Anomalous electrophoretic migration of oligodeoxynucleotides with terminal OH groups: Applications for DNA exonuclease characterization

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule. The theoretical results are in a good accordance with the experimental data.

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Statistical Analysis of the Relationship Between Antioxidant Activity and the Structure of Flavonoid Compounds

Revista de Chimie ◽

10.37358/rc.19.9.7497 ◽

2019 ◽

Vol 70 (9) ◽

pp. 3103-3107 ◽

Cited By ~ 7

Author(s):

Ioana Glevitzky ◽

Gabriela Alina Dumitrel ◽

Mirel Glevitzky ◽

Bianca Pasca ◽

Pavel Otrisal ◽

...

Keyword(s):

Antioxidant Activity ◽

Antioxidant Activities ◽

Basic Structure ◽

Oh Groups ◽

Flavonoid Compounds ◽

Chi Squared ◽

Potential Link ◽

Van Der Waals Surface ◽

The Relationship ◽

Phenolic Oh Groups

Using different methods of statistics, this paper aims to highlight the potential link between the antioxidant activity of flavonoids and the corresponding molecular descriptors. By calculating the descriptors (van der Waals surface (A), molar volume (V), partition coefficient (LogP), refractivity (R), polarizability (a), forming heat (Hformation), hydration energy (Ehidr), the dipole moment (mt)), together with antioxidant activities (RSA) calculated or taken from the literature, number of phenolic -OH groups and the presence (2) or absence (1) of C2=C3 double bond) for 29 flavonoid compounds and by intercorrelation between the studied parameters, the link between the number of phenolic groups grafted to the basic structure of flavonoids and their antioxidant activity was confirmed. Simultaneously, by using the chi-squared test and the intercorrelations matrix, a satisfactorily correlation coefficient (r2=0.5678; r=0.7536) between the structure of the flavonoids and their activity was obtained, fact that confirms the correlation of the antioxidant activity with the number of -OH phenolic groups.

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On the Reaction of 2,5-Dihydroxy-[1,4]-benzoquinone with Diamines – Strain-induced Reactivity Effects

Current Organic Chemistry ◽

10.2174/1385272824666201209112938 ◽

2020 ◽

Vol 24 ◽

Author(s):

Hubert Hettegger ◽

Andreas Hofinger ◽

Thomas Rosenau

Keyword(s):

Nucleophilic Substitution ◽

Product Structure ◽

Carbonyl Groups ◽

Reaction Products ◽

Double Bonds ◽

Oh Groups ◽

Natural Geometry ◽

Quinoid Structure ◽

Bond Localization

: The regioselectivity of the reaction of 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) with diamines could not be explained satisfactorily so far. In general, the reaction products can be derived from the tautomeric ortho-quinoid structure of a hypothetical 4,5-dihydroxy-[1,2]-benzoquinone. However, both aromatic and aliphatic 1,2-diamines form in some cases phenazines, formally by diimine formation on the quinoid carbonyl groups, and in other cases the corresponding 1,2- diamino-[1,2]-benzoquinones, by nucleophilic substitution of the OH groups, the regioselectivity apparently not following any discernible pattern. The reactivity was now explained by an adapted theory of strain-induced bond localization (SIBL). Here, the preservation of the "natural" geometry of the two quinoid C–C double bonds (C3=C4 and C5=C6) as well as the N–N distance of the co-reacting diamine are crucial. A decrease of the annulation angle sum (N–C4–C5 + C4–C5–N) is tolerated well and the 4,5-diamino-ortho-quinones, having relatively short N–N spacings are formed. An increase in the angular sum is energetically unfavorable, so that diamines with a larger N–N distance afford the corresponding ortho-quinone imines. Thus, for the reaction of DHBQ with diamines, exact predictions of the regioselectivity, and the resulting product structure, can be made on the basis of simple computations of bond spacings and product geometries.

