Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology

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    ACTIVITATEA ANTIOXIDANTĂ A UNOR COMPUŞI DIN PRODUSE SECUNDARE VINICOLE LA REDUCEREA NITRITULUI
    (CEP USM, 2007) Gonţa, Maria; Porubin, Diana
    In the stomach, the dietary nitrite reacts with the nitrosable substrates (amines, amides, etc.) forming carcinogenic N-nitroso compounds. The process of inhibition of NOC formation is based on the reduction of the nitrite to NO, which is not a direct nitrosating agent. Considering all this, we have decided to study the nitrite reduction, using various com-pounds, as: quercetin (Que), (+)catechin ((+)Ct), rezveratrol (Rezv), dihydroxyfumaric acid (DFH), the dimethylic ester of the dihydroxyfumaric acid (EDMD), the dimethylic ester of the tartaric acid (EDMT) and ascorbic acid (AA) used as reference. We obtained that the increase of the reductants concentration leads to the increase of the reduction rate of nitrite, which indicates the existence of a dose dependent effect. The reduction rate was investigated function of the pH value: 1.5, 2.6, 3.4, 4.6 and 5.6. The reductants and nitrite concentrations were of 1·10-4 M. The best results were obtained at pH 1.5 for all reductants. Thus, the pH has a direct influence on nitrite reduction. The most efficient nitrite-reducing agents are Cver, (+)Ct, Rezv, and DFH4, followed by EDMD and AAs, whereas EDMT showed very weak antioxidant properties. This can be explained by the chemical structure of the investigated compounds and their behavior in various reaction media.
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    ACTIVITATEA ANTIOXIDANTĂ A FILMELOR CU EXTRACTE DIN PRODUSE VEGETALE DE SOPHORA JAPONICA L.
    (CEP USM, 2024) Grigoraș, Carolina; Ciocârlan, Alexandru; Gonţa, Maria
    Plant products of S. japonica, more precisely: flowers, fruits and seeds collected in May and September, respectively, have been conditioned, and the products obtained serve as a source of raw material. The extracts were obtained from the vegetable raw material by maceration, distillation and hydrodistillation using various solvents, with the subsequent incorporation into the filmogenic mixture of chitosan:pectin, to obtain polymeric films. The obtained films were evaluated according to quality indices, thus the appearance, smell and mechanical properties were analyzed, the thickness of the films was measured and antioxidant properties were determined. The prepared biomaterials are uniform, thin, elastic, flexible, have no smell and have a specific color of the composition, manifest an antioxidant activity, but this varies depending on the composition of the prepared films.
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    ACTIVIZAREA REACTIVILOR ORGANICI PRIN COORDINARE
    (Academia de Ştiinţe a Moldovei, 2013) Revenco, Mihai
    The paper represents a review of the publications devoted to the studies of the infl uence of the thiosemicarbazones and their analogues coordination on the reactivity of the ligands. There are discussed the ways of activation of every atoms from the thiosemicarbazide fragment, highlighted the types of the observed reactions where the activated atoms are involved, and the new transformations, which have not been described previously. The observed effects were putted in use for elaboration of new methods of organic fi ne syntheses, for obtaining substances for biological applications, new materials including molecular magnets, catalysts, analytical reagents for determination, preconcentration and separation of metal ions.
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    ADAPTATION OF THE METHOD FOR DETERMINING VITAMIN B9 IN AQUEOUS SOLUTIONS
    (CEP USM, 2022) Blonschi, Vladislav; Gladchi, Viorica
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    ADSORPTION OF LANTHANIDE (III) CATIONS ON CROSS-LINKED IONIC POLYMER, COMPOSITION AND THERMAL ANALYSIS OF THE FORMED COMPOSITES
    (2021) Guțanu, Vasile; Lisă, Gabriela; Rusu, Daniela
    The adsorption of lanthanide(III) cations by a strongly basic cross-linked polymer containing R4N+ groups was studied at 21 and 50°C. At both temperatures the sorption is best described with the Langmuir model. The maximum adsorption at both 21 and at 50°C increases in the series: La3+ < Eu3+ < Nd3+ < Er3+. The results show that polymers containing strongly basic groups can, under certain conditions, be used to separate lanthanide(III) cations in solutions containing mono- and bivalent cations. SEM EDX studies show that La3+, Nd3+, Eu3+ and Er3+ form composites in the polymer phase. The elemental composition of structural units of the composites is La1Cl13.7S64.3O287.7N122.6C2869, Nd1Cl27.4S50.7O391.6N169.3C2896, Eu1Cl8.5S50.8O285N130C2118 and Er1Cl36.8S263.9O1106N447C8657. The thermodynamic parameters of the sorption process are calculated: free energy, enthalpy, and entropy. Thermogravimetric analysis made it possible to determine the stability of the formed composites, the stages of their decomposition and the corresponding kinetic parameters.
