Molecular insights into inclusion complex formation between β- and γ-cyclodextrins and rosmarinic acid

Enhancement of mannosylerythritol lipid-A on physicochemical stability, antioxidant activity, and bioavailability of bovine lactoferrin emulsion under different pH conditions

This study systematically explored the enhancement of mannosylerythritol lipid-A (MEL-A) on physicochemical stability, antioxidant activity, and bioavailability of bovine lactoferrin (BLF) emulsion under different pH conditions by spectroscopic techniques, molecular simulation, and simulated in vitro digestion model. The bovine lactoferrin-MEL-A (BLF-MEL-A) emulsions were prepared and characterized with the Fourier infrared, of which results showed that high concentration MEL-A (1.00 mg/mL) changed the secondary structure of pH-induced BLF and rendered an increase in β-sheet and random coil fractions. Based on the results of fluorescence spectrum and isothermal titration calorimetry, hydrogen bonding, van der Waals forces, and electrostatic force were the interaction forces of BLF and MEL-A, which were similar to the simulated data of molecular docking and molecular dynamics. BLF-MEL-A emulsion also exerted considerable antioxidant activities and had great potential for functional food development. In addition, MEL-A could improve the stability of BLF emulsion in simulated in vitro digestion test, which promoted the bioavailability of BLF. Therefore, this study will facilitate to explore the interaction between BLF and MEL-A and expand the application of MEL-A as a food additive in food industry.

Interactions of a Novel Anthracycline with Oligonucleotide DNA and Cyclodextrins in an Aqueous Environment

Berubicin, a chemotherapy medication belonging to the class of anthracyclines, is simulated in double-stranded DNA sequences and cyclodextrins in an aqueous environment via full-atom molecular dynamics simulations on the time scale of microseconds. The drug is studied in both the neutral and protonated states so as to better comprehend the role of its charge in the formed complexes. The noncovalent berubicin-DNA and berubicin-cyclodextrin complexes are investigated in detail, paying special attention to their thermodynamic description by employing the double decoupling method, the solvent balance method, the weighted solvent accessible surface model, and the linear interaction energy method. A novel approach for extracting the desolvation thermodynamics of the binding process is also presented. Both the binding and desolvation Gibbs energies are decomposed into entropic and enthalpic contributions so as to elucidate the nature of complexation and its driving forces. Selected structural and geometrical properties of all the complexes, which are all stable, are analyzed. Both cyclodextrins under consideration are widely utilized for drug delivery purposes, and a comparative investigation between their bound states with berubicin is carried out.

Sulfo-butyl ether β-cyclodextrin inclusion complexes of bosutinib: in silico, in vitro and in vivo evaluation in attenuating the fast-fed variability

Bosutinib (BOS) is a BCS class IV drug that shows low oral bioavailability and high fast-fed variability. Various pharmaceutical formulations have been explored thus far in order to improve its bioavailability while avoiding fast-fed variability. In the present study, we explored cyclodextrin (CD) complexation strategy to overcome the aforementioned disadvantages associated with BOS. CD complexation is a simple, versatile and economic approach that enables formation of inclusion complexes, thereby improving aqueous solubility while nullifying pH-dependent solubility and fast-fed variability for poorly soluble drugs. Initially, we performed molecular dynamics and docking studies to select appropriate CD derivative. The results of in silico studies revealed that sulfo-butyl ether β-cyclodextrin (SBE-CD) offered superior binding affinity with BOS. Further, Job's plot revealed that 1:1 stoichiometry of BOS and CD resulted in enhancement of BOS solubility up to ~ 132.6-folds. In vitro release studies in bio-relevant media (fasted and fed state simulated gastric and intestinal fluids) revealed higher drug release while overcoming its pH-dependent solubility. In vitro studies on K562 cells demonstrated a 1.83-fold enhancement in cytotoxicity due to enhanced ROS production and G2/M phase arrest.In vivo pharmacokinetic studies in Sprague-Dawley rats revealed insignificant fast-fed variability with AUCfast/fed 0.9493 and Cmaxfast/fed 0.8291 being closer to 1 in comparison with BOS. Hence, we conclude that SBE-CD complexation could be a promising approach in diminishing fast-fed variability of BOS.

