Irena Kostova

Irena Kostova

Professor, PhD, DSc

About

153
Publications
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5,121
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Additional affiliations
November 1994 - present
Faculty of Pharmacy, Sofia
Position
  • Professor (Full)

Publications

Publications (153)
Article
Full-text available
The superoxide radical ion is involved in numerous physiological processes, associated with both health and pathology. Its participation in cancer onset and progression is well documented. Lanthanum(III) and gallium(III) are cations that are known to possess anticancer properties. Their coordination complexes are being investigated by the scientifi...
Article
Lychee-like Mesoporous Silica Nanoparticles (LMSN) were synthesized and functionalized with 3-Aminopropyltrimethoxysilane (3-APTMS) and a novel binuclear Copper complex. The synthesized materials were characterized by UV-DRS, Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDA...
Article
Full-text available
The neodymium(III) complex of orotic acid (HOA) was synthesized and its structure determined by means of analytical and spectral analyses. Detailed vibrational analysis of HOA, sodium salt of HOA, and Nd(III)–OA systems based on both the calculated and experimental spectra confirmed the suggested metal–ligand binding mode. Significant differences i...
Article
Full-text available
Increased levels of the superoxide radical are associated with oxidative damage to healthy tissues and with elimination of malignant cells in a living body. It is desirable that a chemotherapeutic combines pro-oxidant behavior around and inside tumors with antioxidant action near healthy cells. A complex consisting of a pro-oxidant cation and antio...
Article
The gout disease is spreading worldwide and its drug target is the human xanthine oxidase. Through this work, we investigated the inhibitory effect of the ten lanthanide(III) complexes of biologically active bis-coumarins on xanthine oxidase. We achieved molecular docking studies using GOLD software to study the formed interactions in the enzyme-in...
Article
Background The impact of cancer on modern society cannot be emphasized enough in terms of both economic and human costs. Cancer treatments are known, unfortunately, for their side effects – frequently numerous and severe. Drug resistance is another issue medical professionals have to tackle when dealing with neoplastic illnesses. Cancer rates are r...
Article
To enlarge the highly active fluorophore family of small molecular heterocycles, we present an effective strategy for the synthesis of novel 2-aryl-1,2,3-triazol-4-carboxylic acids (ATAs). The behavior of ATAs in different solvents showed that these new 1,2,3-triazole derivatives had bright blue fluorescence with excellent quantum yields, large Sto...
Article
Background: Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has...
Article
Full-text available
Superoxide and hypochlorite radicals are involved in both normal and pathological processes in the human body. Excessive production of any of them may result in malignization of healthy cells. The ideal chemotherapeutic must exhibit prooxidant action in the tumor and antioxidant behavior in healthy tissues. Lanthanum (III) salts have been investiga...
Article
This work represents the pioneering synthesis of Lychee-like Mesoporous Silica Nanoparticles (LMSN) using a Modified Liquid Template Corrosion (MLTC) method using ethanolamine as a base medium. In this method, the emulsion system containing a cationic surfactant, water, ethylacetate (EA), Tetraethyl orthosilicate (TEOS) was used along-with monoetha...
Conference Paper
The biological activity of hypochlorite is associated with aggressive oxidative interactions with a variety of functional groups leading to oxidative stress in biological systems. Gallium(III) is a well known anticancer agent. Its complex (GaAOA) with 5-aminoorotic acid (HAOA) exhibits antioxidant activity. The aim of the current study is to establ...
Article
Full-text available
The role metals play in living organisms is well established and subject to extensive research. Some of them participate in electron-exchange reactions. Such reactions cause generation of free radicals that can adversely impact biological systems, as a result of oxidative stress. The impact of ‘non-biological’ metals on oxidative stress is also a w...
Article
Condensation reaction of 3-aminopropyltrimethoxysilane with o-hydroxyacetophenone and subsequent complexation with Cu(CH3COO)2.H2O afforded Schiff base copper complex with silane moiety. Covalent functionalisation of MCM-41 with Schiff base copper complex yielded heterogenised Copper complex which mimics the “CuN2O2” coordination site that resemble...
Article
Metal nanoparticles (NPs) are being used in several research fields such as medical and environmental research, because they have unique biophysical properties, mainly owing to high accessible surface. Among several noble metal NPs, gold NPs (AuNPs) have received peculiar interest. Conventionally, AuNPs are synthesized using chemicals as reducing a...
Article
Full-text available
