Characterization of glabridin/hydroxypropyl-β-cyclodextrin inclusion complex with robust solubility and enhanced bioactivity

Formulation and evaluation of β-cyclodextrin-mediated inclusion complexes of isoniazid scaffolds: molecular docking and in vitro assessment of antitubercular properties

Inclusion complexes of isoniazid derivatives with β-CD were synthesized and their potent antitubercular properties were studied.

Preparation and characterization of phloretin by complexation with cyclodextrins

RP and DPPH scavenging activity tests revealed that the antioxidant activity of phloretin improved after the formation of inclusion complexes.

Crystal-Seeded Growth of pH-Responsive Metal-Organic Frameworks for Enhancing Encapsulation, Stability, and Bioactivity of Hydrophobicity Compounds

Zeolitic imidazolate framework-L (ZIF-L) could effectively improve the stability, controlled release, and anticancer activity of natural hydrophobicity drugs in drug delivery systems (DDSs). A simple and universal strategy was developed to prepare the curcumin-loaded ZIF-L (CCM@ZIF-L) by the antisolvent coprecipitation method, which was different from the traditional approaches. The microcrystal molecules of curcumin were used as the core of ZIF-L growth to form CCM@ZIF-L, which has a very high drug encapsulation efficiency of 98.21% and a regular leaf or cruciate flower-like structure. The formation of CCM@ZIF-L with a distinct composite structure was supported by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared, powder X-ray diffraction, and zeta-potential. Because of the protective effect of ZIF-L, CCM@ZIF-L exhibited excellent stability and about a 5-fold increase in temperature stability over free curcumin. CCM@ZIF-L exhibited controlled drug release behavior in simulated in vitro tumor microenvironments (almost 81.2% drug release over a period of 72 h). Furthermore, confocal laser scanning microscopy results and cytotoxicity experiments confirmed that the encapsulated curcumin showed a significant improvement in cellular uptake and anticancer activity against A549 cancer cells. Moreover, the curcumin encapsulated in ZIF-L exhibited remarkable cellular antioxidant activity based on MGC-803 cell models. This work presents a novel approach to solve the drug loading problem by employing ZIF-L and exhibits enormous potential of ZIF-L as an effective DDS in cancer treatments.

Natural and Bioinspired Phenolic Compounds as Tyrosinase Inhibitors for the Treatment of Skin Hyperpigmentation: Recent Advances

One of the most common approaches for control of skin pigmentation involves the inhibition of tyrosinase, a copper-containing enzyme which catalyzes the key steps of melanogenesis. This review focuses on the tyrosinase inhibition properties of a series of natural and synthetic, bioinspired phenolic compounds that have appeared in the literature in the last five years. Both mushroom and human tyrosinase inhibitors have been considered. Among the first class, flavonoids, in particular chalcones, occupy a prominent role as natural inhibitors, followed by hydroxystilbenes (mainly resveratrol derivatives). A series of more complex phenolic compounds from a variety of sources, first of all belonging to the Moraceae family, have also been described as potent tyrosinase inhibitors. As to the synthetic compounds, hydroxycinnamic acids and chalcones again appear as the most exploited scaffolds. Several inhibition mechanisms have been reported for the described inhibitors, pointing to copper chelating and/or hydrophobic moieties as key structural requirements to achieve good inhibition properties. Emerging trends in the search for novel skin depigmenting agents, including the development of assays that could distinguish between inhibitors and potentially toxic substrates of the enzyme as well as of formulations aimed at improving the bioavailability and hence the effectiveness of well-known inhibitors, have also been addressed.

Inclusion complex of saikosaponin-d with hydroxypropyl-β-cyclodextrin: Improved physicochemical properties and anti-skin cancer activity

BACKGROUND

Saikosaponin-d (SSD) is a triterpene saponin isolated from Bupleurum plants. It has been shown to exhibit antioxidant, anti-inflammatory, and anticancer activities. However, its biomedical applications are limited by its poor water solubility. Cyclodextrins are highly water soluble oligosaccharide compounds which can form inclusion complexes with lipophilic drugs.

PURPOSE

We complexed SSD with hydroxypropyl-β-cyclodextrin (HPBCD) in various ratios to form SSD-HPBCD inclusion complexes. The inclusion complexes were evaluated for their solubility, physicochemical properties and cytotoxic effects in cutaneous squamous cell carcinoma cells.