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    ADSORPTION WAVE OF VAN ADIUM COMPLEX WITH 2,3–DIHYDROXYBE NZALDEHYDE
    (Academia de Știinițe a Moldovei, 2009) Kiriyak, Ludmila; Cecoi, Natalia; Cazac, Tatiana; Revenco, Mihail
    The polarographic behavior of the complex formed by V(V) and 2,3–ihydroxybenzaldehyde (2,3–DHBA) in the solution containing acetate buffer (pH 5,2) has been investigated. By means of a.c. polaro-graphy, chronovoltammetry and other techniques, it has been shown that the electrode process is complicated by the adsorption of 2,3-DHBA and its vanadium complex. The kinetic and adsorption parameters of the electrode process have been determined: adsorption equilibrium constant B= 1,32⋅105 mol-1⋅dm3, the attraction constant γ = 1,2, the maximum surface concentration Гmax = 9,10⋅10-11 mol⋅ cm-2; the share of the electrode surface occupied by one particle of the adsorbed complex S = 1,81 nm2 and the free adsorption energy ∆G = - 39,1 kJ· mol-1.
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    ADSORPTION WAVE OF VANADIUM COMPLEX WITH 2,3–DIHYDROXYBENZALDEHYDE
    (Institute of Chemistry of ASM, 2009) Kiriyak, Ludmila; Cecoi, Natalia; Cazac, Tatiana; Revenco, Mihail
    The polarographic behavior of the complex form ed by V(V) and 2,3–dihydroxybenzaldehyde (2,3–DHBA) in the solution containing acetate buffer (pH 5,2) has been investigated. By means of a.c. polarography, chronovoltammetry and other techniques, it has been shown that the electrode process is complicated by the adsorption of 2,3-DHBA and its vanadium complex. Th e kinetic and adsorption para meters of the electrode process have been determined: adso rption equilibrium constant B= 1,32⋅105 mol-1⋅dm3, the attraction constant γ = 1,2, the maximum surface concentration Гmax = 9,10 ⋅10-11 mol⋅ cm-2; the share of the electrode surface occupied by one particle of the adsorbed complex S = 1,81 nm2 and the free adsorption energy ∆G = - 39,1 kJ· mol-1.
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    ANALIZA COMPARATIVĂ A INFLUENȚEI UNOR REMEDII ALE ZINCULUI ŞI SELENIULUI ASUPRA ANUMITOR INDICI MORFOLOGICI AI OUĂLOR DE GĂINĂ
    (2012-09-27) Țurcanu, Ștefan; Gulea, Aurelian; Bârcă, Maria; Ddidilică, Ina
    Experiment were subjected laying hens of Hay-Sex cross. In study was taken two groups that received, according to the ration, zinc trichloroacetate tetrahydrate and zinc hidroselenite dihydrate. The results show a more positive evaluation of quantitative indices of the stock of eggs in presence of last one remedy.
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    ANALIZA DINAMICII MULTIANUALE A COMPOZIŢIEI IONICE A APELOR FLUVIULUI NISTRU
    (CEP USM, 2011) Goreaceva, Nelli; Gladchi, Viorica; Bunduchi, Elena; Şurîghina, Olga; Romanciuc, Lidia
    The present article contains the analysis of the long-term and annual variability of the water content of the Moldovan Middle region of Dniester, performed on the results of annual hydro chemical surveys of 2003-2010.