The success of the cancer treatment depends on the good control over the oxidative stress (OS). Lanthanides and their compounds are promising anticancer agents due to the prooxidant activity of the Ln(III) cations. A complex formed by coordinatively bonding lanthanide ion with antioxidant ligand is promising strategy in the search of efficient anti...
Article
Full-text available
Along with anti-tumor activity, flexible control over oxidative stress (OS) levels is a desirable quality of any anticancer drug. Radicals scavenging activity (RSA) toward 2,2-diphenyl-1-picrylhydrazyl radical (DPPH ) is widely used to evaluate the ability to eliminate free radicals by donating hydrogen. 5-aminoorotic acid (HAOA) is known to have...
Article
Full-text available
Orotic (HOA) and 5-aminoorotic (HAOA) acids are ligands in metal complexes with in vitro antioxidant and anticancer activities. Dietary orotic acid in vivo increases the free radicals formation in the liver by diminishing both activity and mRNA level of Cu,Zn-SOD. It seems that HOA may act as antioxidant by scavenging free radicals, but as prooxida...
Article
Full-text available
Background: Free radicals are frequently generated in vivo and their reactivity varies causing different damages to biological molecules, e.g. DNA, lipids, and proteins. Oxidative stress in the human body is due to the free radicals generation and to the reduced level of antioxidants. Antioxidants are able to reduce the risk for chronic diseases. H...
Presentation
Full-text available
Estimation of the antioxidant properties of HAOA and its gallium(III) complex (GaAOA) toward the DPPH• OH• radicals in model systems.
Article
Nanoparticles (NPs) in different forms have been widely used in medicine and pharmaceutics for diagnosis and drug delivery. So, they are in intimate contact with bio-macromolecules like proteins which are vital and functional elements of cells and organisms. Thus, in vitro studies of the possible interaction between proteins and NPs are necessary f...
Article
The effects of Sm(III), Gd(III) and Dy(III) nitrates on the accumulation of free radicals and uric acid in the model system, Xanthine/Xanthine oxidase (X/XO) was estimated, and compared with that for the model system alone, or in the presence of sodium nitrate. It was found that all Ln(III) nitrates acted as prooxidants. It was proposed that their...
Article
Platinum complexes which are most studied metal complexes due to their importance as adjuvant therapy of cancers aiming to induce tumor-cell-death. Some of the platinum-based antitumor drugs like cisplatin, carboplatin and oxaliplatin, have several disadvantages including side effects, cisplatin-resistant tumors, limited solubility in aqueous media...
Article
The dysprosium(III) complex of 5-aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt in amounts equal to ligand, molar ratio of 1:3. The structure of the complex was determined by means of elemental analysis, FTIR and FT-Raman spectroscopies. Significant differences in the IR and Raman spectra of the complex were ob...
Book
Този учебник е предназначен за студенти по фармация и обхваща материала, включен в курса по обща и неорганична химия. Съдържанието на учебника е съобразено с учебната програма. В дисциплината "Обща и неорганична химия", преподавана във Фармацевтичен факултет , се разглеждат фундаменталните принципи и общи насоки на химията, а в частта й по химия на...
Article
Full-text available
p>The gallium(III) complex of orotic acid (HOA) was synthesized and its structure was determined by means of analytical and spectral analyses. Detailed vibrational analysis of HOA, sodium salt of HOA (NaOA) and Ga(III)-OA systems based on both the calculated and experimental spectra confi rmed the suggested metal-ligand binding mode. Signifi cant d...
Article
A samarium(III) complex (SmAOA) of 5-aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt and ligand in a molar ratio of 1:3. The structure of the complex was determined by means of elemental analysis and UV-visible, NMR, Fourier transform infrared (FT-IR) and FT Raman spectroscopies. Significant differences in the F...
Article
A samarium(III) complex (SmAOA) of 5-aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt and ligand in a molar ratio of 1:3. The structure of the complex was determined by means of elemental analysis and UV–visible, NMR, Fourier transform infrared (FT-IR) and FT Raman spectroscopies. Significant differences in the F...
Article
A new gadolinium(III) complex of 5-aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt in molar ratio of 1:3 to ligand. The structure of the complex was determined by elemental analysis, FT-IR, and FT-Raman spectroscopies. Significant differences in the IR and Raman spectra of the complex were observed as compared t...
Article
Objectives: This study is an extension to our finding of direct anti-oxidant activities of lanthanide(III) complexes with the heterocyclic compound, 5-aminoorotic acid (AOA). In this experiment, we used AOA and coumarin-3-carboxylic acid as the two heterocyclic compounds with anti-oxidant potential, to produce the complexes with different lanthani...
Article
