NMR (1H, ROESY) spectroscopic and molecular modelling investigations of supramolecular complex of β-cyclodextrin and curcumin

Curcumin-based residue-free and reusable photodynamic inactivation system for liquid foods and its application in freshly squeezed orange juice

To enhance curcumin's application in photodynamic inactivation (PDI) of liquid foods, a supramolecular complex of biotin-modified β-cyclodextrin and curcumin (Biotin-CD@Cur) was synthesized. This complex significantly improves curcumin's solubility, stability, and PDI efficiency. Following PDI, Biotin-CD@Cur can be magnetically separated from the liquid matrix using streptavidin-coated magnetic beads (SA-MBs). Leveraging the reversible binding between streptavidin and biotin, Biotin-CD@Cur and SA-MBs fully dissociate in ultrapure water at 70 °C, enabling reuse. Antibacterial tests in freshly squeezed orange juice demonstrated that a low dose of 1.5 J/cm2 from a 420 nm LED array and 10 μg/mL of Biotin-CD@Cur achieved log reductions of 3.287 ± 0.015 for Staphylococcus aureus and 2.961 ± 0.011 for Listeria monocytogenes, while preserving the juice's flavor and nutritional contents. The PDI system remained effective for at least four cycles. Ultra-performance liquid chromatography and atomic absorption spectroscopy confirmed no residues of system components in the juice after magnetic separation.

Enhancing the solubility and potency of tetrahydrocurcumin as an anti-cancer agent using a β-cyclodextrin inclusion complex approach

Curcuminoids originating from turmeric roots are renowned for their diverse pharmacological applications, particularly as a natural anticancer agent. Unfortunately, harnessing the full potential of curcumin derivatives in cancer therapy has been impeded by its inherent limitations, specifically instabilities owing to poor solubility, leading to low systemic bioavailability under normal physiological circumstances. To circumvent this, a novel organic-based drug delivery system employing physically adsorbed β-cyclodextrin (βCD) as an excipient was developed in this study. This resulted in improved aqueous dispersion coupled with anticancer enhancements of tetrahydrocurcumin (THC) at a molar ratio of 2:1. Encapsulation of this agent was confirmed by physicochemical characterisation using UV-vis spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and both in vitro and in vivo approaches. Through the presence of an inclusion complex, a higher aqueous dispersion (65-fold) resulting in a higher drug content and an elevated release profile was achieved. Athymic nude (Nu/Nu) mice exposed to this treatment displayed improvements in tumour regression compared to stand-alone agents, consistent with in vitro cytotoxicity assays with an SI value > 10. The inclusion complex further enhanced apoptosis, as well as anti-migration and anti-invasion rates. Mechanistically, this formulation was consistent in terms of caspase 3 activation. Furthermore, the inclusion complex exhibited reduced systemic toxicity, including reduced inflammation in vital organs as examined by hematoxylin and eosin (H&E) staining. This study also revealed a notable sequential reduction in serum levels of tumour markers, including carcinoembryonic antigen (CEA) and mouse Cytochrome P450 1A2 (CYP1A2), correlating with a significant decrease in tumour bulk volume upon treatment commencement. These compelling findings highlight the potential of this formulation to empower insoluble or poorly soluble hydrophobic agents, thus offering promising prospects for their effective utilisation in colorectal cancer (CRC) chemotherapy.

Inclusion complexes of β-cyclodextrin with isomeric ester aroma compounds: Preparation, characterization, mechanism study, and controlled release

Cyclodextrins (CDs) have been discovered to provide an efficient solution to the limited application of ester aroma molecules used in food, tobacco, and medication due to their strong smell and unstable storage. This work combined molecular modeling and experimental to analyze the conformation and controlled release of isomeric ester aroma compounds/β-CD inclusion complexes (ICs). The investigation revealed that ester aroma compounds could be effectively encapsulated within the β-CD cavity, forming ICs with low binding affinity. Furthermore, the key driving forces in ICs were identified as hydrogen bonds and van der Waals interactions through theoretical simulation. Results from the Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) and Isothermal titration calorimetry (ITC) experiments confirmed the intermolecular interaction predicted by the molecular model. Notably, the release rate of aroma compounds from L-menthyl acetate/β-CD (LMA/β-CD) IC exceeded that of terpinyl acetate/β-CD (TA/β-CD) IC. This difference is attributed to the length of the chain of aroma molecules and the variation in the position of functional groups, influencing the stable formation of ICs with β-CD. These findings hold potential implications for refining the application of ICs across diverse industries.

Solubilization of drugs using beta-cyclodextrin: Experimental data and modeling

Many drug candidates fail to complete the entire drug development process because of poor physicochemical properties. Solubility is an important physicochemical property which plays a vital role in various stages of drug discovery and development. Several methods have been proposed to enhance the solubility of drugs, and complex formation with cyclodextrins is among them. Beta-cyclodextrin (βCD) is a common excipient for solubilization of drugs. The aim of this study is to develop the mechanistic QSPR models to predict the solubility enhancement of a drug in the presence of βCD. In this study, the solubility enhancement of some drugs in the presence of 10mM βCD at 25°C was experimentally determined or collected from the literature. Two different models to predict the solubilization by βCD were developed by binary logistic regression using structural properties of drugs with more than 80% accuracy. Polar surface area and excess molar refraction are the main parameters for estimating solubilization by βCD. Moreover, other descriptors related to hydrophobicity and the capability of hydrogen bonding formation of molecules could improve the accuracy of the established models.

