Experimental and Theoretical Study Of UV-Vis Spectra of Schiff Bases

The UV-Vis properties of ten Schiff bases were systematically investigated. The time-dependent density functional theory (TDDFT) approach in combination with the B3LYP functional was used for simulation of UV-Vis spectra of examined compounds. The shapes of the Kohn-Sham molecular orbitals involved in electronic transitions were misleading. To provide better understanding of distribution of electron density natural bond orbital (NBO) analysis was used. NLMO clusters were constructed and they represent a part of a molecule characterized with eminent electron density. The TDDFT and NBO theories are complementary, and the results from these two approaches are combined to interpret the UV-Vis spectra

QSAR Model for Predicting Antioxidan Capacity of Some Polyphenolic Antioxidants

Quantitative structure–activity relationship model (QSAR models) is useful method for predicting antioxidant capacity of a molecule based on some chemical-physics properties. In our development of QSAR model are included 21 structural similar antioxidants. It is shown that taking into account some thermodynamical and thermochemical parameters of antioxidant and chemical activity is possible to generate fair antiradical QSAR models

Examination of Electron Transfer Mechanism of Cyanidin

Cyanidin, as one important plant pigment, was theoretically (at M05-2X/6-311+G(d,p) level of theory) investigated for its ability to scavenge potentially, highly damaging hydroxyl radical. Free radical scavenging of cyanidin was studied through electron transfer mechanism – ET (the second step in SPLET mechanism) in water and ethanol, as solvents. Examination was performed using density functional theory (DFT) and Marcus theory. Based on the thermochemical and kinetic data, it is clear that O‒H group of cyanidin in position 3` is the most suitable for reaction with hydroxyl radical through mentioned antioxidant mechanism

Antioksidativna i inhibitorska aktivnost Alizarin-2-glikozida

In this paper was investigated the antioxidative activity of alizarin-2-glycoside. All results were obtained using the DFT method. For calculations, the M06-2X method was used in combination with the 6-311++G(d,p) base set. Water was used as a solvent. The values of enthalpy were used as thermodynamic parameters on the basis of which the antioxidative capacity of alizarin-2-glycoside was evaluated. The Molecular Docking method was used for assessing the ability of alizarin-2-glycoside to inhibit the negative effect of P-glycoprotein.U ovom radu je ispitana antioksidativna aktivnost alizarin-2-glikozida. Svi rezultati dobijeni su primenom DFT metode. Za izračunavanja je korišćena M06-2X metoda u kombinaciji sa 6-311++G(d,p) bazisnim skupom. Kao rastvarač korišćena je voda. Vrednosti entalpija korišćene su kao termodinamički parametri na osnovu kojih je procenjen antioksidativni kapacitet alizarin-2-glikozida. Molecular Docking metodom procenjena je sposobnost alizarin-2-glikozida da inhibira negativan uticaj P-glikoproteina

Ligand-protein interakcije 3-(1-(3-hidroksipropilamino)etiliden)hroman-2,4-diona sa humanim C reaktivnim proteinom

The structure of the newly synthesized coumarin derivative, 3-(1-(3-hydroxypropylamino)-ethylidene)-chroman-2,4-dione, was investigated theoretically. The density functional theory calculations, with B3LYP functional (and with empirical dispersion corrections D3BJ) in combination with the 6–311+G(d,p) basis set, are performed in order to optimized the molecular structure of the investigated coumarin derivative. Molecular docking analysis was carried out in order to identify the potency of inhibition of the title molecule against human C-reactive protein. The inhibition activity was obtained for ten conformations of ligand inside protein.Struktura novo sintetisanog derivata kumarina, 3- (1- (3-hidroksipropilamino) -etiliden) -hroman-2,4-diona, ispitana je primenom teorijskih metoda. Za optimizaciju strukture ispitivanog kumarinskog derivata korišćena je teorija funkcionalne gustine: B3LYP funkcional ( sa empirijskim ispravkama disperzije D3BJ) u kombinaciji sa 6-311+G(d, p) bazisnim setom. Urađen je molekulski doking, kao i analiza dobijenih rezultata kako bi se utvrdio potencijal inhibicije molekula ispitivanog jedinjenja prema humanom C-reaktivnom proteinu. Aktivnost inhibicije izračunata je za deset potencijalnih konformacija liganda unutar proteina

Mehanizmi antioksidativnih reakcija alizarina sa slobodnim radikalima

Different metabolic processes as nus products form variety free radicals. Those radicals have damaging influence to people health, when they are formed in human bodies, or react as active components in reactions of nutrients decay. In this article are investigated mechanisms of radical scavenging activity of alizarin in reactions with •OH, •OOH and CH3OO• radicals. All results are obtained using DFT method. For calculations is used M06-2X functional in combination with 6-311++G(d,p) basis set. Lipid and aqueous environment are imitated. All conclusions are based on ΔH values, as thermodynamically indicator for anticipation of reaction pathway.Tokom različitih metaboličkih procesa kao nus-produkti nastaju mnoštvo slobodnih radikala . Ovi radikali imaju štetan uticaj na zdravlje ljudi, ukoliko nastaju u čovekovom organizmu, ili reaguju kao aktivne komponente u reakcijama kvarenja hrane. U ovom radu su ispitani mehanizmi antiradikalske aktivnosti alizarina u reakcijama sa •OH, •OOH i CH3OO• radikalom. Svi rezultati dobijeni su primenom DFT metode. Za izračunavanja je korišćen M06-2X funkcional u kombinaciji sa 6-311++G(d,p) bazisnim skupom. Simulirano je lipidno i vodeno okruženje. Svi zaključci bazirani su na ΔH vrednostima, kao termodinamičkom indikatoru za predviđanje reakcionog puta

Antioksidativna aktivnost nekih šifovih: eksperimentalna i teorijaska ispitivanja

Ten hydroxyl-substituted Schiff bases with the different number and position of hydroxyl group on the two aromatic rings (A and B rings) was synthesized and have been under experimental and theoretical investigation of antioxidant activity. DPPH method was used for experimental examination of antioxidant activity, and DFT method for theoretical investigation in polar and non polar solvents.Sintetisano je deset različitih hidroksi-supstituisanih Šifovih baza, koje imaju različit broj i položaj hidroksilnih grupa koje se nalaze na dva aromatična prstena (prsten A i B). Ispitana je njihova antioksidativna aktivnost, eksperimentalnim i teorijskim metodama. Za eksperimentalna ispitivanja antioksidativne aktivnosti korišćena je DPPH metoda, dok su teorijska ispitivanja u polarnim i nepolarnim rastvaračima urađena DFT metodom