Biomolecules responsible for the total antioxidant capacity (Tac) of human plasma in healthy and cardiopathic individuals: A chemical speciation model

(1) Background: Much effort has been expended to investigate the antioxidant capacity of human plasma, attempting to clarify the roles of both metabolic and food substances in determining defenses against oxidative stress. The relationship between the total antioxidant capacity (TAC) and the concentrations of redox-active biomolecules in the human plasma of healthy and cardiopathic individuals was investigated in the present study to develop a chemical speciation model. (2) Methods: Plasma was collected from 85 blood donors and from 25 cardiovascular surgery patients. The TAC was measured using the CUPRAC-BCS (CUPric Reducing Antioxidant Capacity — Bathocuproinedisulfonic acid) method. Biomolecule concentrations were determined via visible spectrophotometry or HPLC/RP techniques. The relationship between the TAC and the concentrations was defined by applying a multiple regression analysis. The significance of the variables was first tested, and chemical models were proposed for the two datasets. The model equation is βTAC=∑iβi·Ai, where βi and [Ai] are the electronic exchange and the molar concentrations of the ith antioxidant component, respectively. (3) Results: The major contributions to the TAC, ~80%, come from endogenous compounds in both healthy and cardiopathic individuals, whereas the contributions from exogenous compounds were different between the two datasets. In particular, γ-tocopherol showed a different role in the chemical models developed for the two groups

Combining synchrotron radiation techniques for the analysis of gold coins from the Roman Empire

Four gold coins minted in the V century have been studied with non-destructive synchrotron radiation techniques, namely X-Ray Fluorescence (XRF) and X-ray Absorption Near Edge Spectroscopy (XANES). XRF data analyzed coupling standard and statistical methods were used to distinguish the composition of the alloy constituting the coins from that of successive deposits processes. Our analysis presents a quantification of the trace elements present in the metallic alloy providing interesting details for historical insight. Furthermore, on the basis of the XRF maps, some regions of interest were selected for XANES at the K-edge of Fe. Our analysis of the Fe spectra points out two main phases which can be related to Fe oxides naturally present in soil. From the relative abundance of these oxides, information on the site where the coins were found can be obtained, providing additional information on their fate across the centuries

Bioactive glasses functionalized with polyphenols: in vitro interactions with healthy and cancerous osteoblast cells

Bioactive glasses are widely studied as biomaterials for bone contact applications. In this research work, the opportunity to modify the surface of a bioactive glass with polyphenols (gallic acid, and natural polyphenols extracted from red grape skin and green tea leaves) has been investigated in order to induce a selective anti-tumor activity in vitro. The presence of surface grafted molecules has been optically proved by fluorescence microscopy exploiting their autofluorescence. Direct and indirect cytotoxicity assays have been performed with human bone osteosarcoma cells (U2OS) and human fetal pre-osteoblasts (hFOB), as well as the quantification of oxygen and nitrogen reactive species (RONS) engendered from cells in response to the materials. Finally, the DNA damage of U2OS cells upon contact with the bioactive glass has been evaluated in order to verify any selective cytotoxic activity of functionalized materials against cancer cells. Results showed a selective cytotoxic activity of functionalized bioactive glasses toward osteosarcoma cells that was particularly evident when cells were cultivated directly onto glasses surface. Moreover, the presence of grafted polyphenols increased the RONS production and induced a permanent DNA damage on the U2SOS cells while they promote a certain anti-inflammatory action toward hFOB. These preliminary results suggest polyphenols grafted bioactive glasses as promising material for bone substitution in cancer treatment

Voltammetric Study for the Determination of Diclofenac in Aqueous Solutions Using Electro-Activated Carbon Electrodes

Diclofenac (DCF) is a nonsteroidal anti-inflammatory drug to treat pain and inflammatory diseases. The high consumption of the drug leads to a significant change in the ecosystem. With the aim of optimizing a fast screening analysis for DCF detection on many samples with a sensitive and cheap procedure, we considered electrochemical methods using carbon-based electrodes as sensors. The electrochemical behavior of the DCF was studied on glassy carbon electrodes (GCE) and on screen-printed carbon electrodes (SPCEs) from two different suppliers after an anodic activation. The surface of the SPCEs was analyzed by scanning electron microscope (SEM) and Energy Dispersive Spectrometry (EDS). On all the activated electrodes, the voltammetric procedure (Differential Pulse Voltammetry) for the determination of DCF was optimized by the Experimental Design method, and the linearity range of the response, as well as the calibration and limit parameters (limits of detection—LoD; limit of quantification—LoQ), were defined. Analyses on SPCEs were performed both by immersing the electrode in the solution and by deposing a drop of solution on the electrode. DCF signals are stabilized by the polishing process and enhanced by the anodic activation and acid pH. The electrochemical response of DCF is not reversible, and its by-products tend to be adsorbed on the surfaces, particularly on GCE. The lowest limit parameters were obtained using the GCE (LoD = 1.6 µg L−1) and the SPCE, having the smallest surface, immersed in solution (LoD = 7 µg L−1)