Presence Of βCD Research Articles

Suppression of Photocyclization of an Inverse Type Diarylethene Derivative by Inclusion into β‐Cyclodextrin

AbstractDiarylethene derivatives are one of the promising compounds for practical applications including optical memory, display, sensor, and photoactuator. In this work, we newly designed and synthesized an inverse type diarylethene derivative bearing sodium carbonate groups at the p‐position of the lateral phenyl ring and investigated the photochromic behavior in the presence and absence of cyclodextrins (CDs) (αCD, βCD, and γCD). Interestingly, only in the presence of βCD, the photocyclization reactivity decreased. From the results of job‐plots, NOESY spectra, and quantum chemical calculations, it was suggested that the distinctive interaction between the diarylethene and βCD leads to the restriction of molecular geometrical change, resulting in the suppression of the photocyclization reactivity. These results provide information on the rational designing of inverse type diarylethenes with advanced properties.

Thymol essential oil/ β-cyclodextrin inclusion complex into chitosan nanoparticles: Improvement of thymol properties in vitro studies

Thymol (TH) is a natural compound extracted from plants. In the present study, the β-cyclodextrin (βCD) complex of TH as the main constituent of thyme essential oil, was synthesized by freeze-drying (FD) method and TH/βCD inclusion complexes loaded chitosan (CS) nanoparticles (NPs). Phase solubility studies presented that the formation of inclusion complex enhanced water solubility of TH in the presence of βCD also the stability constant was obtained 965 M−1. The TH/βCD-ICs and TH/βCD-CS NPs were characterized using UV–Vis absorption, FT-IR, 1HNMR, XRD, and SEM. Moreover, the theoretical study of molecular modeling demonstrated the most desirable mode of TH encapsulated into the βCD cavity. Complexes exhibited 1:1 host: guest stoichiometry. The antibacterial effect of TH/βCD-ICs and TH/βCD-CS NPs was investigated against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria. The antioxidant test indicated that complexes exhibited better antioxidant activities compared to the pure TH through free radical scavenging assay.

Effect of hydrophilic polymer on solubility and taste masking of linezolid in multi-component cyclodextrin inclusion complex: Physicochemical characterization and molecular docking

The current work deals with the effect of hydrophilic polymer in a multi-component β-cyclodextrin (βCD) inclusion complex for enhancement of solubility and taste masking ability of linezolid (LZ). The phase solubility studies indicated the formation of 1:1 M stoichiometric ratio of LZ to βCD in all complexes in presence or absence of hydrophilic polymer (HPMC e5LV). The high stability constant (Ks; 1089 M−1, 1393 M−1), complexation efficiency (CE; 3.347, 3.761) and more negativity of Gibbs free energy (ΔG; −238.69, −1019.61) of ternary complexes in presence of 2.5% w/v and 5% w/v of HPMCe5LV was compared with binary system (Ks, 1024 M−1: CE, 2.571: ΔG, −59.91), which resulted in the improved complexation stability and solubilizing efficiencies. Solid inclusion complexes of LZ-βCD were prepared in 1:0.3 M ratio by kneading, co-evaporation, physical mixing and microwave irradiation methods with or without addition of HPMC e5LV. The drug content, solubility, dissolution and taste masking of LZ in ternary complexes were significantly higher (p < 0.05) than the binary complexes. The lowest MDT value (0.34 ± 0.007), highest value of DE (30mts) (28.9 ± 0.05) and R (15mts) (70.33 ± 0.57) were observed in case of solid inclusion complexes prepared by microwave irradiation method. The negative binding affinity found in molecular docking indicated the high stability of the ternary complex. No interaction was found in LZ, βCD and HPMC e5LV when analyzed by FTIR study. XRD and DSC results revealed that more amorphization of LZ in presence of βCD and HPMC e5LV. It infers that the multi-component system by microwave irradiation method can be a promising approach for increasing solubility with better palatability.

