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

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

3’-Methyl-4-thio-1H-tetrahydropyranspiro-5’-hydantoin platinum complex as a novel deoxyribonuclease I inhibitor

Deoxyribonuclease I (DNase I) is one of the main nucleases involved in deoxyribonucleic acid (DNA) degradation during apoptosis. It catalyzes the hydrolytic cleavage of DNA, producing 5‘-oligonucleotides. The inhibition of DNase I may serve as an important mechanism for protecting DNA against premature degradation during cell damage. Fourteen hydantoin-containing compounds, including two newly synthesized and seven previously synthesized metal complexes, along with five previously synthesized hydantoin ligands, were evaluated in vitro for their inhibitory properties against bovine pancreatic DNase I. As a result, the 3’-methyl-4-thio-1H-tetrahydropyranspiro-5’-hydantoin platinum complex (8) inhibited the enzyme with an IC50 value of 110.20 ± 24.20 µM, a potency 3-fold greater than that of the reference crystal violet (IC50 = 378.27 ± 47.75 µM). To understand the binding mode and mechanism of inhibition of compound 8 with DNase I, molecular docking calculations were performed. The analysis revealed that compound 8 interacts with the most important catalytic residues of DNase I. To the best of our knowledge, this is the first report of a platinum complex inhibiting DNase I

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

Inhibicija ksantin oksidaze derivatima 1,2,3,4-tetrahidroizohinolina

Xanthine oxidase (XO) is a versatile metalloflavoprotein enzyme that is best known for its rate-limiting role in the purine degradation pathway. Therapeutic inhibition of XO is based on its role in a variety of diseases that is attributed either to the hyperproduction of uric acid, or the hyperproduction of reactive oxygen species. Herein, we report the assessment of XO inhibitory properties of 24 1,2,3,4-tetrahydroisoquinoline derivatives, among which compound 16 exhibited IC50 value of 135.72 ± 2.71 µM. The interaction of compound 16 with XO enzyme was simulated using the Site Finder module, molecular docking and molecular dynamics. Molecular modeling suggests that interactions with Met 1038, Gln 1040, Thr 1077, Gln 1194 and Val 1259 are an important factor for inhibitor affinity toward the XO enzyme. Our proposed binding model might be beneficial for the discovery of new active 1,2,3,4-tetrahydroisoquinoline-based inhibitors of XO enzyme.Ksantin oksidaza (XO) je metaloflavoproteinski enzim, koji je najpoznatiji po svojoj ulozi ograničavanja brzine razgradnje purinskih nukleotida. Terapijska inhibicija XO zasniva se na njenoj ulozi u brojnim bolestima, koje su povezane bilo sa hiperprodukcijom mokraćne kiseline ili hiperprodukcijom reaktivnih kiseoničnih vrsta. U ovom radu izvršeno je ispitivanje sposobnosti inhibicije XO 24 derivata 1,2,3,4-tetrahidroizohinolina, od kojih je jedinjenje 16 pokazalo IC50 vrednost od 135,72 µM ± 2,71 µM. Interakcija jedinjenja 16 sa XO enzimom simulirana je korišćenjem Site Finder modula molekularnog dokinga i molekularne dinamike. Molekulsko modelovanje ukazuje na to da su interakcije sa Met 1038, Gln 1040, Thr 1077, Gln 1194 i Val 1259 važan faktor postojanja afiniteta inhibitora prema XO enzimu. Naš predloženi model vezivanja mogao bi biti od značaja za razvoj novih aktivnih inhibitora XO zasnovanih na 1,2,3,4-tetrahidroizohinolinskom heterociklusu

Microbial Polysaccharides and their Derivatives as Current and Prospective Pharmaceuticals

The ability to produce polysaccharides is widely found among microbial species. The structural diversity of the microbial polysaccharides (MPS) leads to a wide diversity of their applications. This review focuses pharmacological properties of MPS and their derivatives. They have been reported to possess many biological activities, such as antiviral, antitumor, antimicrobial and anticoagulant activities. So, the MPS of the type beta-1,3-D-glucans, including curdlan and scleroglucan, show antitumor and antiviral activity. A number of biological and synthetic sulfated polysaccharides, including sulfated polysaccharides from marine microalgae, inhibit viral infections. Many of MPS demonstrate a series of attractive properties as carrier materials in drug delivery systems and nonviral gene delivery. Furthermore, MPS have found an application as wound-healing agents, blood plasma expanders and vaccines. Some MPS, like chitin, chitosan and alginate have an unusual combination of biological activities and physicochemical properties leading to the development of novel or improved pharmaceuticals. They have become of a great interest not only as drug and cell carriers but also as new functional materials of high biological activity, and recent progress in MPS chemistry is quite noteworthy. This review also examines the advances in the application of MPS in the field of tissue engineering

Chitin and chitosan from microorganisms

Today, a major concern about the use of crustacean chitin/chitosan in the pharmaceutical and biomedical field is still the molecular variability of a natural product, which results in a wide unpredictable range of physicochemical properties. Concurrently, the production of chitin/chitosan from microbial sources appears promising because the process can be manipulated to obtain a pure, rather uniform product with specific characteristics. In addition, the fermentative production of fungi on cheap industrial by-products and wastes is an unlimited and, in principle, a very economic source of chitin/chitosan. As well, the feasibility of obtaining β-glucan from the myceliar chitosanglucan complex, and the simultaneous extraction of chitin and chitosan make the microbial process more interesting (Pomeroy et al. 2001). This chapter highlights the research on microbial chitin and chitosan with a special focus on major sources and methods of their biotechnological production, as well as the difficulties in utilizing and processing them for selected applications