Studies of the Relationship between Structure and Antioxidant Activity in Interesting Systems, Including Tyrosol, Hydroxytyrosol Derivatives Indicated by Quantum Chemical Calculations

In nature, tyrosol (TY) and hydroxytyrosol (HT) are found in olive leaves which are for medical aims, with immune stimulant and antibiotic properties as well as the ability to be used for the treatment of neurodegenerative diseases such as Alzheimer. This ability of phytochemical TY and HT compounds are mainly believed to be of higher radical scavenging potential with effective antioxidant properties. In order to establish the possible structure-antioxidant activity relationship of tyrosol, hydroxytyrosol, hydroxytyrosol acetate and two designed hydroxytyrosol derivatives were studied by the help of quantum chemical calculations. The molecular electronic properties such as heat formation of the neutral, radical and orbitals energies were calculated as descriptors to predict the H atom donating abilities of compounds. Considering the results from the calculated descriptors, the derivatives having OH group substitutions in position number four of the aromatic ring can be classified highly active and better antioxidant compound. Therefore, the designed hydroxytyrosol derivatives showed most active feasible H atom donation. This work can be useful to design novel antioxidants.

Synthesis and Physicochemical Characterization of Biodegradable Star-Shaped Poly Lactide-Co-Glycolide-<i>β</i>-Cyclodextrin Copolymer Nanoparticles Containing Albumin

The purposes of this research were to synthesize and characterize star-shaped poly lactide-co-glycolide-β-cyclo-dextrin (PLGA-β-CD) copolymer by reacting L-lactide, glycolide and β-cyclodextrin in the presence of stannous octoate as a catalyst. The structure of PLGA-β-CD copolymer was confirmed with 1H-NMR, 13C-NMR and FT-IR spectra. Albumin as a model peptide drug was encapsulated within nanoparticles made of PLGA-β-CD with a modified double emulsion method. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) photomicrographs showed that the nanoparticles have the mean diameter within the range of 80 - 210 nm. Also they were almost spherical in shape. Effects of the experimental parameters, such as copolymer composition, copolymer concentration, and reaction temperature, on particular size and encapsulation efficiency were investigated.

<i>In Vitro</i>Studies of NIPAAM-MAA-VP Copolymer-Coated Magnetic Nanoparticles for Controlled Anticancer Drug Release

Thermosensetive poly(N-isopropylacrylamide)-based magnetic nanoparticles were synthesized by free radical polymerization of N-isopropylacrylamide (NIPPAMs), methacrylic acid (MAA), and vinyl pyrrolidone (VP) in the presence of methylene-bis-acrylamide as cross linking agent. The Fe3O4 magnetic nanoparticls were prepared by chemical precipitation of Fe salts in the ratio of 1:2 under alkaline and inert condition. Thermosensitive crosslinked P (NI-PAAM-MAA-VP) copolymers were characterized by FT-IR and H-NMR. The pH and thermosensitive copolymer was used for preparation of drug loaded magnetic nanoparticles, and doxorubicin (DOX) was used as a typical anticancer drug. The amount of the loaded drug and drug release amount were determined by UV measurements. Scanning electron microscopy (SEM) and lower critical solution temperature (LCST) were used to determine the particle surface morphology and the phase transition temperature of the nanoparticles respectively. The release behavior of DOX at pH = 7.4 and 37°C was studied. The result indicated that this thermosensetive magnetic nanoparticle has a high drug loading capacity and favorable linear release property for DOX without initial burst release. Thus this system is promising for the application in targeted smart anticancer drug delivery.

Nanocomposite Electrospun Scaffold Based on Polyurethane/Polycaprolactone Incorporating Gold Nanoparticles and Soybean Oil for Tissue Engineering Applications

Electrospun nanofibers combined with a wide range of functional additives can be used for a various tissue engineering applications due to their desired biomimetic and physicochemical properties.Therefore,the present study was conducted to obtain a highly efficient nanocomposite electrospun scaffold with appropriate physicochemical performance and biological properties based on Polycaprolactone/Polyurethane(PCL/PU)mixed with gold nanoparticles(GNPs)and soybean oil(SO).In the present study,the desired nanofibers were fabricated by electrospinning PCL/PU mixed solution with GNPs and SO.The nanocomposite electrospun PU/PCL/SO/GNP nanofibers were characterized in terms of chemical composition by attenuated total reflectance-Fourier transform infrared spectroscopy(ATR-FTIR),morphological structure by field-emission scanning electron microscopy(FE-SEM),and mechanical and biological properties.The surface topography and wettability were determined by atomic force microscopy(AFM)and water contact angle measurements,respectively.It was found that the presence of GNPs along with SO in the structure of PCL/PU nanofiber created a smoother surface in terms of surface roughness and also a more homogeneous fibrous structure.In addition,it was observed that both SO and GNPs caused an increase in the electrical conductivity of the fibrous mats.In the biocompatibility evaluations by measuring cell viability and cell adherence to the scaffold's surfaces,it was found that adding of SO and GNPs supports fibroblasts.Taken together,the fabricated nanocomposite fibrous scaffolds can be a potential candidate for various tissue engineering purposes.