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Synthesis, Conformational Analysis, Infrared, Raman and UV-Visible Spectra of Novel Schiff Bases compiled with DFT Calculations

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666200127161207 ◽

2020 ◽

Vol 23 (7) ◽

pp. 568-586

Author(s):

Samy M. Ahmed ◽

Ibrahim A. Shaaban ◽

Elsayed H. El-Mossalamy ◽

Tarek A. Mohamed

Keyword(s):

Schiff Bases ◽

1H Nmr ◽

Electronic Absorption Spectra ◽

Chemical Shifts ◽

Basis Set ◽

Oh Groups ◽

Vibrational Assignments ◽

Cartesian Coordinate ◽

Surface Scan ◽

Ir And Raman

Objective: Two novel Schiff bases named, 2-((2-Hydroxybenzylidene)amino)-4,5,6,7- tetrahydrobenzo[b] thiophene-3-carbonitrile (BESB1) and 2-((Furan-2-ylmethylene)amino)-4,5,6, 7-tetrahydro-benzo[b]thiophene-3-carbonitrile (BESB2) were synthesized. Methods: The structures were characterized based on CHN elemental analysis, mid-infrared (400– 4000 cm-1), Raman (100-4000 cm-1), 1H NMR, mass and UV-Vis spectroscopic measurements. In addition, quantum mechanical calculations using DFT-B3LYP method at 6-31G(d) basis set were carried out for both Schiff bases. Initially, we have carried out complete geometry optimizations followed by frequency calculations for the proposed conformational isomers; BESB1 (A–E) and BESB2 (F–J) based on the orientations of both CN and OH groups against the azomethine lonepair (NLP) in addition to the 3D assumption. Results: The computational outcomes favor conformer A for BESB1 in which the C≡N and OH moieties are cis towards the NLP while conformer G is preferred for BESB2 (the C≡N/furan-O are cis/trans towards the NLP) which was found consistent with the results of relaxed potential energy surface scan. Aided by normal coordinate analysis of the Cartesian coordinate displacements, we have suggested reliable vibrational assignments for all observed IR and Raman bands. Moreover, the electronic absorption spectra for the favored conformers were predicted in DMSO solution using TD-B3LYP/6-31G(d) calculations. Similarly, the 1H NMR chemical shifts were also estimated using GIAO approach implementing PCM including solvent effects (DMSO-d6). Conclusion: Proper interpretations of the observed electronic transition, chemical shifts, IR and Raman bands were presented in this study.

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Cucurbitacins as Anticancer Agents: A Patent Review

Recent Patents on Anti-Cancer Drug Discovery ◽

10.2174/1574892813666181119123035 ◽

2019 ◽

Vol 14 (2) ◽

pp. 133-143 ◽

Cited By ~ 3

Author(s):

Hidayat Hussain ◽

Ivan R. Green ◽

Muhammad Saleem ◽

Khanzadi F. Khattak ◽

Muhammad Irshad ◽

...

Keyword(s):

Anticancer Agents ◽

Wide Spectrum ◽

Biological Effects ◽

Therapeutic Effects ◽

Cytotoxic Effects ◽

Natural Sources ◽

Oh Groups ◽

Drug Candidates ◽

The Past ◽

Wide Range

Background: Cucurbitacins belong to a group of tetracyclic triterpenoids that display a wide range of biological effects. In the past, numerous cucurbitacins have been isolated from natural sources and many active compounds have been synthesized using the privileged scaffold in order to enhance its cytotoxic effects. Objective: his review covers patents on the therapeutic effects of natural cucurbitacins and their synthetic analogs published during the past decade. By far, the majority of patents published are related to cancer and Structure-Activity Relationships (SAR) of these compounds are included to lend gravitas to this important class of natural products. Methods: The date about the published patents was downloaded via online open access patent databases. Results: Cucurbitacins display significant cytotoxic properties, in particular cucurbitacins B and D which possess very potent effects towards a number of cancer cells. Numerous cucurbitacins isolated from natural sources have been derivatized through chemical modification at the C(2)-OH and C(25)- OH groups. Most importantly, an acyl ester of the C(25)-OH and, iso-propyl, n-propyl and ethyl ether groups of the C(2)-OH demonstrated the most increased cytotoxic activity. Conclusion: The significant cytotoxic effects of natural and semi-synthetic cucurbitacins make them attractive as new drug candidates. Moreover, cucurbitacins have the capability to form conjugates with other anticancer drugs which will synergistically enhance their anticancer effects. The authors believe that in order to get lead compounds, there should be a greater focus on the synthesis of homodimers, heterodimers, and halo derivatives of cucurbitacins. In the opinion of the authors the analysis of the published patents on the cucurbitacins indicates that these compounds can be developed into a regimen to treat a wide spectrum of cancers.

