Solubility Of Quercetin Research Articles

Solubility and extractability enhancement of the main food flavonoids by using choline chloride-based natural deep eutectic solvents

This study investigates the solubility of ten primary food flavonoids in both conventional solvents and natural deep eutectic solvents (NADES), utilizing five choline chloride-based NADES. These NADES were formulated with lactic acid, ascorbic acid, urea, sorbitol, and 1,2-propanediol as hydrogen bond donors (HBD). Conventional solvents used in the comparison included water, menthol, and ethanol. The flavonoids studied—catechin, daidzein, quercetin, naringenin, luteolin, genistein, kaempferol, apigenin, diosmetin, and chrysin—were analyzed for solubility and extractability via both solvents. Flavonoid solubility was observed to vary based on both the structural characteristics of the flavonoid and the choice of HBD. Notably, catechin demonstrated the highest solubility across all solvent systems, followed by naringenin and quercetin. Among the NADES systems, the blend based on 1,2-propanediol notably enhanced the solubility of quercetin and luteolin to 53.4 mg/mL and 26.9 mg/mL, respectively, surpassing their solubility in conventional solvents. The empirical findings were consistent with theoretical predictions made using the COSMO-RS method, confirming the efficacy of NADES in solubilizing food flavonoids more effectively than conventional solvents.

Tea saponin-Zein binary complex as a quercetin delivery vehicle: preparation, characterization, and functional evaluation

In this study, in order to solve the application problems of poor water solubility and low bioavailability of quercetin, we prepared a nano-delivery system with core-shell structure by anti-solvent method, including a hydrophilic shell composed of tea saponin and a hydrophobic core composed of Zein, which was used to improve the delivery efficiency and biological activity of quercetin. Through the optimal experiments, the loading rate and encapsulation rate of nanoparticles reached 89.41 % and 7.94 % respectively. And the water solubility of quercetin is improved by 30.16 times. At the same time, the quercetin acted with Zein through non-covalent interaction and destroyed its spatial network through structural characterization, while tea saponin covered the surface of Zein through electrostatic interaction, making it change into amorphous state. In addition, the addition of tea saponin makes the nanoparticles remain stable under the changes of external environment. During simulating gastrointestinal digestion procedure, ZQTNPs has higher release rate and bioavailability than free quercetin. Importantly, ZQTNPs can overcome the limitations of a single substance through synergy. These results will promote the innovative development of quercetin precision nutrition delivery system.

Antibacterial, Anti-Inflammatory, and Antioxidant Cotton-Based Wound Dressing Coated with Chitosan/Cyclodextrin-Quercetin Inclusion Complex Nanofibers.

Quercetin, recognized for its antioxidant, anti-inflammatory, and antibacterial properties, faces limited biomedical application due to its low solubility. Cotton, a preferred wound dressing material over synthetic ones, lacks inherent antibacterial and wound-healing attributes and can benefit from quercetin features. This study explores the potential of overcoming these challenges through the inclusion complexation of quercetin with cyclodextrins (CDs) and the development of a nanofibrous coating on a cotton nonwoven textile. Hydroxypropyl-beta-cyclodextrin (HP-β-CD) and hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) formed inclusion complexes of quercetin, with chitosan added to enhance antibacterial properties. Phase solubility results showed that inclusion complexation can enhance quercetin solubility up to 20 times, with HP-γ-CD forming a more stable inclusion complexation compared with HP-β-CD. Electrospinning of the nanofibers from HP-β-CD/Quercetin and HP-γ-CD/Quercetin aqueous solutions without the use of a polymeric matrix yielded a uniform, smooth fiber morphology. The structural and thermal analyses of the HP-β-CD/Quercetin and HP-γ-CD/Quercetin nanofibers confirmed the presence of inclusion complexes between quercetin and each of the CDs (HP-β-CD and HP-γ-CD). Moreover, HP-β-CD/Quercetin and HP-γ-CD/Quercetin nanofibers showed a near-complete loading efficiency of quercetin and followed a fast-releasing profile of quercetin. Both HP-β-CD/Quercetin and HP-γ-CD/Quercetin nanofibers showed significantly higher antioxidant activity compared to pristine quercetin. The HP-β-CD/Quercetin and HP-γ-CD/Quercetin nanofibers also showed antibacterial activity, and with the addition of chitosan in the HP-γ-CD/Quercetin system, the Chitosan/HP-γ-CD/Quercetin nanofibers completely eliminated the investigated bacteria species. The nanofibers were nontoxic and well-tolerated by cells, and exploiting the quercetin and chitosan anti-inflammatory activities resulted in the downregulation of IL-6 and NO secretion in both immune as well as regenerative cells. Overall, CD inclusion complexation markedly enhances quercetin solubility, resulting in a biofunctional antioxidant, antibacterial, and anti-inflammatory wound dressing through a nanofibrous coating on cotton textiles.

