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Štekláč M, Breza M. DFT studies of camptothecins cytotoxicity IV — active and inactive forms of irinotecan. ACTA CHIMICA SLOVACA 2023. [DOI: 10.2478/acs-2023-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
Abstract
Structures of irinotecan (CPT-11) in neutral lactone, neutral carboxyl, and anionic carboxylate forms in singlet ground states and of their complexes with Cu(II) in doublet ground states are optimized using B3LYP/6-311G* treatment. Metal ion affinities (MIA), Cu charges and Laplacians of Cu-ligand bond critical points of possible CPT active sites are evaluated. The formation of Cu(II) complexes with the anionic carboxylate ligand leads to the release of CO2 that can cause a decrease in the concentration of the active lactone form due to equilibria between all forms of the drug. MIA values and electron density transfer to Cu increase in the sequence lactone < neutral carboxyl < anionic carboxylate. Both neutral forms of irinotecan exhibit lower MIA values than those of camptothecin, unlike the anionic carboxylate form.
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Štekláč M, Breza M. DFT studies of camptothecins cytotoxicity II. Protonated lactone forms of camptothecin. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113677] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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3
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DFT studies of camptothecins cytotoxicity III: camptothecin, irinotecan and SN-38. ACTA CHIMICA SLOVACA 2022. [DOI: 10.2478/acs-2022-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Geometries of camptothecin, irinotecan, SN-38, and of their hypothetical Cu(II) complexes were optimized at the B3LYP/6-311G* level of theory. Their electron structure, evaluated in terms of Mulliken population analysis and Quantum Theory of Atoms-in-Molecule, was subsequently related to in vitro cytotoxicity. Electron density transfer from the relevant active sites to Cu decreases in the sequence irinotecan > SN-38 > camptothecin. The absolute values of their metal-ligand interaction energies exhibit the same trend. Discrepancy with the least relative in vitro cytotoxicity of irinotecan can be explained by differences in its pharmacokinetics.
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Štekláč M, Breza M. DFT Studies of Substituted Phenols Cytotoxicity I.
Para
‐substituted Phenols. ChemistrySelect 2021. [DOI: 10.1002/slct.202101568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Marek Štekláč
- Department of Physical Chemistry Faculty of Chemical and Food Technology Slovak Technical University, SK- 81237 Bratislava Slovakia
| | - Martin Breza
- Department of Physical Chemistry Faculty of Chemical and Food Technology Slovak Technical University, SK- 81237 Bratislava Slovakia
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Madala NE, Kabanda MM. LC-MS based validation and DFT investigation on the antioxidant properties of clovamide: •OH and •OOH scavenging and Cu(II) chelation mechanisms. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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9
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Quantum-chemical studies of rutile nanoparticles toxicity II. Comparison of B3LYP and PM6 data. ACTA CHIMICA SLOVACA 2021. [DOI: 10.2478/acs-2021-0006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The relation between copper atomic charges and metal-ligand interaction energies obtained by PM6 and DFT-B3LYP methods for cytotoxicity prediction of model rutile nanoparticles [Ti40O124H81]7–, [Ti7O28H26]2–, [Ti2O10H10]2–, [Ti7O30H30]2– and their Cu(II) complexes is investigated. Except for Mulliken charges, very good statistical parameters were obtained for the linear relation between the results obtained by both methods if standard accuracy of quantum-chemical calculations is achieved.