The Antitumoral Effect In Ovo of a New Inclusion Complex from Dimethoxycurcumin with Magnesium and Beta-Cyclodextrin

Breast cancer is one of the leading causes of death in the female population because of the resistance of cancer cells to many anticancer drugs used. Curcumin has cytotoxic activities against breast cancer cells, although it has limited use due to its poor bioavailability and rapid metabolic elimination. The synthesis of metal complexes of curcumin and curcuminoids is a relevant topic in the search for more active and selective derivatives of these molecular scaffolds. However, solubility and bioavailability are concomitant disadvantages of these types of molecules. To overcome such drawbacks, the preparation of inclusion complexes offers a chemical and pharmacologically safe option for improving the aqueous solubility of organic molecules. Herein, we describe the preparation of the inclusion complex of dimethoxycurcumin magnesium complex (DiMeOC-Mg, (4)) with beta-cyclodextrin (DiMeOC-Mg-BCD, (5)) in the stoichiometric relationship 1:1. This new inclusion complex's solubility in aqueous media phosphate buffer saline (PBS) was improved by a factor of 6x over the free metal complex (4). Furthermore, 5 affects cell metabolic rate, cell morphology, cell migration, induced apoptosis, and downregulation of the matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), and signal transducer and activator of transcription-3 (STAT3) expression levels on MD Anderson metastasis breast-231 cancer (MDA-MB-231) cell lines. Results of an antitumor assay in an in ovo model showed up to 30% inhibition of tumor growth for breast cancer (MDA-MB-231) when using (5) (0.650 mg/kg dose) and 17.29% inhibition with the free homoleptic metal complex (1.5 mg/kg dose, (4)). While the formulation of inclusion complexes from metal complexes of curcuminoids demonstrates its usefulness in improving the solubility and bioavailability of these metallodrugs, the new compound (5) exhibits excellent potential for use as a therapeutic agent in the battle against breast cancer.

Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-β-cyclodextrin complex film for pork freshness monitoring and maintenance

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-β-cyclodextrin complex (Cur-β-CD) was prepared. The CS/P/CP/Cur-β-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10-11 g·(m·s·Pa)-1), and oxygen (1.50 ± 0.06 × 10-12 g·(m·s·Pa)-1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-β-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

The protective impact of curcumin, vitamin D and E along with manganese oxide and Iron (III) oxide nanoparticles in rats with scrotal hyperthermia: Role of apoptotic genes, miRNA and circRNA

BACKGROUND

Infertility is one of the major factors affecting most people around the world. Short-term exposure to high temperatures can cause hyperthermia, which is one of the causes of male infertility. The aim of this study was to investigate the protective effect of curcumin, vitamins D and E along with Iron (III) oxide nanoparticles (Fe2O3-NPs) and manganese oxide nanoparticles (MnO2-NPs) on semen parameters and its effect on miRNA21 and circRNA0001518 expression.

MATERIAL AND METHODS

In this study, the lower part of the rat was exposed to 43 °C for 5 weeks every other day for 5 weeks. Then the animals were killed. Tissue samples were collected for sperm parameters analysis, and tissue samples were taken for evaluation of apoptosis levels in germ cells, and RNA extraction in order to examine the expression of Bax, Bcl-2, miRNA, and CircRNA genes.

RESULTS

The results of this study showed that administration of curcumin, vitamin D, and vitamin E with Fe2O3-NPs and MnO2-NPs can improve the parameters of semen, Bax gene expression, Bcl-2 as well as miRNA and CircRNA in rats with testicular hyperthermia. In addition, curcumin by reducing the toxicity of Fe2O3 nanoparticles was able to reduce its negative effects and also reduce apoptosis in germ cells. This decrease in apoptosis was attributed to decreased Bcl-2 gene expression and increased expression of Bax, miRNA-21, and circRNA0001518.

CONCLUSION

All the results of this study confirmed that Fe2O3-NPs and Mno2-NPs containing antioxidants or vitamins are useful in improving fertility in rats due to scrotal hyperthermia. Although Fe2O3-NPs and Mno2-NPs containing both antioxidants and vitamins had a greater effect on improving fertility and reducing the toxic effects of nanoparticles.

Highly robust quantum mechanics and umbrella sampling studies on inclusion complexes of curcumin and β-cyclodextrin

The poor aqueous solubility of curcumin (CUR) obstructs its wide utilization in nutraceuticals, cosmetics, and pharmaceutical companies. This study is dedicated to investigate the stability of CUR inside the hydrophobic pocket of β-cyclodextrin (β-CD), hydroxypropyl-β-CD (HP-β-CD), and 2,6-Di-O-methyl-β-CD (DM-β-CD). Initially, molecular mechanics (MM) calculations and subsequently quantum mechanical (QM) calculations were performed on inclusion complexes to strengthen the MM results. We performed microsecond timescale MD simulations to observe the structural dynamics of CUR inside the cavity of CDs. We elucidated the most stable binding orientations of CUR inside the cavity of CDs based on binding free energy obtained from the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and umbrella sampling simulations. Furthermore, the two-layered ONIOM (B3LYP/6-311+G(2d,p):PM7) method with CPCM implicit water model was used to derive the complete energetics and thermodynamics of inclusion complexes at 1:1 stoichiometry. Each inclusion reaction was exothermic and spontaneous. The chemical reactivity and kinetic stability of inclusion complexes were described by HOMO-LUMO molecular orbital energies. In conclusion, our studies revealed that HP-β-CD had the highest binding affinity for CUR with the most negative complexation energy (-6520.69 kJ/mol) and Gibb's free energy change (-6448.20 kJ/mol). The atomic-level investigation of noncovalent interactions between CUR and the hydroxypropyl groups in HP-β-CD/CUR complex may be helpful to drive new derivatives of HP-β-CD with better host capacity. The computational strategy adopted here might serve as a benchmark for increasing the solubility of numerous clinically significant molecules.