METHODS

Surface morphology of pure SSD and SSD-HPBCD inclusion complexes was evaluated by scanning electron microscopy. Crystalline structure was determined by X-ray diffractometry. Intermolecular hydrogen bond formation between SSD and HPBCD was investigated by Fourier transform infrared spectroscopy. Human cutaneous squamous cell carcinoma HSC-1 cell viability was determined by the MTS assay, and cell apoptosis by the caspase 3/7 assay. Signal transduction pathways were investigated by Western blotting.

RESULTS

SSD-HPBCD inclusion complexes showed greatly increased water solubility. This was associated with an improvement in physicochemical properties, including transformation of crystalline structure to amorphous form, and formation of hydrogen bonds between SSD and HPBCD. In addition, SSD-HPBCD inclusion complexes induced apoptosis in HSC-1 cells, and this was mediated through activation of MAPK and suppression of Akt-mTOR signaling pathways.

CONCLUSION

SSD-HPBCD inclusion complex shows improvement in water solubility and physicochemical properties, and exhibits anticancer effects against cutaneous squamous cell carcinoma cells. Therefore, it may be a potential drug formulation for the treatment of skin cancer.

Development of morin/hydroxypropyl-β-cyclodextrin inclusion complex: Enhancement of bioavailability, antihyperalgesic and anti-inflammatory effects

Morin is a flavonoid has been reported with several pharmacological effects such as, antioxidant, anti-inflammatory, anticancer, antidiabetic, etc. However, morin has low solubility in water, which decreases the bioavailability and limits its clinical application. In this way, to improve the pharmaceutical properties, morin was complexed in hydroxypropyl-β-cyclodextrin (HP-β-CD) and its oral bioavailability and anti-inflammatory effects were evaluated. Initially, a phase solubility study was performed, which showed that HP-β-CD would be the better cyclodextrin for the formation of complexes with morin. The morin/HP-β-CD inclusion complex (1:1) was prepared by freeze-drying method. The sample obtained was characterized by DSC, FTIR, PXRD, SEM and ¹H NMR techniques, evidencing the formation of morin/HP-β-CD inclusion complex. In addition, complexation efficiency (98.3%) and loading content (17.63%), determined by HPLC demonstrated that morin was efficiently complexed in HP-β-CD. In vitro dissolution study confirmed that morin/HP-β-CD inclusion complex increased the solubility and dissolution rate of morin. The oral bioavailability of the morin/HP-β-CD complex and free morin were evaluated through a pharmacokinetic study in rat plasma. The oral bioavailability of morin complexed with HP-β-CD was increased by 4.20 times compared with the free morin. Hyperalgesia induced by carrageenan and carrageenan-induced pleurisy were carried out in mice to evaluate the antihyperalgesic and anti-inflammatory activities of free morin and inclusion complex. Morin/HP-β-CD inclusion complex showed antihyperalgesic effect in inflammatory pain model and anti-inflammatory effect decreasing leukocyte migration and TNF-α levels at a lower dose than free morin. Therefore, the morin/HP-β-CD inclusion complex improved the solubility, dissolution rate, oral bioavailability, antihyperalgesic and anti-inflammatory effects of morin. In this way, the morin/HP-β-CD inclusion complex exhibits potential for development of new pharmaceutical product for future clinical applications.

Browning control of fresh-cut Chinese yam by edible coatings enriched with an inclusion complex containing star anise essential oil

Star anise essential oil (SAEO) has a variety of antioxygenic and antimicrobial properties, and is widely used in food preservation. However, its application is still challenging due to poor water solubility and physicochemical stability. We now report that encapsulation of SAEO in hydroxypropyl-β-cyclodextrin (HPCD) enhances its water solubility, as well as its thermal, storage, and photostability. The solubility of SAEO encapsulated by HPCD was increased by 47.5 times at 45 °C, and the onset temperature of thermal volatilization was delayed by at least 200 °C. The encapsulated material is also more uniformly and more stably dispersed in xanthan gum, and is thus released in a controlled manner. Importantly, fresh-cut Chinese yam coated with xanthan gum containing encapsulated SAEO is more effectively preserved, as assessed using weight loss, L* value, browning index, and polyphenol oxidase activity. The data suggest that the encapsulated SAEO reduced the weight loss of the samples by more than 30%, and the encapsulation of HPCD increased the inhibitory effect of SAEO on browning and polyphenol oxidase activity of the samples by nearly 8 times and more than 7 times, respectively. Collectively, SAEO encapsulated in HPCD is promising as a preservative coat for fresh-cut fruits and vegetables.

