Insight into Unusual Downfield NMR Shifts in the Inclusion Complex of Acridine Orange with Cucurbit[7]uril

Liu, Jinshui; Jiang, Nan; Ma, Jing; Du, Xuezhong

doi:10.1002/ejoc.200900696

Cited by 29 publications

(13 citation statements)

References 53 publications

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“…It is interesting to note that only the AO + @CB [7] complex seems to interact with the protein and not the AO + 2 @CB[8] complex, based on the combined fluorescence analysis presented here. 1 H NMR studies, 49,50 and computer calculations, 48 show that protonation of the central nitrogen of AO + induces a configuration in the complex where AO + protrudes from the CB [7] cavity. 48 The fact that AO + is only partially encapsulated into CB [7] possibly allows the interaction of the protruding moiety of AO + with HSA, and/or makes possible the interaction of a protein amino acid with the partially filled CB [7] cavity.…”

Section: Discussionmentioning

confidence: 99%

Time-resolved fluorescence anisotropy as a tool to study guest–cucurbit[n]uril—protein ternary supramolecular interactions

Scholtbach

Venegas

Bohne

et al. 2015

Photochem Photobiol Sci

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Ternary supramolecular complexes involving cucurbit[n]urils and proteins are of potential interest for improving drug transport and delivery. We report here time-resolved fluorescence studies for acridine orange complexes with cucurbit[7]uril and cucurbit[8]uril in the presence of human serum albumin as a model system. A detailed characterization of the fluorescence lifetime and anisotropy properties of the different acridine orange complexes with cucurbit[n]urils and human serum albumin was performed. Of particular importance is the analysis of the stepwise binding for acridine orange-cucurbit[8]uril complexes and the assignment of the fluorescence and anisotropy properties to the 2 : 1 complex. Anisotropy decay measurements were essential to detect protein-bound species and to discriminate between different complexes. Based on the fluorescence evidence, ternary interactions with the protein are suggested for the acridine orange-cucurbit[7]uril complex but not for the cucurbit[8]uril complex. We highlight here the usability and sensitivity of the combined fluorescence analysis.

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Section: Discussionmentioning

confidence: 99%

Time-resolved fluorescence anisotropy as a tool to study guest–cucurbit[n]uril—protein ternary supramolecular interactions

Scholtbach

Venegas

Bohne

et al. 2015

Photochem Photobiol Sci

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“…However, there is no formation of a ternary complex with HSA. This is probably because unlike AO + , that protrudes out of the cavity of CB [7], 84,85 MB + is fully included in the cavity of CB [7] as previous studies suggest. 59,71 For MB + in the presence of CB [7], the photo-oxidation of HSA was lower compared to the sample in the absence of CB [7] (figure 5 inset).…”

Section: Comparison Of the Effect Of Cb[n]s On Protein Photo-oxidatiomentioning

confidence: 99%

Photochemical behavior of biosupramolecular assemblies of photosensitizers, cucurbit[n]urils and albumins

Cáceres

Robinson‐Duggon

Tapia

et al. 2017

Phys. Chem. Chem. Phys.

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Biosupramolecular assemblies combining cucurbit[n]urils (CB[n]s) and proteins for the targeted delivery of drugs have the potential to improve the photoactivity of photosensitizers used in the photodynamic therapy of cancer. Understanding the complexity of these systems and how it affects the properties of photosensitizers is the focus of this work. We used acridine orange (AO) as a model photosensitizer and compared it with methylene blue (MB) and a cationic porphyrin (TMPyP). Encapsulation of the photosensitizers into CB[n]s (n = 7, 8) modified their photoactivity. In particular, for AO, the photo-oxidation of HSA was enhanced in the presence of CB[7]; meanwhile it was decreased when included into CB[8]. Accordingly, peroxide generation and protein fragmentation were also increased when AO was encapsulated into CB[7]. The triplet excited state lifetimes of all the photosensitizers were lengthened by their encapsulation into CB[n]s, while the singlet oxygen quantum yield was enhanced only for AO and TMPyP, but it decreased for MB. The results obtained in this work prompt the necessity of further investigating these kinds of hybrid assemblies as drug delivery systems because of their possible applications in biomedicine.

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“…Although further investigations in detail are required for structural elucidation of the host-guest interactions in the tripartite complex of AOH + /CB7/2 -dAde, it was clear that AOH + was partially displaced, but not as a free molecule. The possibility of Exo complex formation between AOH + /CB7 and AOH + /sulfobutylether-β-cyclodextrin was suggested by Liu et al (2009) and Sayed et al (2017) [24,25]. In this study, the formation of Exo complex with 2 -dAde/CB7 may explain the fate of AOH + after moved from the CB7 cavity (Figure 4d).…”

Section: Fluorescence Detection Of Deoxyadenosine and The Selectivity Of Idamentioning

confidence: 50%

“…This result agrees well with the 1 H-NMR spectrum that 2 -dAde could not liberate the AO from the CB7 cavity, but instead spurred the formation of a three-component AOH + /CB7/2 -dAde complex. 2017) [24,25]. In this study, the formation of Exo complex with 2′-dAde/CB7 may explain the fate of AOH + after moved from the CB7 cavity (Figure 4d).…”

Section: Fluorescence Detection Of Deoxyadenosine and The Selectivity Of Idamentioning

confidence: 56%

Fluorescence Detection of Deoxyadenosine in Cordyceps spp. by Indicator Displacement Assay

et al. 2020

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A rapid, sensitive and reliable indicator displacement assay (IDA) for specific detection of 2′- and 3′-deoxyadenosine (2′-dAde and 3′-dAde), the latter is also known as cordycepin, was established. The formation of inclusion complex between protonated acridine orange (AOH+) and cucurbit[7]uril (CB7) resulted in the hypochromic shift of fluorescent emission from 530 nm to 512 nm. Addition of cordycepin to the highly fluorescent AOH+/CB7 complex resulted in a unique tripartite AOH+/CB7/dAde complex with diminished fluorescence, and such reduction in emission intensity serves as the basis for our novel sensing system. The detection limits were 11 and 82 μM for 2′- and 3′-deoxyadenosine, respectively. The proposed method also demonstrated high selectivity toward 2′- and 3′-deoxyadenosine, owing to the inability of other deoxynucleosides, nucleosides and nucleotides commonly found in Cordyceps spp. to displace the AOH+ from the AOH+/CB7 complex, which was confirmed by isothermal titration calorimetry (ITC), UV-Visible and proton nuclear magnetic resonance (1H-NMR) spectroscopy. Our method was successfully implemented in the analysis of cordycepin in commercially available Ophiocordyceps and Cordyceps supplements, providing a novel and effective tool for quality assessment of these precious fungi with several health benefits.

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Insight into Unusual Downfield NMR Shifts in the Inclusion Complex of Acridine Orange with Cucurbit[7]uril

Cited by 29 publications

References 53 publications

Time-resolved fluorescence anisotropy as a tool to study guest–cucurbit[n]uril—protein ternary supramolecular interactions

Time-resolved fluorescence anisotropy as a tool to study guest–cucurbit[n]uril—protein ternary supramolecular interactions

Photochemical behavior of biosupramolecular assemblies of photosensitizers, cucurbit[n]urils and albumins

Fluorescence Detection of Deoxyadenosine in Cordyceps spp. by Indicator Displacement Assay

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