Microcurrent Cloth-Assisted Transdermal Penetration and Follicular Ducts Escape of Curcumin-Loaded Micelles for Enhanced Wound Healing

Purpose

Larger nanoparticles of bioactive compounds deposit high concentrations in follicular ducts after skin penetration. In this study, we investigated the effects of microcurrent cloth on the skin penetration and translocation of large nanoparticle applied for wound repair applications.

Methods

A self-assembly of curcumin-loaded micelles (CMs) was prepared to improve the water solubility and transdermal efficiency of curcumin. Microcurrent cloth (M) was produced by Zn/Ag electrofabric printing to facilitate iontophoretic transdermal delivery. The transdermal performance of CMs combined with M was evaluated by a transdermal system and confocal microscopy. The CMs/iontophoretic combination effects on nitric oxide (NO) production and inflammatory cytokines were evaluated in Raw 264.7 cells. The wound-healing property of the combined treatment was assessed in a surgically created full-thickness circular wound mouse model.

Results

Energy-dispersive X-ray spectroscopy confirmed the presence of Zn/Ag on the microcurrent cloth. The average potential of M was measured to be +214.6 mV in PBS. Large particle CMs (CM-L) prepared using surfactant/cosurfactant present a particle size of 142.9 nm with a polydispersity index of 0.319. The solubility of curcumin in CM-L was 2143.67 μg/mL, indicating 250-fold higher than native curcumin (8.68 μg/mL). The combined treatment (CM-L+M) demonstrated a significant ability to inhibit NO production and increase IL-6 and IL-10 secretion. Surprisingly, microcurrent application significantly improved 20.01-fold transdermal performance of curcumin in CM-L with an obvious escape of CM-L from follicular ducts to surrounding observed by confocal microscopy. The CM-L+M group also exhibited a better wound-closure rate (77.94% on day 4) and the regenerated collagen intensity was approximately 2.66-fold higher than the control group, with a closure rate greater than 90% on day 8 in vivo.

Conclusion

Microcurrent cloth play as a promising iontophoretic transdermal drug delivery accelerator that enhances skin penetration and assists CMs to escape from follicular ducts for wound repair applications.

pH-responsive double-layer film based on chitosan/curcumin-β-cyclodextrin complex/cinnamaldehyde and zein/alizarin for pork freshness monitoring and maintaining

A pH-responsive double-layer film comprising chitosan (CS), zein (Z), curcumin-β-cyclodextrin complex (Cur- β-CD), alizarin (AL) and cinnamaldehyde (CIN) was developed to detect spoilage and prolong the shelf life of pork. The outer Z/AL is the colorimetric responsive and highly protective outer layer, while the CS/Cur- β-CD/CIN is the fluorescence responsive and functional layer. The CS/Cur- β-CD/CIN-Z/AL film demonstrated excellent barrier properties against oxygen (8.48 × 10-13 g (m s Pa)-1) and water (2.42 × 10-11 g (m s Pa)-1) primarily due to the polar interactions in the Z structure and its hydrophobic nature. The addition of AL and Cur provided the CS/Cur- β-CD/CIN-Z/AL film with pH colorimetric and fluorescence response capabilities, respectively. Furthermore, the inclusion of Cur- β-CD, CIN and AL significantly enhanced the film's antioxidant and antibacterial properties, with radical scavenging rates of 79.29 % (DPPH) and 89.84 % (ABTS), as well as antibacterial efficiencies of 96.2 % (S. aureus) and 85.78 % (E. coli). To test the effectiveness of the double-layer film, a freshness monitoring and maintenance experiment was conducted on pork stored at 4 °C for 8 days. Various parameters of pork, including surface color, pH value, total volatile bases nitrogen (TVB-N), total viable counts (TVC), thiobarbituric acid reactive substance (TBARS), hardness and springiness, were measured, along with the color and fluorescence intensity (FL) of the film. The shelf life of the pork was extended by at least 2 days compared to the control group, and the pork was considered inedible if ΔE ≥ 12 or FL intensity ≤ 2160. Overall, this food packaging film shows promise in simultaneously monitoring and maintaining the freshness of pork.

Curcumin-sulfobutyl-ether beta cyclodextrin inclusion complex: preparation, spectral characterization, molecular modeling, and antimicrobial activity

Urinary tract infections (UTIs) caused by Gram-negative bacteria E. coli is responsible for 80-90% of uncomplicated cases in women. The increased prevalence of antibiotic resistance has made the management of UTIs more challenging. Plant-derived compounds have long been used to treat various diseases, and constitute an alternative to antibiotic resistance. Curcumin (CUR), a naturally occurring polyphenolic phytoconstituent obtained from Curcuma longa is endowed with diverse medicinal properties. The present study aims to form a complex of CUR with Sulfobutyl ether-β-cyclodextrin (SBEβCD) to overcome the poor solubility and bioavailability of CUR and to evaluate the antimicrobial activity of CUR-SBEβCD. Phase solubility studies and spectral characterization showed the entrapment of CUR in the SBEβCD cavity. In silico docking studies performed to investigate the complexation process of CUR with SBEβCD, revealed that the methoxy group and OH group of CUR interacted with SBEβCD. The cytotoxicity and HET-CAM assays confirmed that CUR-SBEβCD was non-irritant. The prepared complex investigated with the disc diffusion method showed antimicrobial activity with a zone of inhibition (ZOI) of 13 mm against Escherichia coli (E. coli) and 11.5 mm against Staphylococcus aureus (S. aureus) whereas CUR alone did not show any ZOI. It can be concluded that prepared CUR-SBEβCD demonstrated superior antimicrobial activity and therefore can be a promising alternative for the treatment of UTIs.Communicated by Ramaswamy H. Sarma.

