stilbenes and titanium-dioxide

The phytochemical resveratrol has undergone extensive preclinical investigation for its putative cancer chemopreventive properties. Low systemic availability of the parent compound due to rapid and extensive metabolism may confound its usefulness as a potential agent to prevent malignancies in organs remote from the site of absorption. Micronization allows increased drug absorption, thus increasing availability. Here we describe a pilot study of SRT501, micronized resveratrol, given as 5.0 g daily for 14 days, to patients with colorectal cancer and hepatic metastases scheduled to undergo hepatectomy. The purpose of the study was to assess the safety, pharmacokinetics, and pharmacodynamics of the formulation. SRT501 was found to be well tolerated. Mean plasma resveratrol levels following a single dose of SRT501 administration were 1,942 ± 1,422 ng/mL, exceeding those published for equivalent doses of nonmicronized resveratrol by 3.6-fold. Resveratrol was detectable in hepatic tissue following SRT501 administration (up to 2,287 ng/g). Cleaved caspase-3, a marker of apoptosis, significantly increased by 39% in malignant hepatic tissue following SRT501 treatment compared with tissue from the placebo-treated patients. SRT501 warrants further clinical exploration to assess its potential clinical utility.

Topics: Aged; Antineoplastic Agents, Phytogenic; Caspase 3; Combined Modality Therapy; Double-Blind Method; Female; Hepatectomy; Humans; Liver Neoplasms; Male; Middle Aged; Neoplasm Metastasis; Pilot Projects; Placebos; Postoperative Complications; Resveratrol; Stilbenes; Titanium

The preparation of water-soluble, N-heterocyclic-carbene-stabilized Au-Pd alloy nanoparticles by a straightforward ligand exchange process is presented. Extensive analysis revealed excellent size retention and stability over years in water. The alloy nanoparticles were applied as biomimetic catalysts for aerobic oxidation of d-glucose, for which monometallic Au and Pd nanoparticles showed no or negligible activity. The alloy nanoparticles were further applied as titania-supported heterogeneous catalysts for the mild hydrogenation of nitroarenes and the semihydrogenation of 1,2-diphenylacetylene with a solvent-dependent selectivity switch between E- and Z-stilbene.

Topics: Alloys; Catalysis; Glucose; Gold; Hydrogenation; Methane; Nanoparticles; Oxidation-Reduction; Palladium; Particle Size; Stereoisomerism; Stilbenes; Titanium

Titanium dioxide nanoparticle (TiO2 NP) is an authorized food additive. Previous studies determined oral administration of TiO2 NPs increases plasma glucose in mice via inducing insulin resistance. An increase in reactive oxygen species (ROS) has been considered the possible mechanism of increasing plasma glucose. However, persistently high plasma glucose is also a mechanism of increasing ROS. This study aims to explore whether TiO2 NPs increase plasma glucose via ROS. We found after oral administration of TiO2 NPs, an increase in ROS preceded an increase in plasma glucose. Subsequently, mice were treated with two antioxidants (resveratrol and vitamin E) at the same time as oral administration of TiO2 NPs. Results showed resveratrol and vitamin E reduced TiO2 NPs-increased ROS. An increase in plasma glucose was also inhibited. Further research showed resveratrol and vitamin E inhibited the secretion of TNF-α and IL-6, and the phosphorylation of JNK and p38 MAPK, resulting in improved insulin resistance. These results suggest TiO2 NPs increased ROS levels, and then ROS activated inflammatory cytokines and phosphokinases, and thus induced insulin resistance, resulting in an increase in plasma glucose. Resveratrol and vitamin E can reduce TiO2 NPs-increased ROS and thereby inhibit an increase in plasma glucose in mice.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Blood Glucose; Insulin Resistance; Male; Metal Nanoparticles; Mice; Reactive Oxygen Species; Resveratrol; Stilbenes; Titanium; Vitamin E

In this study, a nano-structured copolymer of luminol/aniline (PLA) was deposited onto nano-TiO2-functionalised indium tin oxide (ITO)-coated glass by electrochemical polymerisation using cyclic voltammetry (CV). The resulting reagentless electrochemiluminescent (ECL) electrode (ECLode) can be used for flow injection analysis (FIA). The properties of the ECLode were characterised by CV, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The ECLode has high background ECL emission as well as excellent stability and reproducibility, and yielding sensitive response towards target analytes. The ECL emissions of the ECLode were 50 times higher than PLA/ITO, and 500 times higher than polyluminol (PL)/ITO. The ECLode showed sensitive responses to reactive oxygen species (ROSs), permitting its application for determination of antioxidants by quenching. Under optimised conditions, an absolute detection limit of 69.9 pg was obtained for resveratrol, comparable to the highest levels of sensitivity achieved by other methods. Thus, the gross antioxidant content of red wine was determined, with satisfactory recoveries between 87.6% and 108.3%. These results suggest a bright future for the use of the ECLode for single-channel FIA due to its high sensitivity, accuracy and reproducibility.

Topics: Aniline Compounds; Antioxidants; Electrochemical Techniques; Electrochemistry; Electrodes; Flow Injection Analysis; Glass; Indium; Luminescence; Luminol; Microscopy, Electron, Scanning; Molecular Structure; Polymers; Reactive Oxygen Species; Reproducibility of Results; Resveratrol; Stilbenes; Tin Compounds; Titanium; Wine

Photochemical and photocatalytic degradation of the emerging pollutant trans-resveratrol has been studied under different irradiation wavelengths and using different TiO2 catalysts. trans-Resveratrol was more easily degraded when irradiated using the whole spectral range (UV-Vis) rather than with UV and near-UV to visible irradiation. The main intermediate of trans-resveratrol phototransformation was identified as its isomer cis-resveratrol. Different TiO2 catalysts were used to carry out the photocatalytic degradation of trans-resveratrol. Catalysts properties such as crystallite dimensions, surface area and presence of hydroxy surface groups are shown to be crucial to the photocatalytic efficiency of the materials tested. From the point of view of trans-resveratrol abatement, the photocatalytic process was more efficient than the pure photochemical one resulting in higher degradation rates and higher organic content removal. Six photoproducts of trans-resveratrol phototransformation were identified mainly resulting from the attack of the hydroxyl radical to the organic molecule.

Topics: Catalysis; Isomerism; Kinetics; Light; Photolysis; Resveratrol; Spectroscopy, Fourier Transform Infrared; Stilbenes; Titanium; Ultraviolet Rays

We have developed a simple electrochemical method to detect DNA damage caused by the photovoltaic effect of nano-TiO(2). Meanwhile, we have found that resveratrol, a Chinese Traditional Medicinal Herb species, can have a repairing effect to the oxidized DNA, which can also be detected with the proposed technique in this paper.

Topics: Antioxidants; Biosensing Techniques; Chromatography, High Pressure Liquid; DNA Damage; DNA Repair; Drugs, Chinese Herbal; Electrochemistry; Molecular Structure; Nanotechnology; Reactive Oxygen Species; Resveratrol; Stilbenes; Surface Properties; Titanium