NMR and molecular fluorescence spectroscopic study of the structure and thermodynamic parameters of EGCG/β-cyclodextrin inclusion complexes with potential antioxidant activity

Folch-Cano, Christian; Guerrero, Juan; Speisky, Hernán; Jullian, Carolina; Olea‐Azar, Claudio

doi:10.1007/s10847-013-0297-y

Cited by 29 publications

(24 citation statements)

References 32 publications

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“…However for the three compounds, the SMIP1 had the smallest adsorption capacity for C (Q max = 20.55 mg⋅g -1 ). This indicates that the shape and/or the spatial group arrangement of the cavities left by EGCG are not suitable for C. As mentioned previously, the EGCG A ring goes inside the β-CD [38,39]. In the contrast, the B ring of the molecule C has a chance to enter cavity of the β-CD [55,56].…”

Section: Binding Specificity and Selectivity Of The Smip1mentioning

confidence: 90%

“…The mixture was purged with nitrogen and incubated 2 h under stirring to form completely self-assembled complexes between EGCG, β-CD and MAA. In these complexes the benzopyrene ring of EGCG can access the hydrophobic cavity of β-CD [38,39] and the MAA carbonyl groups can form hydrogen bonds with the EGCG hydroxyl groups.…”

Section: Synthesis Of Surface Molecularly Imprinted Polymersmentioning

confidence: 99%

“…The EGCG and β-CD form a 1 : 1 complex and the B and B' ring moieties remain outside of the inclusion complex cavity (Fig. 1(b)) [38,39]. When MAA is added, it helps to stabilize the inclusion complex by forming multiple hydrogen bonds with the hydroxyl groups of the B and B' rings.…”

Section: Adsorption Properties Of the Molecularly Imprinted Polymersmentioning

confidence: 99%

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Surface molecularly imprinted polymers for solid-phase extraction of (–)-epigallocatechin gallate from toothpaste

Gao

Yao

2015

Front. Chem. Sci. Eng.

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Surface molecularly imprinted polymers (SMIPs) have been synthesized to selectively determine ( -)-epigallocatechin gallate in aqueous media. SMIPs were prepared using a surface grafting copolymerization method on a functionalized silica gel modified with β-cyclodextrin and vinyl groups. The morphology and composition of the SMIPs were investigated by scanning electron microscopy, Fourier transform-infrared spectroscopy and thermogravimetric analysis. In addition, the molecular binding capacity, recognition properties and selectivity of the SMIPs were evaluated. The imprinted polymers were found to have a highly specific recognition and binding capacity for ( -)-epigallocatechin gallate in aqueous media which is the result of the hydrophobic properties of the β-cyclodextrin and the hydrogen-bonding interactions of methacrylic acid. The SMIPs were successfully employed as solid-phase extraction adsorbents prior to the HPLC determination of ( -)-epigallocatechin gallate in toothpaste. The HPLC analysis had a linear dynamic range of 0.5-50.0 µg⋅mL -1 with a correlation coefficient of 0.9998 and the recoveries ranged from 89.4% to 97.0% with relative standard deviations less than 4.8%. The limit of detection and limit of quantification were 0.17 and 0.33 µg⋅mL -1 , respectively. The method provides a promising approach for the preparation of selective materials for the purification and determination of complex samples.

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Section: Binding Specificity and Selectivity Of The Smip1mentioning

confidence: 90%

Section: Synthesis Of Surface Molecularly Imprinted Polymersmentioning

confidence: 99%

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Surface molecularly imprinted polymers for solid-phase extraction of (–)-epigallocatechin gallate from toothpaste

Gao

Yao

2015

Front. Chem. Sci. Eng.