Controlled Delivery of Celecoxib-β-Cyclodextrin Complexes from the Nanostructured Titanium Dioxide Layers

Considering the potential of nanostructured titanium dioxide layers as drug delivery systems, it is advisable to indicate the possibility of creating a functional drug delivery system based on anodic TiO₂ for celecoxib as an alternative anti-inflammatory drug and its inclusion complex with β-cyclodextrin. First, the optimal composition of celecoxib-β-cyclodextrin complexes was synthesized and determined. The effectiveness of the complexation was quantified using isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR) nuclear magnetic resonance (¹H NMR), and scanning electron microscopy (SEM). Then, nanostructured titanium dioxide layers (TiO₂) were synthesized using the electrochemical oxidation technique. The TiO₂ layers with pore diameters of 60 nm and layer thickness of 1.60 µm were used as drug delivery systems. The samples were modified with pure celecoxib and the β-cyclodextrin-celecoxib complex. The release profiles shown effective drug release from such layers during 24 h. After the initial burst release, the drug was continuously released from the pores. The presented results confirm that the use of nanostructured TiO₂ as a drug delivery system can be effectively used in more complicated systems composed of β-cyclodextrin-celecoxib complexes, making such drugs available for pain treatment, e.g., for orthopedic surgeries.

Triple-function chitosan-based film for pork and shrimp packaging

A film simultaneously with colorimetric, fluorescent and active functions was engineered using chitosan (CS) and polyvinyl alcohol (PVA) as the film matrix and curcumin-β-cyclodextrin complex (Cur-β-CD) as the indicator for freshness monitoring and maintaining of pork and shrimp. In addition to the efficacy of prolonging shelf life, the film's color could change from yellow to orange with ΔE > 5 and its fluorescence intensity could decrease during storage. The incorporation of PVA significantly enhanced the mechanical properties of CS film with tensile strength of 31.80 MPa and elongation at break of 127.22 %. The Cur-β-CD improved the antioxidant and antibacterial properties, water contact angle (from 86.3° to 111.2°), water vapor permeability (from 3.28 × 10^-10 g (m s Pa)^-1 to 0.42 × 10^-10 g (m s Pa)^-1) and mechanical properties of CS/PVA film. These results show the potential of the film as promising alternatives for intelligent and active food packaging.

Improving Lurasidone Hydrochloride's Solubility and Stability by Higher-Order Complex Formation with Hydroxypropyl-β-cyclodextrin

The biopharmaceutical classification system groups low-solubility drugs into two groups: II and IV, with high and low permeability, respectively. Most of the new drugs developed for common pathologies present solubility issues. This is the case of lurasidone hydrochloride-a drug used for the treatment of schizophrenia and bipolar depression. Likewise, the stability problems of some drugs limit the possibility of preparing them in liquid pharmaceutical forms where hydrolysis and oxidation reactions can be favored. Lurasidone hydrochloride presents the isoindole-1,3-dione ring, which is highly susceptible to alkaline hydrolysis, and the benzisothiazole ring, which is susceptible to a lesser extent to oxidation. Herein, we propose to study the increase in the solubility and stability of lurasidone hydrochloride by the formation of higher-order inclusion complexes with hydroxypropyl-β-cyclodextrin. Several stoichiometric relationships were studied at between 0.5 and 3 hydroxypropyl-β-cyclodextrin molecules per drug molecule. The obtained products were characterized, and their solubility and stability were assessed. According to the obtained results, the formation of inclusion complexes dramatically increased the solubility of the drug, and this increased with the increase in the inclusion ratio. This was associated with the loss of crystalline state of the drug, which was in an amorphous state according to infrared spectroscopy, calorimetry, and X-ray analysis. This was also correlated with the stabilization of lurasidone by the cyclodextrin inhibiting its recrystallization. Phase solubility,¹H-NMR, and docking computational characterization suggested that the main stoichiometric ratio was 1:1; however, we cannot rule out a 1:2 ratio, where a second cyclodextrin molecule could bind through the isoindole-1,3-dione ring, improving its stability as well. Finally, we can conclude that the formation of higher-order inclusion complexes of lurasidone with hydroxypropyl-β-cyclodextrin is a successful strategy to increase the solubility and stability of the drug.

A Review of Cyclodextrin Encapsulation and Intelligent Response for the Release of Curcumin

To overcome the low water solubility and low bioavailability of curcumin (CUR), multiple delivery strategies have been proposed. Among these, cyclodextrin-based carriers have been widely used for the encapsulation and delivery of CUR. Cyclodextrins (CDs), as natural oligosaccharides, have been well known for their biodegradability, biocompatibility, non-toxicity, and internal hydrophobic and external hydrophilic structural features. This paper summarizes the recently reported CD-based carriers for encapsulating CUR. Particularly, the polymerization properties of CD self-assembly to enhance the encapsulation of CUR are discussed. In addition, the current progress on stimuli-responsive CD carriers for controlled release of CUR is described, which laid an important foundation for the development of CUR-based precision therapy in clinical practice. In conclusion, this review may provide ideas for the future development of a CD-based encapsulant for CUR.