Unveiling the synergy: a combined experimental and theoretical study of β-cyclodextrin with melatonin

Melatonin (MT) is a vital hormone controlling biorhythms, and optimizing its release in the human body is crucial. To address MT's unfavorable pharmacokinetics, we explored the inclusion complexes of MT with β-cyclodextrin (β-CD). Nano spray drying was applied to efficiently synthesize these complexes in three molar ratios (MT : β-CD = 1 : 1, 2 : 1, and 1 : 2), reducing reagent use and expediting inclusion. The complex powders were characterized through thermal analyses (TGA and DSC), Fourier transform infrared spectroscopy (FTIR), and in vitro MT release measurements via high-performance liquid chromatography (HPLC). In parallel, computational studies were conducted, examining the stability of MT : β-CD complexes by means of unbiased semi-empirical conformational searches refined by DFT, which produced a distribution of MT : β-CD binding enthalpies. Computational findings highlighted that these complexes are stabilized by specific hydrogen bonds and non-specific dispersive forces, with stronger binding in the 1 : 1 complex, which was corroborated by in vitro release data. Furthermore, the alignment between simulated and experimental FTIR spectra demonstrated the quality of both the structural model and computational methodology, which was crucial to enhance our comprehension of optimizing MT's release for therapeutic applications.

Electrospun Materials Based on Cellulose Acetate Loaded with Rosmarinic Acid with Antioxidant and Antifungal Properties

Fibrous cellulose acetate (CA) materials loaded with rosmarinic acid (RA) were successfully created by one-pot electrospinning. In order to improve the water solubility of the polyphenolic acid and to facilitate its release from the fibrous materials, the non-ionic water-soluble polyethylene glycol (PEG) was added. Detailed characterization of the fabricated fibrous CA/RA and CA/PEG/RA materials was performed using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), UV-Vis spectroscopy and water contact angle analysis. The optimal ratio between CA, RA and PEG for preparation of defect-free and uniform fibers was accomplished by varying their concentrations. Furthermore, the incorporation of the PEG improved the hydrophilicity and wettability of the fibrous CA materials. Moreover, PEG facilitated the RA release and over 360 min, the amount released from fibrous CA/PEG/RA fibers was 91%, while that released from CA/RA materials was 53%. Both of the RA-containing fibrous materials, with and without PEG, manifested high antioxidant activity as determined by the DPPH free radical-scavenging method. In addition, the electrospun CA/PEG/RA materials displayed good antifungal activity against C. albicans. These features make the fibrous CA/PEG/RA materials promising candidates for treatment of wound infections.

Encapsulation of Benzaldehyde Produced by the Eco-Friendly Degradation of Amygdalin in the Apricot Kernel Debitterizing Wastewater

In order to fully utilize the by-products of apricot kernel-debitterizing and address the chemical instability of benzaldehyde in the food industry, benzaldehyde was first prepared by adding the apricot kernel powder to degrade the amygdalin present in the apricot kernel-debitterizing water. Subsequently, β-cyclodextrin was employed to encapsulate the benzaldehyde, and its encapsulation efficacy was evaluated through various techniques including Fourier transform infrared spectroscopy, thermogravimetric analysis, release kinetics fitting inhibitory effect and the effect on Botrytis cinerea. Finally, the encapsulation was explored via molecular docking and molecular dynamics simulations. The results indicate that the optimal preparation conditions for the benzaldehyde were 1.8 h, 53 °C and pH 5.8, and the encapsulation of benzaldehyde with β-cyclodextrin (wall-core ratio of 5:1, mL/g) has been verified by the deceleration in the release rate, the enhanced thermal stability and the prolonged inhibition effect against Botrytis cinerea. The encapsulation proceeded spontaneously without steric hindrance in the simulation, which led to a reduction in the hydrophobic cavity of β-cyclodextrin. In conclusion, the amygdalin in the debitterizing wastewater can be degraded in an eco-friendly way to produce benzaldehyde by adding apricot kernel powder, which contains β-glucosidase; the encapsulation of benzaldehyde is stable, thus enhancing the utilization of amygdalin in the debitterizing wastewater of apricot kernels.

