KINETICS OF QUERCETIN NITRATIO N BY HORSERADISH PEROXIDASE

In this study we investigated the kinetics of the nitration of quercetin by horseradish peroxidase. Quercetin nitration reaction was followed by recording the spectral changes over the time at 380 nm. The reaction rate increases with increasing of the quercetin concentration and follows the Michaelis-Menten type kinetics. Kinetic parameters of the studied enzymatic reaction were determined

Inhibicija ksantin-oksidaze depsipeptidima i 2-amino-5-alkiliden-tiazol-4-onima

In this dissertation, depsipeptides and 2-amino-5-alkylidene-thiazol-4-ones were evaluated for inhibitory activity against commercial enzyme xanthine oxidase in vitro and xanthine oxidase in rat liver homogenate. Three studied 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones inhibit commercial xanthine oxidase and xanthine oxidase in rat liver homogenate with IC50 values below 50 μg/mL. Three studied N-(α-bromoacyl)-α-amino esters did not show the significant inhibitory effect against xanthine oxidase. Nineteen of thirty studied 2-amino-5-alkylidene-thiazol-4-ones inhibit commercial xanthine oxidase with IC50 values below 50 μg/mL. Eight of thirty 2-amino-5-alkylidene-thiazol-4-ones inhibit xanthine oxidase in rat liver homogenate with IC50 values lower than 50 μg/mL. 4-((2-Benzylamino-4-oxothiazol-5(4H)-ylidene)-methyl)-benzonitrile showed the most potent inhibitory effect against commercial xanthine oxidase (IC50 = 17.16 μg/mL) as well as against rat liver xanthine oxidase (IC50 = 24.50 μg/mL). Allopurinol exhibited stronger inhibitory effect on commercial xanthine oxidase as well as rat liver xanthine oxidase than all assayed compounds. Molecular docking studies were performed to gain an insight into the binding modes of the most potent studied depsipeptides and 2-amino-5-alkylidene-thiazol-4-ones with xanthine oxidase. The binding modes of 6-(propan-2-yl)-4-methyl-morpholine-2,5-diones resemble those found on complexes of xanthine oxidase with salicylic acid and febuxostat which do not form a covalent bond with the molybdenum atom. There are two possible binding modes for the studied 2-amino-5-alkylidene-thiazol-4-ones that depend upon the nature of the "amine" part of the molecule. Summarizing the in silico predicted physico-chemical, pharmacokinetic and toxicological properties of the studied compounds and the other xanthine oxidase inhibitors it might be concluded that the majority of compounds obey the Lipinski "Rule of five" and meet all criteria for good solubility and permeability. The assayed compounds obey the Veber rules and are likely to possess the ability to penetrate biological membranes and have satisfactory bioavailability. Predicted pharmacokinetic properties of selected xanthine oxidase inhibitors indicate to the favorable human intestinal absorption for almost all inhibitors, while the favorable toxicological properties are predicted for the majority of compounds. General conclusion of this dissertation is that the most potent xanthine oxidase inhibitors of the studied depsipeptides and 2-amino-5-alkylidene-thiazol-4-ones represent the promising structures for design of novel xanthine oxidase inhibitors which are potential drug candidates for the treatment of hyperuricemia and gout

DESIGNING ENERGY EFFICIENT AND ECOLOGICAL SOLAR HOUSE

The goal of the paper is to represent the energy efficient activities on an ecological solar house and to improve its ecological solar compositionality. The subject of this paper is the optimization of energy consumption, insulation capacity, optimization of air and other parameters, all in view of reaching and improving energy efficiency and ecological aspect when designing solar passive houses. Having analysed micro and macro influences and taken into account the energy factors of a parcel of land, the structure is envisioned through the application of an indirect-passive approach, so as to have the passive solar structure simultaneously as a solar collector and heat storage, while the emphasis is put on an optimal, efficient and ecologically functional design. In order to make the process of construction of the ecological solar house a compatible and energy efficient one, constructing the structure with ecological materials is foreseen. In accordance with this, in this paper a representation of the design of the ecological solar house is provided, with the optimal use of solar energy and heat in focus