Preparation and Characterization of Orodispersible Films Loaded Diclofenac Sodium/β-Cyclodextrin Inclusion Complexes

Orodispersible films (ODFs) is orally pharmaceutical dosage form that rapidly disintegrates and instantly releases the drug when placed on the tongue. This study was firstly aimed to investigate physicomechanical properties of ODFs containing diclofenac sodium/β-cyclodextrin (DS/βCD) inclusion complexes prepared by solvent casting method. The influence of plasticizer, βCD and DS on hydroxypropyl metlhycellulose (HPMC) film was studied. Increasing of plasticizer concentration (e.g. PEG400 amd glycerol) resulted in decrement of disintegration time, strength and elasticity of HPMC films. When βCD was incorporated, opaque films were observed. Presence of βCD resulted in degrading of physicomechanical properties, except percentage of elongation representing the film’s elasticity. βCD films containing DS (DS/βCD films) were more brittle and transparent than blank βCD films. Amount of incorporated DS influenced on disintegration time and strength of obtained films. Cross-section scanning electron microscope (SEM) photomicrographs showed spherical particles scattered on DS/βCD films illustrating the occurrence of DS/βCD inclusion complexes during casting process. The DS/βCD inclusion complexes were then confirmed in both solid and solution. Furthermore, DS/βCD ODFs were prepared by incorporation of artificial sweeteners in DS/βCD films. It was found that DS/βCD ODFs containing xylitol were more brittle and their disintegration times were faster then those containing sucralose. Dissolution profiles were investigated then reported that release kinetic of DS/βCD films and ODFs were fitted to Higuchi model. In summary, the βCD-based ODFs containing DS were successfully developed.

Electrochemical Regulation of Antibacterial Activity Using Ferrocene-Containing Antibiotics

Electrochemical Regulation of Antibacterial Activity Using Ferrocene-Containing Antibiotics

Nanostructured Insecticide Composition through the Incorporation of Natural Abamectin in β-Cyclodextrin: Activity against Aedes aegypti Larvae

This study searched for a new pre-formulation based on the natural compound from the class of the avermectins, named abamectin (ABA), in order to improve its action against Aedes aegypti larvae by complexation with β-cyclodextrin (βCD). Concerning the low aqueous solubility of ABA, even in the presence of βCD, it was also invoked the strategy of working with hydrophobic nanoprecipitates (HNPs). For these purposes, molecular and supramolecular characterizations of 1:1 ABA/βCD complex and evaluation of its toxicity against A. aegypti larvae were performed. In the physical-chemistry characterizations, changes in the infrared spectra and thermal profiles in relation to precursors confirmed the occurrence of interactions between ABA and βCD in solid state. Nuclear magnetic resonance (NMR) data suggest the inclusion of ABA in βCD via benzofuran ring. Isothermal titration calorimetry (ITC) experiments allowed to verify the formation of complex with a 1:1 stoichiometry, which was entropy driven. The dynamic light scattering and zeta potential data from inclusion compounds demonstrated changes in the size of the ABA/βCD HNP if compared with the ABA HNP. Finally, the results for biological assays demonstrate that the strategy to prepare the inclusion compound led to an increase in the larvicidal activity in relation to free ABA.

Biophysical insights into the binding characteristics of bovine serum albumin with dipyridamole and the influence of molecular interaction with β cyclodextrin

The binding characteristic of anti-platelet drug dipyridamole has been investigated with a transport protein, serum albumin. A multi-spectroscopic approach has been employed, and the results were well supported by in silico molecular docking and simulation studies. The fluorescence quenching of serum albumin at three different temperatures revealed that the mechanism involved is static and the binding constant of the interaction was found to be of the order of 104 M−1. The reaction was found to be spontaneous and involved hydrophobic interactions. Synchronous, 3D fluorescence and CD spectroscopy indicated a change in conformation of bovine serum albumin (BSA) on interaction with DP. Using site-selective markers, the binding site of DP was found to be in subdomain IB. Molecular docking studies further corroborated these results. Molecular dynamic (MD) simulations showed lower RMSD values on interaction, suggesting the existence of a stable complex between DP and BSA. Furthermore, since β-Cyclodextrin (βCD) is used to improve the solubility of DP in ophthalmic solutions, therefore, the effect of (βCD) on the interaction of BSA and DP was also studied, and it was found that in the presence of βCD, the binding constant for BSA-DP interaction decreased. The present study is an attempt to characterize the transport of DP and to improve its bioavailability, consequently helping in dosage design to achieve optimum therapeutic levels. Communicated by Ramaswamy H. Sarma

Inclusion vs. micellization in the cethylpyridine chloride / β-cyclodextrin system: A structural and thermodynamic approach

