Investigation of antioxidant activity of Quercetin (2-(3, 4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one) in aqueous micellar media

Kinetics of Flavonoid Degradation and Controlled Release from Functionalized Magnetic Nanoparticles

Flavonoids are naturally occurring antioxidants that have been shown to protect cell membranes from oxidative stress and have a potential use in photodynamic cancer treatment. However, they degrade at physiological pH values, which is often neglected in drug release studies. Kinetic study of flavonoid oxidation can help to understand the mechanism of degradation and to correctly analyze flavonoid release data. Additionally, the incorporation of flavonoids into magnetic nanocarriers can be utilized to mitigate degradation and overcome their low solubility, while the release can be controlled using magnetic fields (MFs). An approach that combines alternating least squares (ALS) and multilinear regression to consider flavonoid autoxidation in release studies is presented. This approach can be used in general cases to account for the degradation of unstable drugs released from nanoparticles. The oxidation of quercetin, myricetin (MCE), and myricitrin (MCI) was studied in PBS buffer (pH = 7.4) using UV-vis spectrophotometry. ALS was used to determine the kinetic profiles and characteristic spectra, which were used to analyze UV-vis data of release from functionalized magnetic nanoparticles (MNPs). MNPs were selected for their unique magnetic properties, which can be exploited for both targeted drug delivery and control over the drug release. MNPs were prepared and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, superconducting quantum interference device magnetometer, and electrophoretic mobility measurements. Autoxidation of all three flavonoids follows a two-step first-order kinetic model. MCE showed the fastest degradation, while the oxidation of MCI was the slowest. The flavonoids were successfully loaded into the prepared MNPs, and the drug release was described by the first-order and Korsmeyer-Peppas models. External MFs were utilized to control the release mechanism and the cumulative mass of the flavonoids released.

Adsorption and volumetric properties of some nonionic surfactants and their mixtures with quercetin and rutin

The adsorption and volumetric properties of the Triton X-114 (TX114), Tween 80 (T80), quercetin (Q) and rutin (Ru) at the different temperatures in relation to above properties of the TX114 and T80 mixtures with quercetin and rutin in the absence and presence of alcohol were discussed based on the studies reported in the literature. The adsorption isotherms of the mixtures of the nonionic surfactants with flavonoids in the presence and absence of alcohol were analyzed based on the isotherms of the surface tension of the particular mixture components and thermodynamic parameters of the adsorption of these components at the water-air interface. The surface tension isotherms of the particular component of the mixtures were taken into account while considering the surface tension isotherms of the mixtures and the composition of the mixed surface layer at the water-air interface. Different ways of the mixed surface layer composition determination were shown. The values of the surface tension and composition of the mixed surface layers obtained using different methods were discussed in the light of the intermolecular interactions and their contribution to the surface tension of the surfactants mixture with flavonoids and alcohol. The composition of the mixed monolayer and the bulk phase were compared and the differences between them were explained. The behaviour of the nonionic surfactants and flavonoids in the presence and absence of alcohol was analyzed in relation to the micelle formations and molar volumes of the mixtures and their components. Moreover, the micelles composition and their size as well as the thermodynamic parameters of the micellization process were analyzed.

Synthesis and characterization of a novel Fe3O4@SiO2–BenzIm-Fc[Cl]/BiOCl nano-composite and its efficient catalytic activity in the ultrasound-assisted synthesis of diverse chromene analogs

A new magnetic nano-catalyst bearing ionic liquid, ferrocene and BiOCl was synthesized and its catalytic activities were evaluated in the synthesis of a wide variety of 2-amino-3-cyano-4H-chromene derivatives (54 compounds) under ultrasound irradiation.

Flavonoid-surfactant interactions: A detailed physicochemical study

The aim of this article is to study the interactions between flavonoids and surfactants with attention of finding the probable location of flavonoids in micellar media that can be used for controlling their antioxidant behavior. In present study, the micellar and interfacial behavior of twin tailed anionic surfactants viz. sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) in the presence of two flavonoids, namely quercetin (QUE) and kaempferol (KFL) have been studied by surface tension measurements. UV-visible, fluorescence and differential pulse voltammetric (DPV) measurements have been employed to predict the probable location of flavonoids (QUE/KFL) within surfactant (AOT/NaDEHP) aggregates. Dynamic light scattering (DLS) measurements further confirmed the solubilization of QUE/KFL in AOT/NaDEHP aggregates deduced from increased hydrodynamic diameter (Dh) of aggregates in the presence of flavonoids. Both radical scavenging activity (RSA) and degradation rate constant (k) of flavonoids are found to be higher in NaDEHP micelles as compared to AOT micelles.

Free radical nano scavenger based on amphiphilic novolacs

Synthetic amphiphilic novolacs via click chemistry are capable of forming micelles, and interestingly, can act as highly efficient nano-scavengers for hydroxyl free radicals.