Water content of flavonoid/cyclodextrin nanoparticles: Relationship with the structural descriptors of biologically active compounds

Beneficial Effects of Resveratrol and γ-Cyclodextrin on the Hematological and Biochemical Parameters of Healthy Wistar Rats Treated with Cisplatin: A PCA Approach

It is well known that platinum-based antineoplastic agents, including cisplatin (CP), have side effects that limit their use. Nefrotoxicity, neurotoxicity, and hemolytic anemia are the most common side effects. There are few studies on the reduction in these effects that involves nanoencapsulation; however, almost none involve cyclodextrins (CDs). Changes in the hematological and biochemical parameters of healthy Wistar rats treated with solutions of γ-cyclodextrin/resveratrol/cisplatin (γ-CD/Rv/CP) ternary complexes are investigated for the first time. They are intraperitoneally injected with γ-CD/Rv/CP solutions containing 5 mg CP/kg.b.w. Single shots were administered to six groups of Wistar rats (six individuals for every group) using γ-CD/Rv/CP, γ-CD/CP, γ-CD/Rv complexes, as well as positive- and negative-control groups, respectively. Thirty-two hematological and biochemical parameters were evaluated from blood samples and used as input variables for the principal component analysis (PCA) discrimination of the groups. The best protection was obtained for the γ-CD/Rv/CP ternary complex, which determined closer biochemical values to the control group. These values significantly differ from those of the γ-CD/CP treated group, especially for the IP, UA, and T-Pro kidney-related biochemical parameters. This finding proves the beneficial influence of Rv during CP administration through CD-based carriers.

Estimation of the Controlled Release of Antioxidants from β-Cyclodextrin/Chamomile (Matricaria chamomilla L.) or Milk Thistle (Silybum marianum L.), Asteraceae, Hydrophilic Extract Complexes through the Fast and Cheap Spectrophotometric Technique

This is the first study on the modeling of the controlled release of the estimated antioxidants (flavonoids or flavonolignans) from β-cyclodextrin (β-CD)/hydrophilic vegetable extract complexes and the modeling of transdermal pharmaceutical formulations based on these complexes using an overall estimation by the spectrophotometric method. The Korsmeyer-Peppas model was chosen for evaluating the release mechanisms. β-CD/chamomile (Matricaria chamomilla L., Asteraceae) ethanolic extract and β-CD/milk thistle (Silybum marianum L., Asteraceae) ethanolic extract complexes were obtained by the co-crystallization method with good recovering yields of 55-76%, slightly lower than for β-CD/silibinin or silymarin complexes (~87%). According to differential scanning calorimetry (DSC) and Karl Fischer water titration (KFT), the thermal stability of complexes is similar to β-CD hydrate while the hydration water content is lower, revealing the formation of molecular inclusion complexes. In the Korsmeyer-Peppas model, β-CD/M. chamomilla flower extract complexes reveal Case II transport mechanisms, while the corresponding complexes with leaf extracts indicate non-Fickian diffusion for the controlled release of antioxidants in ethanol 60 and 96%. The same non-Fickian diffusion was revealed by β-CD/S. marianum extract and β-CD/silibinin complexes. On the contrary, almost all model transdermal pharmaceutical formulations based on β-CD/M. chamomilla extract complexes and all those based on β-CD/S. marianum extract complexes revealed non-Fickian diffusion for the antioxidant release. These results indicate that H-bonding is mainly involved in the diffusion of antioxidants into a β-CD based matrix, while the controlled release of antioxidants in model formulations is mainly due to hydrophobic interactions. Results obtained in this study can be further used for studying the particular antioxidants (namely rutin or silibinin, quantified, for example, by liquid chromatographic techniques) for their transdermal transport and biological effects in innovatively designed pharmaceutical formulations that can be obtained using "green" methods and materials.