Improving the solubilization, stability, dialysis performance and antioxidant properties of quercetin in surfactant-free microemulsion

The flavonol compound quercetin with poor water solubility, was solubilized in a novel green solvent constructed in this work. The solvent is composed of tributyl citrate, ethanol and water, recognized as surfactant-free microemulsion (SFME). The solubilization behavior and mechanism of quercetin were investigated, the light, thermal, storage stability and antioxidant properties were examined, as well as the dialysis properties and release kinetics. The results reveal that there are interactions existing between quercetin and tributyl citrate. Ethanol and tributyl citrate in SFME also have a synergistic solubilization effect on quercetin. Therefore, the content of quercetin increases with tributyl citrate, and the solubility of quercetin in oil in water SFME (RE/W = 7:3, ƒO = 0.1) is 9.88 mg/ml, much higher than that in water or ethanol. The light, heat, storage stability and antioxidant properties of quercetin are greatly improved by SFME. In the dialysis process, the release of quercetin in SFME follows a non-Fickian diffusion mechanism with a slow-release action. The SFME established has green and non-toxic advantages in the application of the solubilization field, and it is expected to provide important guidance for the extraction and separation of natural foods.

Formulation of double nanoemulsions based on pH-sensitive carboxymethyl cellulose /Starch copper doped carbon quantum dots for quercetin controlled release

Nanocomposite Hydrogels are versatile and adaptable in drug delivery, suitable for various administrations. They offer prolonged and regulated drug release which makes them valuable in targeting cancer treatments. This study used the water/oil/water approach to construct a drug nanocarrier. It encapsulated hazelnut oil, serving as a protective and organic membrane that enveloped the nanocarrier and regulated drug release. Quercetin (QC), a potent flavonoid with potential therapeutic applications, faces challenges due to its hydrophobic nature and poor solubility. This approach presents a novel approach to enhance QC's solubility and stability by integrating it with copper carbon quantum dots (Cu-CQDs) into a pH-sensitive carboxymethyl cellulose (CMC) and starch-based hydrogel nanocomposite. This system aims to improve QC delivery while minimizing adverse effects. The nanocomposite exhibited exceptional drug loading and encapsulation efficiencies of 47.00 % ± 0.45 and 86.25 % ± 0.75, respectively, ranking among the top-reported values for similar systems. Fourier-transform infrared spectroscopy (FTIR) was used to examine molecular interactions. X-ray diffraction (XRD) assessment demonstrated the presence of components beneficial for drug solubility enhancement at 2Θ = 17–24°, where QC's crystalline peaks are absent from the CMC/Starch/Cu-CQDs@QC XRD pattern. A particle size of 151.57 ± 37 nm is optimized for selectively targeting cancer cells, minimizing interaction with healthy cells, as revealed through DLS assessment. Morphological characteristics analyzed by FE-SEM support this observation as well. Zeta potential measurement (+38.8 mV) highlights nanocarrier stability. CMC/Starch/Cu-CQDs@QC displayed remarkable cytotoxicity against cancerous cells, reducing U87-MG cell viability to 48 % while maintaining high cell viability (92 %) for normal L929 cells. These results emphasize the promise of this nanocomposite as a QC drug delivery system by indicating improved anticancer efficacy with fewer adverse effects.