Development of nano-delivery systems for loaded bioactive compounds: using molecular dynamics simulations

Over the past decade, a remarkable surge in the development of functional nano-delivery systems loaded with bioactive compounds for healthcare has been witnessed. Notably, the demanding requirements of high solubility, prolonged circulation, high tissue penetration capability, and strong targeting ability of nanocarriers have posed interdisciplinary research challenges to the community. While extensive experimental studies have been conducted to understand the construction of nano-delivery systems and their metabolic behavior in vivo, less is known about these molecular mechanisms and kinetic pathways during their metabolic process in vivo, and lacking effective means for high-throughput screening. Molecular dynamics (MD) simulation techniques provide a reliable tool for investigating the design of nano-delivery carriers encapsulating these functional ingredients, elucidating the synthesis, translocation, and delivery of nanocarriers. This review introduces the basic MD principles, discusses how to apply MD simulation to design nanocarriers, evaluates the ability of nanocarriers to adhere to or cross gastrointestinal mucosa, and regulates plasma proteins in vivo. Moreover, we presented the critical role of MD simulation in developing delivery systems for precise nutrition and prospects for the future. This review aims to provide insights into the implications of MD simulation techniques for designing and optimizing nano-delivery systems in the healthcare food industry.

Alginate-based edible coating with oregano essential oil/β-cyclodextrin inclusion complex for chicken breast preservation

A sodium alginate (SA) edible coating containing oregano essential oil (OEO)/β-cyclodextrin (β-CD) inclusion complexes (SA/OEO-MP coating) was developed to extend the shelf life of fresh chicken breast during refrigeration storage. First, OEO was inserted into the hydrophobic interior of β-CD to form an inclusion complex (OEO-MP) that maintained its excellent antioxidant and antibacterial activities. The formed OEO-MP was characterized using fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). In addition, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results demonstrated that β-CD could improve the thermal stability of OEO. The encapsulation efficiency reached 71.6 %, and OEO was released continuously from the OEO-MP. The lipid oxidation, total viable count (TVC) and sensory properties of chicken breasts were regularly monitored when OEO-MP was incorporated into the SA coating for chicken breast preservation. Compared with the uncoated group, the SA/OEO-MP-coated groups showed significantly reduced increases in pH, thiobarbituric acid reactive substances (TBARS), total volatile base nitrogen (TVB-N), and TVC, especially in the SA/OEO-MP1 group. In summary, the SA/OEO-MP coating could preserve the chicken breast by reducing lipid oxidation and inhibiting the proliferation of microorganisms. It would be developed as a prospective edible packaging for chicken preservation.

Molecular dynamics simulation and in vitro digestion to examine the impact of theaflavin on the digestibility and structural properties of myosin

In this study, the interaction mechanism between theaflavin and myosin was explored to confirm the potential application of theaflavin in the meat protein system. A series of theaflavin and myosin solutions were prepared for spectroscopic studies. Spectroscopy results showed that theaflavins formed complexes with myosin and affected the microenvironment of myosin. And that addition of theaflavin cause static quenching of the myosin solution. Theaflavin and bovine myosin combined through hydrophobic interaction to form a complex, and gradually increasing the temperature was conducive to the binding of theaflavin and bovine myosin. This interaction results in a decrease in the α -helix content of myosin. Molecular dynamics simulation results confirmed that hydrophobic interactions and hydrogen bonds made the protein structure more compact and stable. And the in vitro digestion process was simulated. The results showed that the addition of theaflavin could significantly reduce the digestibility of myosin.