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

The goal of the study was the discrimination of β-cyclodextrin (β-CD)/hazelnut (Corylus avellana L.) oil/antioxidant ternary complexes through Fourier-transform infrared spectroscopy coupled with principal component analysis (FTIR-PCA). These innovative complexes combine the characteristics of the three components and improve the properties of the resulting material such as the onsite protection against oxidative degradation of hazelnut oil unsaturated fatty acid glycerides. Also, the apparent water solubility and bioaccessibility of the hazelnut oil components and antioxidants can be increased, as well as the controlled release of bioactive compounds (fatty acid glycerides and antioxidant flavonoids, namely hesperidin, naringin, rutin, and silymarin). The appropriate method for obtaining the ternary complexes was kneading the components at various molar ratios (1:1:1 and 3:1:1 for β-CD hydrate:hazelnut oil (average molar mass of 900 g/mol):flavonoid). The recovering yields of the ternary complexes were in the range of 51.5-85.3% and were generally higher for the 3:1:1 samples. The thermal stability was evaluated by thermogravimetry and differential scanning calorimetry. Discrimination of the ternary complexes was easily performed through the FTIR-PCA coupled method, especially based on the stretching vibrations of CO groups in flavonoids and/or CO/CC groups in the ternary complexes at 1014.6 (± 3.8) and 1023.2 (± 1.1) cm^-1 along the second PCA component (PC₂), respectively. The wavenumbers were more appropriate for discrimination than the corresponding intensities of the specific FTIR bands. On the other hand, ternary complexes were clearly distinguishable from the starting β-CD hydrate along the first component (PC₁) by all FTIR band intensities and along PC₂ by the wavenumber of the asymmetric stretching vibrations of the CH groups at 2922.9 (± 0.4) cm^-1 for ternary complexes and 2924.8 (± 1.4) cm^-1 for β-CD hydrate. The first two PCA components explain 70.38% from the variance of the FTIR data (from a total number of 26 variables). Other valuable classifications were obtained for the antioxidant flavonoids, with a high similarity for hesperidin and naringin, according to FTIR-PCA, as well as for ternary complexes depending on molar ratios. The FTIR-PCA coupled technique is a fast, nondestructive and cheap method for the evaluation of quality and similarity/characteristics of these new types of cyclodextrin-based ternary complexes having enhanced properties and stability.

Structure-property relationships on recrystallized β-cyclodextrin solvates: A focus on X-ray diffractometry, FTIR and thermal analyses

The goal of the study was to evaluate the influence of the solvent properties on the crystal characteristics of β-cyclodextrin (β-CD) recrystallized from alcohol-water solvent mixtures, with possible applications for the preparation, purifying and complexation of β-CD. For the first time, structure-property relationships (QSPRs) between the hydrophobicity of alcohols or dielectric constant of solvents used for recrystallization of β-CD and its properties (such as crystallinity index, CI) have been obtained. Recrystallized β-CD from water and C₁-C₄ alcohol-water solutions provide β-CD with higher CI values of 99.4(±5.9)% for ethanol-water (1:4, v/v) as recrystallizing system. This property has a parabolic variation with the logP (octanol/water partition coefficient) of the alcohol (r² = 0.998). Solvent parameters also influence the β-CD crystal characteristics, as was demonstrated by X-ray diffractometry refinement, infrared spectroscopy and thermal analyses.

Karl Fischer Water Titration—Principal Component Analysis Approach on Bread Products

(1) Background: The water content and the way of bonding in the food matrices, including bread, can be easily and simply evaluated by Karl Fischer titration (KFT). The goal was to identify the main KFT parameters that influence the similarity/dissimilarity of commercial bread products, using multivariate statistical analysis. (2) Methods: Various commercial bread samples were analyzed by volumetric KFT and the water content, parameters from titration process and KFT kinetics were used as input for principal component analysis (PCA). (3) Results: The KFT water content was in the range of 35.1–44.2% for core samples and 19.4–22.9% for shell samples. The storage and transportation conditions consistently influence the water content of bread. The type of water molecules can be evaluated by means of KFT water reaction rates. The mean water reaction rates up to 2 min are consistently higher for bread core samples, which indicates a high fraction of “surface” water. PCA reveals the similarity of core samples and various bread types, as well as dissimilarity between bread parts, mainly based on KFT kinetic parameters. (4) Conclusions: KFT kinetics can be a useful tool for a rapid and simple differentiations between various types of bread products.