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The effect of individual OH-groups in monodeoxy-α-D-glucopyranosyl phosphates on their hydrolysis rates in acid medium

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19771379 ◽

1977 ◽

Vol 42 (4) ◽

pp. 1379-1384

Author(s):

J. Zámocký ◽

J. Zemek ◽

Š. Kučár ◽

V. Soukupová

Keyword(s):

Acid Medium ◽

Oh Groups ◽

Hydrolysis Rates

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Biologically Important Physicochemical Properties of Some Cephalosporins

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19921739 ◽

1992 ◽

Vol 57 (8) ◽

pp. 1739-1746

Author(s):

Katarína Škvareninová ◽

Štefan Baláž ◽

Ernest Šturdík ◽

Miroslav Veverka ◽

Jana Adamcová ◽

...

Keyword(s):

Physicochemical Properties ◽

Partition Coefficients ◽

Dissociation Constants ◽

Transport Rate ◽

Hydrolysis Rate ◽

Antibacterial Effects ◽

Oh Groups ◽

Non Linear Equation ◽

Cell Components ◽

The Relationship

In the series of cephalosporin derivatives, consisting of eight 7-(R1-CH2-CO-NH)cephalosporanic acids and of seven analogical compounds with 3-acetoxymethyl replaced by 3-CH3, physicochemical properties, which are expected to play a role in their antibacterial effects (the transport rate parameters and partition coefficients in the systems 1-octanol-water and 1-octanol-buffer, dissociation constants of the 4-carboxyl group, reactivity towards L-glutathione imitating the nucleophilic groups of the cell components and hydrolysis rate parameters), were determined. Linear dependences were observed between the partition coefficients and the π-constants of the varying substituents as well as between reactivity towards SH-groups of L-glutathione and OH-groups. The relationship between the transport rate parameters and partition coefficients, both measured in buffered as well as non-buffered system, was described by a common non-linear equation.

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The Effect of Acidity of Al and Fe Silicates with MFI Structure on Benzene and Toluene Alkylation with Isopropyl Alcohol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19961115 ◽

1996 ◽

Vol 61 (8) ◽

pp. 1115-1130 ◽

Cited By ~ 2

Author(s):

Jiří Čejka ◽

Naděžda Žilková ◽

Blanka Wichterlová

Keyword(s):

Kinetic Study ◽

Molecular Sieves ◽

Isopropyl Alcohol ◽

Acid Sites ◽

Transport Rate ◽

Reaction Products ◽

Oh Groups ◽

Benzene Alkylation ◽

Toluene Alkylation ◽

Low Strength

Kinetic study of toluene and benzene alkylation with isopropyl alcohol on alumo- and ferrisilicates of MFI structure has shown that the alkylation activity does not follow the acidity (both the number and strength of bridging OH groups) of these molecular sieves. The rate of the overall reaction is controlled by the desorption/transport rate of bulky, strongly adsorbed cymenes and cumene. A higher concentration of n-propyltoluenes compared to n-propylbenzene, both undesired reaction products, formed via a bimolecular isomerization of isopropyl aromate with benzene or toluene, was due to the higher reactivity of isopropyltoluene with toluene in comparison with that of cumene with benzene. It is concluded that ferrisilicates of MFI structure possessing low strength acid sites appear to be promising catalysts for achieving both a high isopropyl- and para-selectivity in toluene alkylation to p-cymene.