Quercetin@UiO-66 NPs and chloroquine in combined tumor therapy by dual autophagy-ubiquitination system blockade.

In this study, we propose a novel therapy system composed of UiO-66 nanoparticles, which contain quercetin combined with chloroquine (UQCNP), to achieve dual autophagy-ubiquitination blockade. Through UiO-66 NP drug loading, the solubility of quercetin (a proteasome inhibitor) was improved under physiological conditions, thereby increasing its effective concentration at the tumor site. The cell experiment results showed that UQCNP significantly increased the apoptosis rate of 4T1 cells by 73.6%, which was significantly higher than other groups. Transmission electron microscopy results showed that the autophagosome of cells in the UQCNP treatment group was significantly lower than that in other treatment groups. Moreover, western blot results showed that, compared with other groups, LC3 expression and proteasome activity (p < 0.01), as well as the tumor volume of mice treated with UQCNP (p < 0.01) were significantly reduced. These results indicate that UQCNP achieves effective tumor therapy by blocking the autophagy and proteasome pathways synchronously.

Quercetin-maleic acid co-crystal engineering using solvent evaporation to ıncrease quercetin solubility

Quercetin-maleic acid co-crystal engineering using solvent evaporation to ıncrease quercetin solubility

Cellulose nanocrystals from celery stalk as quercetin scaffolds: A novel perspective of human holo-transferrin adsorption and digestion behaviours.

In this study, cellulose nanocrystals (CNCs) were synthesized from celery stalks to be used as the platform for quercetin delivery. Additionally, CNCs and CNCs-quercetin were characterized using the results of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and zeta potential, while their interactions with human holo-transferrin (HTF) were also investigated. We examined their interaction under physiological conditions through the exertion of fluorescence, resonance light scattering, synchronized fluorescence spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, and fluorescence resonance energy transfer techniques. The data from SEM and TEM exhibited the spherical shape of CNCs and CNCs-quercetin and also, a decrease was detected in the size of quercetin-loaded CNCs from 676 to 473 nm that indicated the intensified water solubility of quercetin. The success of cellulose acid hydrolysis was confirmed based on the XRD results. Apparently, the crystalline index of CNCs-quercetin was reduced by the interaction of CNCs with quercetin, which also resulted in the appearance of functional groups, as shown by FTIR. The interaction of CNCs-quercetin with HTF was also demonstrated by the induced quenching in the intensity of HTF fluorescence emission and Stern-Volmer data represent the occurrence of static quenching. Overall, the effectiveness of CNCs as quercetin vehicles suggests its potential suitability for dietary supplements and pharmaceutical products.

Retracted: Porous Lactose as a Novel Ingredient Carrier for the Improvement of Quercetin Solubility In Vitro

Retracted: Porous Lactose as a Novel Ingredient Carrier for the Improvement of Quercetin Solubility <i>In Vitro</i>

Self-emulsifying drug delivery systems (SEDDS): How organic solvent release governs the fate of their cargo

Organic solvents are commonly used in self-emulsifying drug delivery systems (SEDDS) to increase payloads of orally administered poorly soluble drugs. Since such solvents are released to a varying extent after emulsification, depending on their hydrophilic nature, they have a substantial impact on the cargo.To investigate this impact in detail, quercetin and curcumin as model drugs were incorporated in SEDDS comprising organic solvents (SEDDS-solvent) of logP < 2 and > 2. SEDDS were characterized regarding size, payload, emulsification time and solvent release. The effect of solvent release on the solubility of these drugs was determined.Preconcentrates of SEDDS-solventlogP < 2 emulsified more rapidly (< 1.5 min) forming smaller droplets than SEDDS-solventlogP > 2. Although, SEDDS-solventlogP < 2 preconcentrates provided higher quercetin solubility than the latter, a more pronounced solvent release caused a more rapid quercetin precipitation after emulsification (1.5 versus 4 h). In contrast, the more lipophilic curcumin was not affected by solvent release at all. Particularly, SEDDS-solventlogP < 2 preconcentrates provided high drug payloads without showing precipitation after emulsification.According to these results, the fate of moderate lipophilic drugs such as quercetin is governed by the release of solvent, whereas more lipophilic drugs such as curcumin remain inside the oily phase of SEDDS even when the solvent is released.