In Vitro and In Silico Study on the Molecular Encapsulation of α-Tocopherol in a Large-Ring Cyclodextrin

α-tocopherol is the physiologically most active form of vitamin E, with numerous biological activities, such as significant antioxidant activity, anticancer capabilities, and anti-aging properties. However, its low water solubility has limited its potential use in the food, cosmetic, and pharmaceutical industries. One possible strategy for addressing this issue is the use of a supramolecular complex with large-ring cyclodextrins (LR-CDs). In this study, the phase solubility of the CD26/α-tocopherol complex was investigated to assess the possible ratios between host and guest in the solution phase. Next, the host-guest association of the CD26/α-tocopherol complex at different ratios of 1:2, 1:4, 1:6, 2:1, 4:1, and 6:1 was studied by all-atom molecular dynamics (MD) simulations. At 1:2 ratio, two α-tocopherol units interact spontaneously with CD26, forming an inclusion complex, as supported by the experimental data. In the 2:1 ratio, a single α-tocopherol unit was encapsulated by two CD26 molecules. In comparison, increasing the number of α-tocopherol or CD26 molecules above two led to self-aggregation and consequently limited the solubility of α-tocopherol. The computational and experimental results indicate that a 1:2 ratio could be the most suitable stoichiometry to use in the CD26/α-tocopherol complex to improve α-tocopherol solubility and stability in inclusion complex formation.

Fabrication and Characterization of β-Cyclodextrin/Mosla Chinensis Essential Oil Inclusion Complexes: Experimental Design and Molecular Modeling

Essential oils (EOs) are primarily isolated from medicinal plants and possess various biological properties. However, their low water solubility and volatility substantially limit their application potential. Therefore, the aim of the current study was to improve the solubility and stability of the Mosla Chinensis (M. Chinensis) EO by forming an inclusion complex (IC) with β-cyclodextrin (β-CD). Furthermore, the IC formation process was investigated using experimental techniques and molecular modeling. The major components of M. Chinensis 'Jiangxiangru' EOs were carvacrol, thymol, o-cymene, and terpinene, and its IC with β-CD were prepared using the ultrasonication method. Multivariable optimization was studied using a Plackett-Burman design (step 1, identifying key parameters) followed by a central composite design for optimization of the parameters (step 2, optimizing the key parameters). SEM, FT-IR, TGA, and dissolution experiments were performed to analyze the physicochemical properties of the ICs. In addition, the interaction between EO and β-CD was further investigated using phase solubility, molecular docking, and molecular simulation studies. The results showed that the optimal encapsulation efficiency and loading capacity of EO in the ICs were 86.17% and 8.92%, respectively. Results of physicochemical properties were different after being encapsulated, indicating that the ICs had been successfully fabricated. Additionally, molecular docking and dynamics simulation showed that β-CD could encapsulate the EO component (carvacrol) via noncovalent interactions. In conclusion, a comprehensive methodology was developed for determining key parameters under multivariate conditions by utilizing two-step optimization experiments to obtain ICs of EO with β-CD. Furthermore, molecular modeling was used to study the mechanisms involved in molecular inclusion complexation.

Encapsulation of phenolic acids into cyclodextrins: A global statistical analysis of the effects of pH, temperature and concentrations on binding constants measured by ACE methods

Affinity capillary electrophoresis was used for the simultaneous measurement of the pK_a values and of the binding constants relative to the encapsulation of naturally occurring phenolic acids (rosmarinic and caffeic acids) with cyclodextrins. A thorough study as a function of pH and temperature was coupled to a detailed statistical analysis of the resulting experimental data. A step-by-step curve fitting process was sufficient for obtaining individual binding constant for each experimental condition, but the influence of temperature remained unclear. A quantitative and qualitative gain was then obtained by supplementing this initial analysis with global multiparameter optimization. This leads to the estimation of both entropy and enthalpy of reaction and to the full description of the binding reactions as a function of pH and temperature. The encapsulation was shown to be very sensitive to pH and temperature, with optimal complexation occurring at low pH and low temperature, gaining up to a factor of 3 by cooling from 36 to 15°C, and up to a factor of 10 by lowering the pH from 7 to 2.