Complexation of Danube common nase (Chondrostoma nasus L.) oil by β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin

β-Cyclodextrin- and 2-hydroxypropyl-β-cyclodextrin/Danube common nase (Chondrostoma nasus L.) oil complexes (β-CD- and HP-β-CD/CNO) have been obtained for the first time. The fatty acid (FA) profile of the CNO indicates an important content of polyunsaturated fatty acids, the most important being eicosapentaenoic acid (EPA, 6.3%) and docosahexaenoic acid (DHA, 1.6%), both ω-3 FAs. The complexes have been obtained by kneading method. The moisture content and successful of molecular encapsulation have been evaluated by thermal and spectroscopic techniques. Thermogravimetry and differential scanning calorimetry analyses reveals that the moisture content of CD/CNO complexes significantly decreased, compared to starting CDs. On the other hand, the crystallinity index was for the first time determined for such type of complexes, the β-CD/CNO complex having values of 43.9(±18.3)%, according to X-ray diffractometry. FA profile and CD/CNO characteristics sustain the use of these ω-3 based complexes for food supplements or functional food products, but further studies are needed.

Liver Targeting Albumin-Coated Silybin-Phospholipid Particles Prepared by Nab™ Technology for Improving Treatment Effect of Acute Liver Damage in Intravenous Administration

In this study, a novel human serum albumin nanoparticle loading silybin-phospholipid complex (SLNPs) was developed for liver targeting after intravenous administration. The preparation of the drug delivery system consisted of two steps; initially, a silybin-phospholipid complex (SLC) was produced to improve the lipophilicity of SLB to then achieve enhanced encapsulation of SLB in albumin nanoparticles. FT-IR and XRD analysis confirmed the successful formation of SLC. The complex ratio of SLC in the first step was 99.6%. The encapsulation efficiency and drug loading of SLNPs in the second step were 96.2% and 5.6%, respectively. SLNPs were spherical and well-dispersed, with a zeta potential of approximately - 10 mV, and a mean particle size around 200 nm. An in vivo tissue distribution experiment and a pharmacodynamic experiment showed that, compared with SLB solution, SLNPs had an improved SLB accumulation in the liver. The hepatoprotective effect of SLNPs on CCl₄-induced acute liver damage was evaluated. CCl₄-damaged mice showed an increased enzymatic activity of ALT and AST; however, enzyme levels returned to near-normal levels in high-dose SLNP-treated mice. As SLNPs combine the enhanced oil solubility of SLC and the passive targeting of albumin nanoparticles, they possess great potential for the treatment of acute liver damage.

Evaluation of the Molecular State of Piperine in Cyclodextrin Complexes by Near-Infrared Spectroscopy and Solid-State Fluorescence Measurements

The purpose of this study was to evaluate the physicochemical properties of piperine (PP) in ground mixtures (GMs) of PP with α-, β-, or γ-cyclodextrin (CD) under conditions of humidity, heat, and humidity-heat. In solid-state fluorescence measurements, the fluorescence maxima for GM (PP/αCD = 1/2), GM (PP/βCD = 1/1), and GM (PP/γCD = 1/1) were observed at 463, 472, and 469 nm, respectively. On the other hand, the humidified GMs exhibited maxima at 454, 460, and 465 nm, while the humidified-heated samples displayed fluorescence maxima at 455, 455, and 469 nm, respectively. Therefore, the molecular behavior of PP with α, β, and γCD was concluded to vary upon the coordination of water molecules. NIR and solid-state fluorescence measurements revealed that the molecular behavior of PP inside the α, β, and γCD cavity changed by water and heat factors depends on the mobility of the methylenedioxyphenyl group.