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Comparative DFT study of the effectiveness of p-phenylenediamine antioxidants through their coordination ability towards the late 1st row transition metals. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2020.109438] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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11
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Kabanda MM, Gbashi S, Madala NE. Proportional coexistence of okanin chalcone glycoside and okanin flavanone glycoside in Bidens pilosa leaves and theoretical investigation on the antioxidant properties of their aglycones. Free Radic Res 2020; 55:53-70. [PMID: 33267705 DOI: 10.1080/10715762.2020.1859107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Bidens pilosa plant has been shown to produce okanin flavanone glycoside and its chalcone derivative. In most other plants, due to chalcone isomerase enzyme, the flavanone tends to exist in higher proportions than their chalcone precursors. Herein we have utilized liquid chromatography-mass spectrometry approach and shown that within the leaves of Bidens pilosa plant the two okanin glycosides exist in unusual equal proportional distribution, which indicates that Bidens pilosa plant is an alternative rich source of these highly sought-after antioxidant molecules. The aglycone okanin chalcone (ONC) and okanin flavanone (ONF) have experimentally been shown to exhibit antioxidant activity. However, experimental findings have not conclusively determined which of the two compounds is a more potent antiradical than the other. Herein, the density functional theory (DFT) method is utilized to establish, from structural and thermodynamic energetic considerations, the preferred antioxidant molecule between the two aglycone okanins. A theoretical study on the antioxidant properties of ONC and ONF has been performed by considering their radical scavenging and metal cation (Mn+, where M = Cu(II) or Fe (III)) chelation ability. The study has been performed using B3LYP/6-31 + G(d,p) method. In the case of the metal chelation mechanism, the LANL2DZ pseudo-potential was selected to describe the selected Mn+ cations. The results of the study suggest that ONC is a better radical scavenger than ONF because of the extended electron delocalization on its neutral radical, which is due to the presence of conjugation within the ONC neutral radical after hydrogen atom abstraction. In the metal chelation mechanism, it is noted that the binding energies depend on the media, the nature of the ligand and the cation and the cation coordination site on the ligand. The charge and the spin density on Mn+ decrease on coordination to the ligand. The ability of the ligands to reduce Mn+ cations, coupled with the strong Mn+ binding properties, has significant implication on the antioxidant ability of both okanins. However, since ONC⋅⋅⋅M+n interaction results in higher binding energy than ONF⋅⋅⋅M+n interaction, the implication is that ONC is a preferred free metal ion chelator than ONF.
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Affiliation(s)
- Mwadham M Kabanda
- Department of Chemistry, University of Venda, Thohoyandou, South Africa
| | - Sefater Gbashi
- Department of Biotechnology and Food Technology, University of Johannesburg, Auckland Park, South Africa
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Mammino L. Tube-shaped molecular structures built from acylphloroglucinols: an ab initio and DFT study. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1784477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Liliana Mammino
- School of Mathematical and Natural Sciences, University of Venda, Thohoyandou, South Africa
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Antioxidant Properties of Lapachol and Its Derivatives and Their Ability to Chelate Iron (II) Cation: DFT and QTAIM Studies. Bioinorg Chem Appl 2020; 2020:2103239. [PMID: 32318101 PMCID: PMC7150675 DOI: 10.1155/2020/2103239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/09/2019] [Accepted: 08/21/2019] [Indexed: 01/06/2023] Open
Abstract
The elucidation of the complexation of lapachol and its derivatives to Fe2+ cation has been done using the density functional theory (DFT). This complexation has been limited to bidentate and tridentate to Fe2+ cation. Geometry optimizations have been implemented in gas and solution phase (water, acetonitrile, chlorobenzene, benzene, and toluene) for ligands at B3LYP/6-311++G (d,p) level of theory using B3LYP/6-31+G(d,p) optimized data as starting point. But, the geometrical optimizations in solution phase of the 22 complexes analyzed of lapachol and its derivatives to Fe2+ cation were restricted to acetonitrile and benzene. The complexation energy and the metal ion affinity (MIA) have also been calculated using the B3LYP method. The results obtained indicated a proportionality between the MIA values and the retained charge on Fe2+ cation for k2-(O1,O2) modes. But, an inverse proportionality has been yielded between these two parameters for k3-(O2, C=C) tridentate modes. For k3-(O3,C=C) tridentate mode coordination, the higher stability has been obtained. In this latter tridentate coordination in gas phase, the topological analysis of complexes exhibits the fact that the electron density is concentrated between the O3 oxygen atom of the ligand attached to Fe2+ and this metal cation. Moreover, the hydrogen bond strength calculated for isolated ligands (situated between 23.92 and 30.15 kJ/mol) is in the range of normal HBs. Collectively, all the complexation processes have shown to be highly exothermic. Our results have also shown that the electron extraction from Fe2+...Lai complexes is more difficult compared to that from free ligands.
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Quantum-chemical studies of rutile nanoparticles toxicity I. Defect-free rod-like model clusters. ACTA CHIMICA SLOVACA 2020. [DOI: 10.2478/acs-2019-0023] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
Using the semiempirical PM6 method, structures of a rod-like [Ti40O124H81]7– model cluster and of [Ti40O124H81Cu]5– with Cu2+ coordinated at various sites were optimized in order to assess the toxicity of rutile nanoparticles. If the relative toxicity of individual Ti centers in rod-like rutile nanoparticles can be evaluated by the electron density transfer to a Cu2+ probe, its maximal values can be ascribed to the pentacoordinated corner and hexacoordinated edge Ti centers with three Ti—OH bonds. However, these centers exhibit the least negative interaction energies which can be compensated by the significantly better accessibility of the corner Ti center compared with that of the remaining ones. Ti centers with the most negative interaction energy parameters exhibit the lowest extent of electron density transfer to a Cu2+ probe. Rutile nanoparticles destruction starts at pentacoordinated Ti face centers.