Cyclodextrin-Based Delivery Systems and Hydroxycinnamic Acids: Interactions and Effects on Crucial Parameters Influencing Oral Bioavailability-A Review

Hydroxycinnamic acids (HCAs) are a subclass of phenolic acids presenting caffeic acid (CA), chlorogenic acid (CGA), coumaric acid (COA) isomers, ferulic acid (FA), and rosmarinic acid (RA) as the major representants, being broadly distributed into vegetal species and showing a range of biological potentials. Due to the low oral bioavailability of the HCAs, the development of delivery systems to promote better administration by the oral route is demanding. Among the systems, cyclodextrin (CD)-based delivery systems emerge as an important technology to solve this issue. Regarding these aspects, in this review, CD-based delivery systems containing HCAs are displayed, described, and discussed concerning the degree of interaction and their effects on crucial parameters that affect the oral bioavailability of HCAs.

Application of γ-cyclodextrin-lysozyme as host materials for encapsulation of curcumin: characterization, stability, and controlled release properties

BACKGROUND

In this study, a safe and relatively stable γ-cyclodextrin-lysozyme (γ-CD-Lys) was synthesized using epichlorohydrin as the cross-linking agent, and curcumin was successfully encapsulated in γ-CD-Lys.

RESULTS

The successful Lys grafting onto γ-CD can be demonstrated by a high grafting ratio (79.02%) and was further confirmed by Fourier transform infrared (FTIR) band shifts and the new signal obtained at δ 2.75 in proton nuclear magnetic resonance. The encapsulation efficiency value of γ-CD-Lys was 76.74%, and the successful encapsulation of curcumin into γ-CD-Lys was confirmed by crystal structure change, increased melting point, and FTIR band shifts. The intermolecular bonds results suggested that associative forces between curcumin and γ-CD-Lys were electrostatic interaction, hydrogen bonds interaction, and hydrophobic interaction. The designed nanoparticles had excellent stability at low pH and low salt concentration. The release rate of these nanoparticles was inhibited in simulated gastric conditions, whereas it increased significantly in intestinal media. Simulated gastrointestinal digestion experiments further confirmed that nanoparticles showed higher bioaccessibility (86.05%) compared with curcumin (58.82%).

CONCLUSION

Overall, our study showed that the nanoparticles were highly promising for delivering curcumin because of their enhanced functional attributes and stabilization in acid or low salt environments. Also, it was an excellent wall material for targeting hydrophobic bioactive compounds in the intestinal tract via oral administration. © 2022 Society of Chemical Industry.

Cannabidiol/hydroxypropyl-β-cyclodextrin inclusion complex: structure analysis, release behavior, permeability, and bioactivity under in vitro digestion

The inclusion complex of CBD greatly improved its release performance and bioactivity.

Novel β-cyclodextrin based copolymers: fabrication, characterization and in vitro release behavior

A novel cyclodextrin-contained copolymer poly(AAc-co-SA-AC-co-allyl-β-CD) was synthesized based on the method of redox radical polymerization. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectra were used to study the structure of the obtained copolymer. The molecular weight of the copolymer was studied by gel permeation chromatography (GPC). The polymeric nanoparticles (NPs) were fabricated by a solvent evaporation method. The morphology and particle size distribution of the cargo-free NPs were investigated with transmission electron microscope (TEM), atomic force microscope (AFM), and laser particle analyzer, respectively. Curcumin (Cur) was selected as a model drug and encapsulated into the above NPs. The distribution of Cur in the drug-loaded NPs was analyzed by the method of differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Moreover, the release profiles of Cur from Cur-loaded NPs were studied in pH 6.8 and 7.4 buffers. The results of FTIR and ¹H NMR spectra confirmed the successful synthesis of poly(AAc-co-SA-AC-co-allyl-β-CD). GPC curve proved that the molecular weight of the copolymer was more than 60 kDa. TEM and AFM images illustrated that the cargo-free NPs were in spherical shape with a diameter about 40 nm. XRD patterns and DSC curves indicated that most of Cur distributed in the Cur-loaded NPs with amorphous state. Importantly, the medicated NPs showed sustained release characteristics toward Cur.