In the present work we have performed a structural and thermodynamic characterization of supramolecular structures formed by interaction between cethylpyridine chloride (CPC) surfactant and β-cyclodextrin (βCD), using several physical-chemistry methods. Initially, qualitative CPC/βCD interactions in solid state were confirmed by FTIR and TGA/DTA. 2D NMR ROESY experiment showed strong correlations between hydrogens of βCD cavity with aromatic and aliphatic hydrogens of CPC, suggesting the existence of different complexes in solution. This information was corroborated by structures assessed by computational approach and stoichiometric coefficient obtained by ITC (N = 1.45). ITC experiments (at constant concentration of CPC) also showed that host-guest complexation occur with very high binding constant (Kb = 38,300.0), and driven by enthalpy and entropy. However, as CPC is an amphiphilic molecule, it is able to form micelles at critical micellar concentration close to 1 mM. In presence of βCD, it was observed that micellization was delayed, so that the cmc values increased according to the empiric equation: cmc = 1.02 + 0.5[βCD]. Moreover, thermodynamic data obtained by combination of conductometric and isothermal calorimetry titrations showed that the presence of increasing concentrations of βCD causes an increase of free energy of micellization, specially by gradual reduction of entropy of micellization, due to the difficult of micelles encapsulate the inclusion compounds. The overall study was rationalized in terms of competition between micellization vs. host-guest complexation.

Hydrophobic Nanoprecipitates of β-Cyclodextrin/Avermectins Inclusion Compounds Reveal Insecticide Activity against Aedes aegypti Larvae and Low Toxicity against Fibroblasts.

In the present work, hydrophobic nanoprecipitates (HNPs) of inclusion complexes formed between β-cyclodextrin (βCD) and the avermectins (AVMs) named eprinomectin (EPRI) and ivermectin (IVER) were synthesized and characterized, and their larvicidal activity against Aedes aegypti and human safety against fibroblasts were evaluated. Initially, thermogravimetric analysis/differential thermal analysis data revealed that inclusion increased the thermal stability of AVMs in the presence of βCD. Nuclear magnetic resonance experiments and density functional theory calculations pointed out the inclusion of the benzofuran ring of the two AVMs in the βCD cavity. Isothermal titration calorimetry experiments allowed identification of different binding constants for EPRI/βCD ( Kb = 1060) and βCD/IVER ( Kb = 1700) systems, despite the structural similarity. Dynamic light scattering titrations of AVMs' dimethyl sulfoxide solution in βCD aqueous solution demonstrated that the formed HNPs have lower sizes in the presence of βCD. Finally, the inclusion of EPRI in βCD increased its larval toxicity and reduced its human cytotoxicity, while for IVER/βCD no beneficial effect was observed upon inclusion. These results were rationalized in terms of structural differences between the two molecules. Finally, the EPRI/βCD complex has great potential as an insecticide against A. aegypti larvae with high human safety.

Bioresorbable antibacterial PCL‐PLA‐nHA composite membranes for oral and maxillofacial defects

Degradable implant membranes designed to separate hard and soft tissues and to trigger the growth of underlying bone and with antimicrobial properties are needed for the management of bone defects, ridge augmentation and to facilitate dental implants. In this study, the composite scaffolds of poly(lactic acid) (PLA), poly(caprolactone) (PCL) blended with nano hydroxyapatite and cefixime‐β cyclodextrin (Cfx‐βCD) inclusion complexes were synthesized by electrospinning. The prepared electrospun fibrous membranes were characterized by scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. Membranes were microporous with random fibers in the range of 0.2–0.37 µm. The data from FTIR spectral analysis helped to characterize the presence of PCL, PLA, Cfx, and βCD in the electrospun membranes. In addition, the mechanical properties (i.e., elastic modulus and tensile strength) of the scaffolds were investigated. The mechanical strength and suture retention ability of the membranes was comparable to that of skin grafts. Drug release assays confirmed the slow release of Cfx from the membranes in the presence of βCD and antimicrobial studies showed that the membranes possessed antibacterial properties. The interaction of cells with membranes was evaluated by culturing them with the mouse pre‐osteoblast cell line MC3T3 and assessment of bone formation was done using Alizarin Red Assay. Culturing MC3T3 cells on the scaffolds showed that cells attached and entered the membranes and increased in number over time. In summary, these membranes are flexible, strong, bactericidal and osteogenic, which are the ideal implant properties for dental and maxillofacial surgery. POLYM. COMPOS., 40:1564–1575, 2019. © 2018 Society of Plastics Engineers

Physicochemical characterization and biological activities of the ethanol extract of Bryophyllum pinnatum (Lam.) Oken incorporated in β-cyclodextrin