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Mammino L. Five- and six-member bowl-shaped structures from acylphloroglucinols: an ab initio and DFT study. J Mol Model 2019; 26:13. [PMID: 31838594 DOI: 10.1007/s00894-019-4208-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 09/12/2019] [Indexed: 11/29/2022]
Abstract
Molecular structures containing bowl-shaped cavities are interesting for purposes such as hosting molecules or metal ions. Acylphloroglucinols are derivatives of phloroglucinol (1,3,5-trihydroxybenzene) containing a CRO group. A previous study had considered bowl-shaped structures consisting of 3 or 4 identical acylphloroglucinol units linked by methylene bridges, selecting representative R chains and including also a structure with phloroglucinol units. The presence of three 'binding' levels between neighbouring units (consecutive hydrogen bonds in the lower rim, the methylene bridges at intermediate level, and another set of hydrogen bonds in the upper rim) makes these bowls 'deeper' than bowls from other hydroxybenzenes. The current study considers larger bowls, consisting of 5 and 6 identical units, to investigate how the molecular properties change with the increase in the size of the bowl. The monomeric units are the same as in the previous study, and the levels of theory are the same as in the previous study, to enable meaningful comparisons. Like in the previous study, two conformers are considered for each bowl, differing by the orientation of the OH groups in the lower rim. Calculations were performed at the HF/6-31G(d,p) and DFT/B3LYP/6-31+G(d,p) levels with fully relaxed geometry, complemented by single-point MP2/HF/6-31G(d,p) calculations. The results show that the Cnv symmetry (with n being the number of constituting monomers) is maintained for 5-member bowls, while 6-member bowls do not show C6v symmetry but only C2v symmetry. The molecular properties of the calculated bowls are analysed in detail and also compared with the properties of the previously calculated 4- and 5-member bowls. Graphical abstract Bowls built from acylphloroglucinol units have three levels of intermonomer linkages: hydrogen bonds in the bottom rim, methylene bridges at intermediate level, and other hydrogen bonds in the upper rim. They are the deepest bowls that can be built from hydroxybenzene units.
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Affiliation(s)
- Liliana Mammino
- School of Mathematical and Natural Sciences, University of Venda, Thohoyandou, South Africa.
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Mammino L. Effects of complexation with a metal ion on the intramolecular hydrogen bonds in acylphloroglucinols. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2481-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mammino L. Computational study of acylphloroglucinols: an investigation with many branches. PURE APPL CHEM 2019. [DOI: 10.1515/pac-2018-0909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Abstract
Acylphloroglucinols (ACPLs) are a broad class of compounds structurally derived from phloroglucinol and characterised by the presence of a CRO group. They are interesting for their biological activities and their potentialities as lead compounds in drug development. The current review considers a series of works which, altogether, sum up to a systematic computational study of ACPLs in vacuo and in three solvents – chloroform, acetonitrile and water. An initial set of studies, focusing on ACPLs as a class and utilising an adequately representative selection of molecules, identified patterns in the conformational preferences and molecular properties of ACPLs, which appear valid for the whole class or for specific subclasses such as monomeric ACPLs, dimeric ACPLs, ACPLs with substituents containing C=C double bonds, etc. The validity of the identified patterns was further verified through the study of additional and significantly different ACPL molecules, as well as other molecular structures containing ACPL units. Furthermore, the computational study of ACPLs proved interesting for the insights into the factors stabilising their conformers, first of all intramolecular hydrogen bonding, which plays dominant roles in determining conformational preferences and energetics. The current review outlines the objectives, approaches and main results of these studies. The obtained information may be relevant for further studies aimed at a better understanding of the molecular bases of the biological activities of ACPLs.
