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Hernandes IS, Da Silva HC, Dos Santos HF, Ávila EP, De Almeida MV, De Almeida WB. Quantum chemical investigation of predominant conformation of the antibiotic azithromycin in water and DMSO solutions: thermodynamic and NMR analysis. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230409. [PMID: 37830015 PMCID: PMC10565400 DOI: 10.1098/rsos.230409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 09/12/2023] [Indexed: 10/14/2023]
Abstract
Azithromycin (AZM) is a macrolide-type antibiotic used to prevent and treat serious infections (mycobacteria or MAC) that significantly inhibit bacterial growth. Knowledge of the predominant conformation in solution is of fundamental importance for advancing our understanding of the intermolecular interactions of AZM with biological targets. We report an extensive density functional theory (DFT) study of plausible AZM structures in solution considering implicit and explicit solvent effects. The best match between the experimental and theoretical nuclear magnetic resonance (NMR) profiles was used to assign the preferred conformer in solution, which was supported by the thermodynamic analysis. Among the 15 distinct AZM structures, conformer M14, having a short intramolecular C6-OH … N H-bond, is predicted to be dominant in water and dimethyl sulfoxide (DMSO) solutions. The results indicated that the X-ray structure backbone is mostly conserved in solution, showing that large flexible molecules with several possible conformations may assume a preferential spatial orientation in solution, which is the molecular structure that ultimately interacts with biological targets.
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Affiliation(s)
- Isabel S. Hernandes
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, 24020-141, Centro, Niterói, RJ, Brazil
| | - Haroldo C. Da Silva
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, 24020-141, Centro, Niterói, RJ, Brazil
| | - Hélio F. Dos Santos
- Núcleo de Estudos em Química Computacional, Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil
- Departamento de Química, ICE, Universidade Federal de Juiz de Fora (UFJF), Campus Universitário, Martelos, Juiz de Fora, MG 36036-330, Brazil
| | - Eloah P. Ávila
- Departamento de Química, ICE, Universidade Federal de Juiz de Fora (UFJF), Campus Universitário, Martelos, Juiz de Fora, MG 36036-330, Brazil
| | - Mauro V. De Almeida
- Departamento de Química, ICE, Universidade Federal de Juiz de Fora (UFJF), Campus Universitário, Martelos, Juiz de Fora, MG 36036-330, Brazil
| | - Wagner B. De Almeida
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, 24020-141, Centro, Niterói, RJ, Brazil
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Kaeswurm JAH, Scharinger A, Teipel J, Buchweitz M. Absorption Coefficients of Phenolic Structures in Different Solvents Routinely Used for Experiments. Molecules 2021; 26:molecules26154656. [PMID: 34361808 PMCID: PMC8348453 DOI: 10.3390/molecules26154656] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
Phenolic structures are of great interest due to their antioxidant properties and various postulated benefits on human health. However, the quantification of these structures in fruits and vegetables, as well as in vivo or in vitro experiments, is demanding, as relevant concentrations are often low, causing problems in exactly weighing the respective amounts. Nevertheless, the determination of used concentrations is often a prerequisite for accurate results. A possibility to quantify polyphenol is the use of UV/vis spectroscopy. Therefore, the absorption coefficients of selected phenolic structures were determined in three different solvents relevant for polyphenol research (water/methanol (50/50, v/v), water, and phosphate buffer at pH 7.5). To confirm the values based on weight and to avoid errors due to impurities, hygroscopic effects, and inadequate balance care, the mass concentrations were additionally determined by quantitative NMR (q-NMR). The coefficients presented in this article can help to quickly and easily determine accurate concentrations in a laboratory routine without wasting the often-precious standard compounds.
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Affiliation(s)
- Julia A. H. Kaeswurm
- Department of Food Chemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany;
| | - Andreas Scharinger
- Chemisches und Veterinäruntersuchungsamt Karlsruhe, Weißenburger Str. 3, 76187 Karlsruhe, Germany; (A.S.); (J.T.)
| | - Jan Teipel
- Chemisches und Veterinäruntersuchungsamt Karlsruhe, Weißenburger Str. 3, 76187 Karlsruhe, Germany; (A.S.); (J.T.)
| | - Maria Buchweitz
- Department of Food Chemistry, Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany;
- Correspondence: ; Tel.: +49-71168569231
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Da Silva HC, Hernandes IS, De Almeida WB. Quantum chemical investigation of beta-CD–catechin flavonoid encapsulation in solution through NMR analysis: an adequate controlled drug-delivery system. NEW J CHEM 2021. [DOI: 10.1039/d1nj02756e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT–PCM–water calculations of 1H NMR chemical shifts for 28 optimized catechin–beta-CD complex structures revealed that adsorption mode of complexion should be predominant in aqueous media, with full-inclusion 1 : 1 structure being in total disagreement with experimental 1H NMR profile (D2O).
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Affiliation(s)
- Haroldo C. Da Silva
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM)
- Departamento de Química Inorgânica
- Instituto de Química
- Universidade Federal Fluminense (UFF)
- Niterói
| | - Isabel S. Hernandes
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM)
- Departamento de Química Inorgânica
- Instituto de Química
- Universidade Federal Fluminense (UFF)
- Niterói
| | - Wagner B. De Almeida
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM)
- Departamento de Química Inorgânica
- Instituto de Química
- Universidade Federal Fluminense (UFF)
- Niterói
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