In the present work, a phytocomplex formed by ethanol extract of Bryophyllum pinnatum (Lam.) Oken (EEBP) and β-cyclodextrin (βCD) has been prepared at weight proportion of 1:1, characterized through several physical chemistry methods, and incorporated in an oil-in-water emulsion in order to evaluate its topical anti-inflammatory effect. Changes in the spectra of infrared and UV/VIS as well as TGA and DTA curves suggested the existence of interactions between components of extract and βCD. The incorporation of βCD to the extract also promoted an increase in the zeta potential of the aggregates spontaneously formed in water, with consequent reduction of their size. The in vitro antioxidant activity was also evaluated, showing an improvement of the radical-scavenging ability in presence of βCD. Finally, the topical application of EEBP/βCD semi-solid formulation significantly inhibited the ear edema induced by Croton oil if compared with free EEBP, justifying the use of phytotherapic formulation based on B. pinnatum as a remedy for skin disorders.

Nano-supramolecular complex synthesis: Switch on/off enhanced fluorescence control and molecular release using a simple chemistry reaction

A nanosensor based on β-cyclodextrin (βCD) macrocycles linked to gold nanoparticles for rhodamine B (RhB) sensing was developed applying the metal-enhanced fluorescence effect (MEF). Hence, we have developed many ways to control the distance of supramolecular systems to nanoparticle surface with different bioconjugation strategies in order to optimize signal detection. Different PEG spacer arm lengths were used to cover the nanoparticle surface with molecular spacers. This type of molecular shell is biocompatible, enabling to switch on/off the MEF effect using a dithiane linker by a simple reduction reaction. In the presence of the nanosensor obtained, an increase was observed in RhB fluorescence emission depending on molecular length, that is a characteristic effect of MEF. The major increase measured was 60% compared with RhB emission in buffer at 1nM level, for a spacer length of 3.58nm and an 80% increase as compared with that in the presence of βCD. These differences are ascribed to the fact that, in the presence of macrocycle, we can observe a well-known quenching effect that is overcome by the presence of the metallic core. Even at shorter spacer distances, with PEG lengths of 1.2 and 2.17nm, increases of 25 and 47% respectively allow the analyte detection by the RhB complexation with βCD. The optimal MEF enhancement was measured with the maximal emission signal stabilized after 50min due to plasmonic effects based on inter nanoparticle interactions. Moreover, the emission increase, in the presence of the metallic core, was accompanied with a diminution in the fluorescence lifetime's decay value averages, characteristic of MEF. This fact shows that the excited state is protected from the non-radiative emission decays enhancing the analytical signal.

Preparation and characterization of a new harmine-based antiproliferative compound in complex with cyclodextrin: Increasing solubility while maintaining biological activity

The trisubstituted harmine derivative, 2, present a submicromolar antiproliferative activity on 5 cancer cell lines but a moderate kinetic solubility in pH 7.4 buffer. The aim of this work was to develop a 2-cyclodextrin complex in order to increase the drug solubility while maintaining the biological activity. Firstly, the 2 increasing solubility in presence of several cyclodextrins (CDs) has been shown, with a maximum for 7 glucose subunit CD (βCD and 2HP-βCD). Phase solubility experiment in presence of 2HP-βCD has underline an AL-type profile until 80mM which suggest a 1:1 stoichiometry and a K1:1 of 116M−1 and a CE of 0.28 have been calculated. This 1:1 stoichiometry was confirmed by Job Plot experiment, following the CD H-3 proton by 1H NMR. Secondly, 1H NMR study of compound 2 in presence of βCD and geometry optimization of the complex has underline an inclusion of 2 into the CD, via the indole part of the drug. Finally, the efficiency of the 2 antiproliferative effect is not affected by the complexation, as shown by viability test.

Improving water solubility of nateglinide by complexation of β-cyclodextrin

Inclusion complex of anionic nateglinide (NTG) with β-cyclodextrin (βCD) has been prepared to improve the water solubility of NTG. The mechanism of the complexation was elucidated using isothermal titration calorimetry and molecular modeling study. The solubility of NTG increased linearly with increasing the concentration of βCD and decreased gradually over 6 mM βCD in the solution. The maximum solubility of NTG in the presence of βCD was nine times more than that of NTG only. The stoichiometry (n), association constant (K), and thermodynamic parameters (ΔG, ΔH, ΔS) for the complexation were estimated: n = 1.0, K = 5.8 × 103 M−1, ΔG = −21.5 kJ mol−1, ΔH = −15.7 kJ mol−1, and ΔS = 19.5 J mol−1 K−1 at pH 7.0 and 298.15 K. The conformations and solvation energies for two types of the inclusion complex, type A penetrating the isopropyl cyclohexyl group of NTG into the βCD cavity and type B penetrating the phenyl group of NTG, were calculated. It was indicated that anionic NTG could strongly form the inclusion complex of type A complex with βCD at 1:1 molar ratio to increase the solubility in aqueous solution.