γ-Cyclodextrin-Encapsulated Cinnamaldehyde for Citrus Preservation and Its Potential Mechanisms against Penicillium digitatum

In this study, a γ-cyclodextrin-cinnamaldehyde inclusion compound (γ-CDCL) was prepared to control green mold caused by Penicillium digitatum (P. digitatum) in citrus. The results showed that the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of γ-CDCL against the mycelial growth of P. digitatum were 2.0 g L−1 and 4.0 g L−1, respectively. Simultaneously, eight × MFC γ-CDCL could effectively reduce the incidence of green mold in citrus fruit without impairment of the fruit qualities, meanwhile, eight × MFC γ-CDCL was comparable to Prochloraz in controlling fruit under natural storage conditions. The structure of γ-CDCL was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) analyses. Results showed that the successful preparation of γ-CDCL was due to the spatial interaction between H-4,8 of cinnamaldehyde and H-5′ of γ-cyclodextrin. Meanwhile, the cell membrane permeability of P. digitatum was impaired by γ-CDCL through massive accumulation of reactive oxygen species, whereas the cell wall integrity was barely affected. These results indicated that γ-CDCL might inhibit the growth of P. digitatum through a membrane damage mechanism and it is a promising alternative to chemical fungicides in controlling the post-harvest citrus decay.

Mechanism of the Micellar Solubilization of Curcumin by Mixed Surfactants of SDS and Brij35 via NMR Spectroscopy

The micellar solubilization mechanism of curcumin by mixed surfactants of SDS and Brij35 was investigated at the molecular scale by NMR spectroscopy. Through the investigation of the micelle formation process, types and structures of mixed micelles and solubilization sites, the intrinsic factors influencing the solubilization capacity were revealed. For systems with α_SDS = 0.5 and 0.2, the obtained molar solubilization ratios (MSRs) are consistent with the MSR_ideal values. However, for α_SDS = 0.8, the solubilization capacity of curcumin is weakened compared to the MSR_ideal. Furthermore, only one single mixed SDS/Brij35 micelles are formed for α_SDS = 0.5 and 0.2. However, for α_SDS = 0.8, there are separate SDS-rich and Brij35-rich mixed micelles formed. In addition, NOESY spectra show that the interaction patterns of SDS and Brij35 in mixed micelles are similar for three systems, as are the solubilization sites of curcumin. Therefore, for α_SDS = 0.5 and 0.2 with single mixed micelles formed, the solubility of curcumin depends only on the mixed micelle composition, which is almost equal to the surfactant molar ratio. Although curcumin is solubilized in both separate micelles at α_SDS = 0.8, a less stable micelle structure may be responsible for the low solubility. This study provides new insights into the investigation and application of mixed micelle solubilization.

Inclusion complex of 20(S)-protopanaxatriol with modified β-cyclodextrin: Characterization, solubility, and interaction with bovine serum albumin

20(S)-protopanaxatriol (PPT) is one of the ginsenosides isolated from Panax ginseng which have many pharmaceutical activities. However, the poor water solubility of PPT restrict its applications. Herein, a novel bridged-bis-[6-(3,3'-(ethylenedioxy) bis (propylamine))-6-deoxy-β-cyclodextrin] (EDBA-bis-β-CD) was designed and synthesized, and the inclusion complex (IC) of EDBA-bis-β-CD with PPT was successfully prepared in the solid state, and characterized by UV, ¹H NMR, 2D ROESY, FT-IR, XRD and SEM and molecular modelling methods. The continuous variation method analysis indicated that the stoichiometry of the IC was 1:1. UV-vis spectral analysis demonstrated the binding constant K_s was 995.94 M^-1, and the solubility study showed that the solubility of PPT improved 290 times. The interaction of the IC with bovine serum albumin (BSA) was investigated via fluorescence spectroscopy. The results indicated that fluorescence quenching of BSA by IC was static quenching. Thermodynamic studies showed that van der Waals forces and hydrogen bonding play significant roles in interaction. The esterase-like activity of BSA in the presence of IC showed that it reduce the esterase activity of BSA in a competitive manner. Furthermore, molecular docking and molecular dynamics simulations for EDBA-bis-β-CD/PPT and BSA/IC systems were generated to provide information on the stability and the forces in the binding.

Parietin Cyclodextrin-Inclusion Complex as an Effective Formulation for Bacterial Photoinactivation

Multidrug resistance in pathogenic bacteria has become a significant public health concern. As an alternative therapeutic option, antimicrobial photodynamic therapy (aPDT) can successfully eradicate antibiotic-resistant bacteria with a lower probability of developing resistance or systemic toxicity commonly associated with the standard antibiotic treatment. Parietin (PTN), also termed physcion, a natural anthraquinone, is a promising photosensitizer somewhat underrepresented in aPDT because of its poor water solubility and potential to aggregate in the biological environment. This study investigated whether the complexation of PTN with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) could increase its solubility, enhance its photophysical properties, and improve its phototoxicity against bacteria. At first, the solubilization behavior and complexation constant of the PTN/HP-β-CD inclusion complexes were evaluated by the phase solubility method. Then, the formation and physicochemical properties of PTN/HP-β-CD complexes were analyzed and confirmed in various ways. At the same time, the photodynamic activity was assessed by the uric acid method. The blue light-mediated photodegradation of PTN in its free and complexed forms were compared. Complexation of PTN increased the aqueous solubility 28-fold and the photostability compared to free PTN. PTN/HP-β-CD complexes reduce the bacterial viability of Staphylococcus saprophyticus and Escherichia coli by > 4.8 log and > 1.0 log after irradiation, respectively. Overall, the low solubility, aggregation potential, and photoinstability of PTN were overcome by its complexation in HP-β-CD, potentially opening up new opportunities for treating infections caused by multidrug-resistant bacteria.