ADSORPTION OF PLANT EXTRACTS ON CATIONIZED COTTON

Cotton, like most textile fibers, is negative charged in neutral and alkali aqueous solutions. Dyestuffs, optical brighteners and finishing agents in aqueous solution have the same electrical charge as cotton. Therefore, adsorption processes are difficult due to these repulsive forces. This paper studies the application of water extraction plants of St. Johns wart, marigold and hibiscus for the finishing of modified cotton by mercerization and cationization. The mercerization is the oldest modification since 19th century, while the cationization is researched in last 10 years. In this paper cationization of cotton fabric for achieving electropositive charge and better adsorption properties was carried out with cationic compound, quaternary ammonium salt during the mercerization well as with commercial product for cationization Denimcol Fix-GF (Bezema). The cotton electrokinetic phenomena after modifications were determined by zeta potential, isoelectric point, point of zero charge and specific amount of surface charge. The adsorption ability of plant extracts with and without mordant was investigated

The effect of nonionic surfactant treatment on dyeing of cotton fabrics

Proučavan je utjecaj obrade neionskim tenzidom FN-10 na karakteristike bojadisanja pamučne tkanine direktnim i reaktivnim bojilima. Različitim metodama identificirana je prisutnost neionskog tenzida na površini obrađenih uzoraka i mogućnost interakcije tenzida s upotrijebljenim bojilima. Obrađeni uzorci imaju bolju kvasivost i više upijaju bojilo u odnosu na neobrađen uzorak. Dubine obojenja direktnim i reaktivnim bojilima najveće su na obrađenim uzorcima bojadisanim u otopini sa standardnom količinom soli. Povećanje dubine obojenja može se smatrati razultat zajedničkog djelovanja soli i neionskog tenzida na povećanje afiniteta bojila za pamuk.The effect of nonionic FN-10 surfactant treatment on dyeing characteristics of cotton fabrics dyed with direct and reactive dyes was studied. Using different methods, the presence of nonionic surfactants on the surface of treated samples and the possibility of surfactant to interact with the used dyes were investigated. The treated samples have better wettability and absorb more dye than untreated sample. Intensities of direct and reactive dyes are the highest on treated samples dyed in a solution with standard amount of salt, and the intensity increase can be considered a mutual contribution of salt effect and that of deposited nonionic surfactant layer on the increase of dye affinity for cotton

Transformation of Synthetic Allicin: The Influence of Ultrasound, Microwaves, Different Solvents and Temperatures, and the Products Isolation

The transformation of the synthesized allicin, using conventional method, the influence of ultrasound and microwaves, in different organic solvents (acetonitrile, acetone, methanol, and chloroform), at various temperatures (room temperature, 45°C, and 55°C) was investigated. Allicin degradation kinetic was monitored by HPLC. Allicin transformation under the effect of microwaves is faster than transformations performed under the influence of ultrasound or by conventional method. Increase of the temperature accelerates allicin transformation. Pharmacologically active compounds of (E)-ajoene, (Z)-ajoene, 3-vinyl-4H-1,2-dithiin, 2-vinyl-4H-1,3-dithiin, and diallyl disulfide were isolated from the mixture of transformation products of allicin under the influence of microwaves in methanol at 55°C, which is according to kinetic parameters (highest values of the order of reaction and the lowest activation energy) the optimal method

Effect of variable frequency electromagnetic field on deposit formation in installations with geothermal water in Sijarinjska spa (Serbia)

In this paper we have examined the effect of variable frequency electromagnetic field generated with a homemade device on deposit formation in installations with geothermal water from Sijarinjska Spa. The frequency alteration of the electromagnetic field in time was made by means of the sinusoidal and saw-tooth function. In laboratory conditions, with the flow of geothermal water at 0.015 l/s and temperature of 60 °C for 6 hours through a zig-zag glass pipe, a multiple decrease of total deposit has been achieved. By applying the saw-tooth and sinusoidal function, the decrease in contents of calcium and deposit has been achieved by 8 and 6 times, respectively. A device was also used on geothermal water installation in Sijarinjska Spa (Serbia), with the water flow through a 1'' diameter non-magnetic prochrome pipe at 0.15 l/s and temperature of 75 °C in a ten-day period. A significant decrease in total deposit and calcium in the deposit has also been achieved

