Chemistry ◽  
Molecular Structures ◽  
Physiological Conditions ◽  
Cell Dimensions ◽  
Competitive Products ◽  
Hydrolysis Of

Besides intensive studies into the synthesis of the complex trans-Hlnd[RuCl4(ind)2] (Ind = indazole) 1, which differs remarkably from the usual method for the complexes of the HL[RuCl4L2] - type, competitive products and hydrolysis of this species are described. Stability and pseudo-first-order rate constant under physiological conditions of complex 1 in comparison with the analogous imidazole complex trans-Hlm[RuCl4(im)2] (Im = imidaZole) ICR were examined by means of HPLC, UV and conductivity measurements (Kobs.(1) = 1.55 × 10-4s-1; Kobs.(ICR) = 9.10 × 10-4s-1). An attempt was made to elucidate the bonding conditions in 1 by studying the reactions of Ru(lll) and the two N-methyl isomers of indazole. It can be expected that bonding in the unsubstituted ligand should occur via the N2 nitrogen. The molecular structures of the complex trans-H(1-Melnd)[RuCl4(1-Melnd)2] × 1H2O (1-Melnd = 1-methylindazole) 6 and its hydrolysis product in aqueous solution [RuCl3(H2O)(1-Melnd)2]7 were determined crystallographically. After anisotropic refinement of F values by least squares, R is 0.053 for 6 and 0.059 for 7. Both complexes crystallize with four molecules in a unit cell of monoclinic symmetry. The space group is P2.1/n for 6 with cell dimensions a = 10.511Å, b = 13.87Å, c = 19.93Å, and β = 98.17° and C2/c for 7 with a = 19.90Å, b = 10.94Å, c = 8.490Å and β = 96.74° The fact that the aqua species 7 could be isolated after dissolving 6 in a water/acetone solution confirmed the theory of many Ru(lll) complexes being initially transformed, under physiological conditions, into aqua complexes in a first and often rate-determining hydrolysis step. Compounds 1 and ICR are potent antitumor agents which exhibit activity against a variety of tumor cells and experimental tumor models in animals, including autochthonous colorectal tumors. Clinical studies with 1 are in preparation.

scholarly journals Fe-EDTA-Bisamide and Fe-ADR-925, The Iron-Bound Hydrolysis Product of the Cardioprotective Agent Dexrazoxane, Cleave DNA Via the Hydroxyl Radical

1997 ◽  
Vol 4 (4) ◽  
pp. 199-205 ◽  
Author(s):  
Thomas J. Magliery ◽  
Lizabeth K. Vitellaro ◽  
Ndeye Khady Diop ◽  
Rosemary A. Marusak
Keyword(s):  
Side Effects ◽  
Hydroxyl Radical ◽  
Plasmid Dna ◽  
Dna Cleavage ◽  
Antitumor Agents ◽  
Hydrolysis Product ◽  
Solution Chemistry ◽  
Radical Scavenger ◽  
Radical Production ◽  
Radical Generation

Use of the antitumor drug doxorubicin is limited by cardiomyopathic side-effects which are believed to be due to iron-mediated hydroxyl radical generation. Dexrazoxane reduces this cardiotoxicity, possibly by removal of iron from doxorubicin by the EDTA-like hydrolysis product of dexrazoxane, ADR-925. However, EDTA-diimides like dexrazoxane, previously used as antitumor agents, are themselves carcinogenic, and recent studies have found that Fe-ADR-925 can also promote hydroxyl radical production. This study demonstrates that, like Fe-EDTA, Fe-ADR-925 and a related desmethyl complex can cleave plasmid DNA under Fenton conditions, and suggests by radical scavenger study that this cleavage is probably via the hydroxyl radical. Differences in DNA cleavage dependence upon concentrations of Fe-EDTA, Fe-ADR-925 and Fe-EDTA-bisamide can be explained by differences in the solution chemistry of the complexes.

scholarly journals The properties of a carboxylesterase from the peach-potato aphid, Myzus persicae (Sulz.), and its role in conferring insecticide resistance

1977 ◽  
Vol 167 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Alan L. Devonshire
Keyword(s):  
Insecticide Resistance ◽  
Myzus Persicae ◽  
Order Rate Constant ◽  
Preliminary Evidence ◽  
Exchange Chromatography ◽  
Potato Aphid ◽  
First Order ◽  
Different Strains ◽  
Hydrolysis Of ◽  
Peach Potato Aphid