The encapsulation of hydroxypropyl-β-cyclodextrin improved the inhibitory effect of star anise essential oil on the browning of fresh-cut Chinese yam.

β-Lactoglobulin as a Nanotransporter for Glabridin: Exploring the Binding Properties and Bioactivity Influences

Based on the fact that β-lactoglobulin (β-lg) can solubilize readily in water and bind many small hydrophobic molecules, a novel nanocomplexed glabridin with β-lg was developed by an antisolvent precipitation method. After binding to β-lg, the solubility of glabridin in aqueous solution was enhanced 21 times. Fluorescence spectroscopy of β-lg revealed that the interaction of glabridin with β-lg made the environment of Trp and Tyr residues on β-lg more hydrophilic. The morphology and crystal form of the nanocomplexed glabridin with β-lg was characterized and the changes in β-lg conformation was also been investigated. In combination with molecular docking modeling, the results revealed that glabridin was bound to β-lg by hydrophobic forces and hydrogen-bond interactions. Furthermore, the nanocomplexed glabridin with β-lg had a better 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid radical-scavenging capacity compared to free glabridin at the same concentration during in vitro tests. Thus, nanocomplexing with β-lg, by virtue of its ability to enhance the solubility of glabridin in aqueous systems, provides a suitable opportunity as a nanocarrier molecule.

Improved Ocular Delivery of Nepafenac by Cyclodextrin Complexation

Nepafenac is a nonsteroidal anti-inflammatory drug (NSAID), currently only available as 0.1% ophthalmic suspension (Nevanac®). This study utilized hydroxypropyl-β-cyclodextrin (HPBCD) to increase the water solubility and trans-corneal permeation of nepafenac. The nepafenac-HPBCD complexation in the liquid and solid states were confirmed by phase solubility, differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance spectroscopy (NMR) analyses. Nepafenac 0.1% ophthalmic solution was formulated using HPBCD (same pH and osmolality as that of Nevanac®) and pig eye trans-corneal permeation was studied versus Nevanac®. Furthermore, nepafenac content in cornea, sclera, iris, lens, aqueous humor, choroid, ciliary body, retina, and vitreous humor was studied in a continuous isolated pig eye perfusion model in comparison to the suspension and Nevanac®. Permeation studies using porcine corneas revealed that the solution formulation had a permeation rate 18 times higher than Nevanac®. Furthermore, the solution had 11 times higher corneal retention than Nevanac®. Drug distribution studies using porcine eyes revealed that the solution formulation enables detectable levels in various ocular tissues while the drug was undetectable by Nevanac®. The ocular solution formulation had a significantly higher drug concentration in the cornea compared to the suspension or Nevanac®.

Reactions in NMR Tubes as Key Weapon in Rational Drug Design

NMR spectroscopy is a powerful technique suitable for obtaining detailed structural and dynamic data at atomic resolution. Progress in NMR instrumentation has led the scientific community to produce novel techniques which provide valuable information to resolve demanding and crucial questions of molecular biology and rational drug design. This chapter outlines the progress of NMR spectroscopy in the rational drug design. In addition, it offers an example of a reaction in NMR tube for achieving rational drug design.

Mesalazine/hydroxypropyl-β-cyclodextrin/chitosan nanoparticles with sustained release and enhanced anti-inflammation activity

This study aimed to develop a novel sustained release system for mesalazine (MSZ) by preparing hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex loaded chitosan (CS) nanoparticles (NPs). The HP-β-CD/MSZ complex was prepared at 1:1 stoichiometry and characterized by using various analysis techniques. The HP-β-CD/MSZ/CS NPs prepared under the optimum condition had a spherical shape (90±17 nm diameter), a narrow size distribution, and a high loading efficiency. Compared with free MSZ, the HP-β-CD/MSZ/CS NPs exhibited an obvious sustained release of MSZ. The activity of the NPs against a cytokine-triggered inflammatory response was evaluated in cytokine-stimulated HT-29 cell lines by monitoring key inflammatory mediators. The results revealed that compared with free MSZ, the NPs more strongly inhibited the production of NO, PGE₂, and IL-8, indicating the NPs possibly had better anti-inflammatory effects. Therefore, the established HP-β-CD/MSZ/CS NPs may be a promising delivery system of MSZ.