Moisture evaluation of β-cyclodextrin/fish oils complexes by thermal analyses: A data review on common barbel (Barbus barbus L.), Pontic shad (Alosa immaculata Bennett), European wels catfish (Silurus glanis L.), and common bleak (Alburnus alburnus L.) living in Danube river

The moisture content of β-cyclodextrin/Danube fish oils complexes (common barbel, Pontic shad, European wels catfish, common bleak) was evaluated by thermal methods. Saturated and monounsaturated fatty acids were the most concentrated in fish oils (25.3-30.8% and 36.1-45.0%). ω-3 And ω-6 fatty acids were identified in low concentrations of 2.8-12.1% and 4.1-7.1%. The moisture content was significantly lowered after β-CD complexation, as revealed by thermogravimetric (TG) analysis (13.3% for β-CD, 2.5-6.5% for complexes). These results are consistent with the differential scanning calorimetry (DSC) data for the peaks corresponding to dissociation of water (calorimetric effect of 536Jg^-1 for β-cyclodextrin and 304-422.5Jg^-1 for complexes). Furthermore, both TG and DSC results support the formation of inclusion complexes. This is the first study on the nanoencapsulation of Danube fish oils in β-cyclodextrin.

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

The thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) as well as its β-cyclodextrin (β-CD) complexation ability has been verified for the first time. The main omega-3 fatty acids, EPA and DHA, were significantly degraded, even at 50 °C. Their relative concentrations decrease from 6.1% for EPA and 4.1% for DHA to 1.7% and 1.5% after degradation at 150 °C, respectively. On the other hand, the relative concentrations of monounsaturated and saturated fatty acids remained constant or slightly increased by a few percent after degradation (e.g., from 10.7% to 12.9% for palmitic acid). Co-crystallization of ASO with β-CD at a host–guest ratio of 1:1 and 3:1 from an ethanol–water mixture and kneading methods has been used for the preparation of β-CD/ASO complexes. The analysis of the complexes by thermogravimetry, differential scanning calorimetry (DSC), and Karl Fischer titration (KFT) as well as the decrease of the “strongly-retained” water content confirm the formation of the inclusion compound. Furthermore, the DSC parameters correlate well with the KFT kinetic data for β-CD/ASO complexes.

Cyclodextrin-complexed Ocimum basilicum leaves essential oil increases Fos protein expression in the central nervous system and produce an antihyperalgesic effect in animal models for fibromyalgia

O. basilicum leaves produce essential oils (LEO) rich in monoterpenes. The short half-life and water insolubility are limitations for LEO medical uses. β-Cyclodextrin (β-CD) has been employed to improve the pharmacological properties of LEO. We assessed the antihyperalgesic profile of LEO, isolated or complexed in β-CD (LEO/β-CD), on an animal model for fibromyalgia. Behavioral tests: mice were treated every day with either LEO/β-CD (25, 50 or 100 mg/kg, p.o.), LEO (25 mg/kg, p.o.), tramadol (TRM 4 mg/kg, i.p.) or vehicle (saline), and 60 min after treatment behavioral parameters were assessed. Therefore, mice were evaluated for mechanical hyperalgesia (von Frey), motor coordination (Rota-rod) and muscle strength (Grip Strength Metter) in a mice fibromyalgia model. After 27 days, we evaluated the central nervous system (CNS) pathways involved in the effect induced by experimental drugs through immunofluorescence protocol to Fos protein. The differential scanning analysis (DSC), thermogravimetry/derivate thermogravimetry (TG/DTG) and infrared absorption spectroscopy (FTIR) curves indicated that the products prepared were able to incorporate the LEO efficiently. Oral treatment with LEO or LEO-βCD, at all doses tested, produced a significant reduction of mechanical hyperalgesia and we were able to significantly increase Fos protein expression. Together, our results provide evidence that LEO, isolated or complexed with β-CD, produces analgesic effects on chronic non-inflammatory pain as fibromyalgia.

