Papers by Author: Nicoleta Maria Badea

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Authors: Ioana Lacatusu, Nicoleta Maria Badea, Aurelia Meghea
Abstract: This paper aims to study the effect of three alkyl quaternary salts on stability of colloidal sols further used as water-insoluble oligomers for encapsulation of an active flavonoid compound – quercitin. The preparation procedure is described and practical remarks on silica-based sol-gels are included. It is also demonstrated how to exploit the sol-gel preparation route in order to improve the thermal resistance of quercitin and to increase an optical function - fluorescence. The evolution in time of competitive hydrolysis and condensation processes has been observed by dynamic light scattering measurements. The sol-gel materials with entrapped quercitin molecule have been characterised by spectral methods (FT-IR, UV-VIS-NIR), fluorescence and by thermal analysis as well. Sol-gel materials doped with active flavonoid compound may be used in preparation of some functional materials with bioactive properties.
Authors: Cornelia Nichita, Georgeta Neagu, Virginia Vulturescu, Lucia Pirvu, Nicoleta Maria Badea, Radu Albulescu, Maria Giurginca
Abstract: The scavenger properties of some flavonoidic vegetal extracts obtained from Crataegus monogyna Jacq have been studied using the chemiluminescence technique and ex vivo lipid peroxidation assay. A correlation between antioxidant activity and phenolic/flavonoidic content was observed for all the seven extracts, and a parallel behaviour with the antioxidant activity determinated by ex vivo lipid peroxidation assay and in vitro chemiluminescence tests was also noted.
Authors: Marcela Elisabeta Bărbînţă Pătraşcu, Nicoleta Maria Badea, Laura Ţugulea, Aurelia Meghea
Abstract: Photophysical studies on oxidative stress induced by illumination with ultraviolet (UV) light from artificial light sources, were performed on small unilamellar liposomes (SUVs) as models of biomembranes. Different liposoluble antioxidants were incorporated in the liposome bilayer during the lipid film preparation. The quercetin containing bilayers exhibited a high tolerance to photooxidative stress. The light-driven reactive oxygen species (ROS) effects on liposomal membranes were monitored by optical methods: UV-VIS absorption, fluorescence and chemiluminescence (CL), exploiting the spectral properties of chlorophyll a (Chla) embedded into some liposome bilayers (Chla/lipid molar ratio = 1/100). The interaction between Chla and the other liposome components resulted in changes in their absorption and emission fluorescence properties.
Authors: Florina Dumitru, Maria Giurginca, O. Micu, C. Guran, Anca Razvan, Nicoleta Maria Badea
Abstract: Chlorhexidine, 1,1'-hexamethylene-bis-[5-(p-chlorophenyl)-biguanide] is a clinically used antiseptic agent with a broad activity spectrum, effective against either Gram positive bacteria such as Mutans streptococcus or Gram negative bacteria such as Pseudomonas aeruginosa. It has eliminating effects on some mycobacteria. In order to prevent the loss of the biological activity caused by poor solubility of chlorhexidine and to limit the side effects of chlorhexidine when used as antiseptic, we synthesised Zn(II)- and Cu(II)- complexes of chlorhexidine, L1, as well as with chlorhexidine diacetate, L2, in 1:1 and 1:2 M:L molar ratios. Based on the elemental analysis data, IR and UV-Vis spectroscopy, and ESI-MS spectrometry we proposed the appropriate molecular formulae of the complexes.
Authors: Nicoleta Maria Badea, M. Jelinek, T. Tite, Mariana Prodana, A. Campean, Ioana Demetrescu
Abstract: The in-vitro bioactivity of SiC growing using the innovative hybrid laser-magnetron deposition technique was investigated. The biological response has been analysed after being immersed in a human blood plasma solution for 10 days. Surface analysis by SEM microscopy shows clearly an adsorption process after immersion. The products formed are mainly attributed to a rich-calcium phosphate and silica-complexes layers. Citotoxicity test shows a normal phenotype of fibroblast cell culture on SiC and MTT assay indicates an increased viability of cells around 15% after only one day of immersion. Results obtained are supported by FTIR analysis. Strong changes in the absorbance of bands after immersion are observed, which indicates a strong bioactivity of SiC.
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