Explore the vast range of titles available.

Peptide's applications frequently present problems of solubility, stability, activity, or membrane permeability. To overcome these issues, cyclodextrins (CDs) can be used to form inclusion complexes with peptide hydrophobic parts; alkyl‐chains or aromatic‐rings inclusion strongly influences the interacting peptide properties. The study of model tripeptides has revealed that, among the three aromatic amino acids, tyrosine is the best suited to be included within CDs. The interaction with β‐CD of five model peptides (Tyr1‐5), each constituted by one tyrosine and four alanines, is reported: the tyrosine occupies one of the five position within each peptide chain. Among natural CDs, β‐CD has been chosen as it is the most economic, used, and only moderately toxic; its cavity size is the best suited to accommodate the tyrosine ring. Stoichiometry and affinity of each complex are evaluated and in silico and experimental data to describe the molecular determinants of each interaction are combined. The data further defines the role of the aromatic ring position in dictating the stability of formed complexes and demonstrates Tyr3, with its central Tyr, as the most stable complex. Noteworthy, the interaction with β‐CD induces Tyr3 to assume a U‐shaped conformation representing a nice example of conformation stabilization upon formation of inclusion complexes. Here, a systematic investigation of the interaction between β‐Cyclodextrin and five model peptides , each constituted by four alanines and one tyrosine differently positioned along the peptide chain, is reported. This integrated approach combines experimental and in‐silico techniques to describe the molecular determinants of interactions and shows how the tyrosine position within peptide sequence affects the binding affinity and complex stability.

Essential oils (EOs) are used in several pest management applications. Due to their volatility, EOs may experience bioactivity reduction, thus requiring protection to extend their properties. In the present study, we investigated the inclusion complex formation (IC) of β-cyclodextrin (β-CD) with selected EOs with known tick repellent activity using two co-precipitation methods. ICs were characterized by evaluating EO mass concentration and inclusion efficiency (% IE) and other instrumental methods. Co-precipitation method 2 yielded the highest EO mass concentration (88 ± 6 μg/mg β-CD) for the 1:1 molar ratio geranium Egyptian EO IC. The EO volatile release over time from the ICs was investigated by headspace SPME/GC-MS analysis. ICs were also tested in tick repellency bioassays. ICs reported significant tick repellent activity, with lemongrass IC performing best overall. Method 1 showed the best combination of high mass concentration EO, controlled volatile release, and tick repellency with lemongrass EO. The results demonstrated that β-CD had selectively encapsulated different EOs. Moreover, the formation of ICs may improve EO tick repellent properties protecting the active ingredients and providing a better, long-lasting repellent action. These findings will allow the development of more effective naturally derived repellent products to protect individuals from tick bites and prevent tick-borne illnesses.

Food safety issues are a major threat to public health and have attracted much attention. Therefore, exploring accurate, efficient, sensitive, and economical detection methods is necessary to ensure consumers’ health. In this regard, cyclodextrins (CDs) are promising candidates because they are nontoxic and noncaloric. The main body of CDs is a ring structure with hydrophobic cavity and hydrophilic exterior wall. Due to the above characteristics, CDs can encapsulate small guest molecules into their cavities, enhance their stability, avoid agglomeration and oxidation, and, at the same time, interact through hydrogen bonding and electrostatic interactions. Additionally, they can selectively capture the target molecules to be detected and improve the sensitivity of food detection. This review highlights recent advances in CD inclusion technology in food safety analysis, covering various applications from small molecule and heavy metal sensing to amino acid and microbial sensing. Finally, challenges and prospects for CDs and their derivatives are presented. The current review can provide a reference and guidance for current research on CDs in the food industry and may inspire breakthroughs in this field.