Controlled SPION-Exosomes Loaded with Quercetin Preserves Pancreatic Beta Cell Survival and Function in Type 2 Diabetes Mellitus.

Quercetin has an ideal therapeutic effect on islet function improvement in type 2 diabetes mellitus (T2DM). However, the therapeutic benefit of quercetin is hindered by its poor bioavailability and limited concentration in pancreatic islets. In this study, superparamagnetic iron oxide nanoparticle (SPION)-modified exosomes were prepared to load quercetin, hoping to endow quercetin with enhanced water solubility and active targeting capacity with the help of magnetic force (MF). Transferrin-modified SPIONs (Tf-SPIONs) were synthesized by exploiting N-hydroxysuccinimidyl (NHS) conjugation chemistry, and quercetin-loaded exosomes (Qu-exosomes) were acquired by electroporation. Tf-SPION-modified quercetin-loaded exosomes (Qu-exosome-SPIONs) were generated by the self-assembly of transferrin (Tf) and the transferrin receptor (TfR). The solubility of quercetin was determined by high-performance liquid chromatography (HPLC) analysis. The pancreatic islet targeting capacity and insulin secretagogue and antiapoptotic activities of Qu-exosome-SPIONs/MF were evaluated both in vitro and in vivo. The Qu-exosome-SPIONs were well constructed and harvested by magnetic separation with a uniform size and shape in a diameter of approximately 86.2 nm. The water solubility of quercetin increased 1.97-fold when loaded into the SPION-modified exosomes. The application of SPIONs/MF endowed the Qu-exosomes with favorable targeting capacity. In vitro studies showed that Qu-exosome-SPIONs/MF more effectively inhibited or attenuated β cell apoptosis and promoted insulin secretion in response to elevated glucose (GLC) compared with quercetin or Qu-exosome-SPIONs. In vivo studies demonstrated that Qu-exosome-SPIONs/MF displayed an ideal pancreaticislet targeting capacity, thereby leading to the restoration of islet function. The Qu-exosome-SPIONs/MF nano-delivery system significantly enhanced the quercetin concentration in pancreatic islets and thereby improved pancreatic islet protection.

Development of a new solution for determining the solubility limit of quercetin and other poorly soluble substances in aqueous solutions using the method for determining total organic carbon

Aim. Given the incompleteness of literature data on the solubility of quercetin and the importance of this physicochemical characteristic in the study of its bioavailability, there is a need to develop an alternative method for accurately quantifying the solubility limit of quercetin.&#x0D; Materials and methods. The concentration of quercetin in the samples was determined by directly determining the total organic carbon. For measurements, a total organic carbon analyzer 450 TOC (METTLER TOLEDO) was used with a range of measured values of 0.05–1000 ppbC µgC/l.&#x0D; Results. The exact limit of the solubility of quercetin, as a poorly soluble substance, has been established. Having previously measured the value of total organic carbon in the prepared solutions, we obtained data on the concentration of quercetin in solutions depending on the pH of the solution.&#x0D; Having built a graphical dependence of the measured values of the concentration of a substance on the pH values of the studied solutions, we obtain a mathematical equation of the reliance. Using the resulting function equation, one can approximate the concentration value of a substance with a pH value of 7.0. This value will be the solubility limit of the test substance for neutral media.&#x0D; Conclusions. As a result of the research, a new method was proposed for the quantitative determination of the solubility limit of a substance, with an accuracy not exceeding 5.0 %. The method is based on measuring the concentration of total carbon in acidic solutions with different pH values and subsequent approximation of the obtained dependence of the pH value equal to 7.0

Antioxidant Effects of Quercetin Nanocrystals in Nanosuspension against Hydrogen Peroxide-Induced Oxidative Stress in a Zebrafish Model.