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Differences in the Effects of Anthocyanin Supplementation on Glucose and Lipid Metabolism According to the Structure of the Main Anthocyanin: A Meta-Analysis of Randomized Controlled Trials

Nutrients ◽

10.3390/nu13062003 ◽

2021 ◽

Vol 13 (6) ◽

pp. 2003

Author(s):

Risa Araki ◽

Akira Yada ◽

Hirotsugu Ueda ◽

Kenichi Tominaga ◽

Hiroko Isoda

Keyword(s):

Lipid Metabolism ◽

Meta Analysis ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Resistance Index ◽

Lipoprotein Cholesterol ◽

Controlled Trials ◽

Oh Groups ◽

Chemical Structures ◽

Glucose And Lipid Metabolism

The effectiveness of anthocyanins may differ according to their chemical structures; however, randomized clinical controlled trials (RCTs) or meta-analyses that examine the consequences of these structural differences have not been reported yet. In this meta-analysis, anthocyanins in test foods of 18 selected RCTs were categorized into three types: cyanidin-, delphinidin-, and malvidin-based. Delphinidin-based anthocyanins demonstrated significant effects on triglycerides (mean difference (MD): −0.24, p < 0.01), low-density lipoprotein cholesterol (LDL-C) (MD: −0.28, p < 0.001), and high-density lipoprotein cholesterol (HDL-C) (MD: 0.11, p < 0.01), whereas no significant effects were observed for cyanidin- and malvidin-based anthocyanins. Although non-significant, favorable effects on total cholesterol (TC) and HDL-C were observed for cyanidin- and malvidin-based anthocyanins, respectively (both p < 0.1). The ascending order of effectiveness on TC and LDL-C was delphinidin-, cyanidin-, and malvidin-based anthocyanins, and the differences among the three groups were significant (both p < 0.05). We could not confirm the significant effects of each main anthocyanin on glucose metabolism; however, insulin resistance index changed positively and negatively with cyanidin- and delphinidin-based anthocyanins, respectively. Therefore, foods containing mainly unmethylated anthocyanins, especially with large numbers of OH groups, may improve glucose and lipid metabolism more effectively than those containing methylated anthocyanins.

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UV Stimulated Manganese Dioxide for the Persulfate Catalytic Degradation of Bisphenol A

Catalysts ◽

10.3390/catal11040502 ◽

2021 ◽

Vol 11 (4) ◽

pp. 502

Author(s):

Guihua Dong ◽

Bing Chen ◽

Bo Liu ◽

Stanislav R. Stoyanov ◽

Yiqi Cao ◽

...

Keyword(s):

Bisphenol A ◽

Reaction Mechanisms ◽

Reduction Rate ◽

Catalytic Degradation ◽

Gas Chromatography Mass Spectrometry ◽

Degradation Pathways ◽

Industrial Chemicals ◽

Oh Groups ◽

Long Term Adverse Effects

One of the most commonly produced industrial chemicals worldwide, bisphenol A (BPA), is used as a precursor in plastics, resins, paints, and many other materials. It has been proved that BPA can cause long-term adverse effects on ecosystems and human health due to its toxicity as an endocrine disruptor. In this study, we developed an integrated MnO2/UV/persulfate (PS) process for use in BPA photocatalytic degradation from water and examined the reaction mechanisms, degradation pathways, and toxicity reduction. Comparative tests using MnO2, PS, UV, UV/MnO2, MnO2/PS, and UV/PS processes were conducted under the same conditions to investigate the mechanism of BPA catalytic degradation by the proposed MnO2/UV/PS process. The best performance was observed in the MnO2/UV/PS process in which BPA was completely removed in 30 min with a reduction rate of over 90% for total organic carbon after 2 h. This process also showed a stable removal efficiency with a large variation of pH levels (3.6 to 10.0). Kinetic analysis suggested that 1O2 and SO4•− played more critical roles than •OH for BPA degradation. Infrared spectra showed that UV irradiation could stimulate the generation of –OH groups on the MnO2 photocatalyst surface, facilitating the PS catalytic degradation of BPA in this process. The degradation pathways were further proposed in five steps, and thirteen intermediates were identified by gas chromatography-mass spectrometry. The acute toxicity was analyzed during the treatment, showing a slight increase (by 3.3%) in the first 30 min and then a decrease by four-fold over 2 h. These findings help elucidate the mechanism and pathways of BPA degradation and provide an effective PS catalytic strategy.

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