Interaction between bradykinin potentiating nonapeptide (BPP9a) and β-cyclodextrin: A structural and thermodynamic study

Herein, we demonstrate the physical and chemical characterizations of the supramolecular complex formed between β-cyclodextrin (βCD) and bradykinin potentiating nonapeptide (BPP9a), an endogenous toxin found in Bothrops jararaca. Circular dichroism results indicate a conformational change in the BPP9a secondary structure upon its complexation with βCD. Nuclear magnetic resonance results, mainly from NOESY experiments, and theoretical calculations showed a favorable interaction between the tryptophan residue of BPP9a and the βCD cavity. Thermodynamic inclusion parameters were investigated by isothermal titration calorimetry, demonstrating that βCD/BPP9a complex formation is an exothermic process that results in a reduction in entropy. Additionally, in vitro degradation study of BPP9a against trypsin (37 °C, pH 7.2) showed higher stability of peptide in presence of βCD. This βCD/BPP9a complex, which presents new chemical properties arising from the peptide inclusion process, may be useful as an antihypertensive drug in oral pharmaceutical formulations.

Multi-equilibrium system based on sertraline and β-cyclodextrin supramolecular complex in aqueous solution

Sertraline (SRT) is a widely used antidepressant whose poor solubility in water limits its oral applicability. Thus, the aim of this work was the evaluation of a multi-equilibrium system based on β-cyclodextrin (βCD) and SRT. The inclusion compounds (ICs) were investigated by infrared spectroscopy, isothermal titration calorimetry (ITC) and 1H and 2D ROESY nuclear magnetic resonance experiments. SRT solubility was predicted in vitro in water and biomimetic fluids. The SRT in presence of βCD at 1:1 and 1:2 molar ratios was more soluble than free SRT in all biomimetics media investigated. The FTIR-HATR showed that βCD νC–O–C stretching band was reduced in presence of SRT, suggesting the interactions between them. Additionally, titration process and Job's plot provided information on the ICs stoichiometry and evidenced the multi-equilibrium coexistence in aqueous solution. According to the ITC, SRT:βCD interaction process was spontaneous and exothermic with a high affinity binding constant (K=14,726M−1). Additionally, the stoichiometry coefficient (n) was 1.63, which was comparable to that found by FITR-HATR. The 1H and 2D ROESY verified multiple SRT sites included into the host cavity. Theoretical calculations depicted the relative energy of different proposed ICs structures, in which the 1:2 IC was the most stable.

Aggregation of Hydrophobic Substituents of Poly(acrylate)s and Their Competitive Complexation by β- and γ-Cyclodextrins and Their Linked Dimers in Aqueous Solution

Competition between the aggregation of the octadecyl substituents of 3% randomly substituted poly(acrylate), PAAC18, and of the dodecyl substituents of the PAAC12 analogue, and their complexation by β-cyclodextrin, βCD, the linked dimers, N,N′-bis(6A-deoxy-6A-β-cyclodextrin)urea, 66βCD2ur, and N,N′-bis(6A-deoxy-6A-β-cyclodextrin)succinamide, 66βCD2su, and γ-cyclodextrin, γCD, and the analogous dimers 66γCD2ur and 66γCD2su have been studied in aqueous solution. The zero-shear viscosities of 3.3 wt % aqueous solutions of PAAC18, decreases in the presence of βCD, 66βCD2ur, 66βCD2su and γCD, is little changed in the presence of 66γCD2ur, and increases in the presence of 66γCD2su. In contrast, the zero-shear viscosities of aqueous solutions of PAAC12 increase in the presence of βCD, γCD, and their dimers but they are much less than those of the corresponding PAAC18 solutions. These macroscopic variations are due to host–guest complexation of the octadecyl and dodecyl substituents by βCD, γCD, and their dimers (as shown by 2D 1H NOESY NMR spectroscopy) competing with aggregation of the octadecyl and dodecyl substituents where differences in substituent length and cyclodextrin annular size are dominant factors.