Polyester fibres structure modification using some organic solutions

Ispitivanjem obrade poliesterskih vlakana organskim otapalima uočeno je manje smanjenje prekidne čvrstoće, dok je prekidno istezanje značajno povećano, gotovo 150 % u usporedbi s neobrađenim uzorkom. Organska otapala, tj. otopine plastifikatora u mješavini organskih otapala, utječu povoljno na svojstva vlakana, tj. ona mogu omogućiti bolje bojadisanje, bolju apsorpciju vlage, lakšu obradu u daljnjim fazama proizvodnje tekstilnih proizvoda i općenito bolja upotrebna svojstva. Rendgenska strukturalna analiza je korištena za ispitivanje utjecaja obrade PET vlakana u obliku filamentne pređe finoće 75/26 dtex otopinama 0,3, 0,6 i 0,9% hidrokinona i α-naftola u mješavini otapala kloroforma i metanola (topljivosti 11,7), na promjene stupnja kristalnosti i veličinu kristalita. Ustanovljeno je da obrađena vlakna pokazala oštriju refleksiju na difraktogramima nego neobrađena, tj. ona su imala viši stupanj kristalnosti, ali manju veličinu kristalita.The treatment causes only minor decrease in fibre, i.e. yarn strength, while breaking elongation increases significantly, almost up to 150 % in comparison to the untreated sample. Organic solvents, i.e. plasticizer solutions in the organic solvents mixture influence fibre properties in a very favorable way, i.e. they can enable better dyeing, better moisture absorption, easier treatment in further phases of textile products manufacture and generally better usability. X-ray structural analysis was used to examine the influence of the treatment of polyester fibres in the form of filament yarn, fineness 75/26 dtex, with solutions 0.3, 0.6 and 0.9 % hydroquinone and -naphtole in the solvent mixture which contained chlorophorm and methanol (solubility parameter 11.7) on changing of crystalline degree and crystallite size. It was found that treated fibres showed sharper reflexion on diffractograms than untreated ones, i.e. they showed higher crystalline degree but smaller crystallite size

Supporting information for: "Deoxyribonuclease I Inhibitory Properties, Molecular Docking and Molecular Dynamics Simulations of 1-(Pyrrolidin-2-yl)propan-2-one Derivatives"

Experimental Section: 1.1. Chemicals. 1.2. Compounds. 1.3. Evaluation of deoxyribonuclease I inhibition. 1.4. In silico molecular and ADMET properties. 1.5. In silico PAINS and promiscuity assessment. 1.6. Molecular docking. 1.6.1. Ligand preparation. 1.6.2. Receptor preparation 1.6.3. Binding site selection 1.6.4. Docking protocol 1.7. Molecular dynamics simulation . Table S1. Summary of the top five inhibitor-binding sites in DNase I. Additional references.Supporting information for: Ilić, B. S., Gajić, M., Bondžić, B. P., Džambaski, z., Kocić, G.,& Šmelcerović, A. A. (2021). Deoxyribonuclease I Inhibitory Properties, Molecular Docking and Molecular Dynamics Simulations of 1-(Pyrrolidin-2-yl)propan-2-one Derivatives. Chemistry and Biodisversity, Wiley, 18(3), e2000996. [https://doi.org/10.1002/cbdv.202000996]Published version of the article: [https://cer.ihtm.bg.ac.rs/handle/123456789/4498]Animation of molecular dynamics simulations - Inhibitor 1/DNase I: [https://cer.ihtm.bg.ac.rs/handle/123456789/4500]Animation of molecular dynamics simulations - Inhibitor 2/DNase I: [https://cer.ihtm.bg.ac.rs/handle/123456789/4501