Carboxylesterases from different strains of Myzus persicae were examined to try to understand their contribution to insecticide resistance. Preliminary evidence that they are involved comes from the good correlation between the degree of resistance and the carboxylesterase and paraoxon-degrading activity in aphid homogenates. Furthermore the carboxylesterase associated with resistance could not be separated from the insecticide-degrading enzyme by electrophoresis or ion-exchange chromatography. Homogenates of resistant aphids hydrolysed paraoxon 60 times faster than did those of susceptible aphids, yet the purified enzymes from both sources had identical catalytic-centre activities towards this substrate and also towards naphth-1-yl acetate, the latter being hydrolysed by both 2×106 times faster than paraoxon. These observations provide evidence that the enzyme from both sources is identical, and that one enzyme hydrolyses both substrates. This was confirmed by relating the rate of paraoxon hydrolysis to the rate at which paraoxon-inhibited carboxylesterase re-activated. Both had the same first-order rate constant (0.01min−1), showing clearly that the hydrolysis of both substrates is brought about by the same enzyme. Its Km for naphth-1-yl acetate was 0.131mm, and for paraoxon 75pm. The latter very small value could not be measured directly, but was calculated from substrate-competition studies coupled with measurements of re-activation of the diethyl phosphorylated enzyme. Since the purified enzymes from resistant and susceptible aphids had the same catalytic-centre activity, the 60-fold difference between strains must be caused by different amounts of the same enzyme resulting from mutations of the regulator gene(s) rather than of the structural gene.

Acid-catalyzed Solvolysis of Isonitriles. I

1971 ◽  
Vol 49 (14) ◽  
pp. 2455-2459 ◽  
Author(s):  
Y. Y. Lim ◽  
A. R. Stein
Keyword(s):  
Formic Acid ◽  
Acid Catalysis ◽  
Hydrolysis Product ◽  
Rate Dependence ◽  
Linear Rate ◽  
First Order ◽  
Methyl Amine ◽  
Acid Catalyzed ◽  
Pseudo First Order ◽  
Hydrolysis Of

The acid-catalyzed hydrolysis of methyl isonitrile has been examined. The initial hydrolysis product is N-methylformamide which is further hydrolyzed to methyl amine and formic acid at a much slower rate. The hydrolysis to N-methylformamide is pseudo-first order in methyl isonitrile and shows a linear rate dependence on concentration of general (buffer) acid at fixed pH. The significance of general acid-catalysis in terms of the mechanism of the hydrolysis is considered and taken as evidence for carbon protonation rather than nitrogen protonation as the initiating step.

The Difference of Serum Protein Transport between Echinosides and Verbascoside

2020 ◽  
Vol 42 (3) ◽  
pp. 369-369
Author(s):  
Ming Guo Ming Guo ◽  
Xiaoxue Zhao Xiaoxue Zhao ◽  
Peter E Brodelius Peter E Brodelius ◽  
Ling Fang Ling Fang ◽  
Zhihong Sun and Rui Wang Zhihong Sun and Rui Wang
Keyword(s):  
Molecular Modeling ◽  
Hydrogen Bonds ◽  
Serum Albumin ◽  
Protein Transport ◽  
Van Der Waals ◽  
Hydrolysis Product ◽  
Van Der Waals Forces ◽  
Molecular Structures ◽  
Hydrophobic Force ◽  
Binding Characteristics

Verbascoside (VER) is the enzymatic hydrolysis product of echinacoside (ECH). The molecular structures of ECH and VER have different glucosyl groups so they bind to serum albumin in different ways, resulting in different pharmacological actions. In this report, we have examined the binding characteristics between human serum albumin (HSA) and ECH/VER by molecular modeling and spectroscopic approaches. Molecular modeling revealed that VER bound to HSA mainly through hydrogen bonds, van der Waals forces and hydrophobic forces. The spectroscopic results showed that the interactions between HSA and VER/ECH involved a static binding process, and the bonding strength of the VER-HSA complex was stronger than that of the ECH-HSA complex. The value of the binding distances (r) was low, which indicated the occurrence of energy transfer. The reaction conformational pattern of HSA-VER and HSA-ECH gave a “two-state model” based on fluorescent phase diagram analysis. According to the thermodynamic model, the main forces between interaction of VER and HSA were hydrogen bonds and van der Waals forces, whereas the interaction between ECH and HSA was hydrophobic force. The fluorescence polarization analysis demonstrated that the interaction between HSA and VER or ECH generated a non-covalent complex. Compared with ECH, VER was more likely to bind with HSA because of its smaller molecular size and low polarity. The results of the spectral analysis concurred with the molecular modeling data, which provides a helpful reference for the study of the molecular reaction mechanism of VER/ECH binding to HSA.

