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A series of organotin complexes with Sn-S bonds of formulae Me_2Sn(SR)_2 (1); Et_2Sn(SR)_2 (2); (n-Bu)_2Sn-(SR)_2 (3); Ph_2Sn(SR)_2 (4); R_2Sn(SR)_2 (5); Me_3SnSR (6); Ph_3SnSR (7) (R = 3,5-di-tert-butyl-4-hydroxyphenyl) were synt...
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A series of organotin complexes with Sn-S bonds of formulae Me_2Sn(SR)_2 (1); Et_2Sn(SR)_2 (2); (n-Bu)_2Sn-(SR)_2 (3); Ph_2Sn(SR)_2 (4); R_2Sn(SR)_2 (5); Me_3SnSR (6); Ph_3SnSR (7) (R = 3,5-di-tert-butyl-4-hydroxyphenyl) were synthesized and characterized by elemental analysis, ~1H, ~(13)C NMR, and IR. The crystal structures of compounds 1, 4, 5, and 7 were determined by X-ray diffraction analysis. The tetrahedral geometry around the Sn center in the monocrystals of 1, 4, 5, and 7 was confirmed by X-ray crystallography. The high radical scavenging activity of the complexes was confirmed spectrophotometrically in a DPPH-test. The binding affinity of 1-7 and the starting R_2SnCl_2 (8) towards tubulin through their interaction with SH groups of proteins was studied. It was found that the hindered organotin complexes could interact with the colchicine site of tubulin, which makes them promising antimitotic drugs. Compounds 1-8 were tested for their in vitro cytotoxicity against human breast (MCF-7) and human cervix (HeLa) adenocarcinoma cells. Complexes 1-8 were also tested against normal human fetal lung fibroblast cells(MRC-5). Complexes 2-4 and 8 exhibit significantly lower cytostatic activity against the normal MRC-5 cell line compared to the tumor cell lines MCF-7 and HeLa used. A high activity against both cell lines 250 nM (MCF-7) and 160 nM (HeLa) was determined for the triphenyltin complex 7 while the introduction of hindered phenol groups decreases the cytotoxicity of the complexes against normal cells.
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The antiradical activity of 5-amino-1,3,6-trimethyluracil was quantitatively measured in the initiated radical chain oxidation of ethylbenzene as the model system. The rate constant of the reaction of 5-amino-1,3,6- trimethyluraci...
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The antiradical activity of 5-amino-1,3,6-trimethyluracil was quantitatively measured in the initiated radical chain oxidation of ethylbenzene as the model system. The rate constant of the reaction of 5-amino-1,3,6- trimethyluracil with the ethylbenzene peroxyl radical at 333 K was found: k _7 = (2.1 ± 0.3) × 10~5 L mol~(-1) s~(-1). The kinetics of 5-amino-1,3,6-trimethyluracil consumption in the course of the radical chain oxidation of ethylbenzene was studied. The stoichiometric inhibition factor was determined to be f = 2.
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The Mallotus species (Euphorbiaceae) are used in traditional medicine for different ailments ranging from minor infections such as gastrointestinal disorders to dysentery, hepatic diseases, cutaneous diseases, fever and malaria, a...
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The Mallotus species (Euphorbiaceae) are used in traditional medicine for different ailments ranging from minor infections such as gastrointestinal disorders to dysentery, hepatic diseases, cutaneous diseases, fever and malaria, and a series of other indications [1]. M. paniculatus is distributed in southeastern Asia and China [2]. Previous investigations on the constituents of M. paniculatus have isolated several compounds such as cardenolides, triterpenoids, steroids, flavonoids, and unsatured fatty acids, and the plant extract was found to possess antioxidant and antiradical activities [3–7]. To find further active principles from M. paniculatus, we investigated the plant.
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Dosage forms intended for ophthalmic use with declared and potential antioxidant properties were investigated. Antioxidant activity was determined using potentiometry with potassium hexacyanoferrate (III) as the oxidant. Antiradic...
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Dosage forms intended for ophthalmic use with declared and potential antioxidant properties were investigated. Antioxidant activity was determined using potentiometry with potassium hexacyanoferrate (III) as the oxidant. Antiradical activity was studied using the stable radical 2,2-diphenyl-1-picrylhydrazyl. The reaction half-lives of the investigated dosage forms were determined. Ratios of the experimental antioxidant activity to the content of main active ingredient were assessed.
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A relationship between the antiradical activity of flavonoids and the molecular descriptors related to the mechanism of their antiradical action was determined by single-variable linear regression analysis in the form of a semiemp...
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A relationship between the antiradical activity of flavonoids and the molecular descriptors related to the mechanism of their antiradical action was determined by single-variable linear regression analysis in the form of a semiempirical single-variable linear equation. The predictive ability of the derived model was evaluated using a test sample; the average error of approximation was no more than 8.5%. The obtained descriptor-activity relationship underlies the prediction of the antiradical properties of flavonoids and their similar structures in aqueous solutions with a physiological pH value of the medium.
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This study was conducted in order to determine the antioxidant activities of certain apple varieties. 'Galaxy Gala', 'Scarlet Spur', 'Fuji', 'Pink Lady' and 'Granny Smith' were characterized in this study. The antioxidant activiti...