Enhanced Antioxidant Activity of Fresh Fruits through Salicylic Acid/β-CD Hydroalcoholic Gels

Oxidation is an important cause of fruit spoilage, and therefore improving the antioxidant capacity of fresh fruits is beneficial to their preservation. Herein, fresh-cut bananas were used as a type of fresh fruit and soaked in 75% hydroalcoholic gels containing salicylic acid (SA) or SA/β-CD inclusion complex (SA/β-CD). After treatment, they were placed in an atmosphere at 85% relative humidity at 20 °C for 12 days. A significant reduction in spoilage in bananas treated with the hydroalcoholic gels in the presence of SA/β-CD was observed, compared with those treated with gels in the presence or absence of SA. The free-radical-scavenging performances of SA and its complex were investigated using the DPPH (1,1-diphenyl-2-picryl-hydrazil) method. Based on the results, the significant increase in antioxidant activity was attributed to the fact that the inclusion complex could break the intramolecular hydrogen bonding of SA, thus efficiently eliminating ROS in the fruits. The formation of the inclusion complex was confirmed by experiments and theoretical calculations. Our findings indicate that treatment with SA/β-CD can provide an efficient method of maintaining postharvest quality and extending the shelf life of bananas.

Evaluation and Characterization of Curcumin-β-Cyclodextrin and Cyclodextrin-Based Nanosponge Inclusion Complexation

Cyclodextrin polymers and cyclodextrin-based nanosponges have been widely investigated for increasing drug bioavailability. This study examined curcumin's complexation stability and solubilization with β-cyclodextrin and β-cyclodextrin-based nanosponge. Nanosponges were prepared through the cross-linking of β-cyclodextrin with different molar ratios of diphenyl carbonate. Phase solubility experiments were conducted to evaluate the formed complexes and evaluate the potential of using β-cyclodextrin and nanosponge in pharmaceutical formulations. Furthermore, physicochemical characterizations of the prepared complexes included PXRD, FTIR, NMR, and DSC. In addition, in vitro release studies were performed for the prepared formulations. The formation of β-cyclodextrin complexes enhanced curcumin solubility up to 2.34-fold compared to the inherent solubility, compared to a 2.95-fold increment in curcumin solubility when loaded in β-cyclodextrin-based nanosponges. Interestingly, the stability constant for curcumin nanosponges was (4972.90 M^-1), which was ten times higher than that for the β-cyclodextrin complex, where the value was 487.34 M^-1. The study results indicated a decrease in the complexation efficiency and solubilization effect with the increased cross-linker amount. This study's findings showed the potential of using cyclodextrin-based nanosponge and the importance of studying the effect of cross-linking density for the preparation of β-cyclodextrin-based nanosponges to be used for pharmaceutical formulations.

Cyclodextrin based bone regenerative inclusion complex for resveratrol in postmenopausal osteoporosis

Recent preclinical studies have shown that resveratrol (RSV), is a promising remedy for osteoporosis owing to its estrogenic, anti-inflammatory, and antioxidant properties. However, RSV has met limited success due to its poor oral bioavailability and inefficient systemic delivery. In this study, we prepared the inclusion complex of RSV with sulfo-butyl ether β-cyclodextrin (SBE-β-CD) to enhance the aqueous solubility of RSV. The in-silico docking studies and Physico-chemical characterization assays were performed to understand the interaction of RSV inside the SBE-β-CD cavity. The in vivo safety assessment of RSV-SBE-β-CD inclusion complex (R-CDIC) was performed in healthy Wistar rats. The efficacy of the inclusion complex against postmenopausal osteoporosis was further investigated in ovariectomized (OVX) rat model. The alteration in the bone micro-architectural structure was evaluated by microcomputed tomographic scanning, serum biochemical estimations, biomechanical strength and histopathological investigation. Administration of RSV-SBE-β-CD inclusion complex was found to be safe and significantly improved micro-architectural deterioration induced by estrogen withdrawal. Results of bone morphometry and biomechanics study further emboldened the efficacy claim of the RSV-SBE-β-CD complex. Thus, the present study demonstrated the efficacy of the RSV-SBE-β-CD inclusion complex for treating osteolytic degradation in osteoporosis.

A study of the freeze-drying process and quality evaluation of Angelica sinensis

The freeze-drying process of Angelica sinensis (Oliv.) Diels was studied and evaluated. Using a single factor investigation, drying temperature and pressure were determined as the main factors affecting the drying process. The central composite design (CCD) combined with response surface method was employed to optimize the drying process. Optimal conditions were determined to be 52 Pa, 63 °C, and a slice thickness of 5 mm. Subsequently, samples were compared in terms of chemical constituents, microstructure, and in vitro absorption profiles under different drying operations. The freeze-drying process was effective for the preservation of ferulic acid (1.82 mg/g), Z-ligustilide (13.91 mg/g), and other compositions. The porous and loose characteristic structure enabled rapid release of ferulic acid (71%, 60 min) and Z-ligustilide (32%, 60 min). Therefore, the freeze-drying method is a reasonable and efficient drying method for the dehydration of A. sinensis.

Preparation and photodynamic bactericidal effects of curcumin-β-cyclodextrin complex

To overcome the poor water solubility of curcumin, a curcumin-β-cyclodextrin (Cur-β-CD) complex was prepared as a novel photosensitizer. Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to verify the formation of Cur-β-CD. Furthermore, the ROS generation capacity and photodynamic bactericidal effect were measured to confirm this Cur-β-CD complex kept photodynamic activity of curcumin. The result showed Cur-β-CD could effectively generate ROS upon blue-light irradiation. The plate count assay demonstrated Cur-β-CD complex possess desirable photodynamic antibacterial effect against food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes and Escherichia coli. The cell morphology determined by scanning electron microscope (SEM) and transmission electron microscope (TEM) showed Cur-β-CD could cause cell deformation, surface collapse and cell structure damage of the bacteria, resulting in the leakage of cytoplasmic; while agarose gel electrophoresis and SDS-PAGE further illustrated the inactivation mechanisms by Cur-β-CD involve bacterial DNA damage and protein degradation.