Polymer nanoparticles for drug delivery – synthetic vs. biopolymers?

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2181-2183
Author(s):  
Martin Gericke ◽  
Thomas Heinze
Keyword(s):  
Quality Standards ◽  
Synthetic Polymer ◽  
Molecular Structures ◽  
Polymer Nanoparticles ◽  
Cell Type ◽  
High Quality ◽  
Medical Products ◽  
Physiological Conditions ◽  
Supramolecular Architectures ◽  
Specific Tissue

Nanoparticles have a great prospect for therapeutic applications. They can protect drugs under physiological conditions and act as a matrix for directed delivery of drugs, e.g., to a specific tissue or cell type. Polymer-based nanomaterials are considered as highly effective in this regard. Their properties can be tailored to meet specific demands for given therapeutic purposes. Considering the high-quality standards placed on medical products, the question arises: Which type of polymer material should be employed? One might select synthetic polymer compounds, which are highly diverse in terms of the molecular structures and supramolecular architectures that can be created, or biopolymers such as polysaccharides that are renowned for their native biocompatibility.

scholarly journals A Dogma in Doubt: Hydrolysis of Equatorial Ligands of Pt IV Complexes under Physiological Conditions

2019 ◽  
Vol 58 (22) ◽  
pp. 7464-7469 ◽  
Author(s):  
Alexander Kastner ◽  
Isabella Poetsch ◽  
Josef Mayr ◽  
Jaroslav V. Burda ◽  
Alexander Roller ◽  
...  
Keyword(s):  
Physiological Conditions ◽  
Hydrolysis Of

scholarly journals Kinetics of the alkaline hydrolysis of crystal violet in micelles, reverse micelles and microemulsions of cetyltrimethylammonium bromide

1970 ◽  
Vol 24 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Ferdousi Begum ◽  
Md Yousuf A Molla ◽  
M Muhibur Rahman ◽  
Md Abu Bin Hasan Susan
Keyword(s):  
Crystal Violet ◽  
Alkaline Hydrolysis ◽  
Reverse Micelles ◽  
Cetyltrimethylammonium Bromide ◽  
Specific Conductivity ◽  
Water System ◽  
Chemical Society ◽  
Order Rate Constant ◽  
Kinetics Of ◽  
Hydrolysis Of

Kinetics of the alkaline hydrolysis of crystal violet (CV) in micelles, reverse micelles and microemulsions of a cationic surfactant, cetyltrimethylammonium bromide (CTAB) was studied at 25 ± 0.1 oC using spectrophotometric method. The rate of alkaline hydrolysis of CV was catalyzed by micellar solutions of CTAB. The pseudo first order rate constant (k') has been found to decrease upon incorporation of 1-butanol to cationic CTAB micelles, which displaces the substrate from the micellar into the aqueous phase. In CTAB/cyclohexane/1-butanol/water system, as the content of 1-butanol increases, specific conductivity and density of the microemulsions and reverse micelles decrease. The change in physical properties also causes change in reaction environment. A change from a micelle-rich (o/w) to a reverse micelle-rich (w/o) condition is apparent for microemulsions and consequently the k' vs. % wt. of 1-butanol profiles show an initial decrease in the k' followed by a gradual increase and finally, to a sharp increase with increasing 1-butanol content. Microemulsions and reverse micelles thus offer the potential to control rate of a reaction by formation of micelles in water phase and reverse micelles in oil phase. DOI: http://dx.doi.org/10.3329/jbcs.v24i2.9706 Journal of Bangladesh Chemical Society, Vol. 24(2), 173-184, 2011

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