Cyclodextrin-mediated crystallization of acid β-glucosidase in complex with amphiphilic bicyclic nojirimycin analogues

Cyclodextrin-based host-guest chemistry has been exploited to facilitate co-crystallization of recombinant human acid β-glucosidase (β-glucocerebrosidase, GlcCerase) with amphiphilic bicyclic nojirimycin analogues of the sp(2)-iminosugar type. Attempts to co-crystallize GlcCerase with 5-N,6-O-[N'-(n-octyl)iminomethylidene]nojirimycin (NOI-NJ) or with 5-N,6-S-[N'-(n-octyl)iminomethylidene]-6-thionojirimycin (6S-NOI-NJ), two potent inhibitors of the enzyme with promising pharmacological chaperone activity for several Gaucher disease-associated mutations, were unsuccessful probably due to the formation of aggregates that increase the heterogeneity of the sample and affect nucleation and growth of crystals. Cyclomaltoheptaose (β-cyclodextrin, βCD) efficiently captures NOI-NJ and 6S-NOI-NJ in aqueous media to form inclusion complexes in which the lipophilic tail is accommodated in the hydrophobic cavity of the cyclooligosaccharide. The dissociation constant of the complex of the amphiphilic sp(2)-iminosugars with βCD is two orders of magnitude higher than that of the corresponding complex with GlcCerase, allowing the efficient transfer of the inhibitor from the βCD cavity to the GlcCerase active site. Enzyme-inhibitor complexes suitable for X-ray analysis were thus grown in the presence of βCD. In contrast to what was previously observed for the complex of GlcCerase with the more basic derivative, 6-amino-6-deoxy-5-N,6-N-[N'-(n-octyl)iminomethylidene]nojirimycin (6N-NOI-NJ), the β-anomers of both NOI-NJ and 6S-NOI-NJ were seen in the active site, even though the α-anomer was exclusively detected both in aqueous solution and in the corresponding βCD:sp(2)-iminosugar complexes. Our results further suggest that cyclodextrin derivatives might serve as suitable delivery systems of amphiphilic glycosidase inhibitors in a biomedical context.

Structure and Self-Aggregation of Mono- and Bis(cyclodextrin) Derivatives in Aqueous Media: Fluorescence, Induced Circular Dichroism, and Molecular Dynamics

Fluorescence and circular dichroism techniques were used to study the water solution behavior of those mono- and bisβCDs derivatives whose appended group or spacer between βCDs contain the fluorescent 1,3-diphenoxy moiety (OB), i.e., 6[4-((3-(prop-2-ynyloxy)phenoxy)methyl]-1H-1,2,3-triazol-1-yl]6-deoxy-βCD (mβCD) and 1,3-bis((1-(6′deoxy-βCD-6′-yl)-1H-1,2,3-triazol-4-yl)methoxy)benzene (bβCD), as well as their 1,3-bis(propargyloxy)benzene (POB) model compound in the presence of βCD. Molecular dynamics calculations were also employed to simulate the conformational behavior of m- and bβCD derivatives, as well as the POB/βCD complexation and self-association of mβCD in the presence of water. Unfortunately, fluorescence techniques are not very useful for studying these systems as the fluorescence properties of the OB chromophore hardly change with the microviscosity and polarity of the environment. However, the combination of the induced circular dichroism measurements and molecular dynamics simulations permit...

β‐Cyclodextrin‐Mediated Removal of Soy Phospholipids from the Air–Water Interface

AbstractBinding of soy phosphatidylcholine (PC) and phosphatidylinositol (PI) with β‐cyclodextrin (βCD) was studied using a spread monolayer technique at the air–water interface. First, surface pressure (π) versus surface concentration (Γ) isotherms of both PC and PI were characterized by forming spread monolayers on an aqueous subphase. PC and PI monolayers reached saturation at Γ of 1.98 and 3.24 μmol/m2, respectively, at 25 °C. Subsequently, desorption of PC or PI from the spread monolayer in the presence of 2–14 mM βCD in the subphase was studied by measuring changes in π of monolayer. This desorption was indicative of a complex formation between βCD and PC or PI. The amount of PC or PI bound to βCD was determined by converting the net change in π to Γ by using π–Γ isotherms. From the saturated monolayers at the air water‐interface, approximately 30% of PC and 50% of PI could be removed by 14 mM βCD. It was calculated that the free energy change required to transfer a PL from the monolayer at air–water interface to the aqueous phase in presence of βCD was decreased by 6–7 kcal/mol. Hydrolysis of PC in the monolayer by phospholipase A2 (PLA2) improved extraction efficiency of βCD. By incorporating 2.29 μM PLA2 and 10 mM βCD in subphase, up to 80% of PC monolayer could be desorbed from the air–water interface. These results are discussed in terms of the potential use of βCD to remove PLs bound to soy protein.