In this work, rutin (RUT)–β-cyclodextrin (β-CD) inclusion complexes are prepared by Supercritical AntiSolvent (SAS) precipitation. Well-defined composite microparticles are obtained at guest:host ratios equal to 1:2 and 1:1 mol:mol. The dimensions of composite particles range between 1.45 ± 0.88 µm and 7.94 ± 2.12 µm. The formation of RUT–β-CD inclusion complexes has been proved by different analyses, including Fourier transform infrared spectroscopy, Differential Scanning Calorimetry, X-ray diffraction, and UV-vis spectroscopy. The dissolution tests reveal a significant improvement in the release rate of RUT from inclusion complexes. Indeed, compared to the unprocessed RUT, the dissolution rate is about 3.9 and 2.4 times faster in the case of the complexes RUT–β-CD 1:2 and 1:1 mol:mol, respectively. From a pharmaceutical/nutraceutical point of view, CD-based inclusion complexes allow the reduction of the polymer amount in the SAS composite formulations.

Supramolecular chemistry, although focused mainly on noncovalent intermolecular and intramolecular interactions, which are considerably weaker than covalent interactions, can be employed to fabricate sensors with a remarkable affinity for a target analyte. In this review the development of cyclodextrin-based electrochemical sensors is described and discussed. Following a short introduction to the general properties of cyclodextrins and their ability to form inclusion complexes, the cyclodextrin-based sensors are introduced. This includes the combination of cyclodextrins with reduced graphene oxide, carbon nanotubes, conducting polymers, enzymes and aptamers, and electropolymerized cyclodextrin films. The applications of these materials as chiral recognition agents and biosensors and in the electrochemical detection of environmental contaminants, biomolecules and amino acids, drugs and flavonoids are reviewed and compared. Based on the papers reviewed, it is clear that cyclodextrins are promising molecular recognition agents in the creation of electrochemical sensors, chiral sensors, and biosensors. Moreover, they have been combined with a host of materials to enhance the detection of the target analytes. Nevertheless, challenges remain, including the development of more robust methods for the integration of cyclodextrins into the sensing unit.

The proposed study concerns the inclusion complexation of dimethoate (DMT) in the β-cyclodextrin (β-CD) molecule cage using a 1:1 stoichiometry. The interactions between DMT and β-CD were evaluated using PM7 and DFT in water and gas, using the CAMB3LYP functional 6-31G(d,p) basis set. All approaches agree with the optimal 3D structure, which includes full DMT inclusion in the β-CD cavity. Complexation, LUMO, and HOMO energies were computed. The natural bond orbital (NBO) and UV–visible calculations were determined and discussed. Additionally, the non-covalent intermolecular interactions between dimethoate and β-cyclodextrin are investigated through RDG, NCI, and IGM. The main forces stabilizing the examined inclusion complex are H-bond and van Der Waals interactions. Furthermore, the energy decomposition analysis (EDA) was applied highlighting the H-bonding by quantifying its strength. The TD-DFT method provided the electronic UV–vis spectra showing significant electronic transitions between the host and the guest by observing the molecular orbitals localizations.

This study concentrated on developing quercetin/cyclodextrin inclusion complex-loaded polyvinyl alcohol (PVA) hydrogel for enhanced stability and solubility. Quercetin was encapsulated in hydroxypropyl-β-cyclodextrin (HP-β-CD) by the solvent evaporation method. The prepared quercetin/HP-β-CD inclusion complex showed 90.50 ± 1.84% encapsulation efficiency (%EE) and 4.67 ± 0.13% loading capacity (%LC), and its successful encapsulation was confirmed by FT-IR and XRD. The quercetin/HP-β-CD inclusion complex was well dispersed in viscous solutions of PVA in various amounts (0.5, 1.0, 1.5. 2.5, and 5.0% w/v ratio), and the drug-loaded polymer solution was physically crosslinked by multiple freeze–thaw cycles to form the hydrogel. The cumulative amount of quercetin released from the prepared hydrogels increased with increasing concentrations of the inclusion complex. The introduction of the inclusion complex into the PVA hydrogels had no influence on their swelling ratio, but gelation and compressive strength reduced with increasing inclusion complex concentration. The potential cytotoxicity of quercetin/HP-β-CD inclusion complex hydrogels was evaluated by MTT assay and expressed as % cell viability. The results show biocompatibility toward NCTC 929 clone cells. The inhibitory efficacy was evaluated with 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, and the results show a higher level of antioxidant activity for quercetin/HP-β-CD inclusion complex hydrogels compared with free quercetin. The findings of our study indicate that the developed quercetin/HP-β-CD inclusion complex hydrogels possess the required properties and can be proposed as a quercetin delivery system for wound-healing applications.