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed-uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC-MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole) was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

Effect of cyclodextrin complexation on phenylpropanoids' solubility and antioxidant activity

The complexation abilities of five cyclodextrins (CDs) with seven phenylpropanoids (PPs) were evaluated by UV–visible spectroscopy, phase solubility studies and molecular modeling. Formation constants (K_f), complexation efficiency (CE), PP:CD molar ratio, increase in formulation bulk and complexation energy were assessed. All complexes exhibited a 1:1 stoichiometry but their stability was influenced by the nature and the position of the phenyl ring substituents. A relationship between the intrinsic solubility of guests (S₀) and the solubilizing potential of CD was proposed. Molecular modeling was used to investigate the complementarities between host and guest. Finally, the antioxidant activity of encapsulated PPs was evaluated by scavenging of the stable DPPH radical.

Encapsulation of rutin and naringenin in multilamellar vesicles for optimum antioxidant activity

Rutin and naringenin, two phenolic compounds with antioxidant properties were encapsulated in lipid-based onion-type multilamellar vesicles (MLVs). After vesicles formation, the free, adsorbed/encapsulated analytes were well separated with size exclusion chromatography (SEC), and rutin and naringenin were quantified with UV-HPLC at 258 nm and 290 nm. A mathematical model was developed to separately calculate the encapsulation and the adsorption yields of both phenols. Naringenin was shown to be poorly encapsulated (<10%) but highly adsorbed on MLVs surface (>60%) whatever MLVs composition. Conversely, rutin showed high encapsulation efficiency (>60%). Entrapment of rutin was proved to be efficient since no leak was observed within 30 days in concentrated MLVs phase, while 16.0±0.3% of rutin was still encapsulated after 30 days when MLVs were diluted in water. Free rutin broke up into quercetin while the encapsulated one remained stable. DPPH assay confirmed that only free and adsorbed rutin participated in antioxidant activity.

Antioxidant and hepatoprotective effects of naringenin and its β-cyclodextrin formulation in mice intoxicated with carbon tetrachloride: a comparative study

The present study evaluated the antioxidant and hepatoprotective effects of the flavonoid naringenin (NGN) and its β-cyclodextrin formulation at a dose of 50 mg/kg b.w. The assessment was done by the investigation of serum-enzymatic and liver antioxidant activity, histopathological and ultrastructural changes in male Swiss mice, which were subjected to acute experimental intoxication with CCl4. Formulated and free flavonoid were orally given to mice for 7 days and then were intraperitoneally injected with 1.0 mL/kg CCl4 on the 8th day. After 24 h of CCl4 administration, an increase in the levels of transaminases aspartate aminotransferase and alanine aminotransferase activities and malondialdehyde concentration occurred and a significant decrease in superoxide dismutase, catalase glutathione-peroxidase activities, and glutathione levels was detected as well. These were accompanied by extended centrilobular necrosis, steatosis, fibrosis, and an altered ultrastructure of hepatocytes. Pretreatment with formulated or free flavonoid retained the biochemical markers to control values. Histopathological and electron-microscopic examination confirmed the biochemical results. In conclusion, both NGN and NGN/β-cyclodextrin complex showed antioxidant and hepatoprotective effects against injuries induced by CCl4.

Titanocene / cyclodextrin supramolecular systems: a theoretical approach

Background

Recently, various metallocenes were synthesized and analyzed by biological activity point of view (such as antiproliferative properties): ruthenocenes, cobaltoceniums, titanocenes, zirconocenes, vanadocenes, niobocenes, molibdocenes etc. Two main disadvantages of metallocenes are the poor hydrosolubility and the hydrolytic instability. These problems could be resolved in two ways: synthetically modifying the structure or finding new formulations with enhanced properties. The aqueous solubility of metallocenes with cytostatic activities could be enhanced by molecular encapsulation in cyclodextrins, as well as the hydrolytic instability of these compounds could be reduced.