Quercetin, a flavonoid compound rich in hydroxyl groups, possesses antioxidant properties, whereas its poor water solubility limits its bioavailability. In pursuit of addressing the water solubility of quercetin and comprehending the impact of nanocrystal particle size on antioxidant efficacy, we prepared three different-sized quercetin nanocrystals, namely small (50 nm), medium (140 nm), and large (360 nm), using a nanosuspension method in this study. Within the in vitro setting, assessments employing solubility and radical scavenging assays revealed that quercetin nanocrystals displayed superior solubility (26, 21, and 13 fold corresponding to small, medium, and large particle sizes) and antioxidant performance compared to the coarse quercetin. Furthermore, quercetin nanocrystals of three particle sizes all demonstrated significant protection effects on the survival rate of H2O2-treated zebrafish at 72 h (77.78%, 73.33%, and 66.67% for small, medium, and large particle sizes, respectively), while the coarse quercetin group exhibited a low survival rate (53.3%) similar to the H2O2-treated group (47.8%). Moreover, all quercetin nanocrystals exhibited potent antioxidant capacity on both the antioxidants and enzymatic antioxidant system in H2O2-treated zebrafish to restore zebrafish to a normal state under oxidative stress. For instance, the levels of reactive oxygen species were reduced to 101.10%, 108.83%, and 109.77% of the normal levels for small, medium, and large particle-sized quercetin nanocrystals, respectively. In conclusion, quercetin nanocrystals demonstrated enhanced solubility, robust antioxidant capacity, and protective effects in zebrafish compared to coarse quercetin.

Computational and spectroscopic analysis of the Quercetin encapsulation in (2HP-β-CD)2 and (2,6Me-β-CD)2 complexes

Quercetin protects against many diseases due to its radical scavenging and anti-inflammatory properties. However, due to its poor bioavailability numerous types of nanocarriers have been evolved to increase quercetin solubility and to design tissue-specific delivery systems. Here, we study the entrapment of quercetin(QUE) in two dimeric assemblies formed by 2HP-β-CD and 2,6Me-β-CD, employing DFT calculations, NMR and fluorescent spectroscopy. Via NMR and fluorescent spectroscopy, it was revealed that the QUE:CDs stoichiometry for optimal complex formation follows a 1:2 pattern. DFT indicated that although both dimeric assemblies of 2HP-β-CD and 2,6Me-β-CD, as well as their encapsulation quercetin complexes are stable, the former dimer and the QUE@2HP-β-CD2 complex demonstrate the highest level of stability. The absorption spectrum of QUE in CD and CD2 was calculated. Encapsulation influences it, resulting in red and blue shifts, and in differences in the intensities. Only, the dimeric assemblies affect the electron density of QUE resulting in major peaks at about 250 nm, which are charge transfer (CT) or partially CT excitations. Finally, for the encapsulated QUE in CDs, the calculated T1→S0 vertical de-excitation is about 570 nm in the single CDs and about 800 nm in the dimeric complexes, making these complexes potential candidates for PDT.

Study of the Influence of the Excipients Used for the Synthesis of Microspheres Loaded with Quercetin: Their Characterization and Antimicrobial Activity