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Affiliation(s)
- Liliana Mammino
- Department of Chemistry , University of Venda , Thohoyandou , South Africa
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Mammino L. Complexes of Hyperguinones A and B with a Cu2+ Ion. ADVANCES IN QUANTUM CHEMISTRY 2019. [DOI: 10.1016/bs.aiq.2018.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mammino L. Intramolecular hydrogen bonding patterns, conformational preferences and molecular properties of dimeric acylphloroglucinols: An ab initio and DFT study. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.07.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Complexes of 1-[3-geranyl-2,4,6-trihydroxyphenyl]-2-methylpropan-1-one with a Cu2+ ion: a DFT study. Theor Chem Acc 2019. [DOI: 10.1007/s00214-018-2381-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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21
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Quantum-chemical study of the active sites of camptothecin through their Cu(II) coordination ability. ACTA CHIMICA SLOVACA 2018. [DOI: 10.2478/acs-2018-0002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
The structures of camptothecin (CPT) lactone form and its complexes with Cu(II) were optimized at B3LYP/6-311G* level of theory. Their electronic structures were evaluated via QTAIM topological analysis of electron density and Mulliken population analysis. Stability, electron density distribution and geometrical factors of the optimized systems were compared. Both CPT nitrogen atoms show lower affinity to Cu(II) compared to the oxygen ones. Both the oxygen atom in the CPT lactone ring and the one in the neighbouring carbonyl group show the highest affinity to Cu(II) and the highest stability of Cu-CPT complexes which indicates the most probable CPT reaction sites.
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Mammino L. Complexes of arzanol with a Cu 2+ ion: a DFT study. J Mol Model 2017; 23:276. [PMID: 28900733 DOI: 10.1007/s00894-017-3443-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 08/15/2017] [Indexed: 11/29/2022]
Abstract
Arzanol (C22H26O7) is a naturally occurring acylphloroglucinol largely responsible for the anti-inflammatory, anti-oxidant, antibiotic and antiviral activities of Helichrysum italicum. Like all acylphloroglucinols, the molecule contains a carboxylic substituent (-COR group); for arzanol, this is a -COCH3 group. The molecule is further characterized by the presence of an α-pyrone ring bonded in meta to -COR through a methylene bridge, and of a prenyl chain bonded to the other meta position. The molecule can form up to three intramolecular hydrogen bonds (IHB) simultaneously, and their presence and patterns are the major stabilizing factors. This work considers complexes of representative conformers of arzanol with a Cu2+ ion, taking into account the different possibilities for the binding of the Cu2+ ion to the electron-density rich sites of the molecule and including simultaneous coordination to two geometrically suitable sites. Calculations were performed at the DFT/B3LYP level, using the 6-31+G(d,p) basis set for the C, O and H atoms and the LANL2DZ pseudopotential for the Cu2+ ion. Interaction energies show preference for simultaneous binding of Cu2+ to two sites. Simultaneous binding to the O of a phenol OH neighboring the prenyl chain and to the π bond of the prenyl chain appears to be the most favorable option, followed by simultaneous binding to the sp2 O of the α-pyrone ring and the O of the phenol OH ortho to -COR on the side of the α-pyrone ring. The charge of the Cu2+ ion is reduced to +1 or slightly less in the complexes, which is consistent with the molecules' antioxidant (reducing) ability. Graphical abstract The copper ion prefers to attach to two sites of the arzanol molecule simultaneously. The arzanol molecule reduces the charge of the copper ion from +2 to +1 by transferring an electron to it; it becomes a radical molecular cation. The distribution of the unpaired electron in the molecule (as highlighted by the spin density maps) depends on the site/s to which the Cu2+ ion binds and on the molecule's conformer.
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Affiliation(s)
- Liliana Mammino
- Department of Chemistry, University of Venda, Thohoyandou, South Africa.