Characterization of Curcumin/Cyclodextrin Polymer Inclusion Complex and Investigation on Its Antioxidant and Antiproliferative Activities

The aims of this study were to characterize the curcumin/cyclodextrin polymer inclusion complex using X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and UV⁻vis spectroscopy, and to determine the antioxidant activity of this complex by methods of scavenging 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals assays and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assays. The inhibitory effect of inclusion complex on A375 cells was also investigated by CCK-8 assay, Annexin-V/PI staining assay, and caspase activity assay. The results showed that the complex exhibited different physicochemical characteristics from that of free curcumin. Moreover, the inclusion complex exhibited novel antioxidant activity by scavenging the ABTS and DPPH free radicals and displayed higher antiproliferative activity on A375 cells. Further investigation revealed that inclusion complex could induce A375 cell apoptosis. These findings suggest that inclusion complex could be developed as a novel natural antioxidant with potential applications in cancer chemoprevention.

Photostability and antioxidant activity studies on the inclusion complexes of trans-polydatin with β-cyclodextrin and derivatives

The inclusion complexes of trans-polydatin and three cyclodextrins (CDs), namely β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD) and (2-hydroxy) propyl-β-cyclodextrin (HP-β-CD) were prepared.

Studies on the Inclusion Complexes of Daidzein with β-Cyclodextrin and Derivatives

The inclusion complexes between daidzein and three cyclodextrins (CDs), namely β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Me-β-CD, DS = 12.5) and (2-hydroxy)propyl-β-cyclodextrin (HP-β-CD, DS = 4.2) were prepared. The effects of the inclusion behavior of daidzein with three kinds of cyclodextrins were investigated in both solution and solid state by methods of phase-solubility, XRD, DSC, SEM, ¹H-NMR and 2D ROESY methods. Furthermore, the antioxidant activities of daidzein and daidzein-CDs inclusion complexes were determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) method. The results showed that daidzein formed a 1:1 stoichiometric inclusion complex with β-CD, Me-β-CD and HP-β-CD. The results also showed that the solubility of daidzein was improved after encapsulating by CDs. ¹H-NMR and 2D ROESY analyses show that the B ring of daidzein was the part of the molecule that was most likely inserted into the cavity of CDs, thus forming an inclusion complex. Antioxidant activity studies showed that the antioxidant performance of the inclusion complexes was enhanced in comparison to the native daidzein. It could be a potentially promising way to develop a new formulation of daidzein for herbal medicine or healthcare products.

Propyl gallate/cyclodextrin supramolecular complexes with enhanced solubility and radical scavenging capacity

This study prepared and investigated the inclusion complexes of propyl gallate (PG) with beta-cyclodextrin (β-CD) and its water-soluble derivatives dimethyl-beta-cyclodextrin (DM-β-CD), hydroxypropyl-beta-cyclodextrin (HP-β-CD), and sulfobutylether-beta-cyclodextrin (SBE-β-CD). Phase solubility studies indicated that the formed complexes were in 1:1 stoichiometry. FT-IR, PXRD, DSC, ¹H-NMR, ROESY-NMR, and SEM analysis results confirmed the formation of the complexes. The NMR results indicated that the aromatic ring of PG was embedded into the CD cavity. The aqueous solubility of PG was markedly improved, and that of the PG/DM-β-CD complex increased by 365.3 times. In addition, the results of the antioxidant activity assay showed that the hydroxyl radical and superoxide radical scavenging capacities of the complexes increased by 3-11 times and 1-6.5 times, respectively, compared with those of PG under the same concentration. Therefore, CD/PG inclusion complexes with improved solubility and radical scavenging capacity can be used as water-soluble antioxidants in the food industry.