The aim of this study was to determine the potential pharmaceutical applications of quercetin—a natural flavonoid compound with a polyphenolic structure—following its encapsulation in polymeric microspheres resistant to degradation. The microspheres were prepared from natural polymeric compounds (chitosan and sodium alginate) via a complex coacervation method, with the goal of protecting quercetin from the degradation reactions that can affect its bioactivity. After the microspheres were prepared, they were characterized using various analytical methods. The encapsulation efficiency (EE (%)), swelling index (idxSWL%), roughness (measured using confocal laser scanning microscopy—CLSM), and surface morphology (measured using scanning electron microscopy—SEM) were all analyzed. In addition, the release capacity of quercetin from the microspheres (mQrel%) and the antimicrobial activity of the microspheres were evaluated in vitro. Finally, a multivariate statistical analysis (MANOVA, p = 0.05, PCA, and AHC) was conducted. This analysis showed that chitosan–sodium alginate–quercetin microspheres (CAQ-Ms) entrap 86.91 ± 1.10–93.11 ± 0.72% quercetin; in vitro, 71.46 ± 0.25–91.06 ± 0.15% quercetin was released, and the swelling index was higher (6701.29 ± 0.39–10,009.30 ± 1.11%) in the phosphate-buffered solution with a pH of 7.4. The CLSM and SEM analyses showed that the polymer concentration in CAQ-Ms was increased, and the roughness and smoothness of the microspheres were also increased. SEM also showed that the external layer of CAQ-Ms was formed from chitosan and the internal layer was formed from sodium alginate. Antimicrobial tests showed that CAQ-Ms had antibacterial and antifungal effects on the analyzed strains and produced larger inhibition zones between 15.3 and 14.4 mm on Escherichia coli and between 13.3 and 14.2 mm on Candida albicans, and smaller inhibition zones, between 12.4 and 13.6 mm, on Staphylococcus aureus. According to the obtained results, after the multivariate statistical analysis, it can be observed that the best performance was presented by samples P1, P2, and P3. In conclusion, the method used for the formulation of CAQ-Ms was efficient because it enabled an increase in the solubility of quercetin in water and its protection against external and internal degradation in the gastrointestinal tract. This system can be further used to produce new pills for oral administration that are able to reach the small intestine, where they can then release loaded active drugs.

Novel oleogels for topical delivery of quercetin based on mesoporous silica MCM-41 and HMS particles

Quercetin is a flavonoid with high antioxidant activity, and thus it is an appropriate candidate for incorporation in dermal dosage forms. Unfortunately, the limited skin penetration, low water solubility and chemical instability of quercetin make it typically difficult for incorporation in sustained-release dermal and transdermal drug formulations where the dissolution speed is controlled mainly by the physio-chemical characteristics of the active substance. In the present study we discussed new sustained-release systems for dermal delivery of quercetin, based on two types of mesoporous silica particles, incorporated in oleogel. The biopharmaceutical evaluation revealed better water solubility of quercetin after its incorporation in the silica materials and achievement of controlled drug release after inclusion of the particles in oleogel. Our studies showed that the drug loaded mesoporous silica nanosystems and the corresponded oleogels demonstrated excellent biocompatibility and lack of hypersensitivity of quercetin formulations.

Development of a method for the quantitative determination of the solubility limits of poorly soluble in water substances on the example of quercetin

Aim. To consider the importance of this physicochemical characteristic as a determining factor in the study of bioequivalence and bioavailability, there is a need to develop a method to quantitatively determine the solubility limit of quercetin. Materials and methods. The quercetin concentration was determined in the obtained samples using chromatographic and external standard methods. The pharmacopeial standard – PS of the SPU was used as a standard. For measurements, an Agilent 1290 liquid chromatograph with an Agilent 6530 TOF mass spectrometric detector was used, using a 50×4.6 mm column filled with a sorbent with a grafted phase of octyl silica gel, particle size – 1.7 μm. Results. The exact limit of the solubility of quercetin, as a poorly soluble substance, has been established. Based on the data obtained, the kinetics of the dissolution of quercetin was studied. In tandem with the QTOF mass spectrometric detector, the HPLC method was utilized in the identification and quantification process. To accurately determine the point that will correspond to the solubility limit of quercetin in water, the obtained experimental dependence was approximated by a polynomial dependence, for which, by solving a system of equations in the Microsoft Excel program, concentration values were found corresponding to the inflection points of the studied dependences. Conclusions. When studying their bioavailability, a new approach has been developed to quantitatively determine the solubility limit of difficult or practically insoluble substances in aqueous media with a neutral pH value. The exact value of the solubility limit for the test sample of quercetin was established, which was 3.02 mcg/ml. The kinetics of the release of quercetin in aqueous solutions was studied

Synthesis and Characterization of Quercetin-Iron Complex Nanoparticles for Overcoming Drug Resistance.