Investigation of molecular mechanisms of interaction between myofibrillar proteins and 1-heptanol by multiple spectroscopy and molecular docking methods

In this study, we investigated the interaction between myofibrillar proteins (MPs) and selected alcohols (1-pentanol, 1-hexanol, and 1-heptanol). Only 1-heptanol exhibited the binding ability to MPs, and the binding ability significantly increased with increasing protein concentration (p < 0.05). In addition, both static and dynamic quenching occurred during the interaction, with a red shift of the maximum absorption peak in the synchronous fluorescence spectra indicating a change in the microenvironment of the MPs. The results of circular dichroism measurements suggested that the interaction between MPs and 1-heptanol altered the secondary structure of the MPs. Furthermore, thermodynamic analysis showed that hydrogen bonding and van der Waals forces dominated the interaction between MPs and 1-heptanol, which was confirmed by the results of molecular docking/dynamics simulations. This study provides an in-depth understanding of the interaction between MPs and alcohols, which can help to improve the flavor control in meat.

Native Cyclodextrins and Their Derivatives as Potential Additives for Food Packaging: A Review

Cyclodextrins (CDs) have been used by the pharmaceutical and food industries since the 1970s. Their cavities allow the accommodation of several hydrophobic molecules, leading to the formation of inclusion complexes (ICs) increasing the guest molecules’ stability, allowing their controlled release, enhancing their water solubility and biodisponibility. Due to these, CDs and their ICs have been proposed to be used as potential allies in food packaging, especially in active packaging. In this review, we present the many ways in which the CDs can be applied in food packaging, being incorporated into the polymer matrix or as a constituent of sachets and/or pads aiming for food preservation, as well as the diverse polymer matrices investigated. The different types of CDs, natives and derivatives, and the several types of compounds that can be used as guest molecules are also discussed.

Rosmarinic Acid and Ulvan from Terrestrial and Marine Sources in Anti-Microbial Bionanosystems and Biomaterials

In order to increase their sustainability, antimicrobial renewable molecules are fundamental additions to consumer goods. Rosmarinic acid is extracted from several terrestrial plants and represents an effective anti-microbial agent. Ulvan, extracted from algae, is an anti-microbial polysaccharide. The present review is dedicated to discussing the sources and the extraction methodologies for obtaining rosmarinic acid and ulvan. Moreover, the preparation of bioanosystems, integrating the two molecules with organic or inorganic substrates, are reviewed as methodologies to increase their effectiveness and stability. Finally, the possibility of preparing functional biomaterials and anti-microbial final products is discussed, considering scientific literature. The performed analysis indicated that the production of both molecules is not yet performed with mature industrial technologies. Nevertheless, both molecules could potentially be used in the packaging, biomedical, pharmaceutical, cosmetic, sanitary and personal care sectors, despite some research being required for developing functional materials with specific properties to pave the way for many more applications.