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23
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DFT studies of the effectiveness of p-substituted diphenyl amine antioxidants in styrene-butadiene rubber through their Cu(II) coordination ability. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.05.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Affiliation(s)
- Liliana Mammino
- Department of Chemistry, University of Venda, Thohoyandou, South Africa
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LoPachin RM, Geohagen BC, Nordstrøm LU, Gavin T. Enolate-Forming Compounds as a Novel Approach to Cytoprotection. Chem Res Toxicol 2016; 29:2096-2107. [PMID: 27989140 DOI: 10.1021/acs.chemrestox.6b00300] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Evidence from laboratory studies and clinical trials suggests that plant-derived polyphenolic compounds such as curcumin, resveratrol, or phloretin might be useful in the treatment of certain diseases (e.g., Alzheimer's disease) and acute tissue injury states (e.g., spinal cord trauma). However, despite this potential, the corresponding chemical instability, toxic potential, and low bioavailability of these compounds could limit their ultimate clinical relevance. We have shown that pharmacophores of curcumin (e.g., 2-acetylcyclopentanone) and phloretin (e.g., 2',4',6'-trihydroxyacetophenone; THA) can provide cytoprotection in cell culture and animal models of oxidative stress injury. These pharmacophores are 1,3-dicarbonyl and polyphenol derivatives, the enol groups of which can ionize in biological solutions to form an enolate. This carbanionic moiety can chelate metal ions and, as a nucleophile, can scavenge toxic electrophiles (e.g., acrolein, 4-hydroxy-2-nonenal, and N-acetyl-p-benzoquinone imine) involved in many pathogenic conditions. Aromatic derivatives such as THA can also trap free oxygen and nitrogen radicals and thereby provide another layer of cytoprotection. The multifunctional character of these enolate-forming compounds suggests an ability to block pathogenic processes (e.g., oxidative stress) at several steps. The purpose of this review is to discuss research supporting our theory that enolate formation is a significant cytoprotective property that represents a platform for development of pharmacotherapeutic approaches to a variety of toxic and pathogenic conditions. Our discussion will focus on mechanism and structure-activity studies that define enolate chemistry and their corresponding relationships to cytoprotection.
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Affiliation(s)
- Richard M LoPachin
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine , Bronx, New York 10461, United States
| | - Brian C Geohagen
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine , Bronx, New York 10461, United States
| | - Lars Ulrik Nordstrøm
- Chemical Synthesis & Biology Core Facility, Albert Einstein College of Medicine , Bronx, New York 10461, United States
| | - Terrence Gavin
- Department of Chemistry, Iona College , New Rochelle, New York 10801, United States
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Serobatse KRN, Kabanda MM. A theoretical study on the antioxidant properties of methoxy-substituted chalcone derivatives: A case study of kanakugiol and pedicellin through their Fe (II and III) coordination ability. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2016. [DOI: 10.1142/s0219633616500486] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A theoretical study on the antioxidant properties of two chalcone derivatives, kanakugiol and pedicellin, is performed by considering their Fe[Formula: see text] and Fe[Formula: see text] coordination ability. The objective of the study is to elucidate the factors influencing the stability of the isolated conformers, the nature of the complexes, metal[Formula: see text]ligand stability, metal ion affinities (MIA) and electronic properties of the cations before and after coordination to the ligand. The study is performed using the B3LYP/6–311[Formula: see text]G(2d,p)//B3LYP/6–31[Formula: see text]G(d,p) method. The LANL2DZ pseudopotential is selected to describe the Fe[Formula: see text] ions. Time-dependent density functional theory (TDDFT) method is used to assess the electronic UV–Vis spectra of the isolated chalcones and their complexes with Fe[Formula: see text] ions. The results suggest that the preferred complexes are those in which the Fe ion is coordinated at the hydroxyl-methoxy and hydroxyl-keto sites for kanakugiol and methoxy-keto site for pedicellin. Both kanakugiol and pedicellin have potential to chelate iron ions as demonstrated by their high MIA values in vacuo and in water solution. However, the ability of pedicellin to chelate iron is slightly lower than that of kanakugiol, indicating that the presence of the hydroxyl group has an effect of enhancing the metal binding abilities of the chalcone derivatives. In all the complexes obtained in vacuo, kanakugiol and pedicellin exhibit the ability to reduce the Fe[Formula: see text] ion. In water solution (which mimics the environment in biological systems or studies performed in vivo), Fe[Formula: see text] is reduced to Fe[Formula: see text] upon coordination to the ligand while the oxidation number of Fe[Formula: see text] upon coordination to the ligand remains virtually unchanged.