Physicomechanical performance and encapsulation efficiency of β-cyclodextrin loaded functional electrospun mats based on aliphatic polyesters and their blends

Designing complex-forming biodegradable and biocompatible electrospun mats (EMs) by incorporating β- cyclodextrin (β-CD) into polylactic acid (PLA)/poly(ε-caprolactone) (PCL) (70:30 w/w) blend based polyester matrix. The influence of β-CD loading on the morphological, thermal, and microstructural properties was investigated using scanning electron microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The studies revealed the presence of characteristic interactions between the polymer matrix and β-CD moieties. Further, the quasi-static mechanical properties of EMs were evaluated using a universal testing machine. An enhancement in modulus and strength was obtained for ∼ 2.5-5 phr of β-CD content and beyond ∼ 5 phr of β-CD content, the mechanical properties of EMs were observed to deteriorate. The contact angle studies indicated a decrease in hydrophobicity of PLA/PCL-based EMs with the increase in β-CD content. The swelling and weight loss studies in phosphate buffer saline (PBS) indicated a subsequent release of β-CD from the EMs. FT-IR and ¹H NMR spectra elucidated the removal of curcumin from ethanol-water solutions and its simultaneous encapsulation in β-CD hydrophobic cavities (released) of fabricated EMs. Thus, the study demonstrates the development of aliphatic polyester-based biodegradable-functional EMs with tunable physico-mechanical properties for biomedical applications, facilitating encapsulation and rapid removal of waste hydrophobic ultrafine molecules from the system.

A reduced graphene oxide-β-cyclodextrin nanocomposite-based electrode for electrochemical detection of curcumin

In this study, a sensitive electrochemical sensor was fabricated based on a beta-cyclodextrin–reduced graphene oxide (β-CD–rGO) nanocomposite for measuring curcumin concentration.

Enhancing the Solubility of Curcumin Using a Solid Dispersion System with Hydroxypropyl-β-Cyclodextrin Prepared by Grinding, Freeze-Drying, and Common Solvent Evaporation Methods

Cyclodextrins (CDs) and their derivatives significantly increase drug solubility by forming drug/CD complexes known as solid dispersions (SDs), which consist of an inclusion complex (IC), where the drug is entrapped within the CD cavity, and a non-IC. Here, the SDs of curcumin (CUR) and hydroxypropyl-β-cyclodextrin (HPβCD) were prepared using the grinding, freeze-drying (FD), and common solvent evaporation (CSE) methods and were physicochemically characterized using solubility, powder X-ray diffraction, Fourier transform infrared, differential scanning calorimetry, and dissolution studies. The second or higher order complex of CUR-HPβCD indicated the co-existence of ICs and non-ICs known as the SD system. When comparing the soluble drug amount with CUR crystals, the solubility of SDs was enhanced by up to 299-, 180-, and 489-fold, corresponding to the ground mixtures (GMs), freeze-drying mixtures (FDs), and common solvent evaporation mixtures (CSEs), respectively. The total transformation into the amorphous phase of CUR was observed in GMs and in CSE12, CSE14, and CSE18. The drug was well dispersed within HPβCD in GMs and CSEs, suggesting the formation of hydrogen bonds between CUR and HPβCD, whereas the dispersed behavior of FDs was similar to that of physical mixtures. In SDs, the melting temperature of CUR was in an increased order of CUR in 1:2 ICs, CUR in 1:1 ICs, and CUR crystals. The dissolution rate of CUR was positively improved as the amount of HPβCD in SDs increased. The SD system consisting of CUR and HPβCD significantly increased the drug solubility compared to ICs.

Effects of Stereochemistry and Hydrogen Bonding on Glycopolymer-Amyloid-β Interactions

Saccharide stereochemistry plays an important role in carbohydrate functions such as biological recognition processes and protein binding. Synthetic glycopolymers with pendant saccharides of controlled stereochemistry provide an attractive approach for the design of polysaccharide-inspired biomaterials. Acrylamide-based polymers containing either β,d-glucose or β,d-galactose pendant groups, designed to mimic GM1 ganglioside saccharides, and their small-molecule analogues were used to evaluate the effect of stereochemistry on glycopolymer solution aggregation processes alone and in the presence of Aβ42 peptide using dynamic light scattering, gel permeation chromatography-multiangle laser light scattering, and fluorescence assays. Fourier transform infrared and nuclear magnetic resonance (NMR) were employed to determine hydrogen bonding patterns of the systems. The galactose-containing polymer displayed significant intramolecular hydrogen bonding and self-aggregation and minimal association with Aβ42, while the glucose-containing glycopolymers showed intermolecular interactions with the surrounding environment and association with Aβ42. Saturation transfer difference NMR spectroscopy demonstrated different binding affinities for the two glycopolymers to Aβ42 peptide.