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“…34 NOE effect is a common phenomenon observed in NMR spectroscopy which consists in the transfer of the spin polarization from one population of nuclear spins to another, occurring between atoms that are separated in space by less than 5 Å. 35,36 The inter-atomic distances derived from the observed NOE are particularly useful to determine molecular geometry. 35 ROESY technique is preferred in the study of mid-sized molecules, such as peptides, oligosaccharides and host-guest complexes because this type of molecules exhibit non-zero and positive NOE in ROESY experiments.…”

Section: H Nmr Analysesmentioning

confidence: 99%

Imiquimod/β-Cyclodextrin Inclusion Complex: Experimental and Theoretical Studies

Guedes

Morgon

Martins

et al. 2020

J. Braz. Chem. Soc.

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Imiquimod (IMQ), an immune response modifier, is used for topical treatment of basal cell carcinoma and actinic keratosis. The very poor aqueous solubility of imiquimod gives rise to difficulties in designing aqueous formulations with this drug. One approach that is widely used to enhance drug solubility is complexation with cyclodextrins. The formation of the inclusion complex between IMQ and β-cyclodextrin was investigated in solution and in solid state. IMQ aqueous solubility was improved in the presence of citric acid. The experimental results and molecular modeling indicated the formation of the inclusion complex in aqueous solution of citric acid pH 3.0; however, the low apparent stability constant suggested weak interaction between β-cyclodextrin and IMQ which hampered the use of this approach to improve imiquimod aqueous solubility and the development of an aqueous formulation containing IMQ in the same concentration as in the commercial product.

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“…45 Because of the extremely poor water solubility of QUE, the specific proton peaks of QUE did not appear in the spectrum (Figure 6(a)). 47,48 The inclusion complex was also analyzed in detail by 2D NMR spectroscopy (Figure 7). The evaluation of the QUE/Et-β-CD complexes by 1 H NMR proved the presence of the specific protons of QUE molecule and implied a significant solubility enhancement for QUE/Et-β-CD relative to that of native QUE (Figure 6(b)).…”

Section: Solubilization Of Querctin By Complexmentioning

confidence: 99%

Enhancement of Solubility and Bioavailability of Quercetin by Inclusion Complexation with the Cavity of Mono‐6‐deoxy‐6‐aminoethylamino‐β‐cyclodextrin

Park

Choi

Cho

et al. 2017

Bulletin Korean Chem Soc

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Quercetin (QUE) has a wide range of health benefits; however, its application is limited due to its low solubility. We synthesized mono-6-deoxy-6-aminoethylamino-β-cyclodextrin (Et-β-CD) to overcome this limitation. The solubility of QUE was increased 35.1-fold compared with QUE, by its complexation with Et-β-CD. Changes in physicochemical properties following successful complexation were investigated using field emission scanning electron microscope, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The complexation behavior of QUE and Et-β-CD in aqueous solution was monitored by 1 H nuclear magnetic resonance (NMR), 2D rotating frame nuclear overhauser, and diffusion-ordered spectroscopy. The molecular docking simulation showed that the oblong shaped QUE is suitable for the formation of a stable complex with a characteristic cavity of Et-β-CD. Furthermore, the antioxidant activity and photostability of QUE was also improved after its complexation with Et-β-CD. From these results, we suggest that the characteristic elliptical cavity of Et-β-CD can be utilized for other hardly soluble drug molecules, which can expand the development of drug delivery systems.

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NMR and molecular fluorescence spectroscopic study of the structure and thermodynamic parameters of EGCG/β-cyclodextrin inclusion complexes with potential antioxidant activity

Cited by 29 publications

References 32 publications

Surface molecularly imprinted polymers for solid-phase extraction of (–)-epigallocatechin gallate from toothpaste

Surface molecularly imprinted polymers for solid-phase extraction of (–)-epigallocatechin gallate from toothpaste

Imiquimod/β-Cyclodextrin Inclusion Complex: Experimental and Theoretical Studies

Enhancement of Solubility and Bioavailability of Quercetin by Inclusion Complexation with the Cavity of Mono‐6‐deoxy‐6‐aminoethylamino‐β‐cyclodextrin

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