Inclusion of Levodopa into β-Cyclodextrin: A Comprehensive Computational Study

This study focused on the inclusion of levodopa (LVDP) into β-cyclodextrin (BCD) using various computational methods such as quantum mechanics (QM), molecular dynamics/steered molecular dynamics (MD/SMD), and QM/molecular mechanics/Poison-Boltzmann surface area (QM/MM/PBSA). The QM results assigned the most significant charge-transfer atoms and the higher stability of LVDP in the aqueous phase. The MD results indicate the formation of a 1:1 complex with a reasonable estimation of the effective radius of the complex, the significant contribution of hydrogen bonding in the binding energy, and the enhancement of the water solubility of LVDP. By accounting for the water hydrogen bonds and their dipolar effects, QM/MM calculations lead to the more accurate IR spectrum and binding energy of the BCD-LVDP complex. By considering carboxylic and amine functional groups' more precise arrangement, QM/MM assigns stronger hydrogen bonds between LVDP and BCD. While all the methods provide a reasonable estimation of the binding energy, the most accurate value (-4.14 kcal/mol) is obtained from QM/MM/PBSA.

Application of Molecular Dynamics Simulations in the Analysis of Cyclodextrin Complexes

Cyclodextrins (CDs) are highly respected for their ability to form inclusion complexes via host-guest noncovalent interactions and, thus, ensofance other molecular properties. Various molecular modeling methods have found their applications in the analysis of those complexes. However, as showed in this review, molecular dynamics (MD) simulations could provide the information unobtainable by any other means. It is therefore not surprising that published works on MD simulations used in this field have rapidly increased since the early 2010s. This review provides an overview of the successful applications of MD simulations in the studies on CD complexes. Information that is crucial for MD simulations, such as application of force fields, the length of the simulation, or solvent treatment method, are thoroughly discussed. Therefore, this work can serve as a guide to properly set up such calculations and analyze their results.

Chemical Composition, Antioxidant and Enzyme Inhibitory Activities of Onosma bourgaei and Onosma trachytricha and in Silico Molecular Docking Analysis of Dominant Compounds

The aim of this study was to investigate the chemical composition, antioxidant and enzyme inhibitory activities of methanol (MeOH) extracts from Onosma bourgaei (Boiss.) and O. trachytricha (Boiss.). In addition, the interactions between phytochemicals found in extracts in high amounts and the target enzymes in question were revealed at the molecular scale by performing in silico molecular docking simulations. While the total amount of flavonoid compounds was higher in O. bourgaei, O. trachytricha was richer in phenolics. Chromatographic analysis showed that the major compounds of the extracts were luteolin 7-glucoside, apigenin 7-glucoside and rosmarinic acid. With the exception of the ferrous ion chelating assay, O. trachytricha exhibited higher antioxidant activity than O. bourgaei. O. bourgaei exhibited also slightly higher activity on digestive enzymes. The inhibitory activities of the Onosma species on tyrosinase were almost equal. In addition, the inhibitory activities of the extracts on acetylcholinesterase (AChE) were stronger than the activity on butyrylcholinesterase (BChE). Molecular docking simulations revealed that luteolin 7-glucoside and apigenin 7-glucoside have particularly strong binding affinities against ChEs, tyrosinase, α-amylase and α-glucosidase when compared with co-crystallized inhibitors. Therefore, it was concluded that the compounds in question could act as effective inhibitors on cholinesterases, tyrosinase and digestive enzymes.

Surface modification of zero-valent iron nanoparticles with β-cyclodextrin for 4-nitrophenol conversion

Environmental pollution causes irreversible damage to ecosystems and their structure. Therefore, the development of novel remedial techniques is a must for an effective response to emerging contaminants and those already persisting in the environment. The nanosized zero-valent iron (nZVI) is considered as an important nanostructure for the degradation of toxic compounds. Furthermore, the degradative potential of nZVI may be improved by surface modification. In this work nZVI was functionalized with β-cyclodextrin (β-CD), which is considered to be an environmentally-friendly and cheap adsorbent for toxic pollutants. Such a 'green' improvement not only enhances the activity of nZVI but also enables the conversion of 4-nitrophenol to 4-aminophenol, which under standard conditions is persistent and does not significantly react with bare nZVI. This research may help to find a solution to treat persistent organic pollutants (POPs) in aqueous environment.