Interactions between cell wall polysaccharides and polyphenols: Effect of molecular internal structure

Cell wall polysaccharides (CPSs) and polyphenols are major constituents of the dietary fiber complex in plant-based foods. Their digestion (by gut microbiota) and bioefficacy depend not only on their structure and quantity, but also on their intermolecular interactions. The composition and structure of these compounds vary with their dietary source (i.e., fruit or vegetable of origin) and can be further modified by food processing. Various components and structures of CPSs and polyphenols have been observed to demonstrate common and characteristic behaviors during interactions. However, at a fundamental level, the mechanisms that ultimately drive these interactions are still not fully understood. This review summarizes the current state of knowledge on the internal factors that influence CPS-polyphenol interactions, describes the different ways in which these interactions can be mediated by molecular composition or structure, and introduces the main methods for the analysis of these interactions, as well as the mechanisms involved. Furthermore, a comprehensive overview is provided of recent key findings in the area of CPS-polyphenol interactions. It is becoming clear that these interactions are shaped by a multitude of factors, the most important of which are the physicochemical properties of the partners: their morphology (surface area and porosity/pore shape), chemical composition (sugar ratio, solubility, and non-sugar components), and molecular architecture (molecular weight, degree of esterification, functional groups, and conformation). An improved understanding of the molecular mechanisms that drive interactions between CPSs and polyphenols may allow us to better establish a bridge between food processing and the bioavailability of colonic fermentation products from CPSs and antioxidant polyphenols, which could ultimately lead to the development of new guidelines for the design of healthier and more nutritious foods.

Supramolecular self-assembled drug delivery system (SADDs) of vancomycin and tocopherol succinate as an antibacterial agent: in vitro, in silico and in vivo evaluations

In this study self-assembled drug delivery system (SADDs) composed of a hydrophobic d-α-tocopherol succinate (TS) and a hydrophilic vancomycin (VCM) were formulated, and its potential for enhancing the antibacterial activity of VCM against Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) were explored. The SADDs were synthesized via supramolecular complexation, then characterized for in silico, in vitro and in vivo studies. In silico studies confirmed the self-assembly of VCM/TS into NPs. The size, surface charge and drug loading of the SADDs was ˂100 nm, -27 mV and 68%, respectively. The SADDs were non-hemolytic and biosafe. A sustained release of VCM from SADDs was noted, with 52.2% release after 48 hr. The in vitro antibacterial test showed a twofold decrease in Minimum inhibitory concentration (MIC) against SA and MRSA, and a significantly higher reduction in MRSA biofilms compared to bare VCM. Further, in silico studies confirmed strong and stable binding of TS to MRSA efflux pumps. The in vivo study using mice skin infection models showed a 9.5-fold reduction in bacterial load after treatment with SADDs, in comparison with bare VCM. These findings affirmed that VCM/TS NPs as a promising novel nano-delivery for treating bacterial infections.

Complexation with β-cyclodextrin enhances apoptosis-mediated cytotoxic effect of harman in chemoresistant BRAF-mutated melanoma cells

Harman, a natural β-carboline alkaloid, has recently gained considerable interest due to its anticancer properties. However, its physicochemical characteristics and poor oral bioavailability have been limiting factors for its pharmaceutical development. In this paper, we described the complexation of harman (HAR) with β-cyclodextrin (βCD) as a promising alternative to improve its solubility and consequently its cytotoxic effect in chemoresistant melanoma cells (A2058 cell line). Inclusion complexes (βCD-HAR) were prepared using a simple method and then characterized by FTIR, NMR and SEM techniques. Through in silico studies, the mechanism of complexation of HAR with βCD was elucidated in detail. Both HAR and βCD-HAR promoted cytotoxicity, apoptosis, cell cycle arrest and inhibition of cell migration in melanoma cells. Interestingly, complexation of HAR with βCD enhanced its pro-apoptotic effect by increasing of caspase-3 activity (p < 0.05), probably due to an improvement in HAR solubility. In addition, HAR and βCD-HAR sensitized A2058 cells to vemurafenib, dacarbazine and 5FU treatments, potentializing their cytotoxic activity. These findings suggest that complexation of HAR with natural polymers such as βCD can be useful to improve its bioavailability and antimelanoma activity.

Nanoparticles based on the zwitterionic pillar[5]arene and Ag+: synthesis, self-assembly and cytotoxicity in the human lung cancer cell line A549

For the first time, stable pillar[5]arene/Ag+ nanoparticles, consisting of water-soluble pillar[5]arene containing γ-sulfobetaine fragments and Ag+ ions without Ag-Ag bonds, were synthesized and characterized. The pillar[5]arene/Ag+ (ratio 1:10) nanoparticles obtained were cubic with a rib length of 100 nm and are less cytotoxic than Ag+ ions. The survival of the A549 model cells in the presence of pillar[5]arene/Ag+ (1:10) nanoparticles at a concentration of 30 and 40 μM was 76% and 55%, while in the absence of pillar[5]arene, the cell survival for free Ag+ ions at the same concentration was 30% and 10%, respectively. The results can be used to create new antibacterial materials and 2D biomedical coatings.

Curcumin Delivery Mediated by Bio-Based Nanoparticles: A Review

Todays, nano-pharmaceutics is emerging as an important field of science to develop and improve efficacy of different drugs. Although nutraceuticals are currently being utilized in the prevention and treatment of various chronic diseases such as cancers, a number of them have displayed issues associated with their solubility, bioavailability, and bio-degradability. In the present review, we focus on curcumin, an important and widely used polyphenol, with diverse pharmacological activities such as anti-inflammatory, anti-carcinogenic, anti-viral, etc. Notwithstanding, it also exhibits poor solubility and bioavailability that may compromise its clinical application to a great extent. Therefore, the manipulation and encapsulation of curcumin into a nanocarrier formulation can overcome these major drawbacks and potentially may lead to a far superior therapeutic efficacy. Among different types of nanocarriers, biological and biopolymer carriers have attracted a significant attention due to their pleiotropic features. Thus, in the present review, the potential protective and therapeutic applications of curcumin, as well as different types of bio-nanocarriers, which can be used to deliver curcumin effectively to the different target sites will be discussed.