Results

This study presents a theoretical approach on the nanoencapsulation of a series of titanocenes with cytotoxic activity in α-, β-, and γ-cyclodextrin. The HyperChem 5.11 package was used for building and molecular modelling of titanocene and cyclodextrin structures, as well as for titanocene/cyclodextrin complex optimization. For titanocene/cyclodextrin complex optimization experiments, the titanocene and cyclodextrin structures in minimal energy conformations were set up at various distances and positions between molecules (molecular mechanics functionality, MM+). The best interaction between titanocene structures and cyclodextrins was obtained in the case of β- and γ-cyclodextrin, having the hydrophobic moieties oriented to the secondary face of cyclodextrin. The hydrophobicity of titanocenes (logP) correlate with the titanocene-cyclodextrin interaction parameters, especially with the titanocene-cyclodextrin interaction energy; the compatible geometry and the interaction energy denote that the titanocene/β- and γ-cyclodextrin complex can be achieved. Valuable quantitative structure-activity relationships (QSARs) were also obtained in the titanocene class by using the same logP as the main parameter for the in vitro cytotoxic activity against HeLa, K562, and Fem-x cell lines.

Conclusions

According to our theoretical study, the titanocene/cyclodextrin inclusion compounds can be obtained (high interaction energy; the encapsulation is energetically favourable). Further, the most hydrophobic compounds are better encapsulated in β- and γ-cyclodextrin molecules and are more stable (from energetically point of view) in comparison with α-cyclodextrin case. This study suggests that the titanocene / β- and γ-cyclodextrin complexes (or synthetically modified cyclodextrins with higher water solubility) could be experimentally synthesized and could have enhanced cytotoxic activity and even lower toxicity.

Ficaria verna Huds. extracts and their β-cyclodextrin supramolecular systems

Background

Obtaining new pharmaceutical materials with enhanced properties by using natural compounds and environment-friendly methods is a continuous goal for scientists. Ficaria verna Huds. is a widespread perennial plant with applications in the treat of haemorrhoids and to cure piles; it has also anti-inflammatory, astringent, and antibiotic properties. The goal of the present study is the obtaining and characterization of new F. verna extract/β-cyclodextrin complexes by using only natural compounds, solvents, and environment-friendly methods in order to increase the quality and acceptability versus toxicity indicator. Thus, the flavonoid content (as quercetin) of Ficaria verna Huds. flowers and leaves from the West side of Romania was determined and correlated with their antioxidant activity. Further, the possibility of obtaining β-cyclodextrin supramolecular systems was studied.

Results

F. verna flowers and leaves extracts were obtained by semi-continuous solid-liquid extraction. The raw concentrated extract was spectrophotometrically analyzed in order to quantify the flavonoids from plant parts and to evaluate the antioxidant activity of these extracts. The F. verna extracts were used for obtaining β-cyclodextrin complexes; these were analyzed by scanning electron microscopy and Karl Fischer water titration; spectrophotometry was used in order to quantifying the flavonoids and evaluates the antioxidant activity. A higher concentration of flavonoids of 0.5% was determined in complexes obtained by crystallisation method, while only a half of this value was calculated for kneading method. The antioxidant activity of these complexes was correlated with the flavonoid content and this parameter reveals possible controlled release properties.

Conclusions

The flavonoid content of F. verna Huds. from the West side of Romania (Banat county) is approximately the same in flowers and leaves, being situated at a medium value among other studies. β-Cyclodextrin complexes of F. verna extracts are obtained with lower yields by crystallisation than kneading methods, but the flavonoids (as quercetin) are better encapsulated in the first case most probably due to the possibility to attain the host-guest equilibrium in the slower crystallisation process. F. verna extracts and their β-cyclodextrin complexes have antioxidant activity even at very low concentrations and could be used in proper and valuable pharmaceutical formulations with enhanced bioactivity.