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    ANTIBACTERIAL, ANTIFUNGAL AND IN VITRO ANTILEUKAEMIA ACTIVITY OF METAL COMPLEXES WITH THIOSEMICARBAZONES
    (Wiley, 2015) Pahonțu, Elena; Julea, Felicia; Rosu, Tudor; Purcarea, Victor; Chumakov, Yurie; Petrenco, Petru; Gulea, Aurelian
    1-phenyl-3-methyl-4-benzoyl-5-pyrazolone 4-ethyl-thiosemicarbazone (HL) and its copper(II), vanadium(V) and nickel(II) complexes: [Cu(L)(Cl)]·C2H5OH·(1), [Cu(L)2]·H2O (2), [Cu(L)(Br)]·H2O·CH3OH (3), [Cu(L)(NO3)]·2C2H5OH (4), [VO2(L)]·2H2O (5), [Ni(L)2]·H2O (6), were synthesized and characterized. The ligand has been characterized by elemental analyses, IR, 1H NMR and 13C NMR spectroscopy. The tridentate nature of the ligand is evident from the IR spectra. The copper(II), vanadium(V) and nickel(II) complexes have been characterized by different physico-chemical techniques such as molar conductivity, magnetic susceptibility measurements and electronic, infrared and electron paramagnetic resonance spectral studies. The structures of the ligand and its copper(II) (2, 4), and vanadium(V) (5) complexes have been determined by single-crystal X-ray diffraction. The composition of the coordination polyhedron of the central atom in 2, 4 and 5 is different. The tetrahedral coordination geometry of Cu was found in complex 2 while in complex 4, it is square planar, in complex 5 the coordination polyhedron of the central ion is distorted square pyramid. The in vitro antibacterial activity of the complexes against Escherichia coli, Salmonella abony, Staphylococcus aureus, Bacillus cereus and the antifungal activity against Candida albicans strains was higher for the metal complexes than for free ligand. The effect of the free ligand and its metal complexes on the proliferation of HL-60 cells was tested.
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    ANTIMICROBIAL AND ANTIFUNGAL ACTIVITY OF CU(II) AND BI(III) COMPLEXES BASED ON AMINOPOLYCARBOXYLATE IONS AND 2-FORMYL AND 2-ACETYLPYRIDINE THIO- SEMICARBAZONES
    (2021) Neguța, Elena; Balan, Greta; Gulea, Aurelian; Bulimestru, Ion
    The biological properties of thiosemicarbazones are often related to metal coordination, which as result affects lipophilicity that controls the rate of entry into the cell. Metal complexes are generally more active than the free ligand, or the metal complex can be a vehicle for activation of the ligand as the cytotoxic agent. Among biologically ac- tive metal compounds, copper (II) complexes with 2-formyl and 2-acetylpyridine thio- semicarbazones proved to be among the most potent antiviral, antitumor and anti-inflam- matory agents. Bismuth compounds have been widely used in medicine for more than two centuries due to their high effectiveness and low toxicity. In the antimicrobial realm, ap- plications have been widespread, due to bismuth antiseptic, astringent, protective, ant- acid, antisecretory and local gastrointestinal properties.
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    ANTIPROLIFERATIVE AND ANTIOXIDANT ACTIVITY OF NITRATO-[4-(3,4-DIMETHYLPHENYL)-2-(2-OXO-3-METHOXYBENZYLIDENE) HYDRAZINECARBOTHIOAMIDO]COPPER
    (Marina Sokolova Publishings, 2018) Gulea, A.P.; Gudumac, V.S.; Garbuz, O.S.; Cebotari, D.Y.; Spinu, I.C.; Pirvu, O.I.; Sardari, V.V.; Tagadiuc, O.C.; Gostev, I.V.; Spinu, C.I.; Scoferta, P.G.
    In the present study, the ability of nitrato-[4-(3,4-dimethylphenyl)-2-(2-oxo-3-methoxybenzylidene) hydrazinecarbothioamido] copper (CDI-14) – new coordination compound of the thiosemicarbazone class of biometals to induce the inhibition of proliferation in HeLa and BxPC-3 cancer cell lines was investigated. Its cytotoxicity against MDCK normal cell line was also evaluated. The viability of each cell line was determined by the Resazurin test. Doxorubicin was used as a positive control. The antioxidant activity was evaluated by ABTS assay and compared with those of the standards, trolox and rutin.Obtained results showed that compound CDI-14 has a good antioxidant potential and high antiproliferative activity against HeLa and BxPC-3 cancer cell lines. It was also observed that the tested compound did not affect the cytotoxic activity of MDCK normal cell line, which indicates its selective toxicity and the possibility of its use as an anticancer agent.