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This study was conducted in order to determine the antioxidant activities of certain apple varieties. 'Galaxy Gala', 'Scarlet Spur', 'Fuji', 'Pink Lady' and 'Granny Smith' were characterized in this study. The antioxidant activities among the varieties were determined via three different procedures. Antiradical activity figures of the apple varieties were between 0.592 ('Galaxy Gala') and 0.802 ('Scarlet Spur'). Inhibition levels of chelating activity with Fe+2 varied between 40.20-55.50%; 'Scarlet Spur' and 'Pink Lady' extracts had the highest inhibition with 55.50% and 'Granny Smith' extract had the lowest with the level. Among the extracts showing H2O2 clearance effect, Granny Smith (62.54%) and Scarlet Spur (44.67%) extracts had the highest inhibition levels. In this study conducted on apple varieties, total phenolic matter levels were determined in 'Scarlet Spur', 'Pink Lady', 'Fuji', 'Galaxy Gala' and 'Granny Smith'.
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In vitro studies have shown a link between the consumption of food rich in (poly)phenols, especially flavonoids, and reduced risk of coronary heart diseases. Several flavonoids have been reported to prevent low density lipoprotein...
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In vitro studies have shown a link between the consumption of food rich in (poly)phenols, especially flavonoids, and reduced risk of coronary heart diseases. Several flavonoids have been reported to prevent low density lipoprotein cholesterol oxidation in vitro. The aim of our work was to determine antioxidant and radical scavenging activity of flavonoids myricetin, quercetin, rutin, luteolin, apigenin, kaempferol, catechin, epicatechin and epigallocatechin gallate and to study the influence of chemical structure and flavonoid interactions on the ability to inhibit oxidation and scavenge free radicals. Two in vitro,methods, i.e. oxidation of β-carotene in an emulsion system and DPPH (1,1-Diphenyl-2-picrylhy-drazyl) radical scavenging assay, were applied. In addition, a review of in vivo studies that investigate the effectiveness of food flavonoids in reducing oxidative damage in human body was done and their results were analyzed and compared to in vitro results obtained in our laboratory. Although all tested flavonoids except apigenin showed strong antioxidant and antiradical properties in vitro, these findings can not be completely confirmed from the reviewed in vivo human studies since those results are sometimes contradictory and inconsistent.
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A series of dihydroxyphenylthiazoles were synthesized via the reaction of 4-(chloroacetyl)catechol with thioamide derivatives. Their antiradical activity was studied using the reaction with the cation-radical 2,2'-azinobis(3-ethyl...
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A series of dihydroxyphenylthiazoles were synthesized via the reaction of 4-(chloroacetyl)catechol with thioamide derivatives. Their antiradical activity was studied using the reaction with the cation-radical 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid). Antimicrobial activity of the dihydroxyphenylthiazoles was studied against P. aeruginosa, C. albicans, S. epidermidis, and S. aureus. These compounds were found to belong to toxicity class 4.
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Different fruit wines, chokeberry, blackcurrant and blueberry, were spray-dried using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and inulin (IN). The structural, physicochemical, and biological properties of the spray-dried wine...
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Different fruit wines, chokeberry, blackcurrant and blueberry, were spray-dried using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and inulin (IN). The structural, physicochemical, and biological properties of the spray-dried wine powders were studied over 12 months of storage in darkness at 8 degrees C. Identification and quantification of single phenolic compounds before and after storage revealed that HP-beta-CD had a positive effect on anthocyanin retention during storage for all microcapsules tested. Similar decreases in anthocyanin were found for blackcurrant and chokeberry powders, ranging from 7.3 to 8.9% with HP-beta-beta-CD and 12.3 to 12.5% with IN. Levels of anthocyanin losses in blueberry wine microcapsules were much greater: 19.9% (HP-beta-CD) and 22.7% (IN). The high antiradical activities of blackcurrant and chokeberry wine microcapsules were stable and remained unchanged during storage. All wine microcapsules revealed significant activity against medically important bacterial strains. The HP-beta-CD samples showed generally higher activity against the test microorganisms compared to IN microcapsules, especially at concentrations of 100 mg/mL. (C) 2017 Elsevier Ltd. All rights reserved.
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The immobilization of caffeic acid (CA) on a polypropylene (PP) film was successfully performed through the covalent binding of the caffeoyl chloride on a modified polymeric surface of PP films grafted with hydroxyethyl methacryla...
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The immobilization of caffeic acid (CA) on a polypropylene (PP) film was successfully performed through the covalent binding of the caffeoyl chloride on a modified polymeric surface of PP films grafted with hydroxyethyl methacrylate as monomer (PP-g-HEMA). The different reaction steps were monitored by FT-IR spectroscopy. The synthesized films were characterized by Folin-Ciocalteu method by measuring the available phenolic groups as caffeic acid equivalents linked to the surface. The antioxidant efficiency of the modified polymers was evaluated by typical spectrophometric methods, such as the bleaching of radicals DPPH~· and ABTS~(·+), and the inhibition of the enzymatically induced coupled oxidation of linoleic acid and betacarotene. The available phenolic groups on the modified film presented a good correlation with the antiradical activity toward DPPH~·. Moreover, the polymer synthesized in this work showed a good protective activity against ascorbib acid oxidation in real samples of orange juice.
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