Quercetin, one of the major natural flavonoids, has demonstrated great pharmacological potential as an antioxidant and in overcoming drug resistance. However, its low aqueous solubility and poor stability limit its potential applications. Previous studies suggest that the formation of quercetin-metal complexes could increase quercetin stability and biological activity. In this paper, we systematically investigated the formation of quercetin-iron complex nanoparticles by varying the ligand-to-metal ratios with the goal of increasing the aqueous solubility and stability of quercetin. It was found that quercetin-iron complex nanoparticles could be reproducibly synthesized with several ligand-to-iron ratios at room temperature. The UV-Vis spectra of the nanoparticles indicated that nanoparticle formation greatly increased the stability and solubility of quercetin. Compared to free quercetin, the quercetin-iron complex nanoparticles exhibited enhanced antioxidant activities and elongated effects. Our preliminary cellular evaluation suggests that these nanoparticles had minimal cytotoxicity and could effectively block the efflux pump of cells, indicating their potential for cancer treatment.

The effect of polysorbate 20 and polysorbate 80 on the solubility of quercetin.

Quercetin acts as an antioxidant, anti-inflammatory, wound healing, and anti-aging so quercetin can be used as a topical preparation. However, it has low solubility in water at 0.01 mg/ml at 25oC. Increasing the solubility of quercetin in water was done by the addition of surfactants. This study compared the solubility of quercetin in Polysorbate 20 (P20) and Polysorbate 80 (P80) in a citrate buffer medium pH 4.5±0.2. The surfactants Polysorbate 80 and Polysorbate 20 differ in their alkyl chain length. Polysorbate 80 has an alkyl chain length of 18, while Polysorbate 20 has an alkyl chain length of 12. The concentrations of surfactant are above, below, and at the critical micelle concentration (CMC) values. The concentrations of quercetin were determined at the maximum wavelength by spectrophotometric method. The results of the quercetin solubility test without surfactant were 3.89±0.59 mg/L. The results of the quercetin solubility test by adding Polysorbate 20 at a concentration of 42.0 ppm; 57.5 ppm; and 73.0 ppm were 3.62±0.72, 4.04±0.23 and 8.35±1.97 mg/L, respectively. While the solubility of quercetin by adding Polysorbate 80 at a concentration of 4.0 ppm, 11.5 ppm, and 19.0 ppm was 11.15±0.72, 11.37±1.23 and 14.17±1.96 mg/L, respectively. The solubility of quercetin is greater after the addition of surfactant Polysorbate 20 only at the concentration above the CMC value and the solubility of quercetin is greater with the addition of surfactant Polysorbate 80 at all concentrations. Surfactant Polysorbate 20 increases the solubility of quercetin in citrate buffer pH 4.5±0.2 only at concentrations above the CMC value of 2.14 times. Polysorbate 80 can increase the solubility of quercetin in citrate buffer pH 4.5±0.2 at concentrations below, at, and above CMC by 2.87, 2.92, and 3.63 times, respectively. Polysorbate 80 can increase the solubility of quercetin in citrate buffer pH 4.5±0.2 higher than Polysorbate 20.

Synthesis of Cationic Quaternized Nanolevan Derivative for Small Molecule and Nucleic Acid Delivery.

Levan is a biopolymer composed of fructose chains covalently linked by β-2,6 glycosidic linkages. This polymer self-assembles into a nanoparticle of uniform size, making it useful for a wide range of applications. Also, levan exhibits various biological activities such as antioxidants, anti-inflammatory, and anti-tumor, that make this polymer very attractive for biomedical application. In this study, levan synthesized from Erwinia tasmaniensis was chemically modified by glycidyl trimethylammonium chloride (GTMAC) to produce cationized nanolevan (QA-levan). The structure of the obtained GTMAC-modified levan was determined by FT-IR, 1H-NMR and elemental (CHN) analyzer. The size of the nanoparticle was calculated using the dynamic light scattering method (DLS). The formation of DNA/QA-levan polyplex was then investigated by gel electrophoresis. The modified levan was able to increase the solubility of quercetin and curcumin by 11-folds and 205-folds, respectively, compared to free compounds. Cytotoxicity of levan and QA-levan was also investigated in HEK293 cells. This finding suggests that GTMAC-modified levan should have a potential application for drug and nucleic acid delivery.