Docetaxel (DTX), as a first-line anti-tumor drug, has been studied for decades for its diverse bioactivities. However, DTX presents poor solubility in water, low bioavailability and serious toxic side effects which has hindered its application in the clinic. To address these problems, docetaxel-sulfobutyl ether-β-cyclodextrin inclusion complex (DTX-SBE-β-CD) was prepared successfully by saturated aqueous solution method. Sulfobutyl ether β-cyclodetrin (SBE-β-CD) is used as delivery material. For this study, the inclusion complex of docetaxel with sulfobutyl ether β-cyclodetrin (DTX-SBE-β-CD) was prepared and optimized its properties to enhance the cytotoxicity of cancer cells. A large number of physical characterization results showed that DTX-SBE-β-CD inclusion complex was successfully prepared by saturated aqueous solution method. DTX-SBE-β-CD inclusion complex was optimized by Central Composite Design. DTX-SBE-β-CD had an inhibitory effect on the in vitro determination of MCF-7 and HepG2 cells by MTT assay. Pharmacokinetic studies were carried out on male Sprague–Dawley rats by tail injection, including the distribution, metabolism and elimination of DTX-SBE-β-CD in vivo. In the experimental study of inhibition of cancer cells, DTX and DTX-SBE-β-CD showed apparent concentration-dependent inhibitory actions on tumor cells and the inhibition of DTX-SBE-β-CD group was more obvious.

Steroid hormones play a crucial role in the body by acting as chemical messengers. They are, however, poorly soluble in water, and cyclodextrins can increase their solubility thus leading to increased bioavailability when used in drug formulations. Accuracy in the prediction of the free energy of binding of cyclodextrin/steroid inclusion complexes with simulation is important because of the potential value it brings by providing low-cost predictions of the real-life behavior of the cyclodextrin/steroid inclusion complex and the potential for high-through-put screening. Many computational methods exist, and it is therefore important to understand the ability of current theoretical models to accurately predict the free energy of binding for these inclusion complexes. We focused specifically on the estimation of the free energy of binding of inclusion complexes of four steroids: Hydrocortisone, dexamethasone, prednisolone, and 6α-methylprednisolone with native α-CD, β-CD, γ-CD, (2-hydroxy)propyl-β-CD, and sulfobutylether-β-CD by phase solubility as well as with α, β, and γ-CD by simulations. The simulations were assessed with both docking and the molecular mechanics combined with the generalized Born and surface area (MM/GBSA) continuum solvation approach. Considering the phase solubility diagram, (2-hydroxy)propyl-β-CD and sulfobutylether-β-CD dissolved more steroids in the higher concentration range as expected. The assessment of the free energy of binding obtained from the phase solubility and theory showed that the MM/GBSA method has shown promise in reliably generating accurate predictions in the field of calculating the free energy of binding of steroids/cyclodextrins with a correlation coefficient (R 2 ) = 0.94.

Glycyrrhizic acid, or glycyrrhizin (GA), a major active component of licorice root, has been widely used in traditional Chinese and Japanese medicine since ancient times. However, only in the last decades has a novel and unusual property of the GA been discovered to form water-soluble, supramolecular complexes with a variety of lipophilic drugs. These complexes show significant advantages over other known delivery systems, in particular, due to strong pH sensitivity, the properties of GA self-associates. In the present study, a supramolecular complex formation of the hypotensive and antiarrhythmic drug nifedipine with GA has been studied at different pH values, corresponding to the different degrees of GA dissociation, including a fully dissociated state of GA. Both NMR experiments and molecular dynamics simulations demonstrate the existence of the nifedipine complex with GA at all dissociation states of GA. However, optical absorption experiments show the decrease of complex stability and solubility at pH > 6 when the GA molecule is fully deprotonated. It means the higher release rate of the drug in a neutral and basic environment compared with acid media. These results could form the basis of follow-up studies of GA self-associates as pH-controlled drug delivery systems.