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Affiliation(s)
- Kemoabetswe R. N. Serobatse
- Faculty of Agriculture, Science and Technology, School of Mathematical and Physical Science, Department of Chemistry, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
| | - Mwadham M. Kabanda
- Faculty of Agriculture, Science and Technology, School of Mathematical and Physical Science, Department of Chemistry, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
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Puškárová I, Breza M. DFT studies of the effectiveness of p-phenylenediamine antioxidants through their Cu(II) coordination ability. Polym Degrad Stab 2016. [DOI: 10.1016/j.polymdegradstab.2016.02.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Geohagen BC, Vydyanathan A, Kosharskyy B, Shaparin N, Gavin T, LoPachin RM. Enolate-Forming Phloretin Pharmacophores: Hepatoprotection in an Experimental Model of Drug-Induced Toxicity. J Pharmacol Exp Ther 2016; 357:476-86. [PMID: 27029584 DOI: 10.1124/jpet.115.231001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 03/22/2016] [Indexed: 12/12/2022] Open
Abstract
Drug-induced toxicity is often mediated by electrophilic metabolites, such as bioactivation of acetaminophen (APAP) to N-acetyl-p-benzoquinone imine (NAPQI). We have shown that APAP hepatotoxicity can be prevented by 2-acetylcyclopentanone (2-ACP). This 1,3-dicarbonyl compound ionizes to form an enolate nucleophile that scavenges NAPQI and other electrophilic intermediates. In this study, we expanded our investigation of enolate-forming compounds to include analyses of the phloretin pharmacophores, 2',4',6'-trihydroxyacetophenone (THA) and phloroglucinol (PG). Studies in a mouse model of APAP overdose showed that THA provided hepatoprotection when given either by intraperitoneal injection or oral administration, whereas PG was hepatoprotective only when given intraperitoneally. Corroborative research characterized the molecular pharmacology (efficacy, potency) of 2-ACP, THA, and PG in APAP-exposed isolated mouse hepatocytes. For comparative purposes, N-acetylcysteine (NAC) cytoprotection was also evaluated. Measurements of multiple cell parameters (e.g., cell viability, mitochondrial membrane depolarization) indicated that THA and, to a lesser extent, PG provided concentration-dependent protection against APAP toxicity, which exceeded that of 2-ACP or NAC. The enolate-forming compounds and NAC truncated ongoing APAP exposure and thereby returned intoxicated hepatocytes toward normal viability. The superior ability of THA to protect is related to multifaceted modes of action that include metal ion chelation, free radical trapping, and scavenging of NAPQI and other soft electrophiles involved in oxidative stress. The rank order of potency for the tested cytoprotectants was consistent with that determined in a parallel mouse model. These data suggest that THA or a derivative might be useful in treating drug-induced toxicities and other conditions that involve electrophile-mediated pathogenesis.
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Affiliation(s)
- Brian C Geohagen
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
| | - Amaresh Vydyanathan
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
| | - Boleslav Kosharskyy
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
| | - Naum Shaparin
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
| | - Terrence Gavin
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
| | - Richard M LoPachin
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (B.C.G., A.V., B.K., N.S., R.M.L.); and Department of Chemistry, Iona College, New Rochelle, New York (T.G.)
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Alfaro RAD, Gomez-Sandoval Z, Mammino L. Evaluation of the antiradical activity of hyperjovinol-A utilizing donor-acceptor maps. J Mol Model 2015; 20:2337. [PMID: 25069138 DOI: 10.1007/s00894-014-2337-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hyperjovinol-A ((2-methyl-1-(2,4,6-trihydroxy-3-(3-hydroxy-3,7-dimethyloct-6-enyl)phen yl)propan-1-one) is an acylated phloroglucinol isolated from Hypericum Jovis and exhibiting good antioxidant activity. The study investigates the compound’s antiradical ability on the basis of the electron-donor and electron-acceptor abilities of its conformers, deriving donor and acceptor indexes and mapping them in terms of donor-acceptor maps (DAM). The DAMs of vitamins C and E and of carotene astaxantine are used as comparison references. Calculations were performed at the DFT/BPW91/6-311+G(d,p) level, with optimizations on fully relaxed geometries to obtain the conformers of the neutral molecule in vacuo, and single point calculations to obtain the energies of the cationic and anionic species in vacuo and of the neutral, cationic, and anionic species in water, ethanol, and pentylethanoate. The calculations in solution utilized the polarizable continuum model (PCM). The results indicate that hyperjovinol-A may have better antiradical activity than vitamin C. This is in agreement with experimental results, showing that the antioxidant activity of hyperjovinol-A is comparable with that of the best drugs currently in clinical use. The activity is maintained in solution. The Fukui function f(·) was also calculated for all the conformers of hyperjovinol-A, to identify the regions of highest reactivity.
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Kabanda MM, Mammino L, Murulana LC, Mwangi HM, Mabusela WT. Antioxidant Radical Scavenging Properties of Phenolic Pent-4-En-1-Yne Derivatives Isolated FromHypoxis Rooperi. A DFT Studyin vacuoand in Solution. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2014. [DOI: 10.1080/10942912.2013.825842] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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