Lanthanides are group of rare-earth elements with growing applications both in the industry and healthcare. Their unique properties impose various possibilities for involvement in electron transfer reactions essential for the cellular survival and health on general. The intensified contact of people with lanthanides and the expanding medicinal appl...
Article
Full-text available
The acquired immunodeficiency syndrome (AIDS) is a result of human immunodeficiency virus (HIV) infection which leads to severe suppression of immune functions. AIDS is a real threat to the health of mankind, and the search for effective therapies is still of great importance. However, besides the high cost, there are adverse effects and limitation...
Article
The search for metal-derived antioxidants has received much attention and effort in order to identify the compounds having high capacity in scavenging free radicals related to various disorders and diseases associated with oxidative damage, caused by reactive oxygen species (ROS). Presently, synthetic antioxidants are widely used because they are e...
Article
Recent years have witnessed an unprecedented progress in biological applications of metal coordination compounds of biologically active ligands because of their key role in clinical therapy. Transition metals are particularly suitable for this purpose because they can adopt a wide variety of coordination numbers, geometries and oxidation states in...
Article
Full-text available
DFT approximation was applied for investigation of a series di-[4-hydroxycoumain]s. Different basis sets were tested in the course of the calculations. The calculated hydrogen bond energies revealed two equivalent hydrogen bonds in DC and two different in strengths hydrogen bonds in PhDC and PyDC. Further, the effect of the substutient on the hydro...
Article
New Ga(III) complex of coumarin-3-carboxylic acid (HCCA) was synthesized and its structure and spectral properties were investigated by elemental analysis, FTIR, FT Raman and NMR measurements. According to the experimental data, the complex formula was suggested. Vibrational frequencies, IR intensities and Raman activities as well as 1H NMR chemica...
Article
Full-text available
The synthesis of a new In(III) complex of coumarin-3-carboxylic acid (HCCA) is described and its structure and spectral properties are investigated by elemental analysis, FTIR, FTRaman and NMR measurements. According to the experimental data the formula of complex is suggested. Vibrational frequencies, IR intensities and Raman activities as well as...
Article
New complexes of coumarin-3-carboxylic acid (HCCA) with holmium [Ho(III)] and erbium [Er(III)] were synthesized and their structures and spectral properties were investigated by elemental analysis, IR, Raman and NMR measurements. According to the experimental data of the complexes, their formulae and geometries have been suggested. Vibrational freq...
Article
Coumarins, a well-known class of naturally occurring compounds, display a remarkable array of biochemical and pharmacological actions, some of which suggest that certain members of this group of compounds may significantly affect the function of various mammalian cellular systems. The development of coumarins as antioxidant agents has attracted muc...
Article
Full-text available
A comparative analysis on the effect of the water on the molecular structure and spectroscopy of 5-halogenated uracils was carried out. Solvent effects were considered by using a variable number (1–10) of explicit water molecules surrounding the 5-halouracil derivatives in order to simulate the first hydration shell. More than 300 cluster structure...
Article
The experimental and theoretical vibrational spectra of Warfarin sodium (WS) were studied. FT-IR and FT-Raman spectra of WS in the solid phase were recorded and analyzed. The optimized geometry and vibrational wavenumbers have been computed using HF/6-31G(d) and for the DFT, B3LYP/6-31G(d), 6-31G(d,p), and cc-pVDZ and B3PW91/6-31G(d) and 6-311++G(2...
Article
New complexes of coumarin-3-carboxylic acid (HCCA) with Ho(III) and Pr(III) were synthesized and their structures and spectral properties were investigated by elemental analysis, IR, Raman and NMR measurements. According to the experimental data the complexes' formula and geometries were suggested. Vibrational frequencies, IR intensities and Raman...
Article
The Fourier transform infrared (4000–400 cm−1) and Fourier transform Raman (3500–500 cm−1) spectra of 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one (Warfarin) have been measured and calculated. The structure optimization has been made using density functional theory (DFT) calculations. Complete vibrational assignments of the observed spec...
Article
A new complex of coumarin-3-carboxylic acid (HCCA) with Pr(III) is synthesized and its structure and molecular properties are investigated by elemental analysis, IR, Raman, NMR measurements and quantum chemical calculations. The elemental analysis suggested the general formula Pr(CCA)2(NO3)(H2O). The HCCA ligand possesses two donor groups (deproton...
Article
The coordination behavior of warfarin towards Pr(III) in Pr(L)3·5H2O complex (L – warfarin) is investigated through molecular modeling at B3LYP/6-31G(d,p) level and consequent exhaustive comparative vibrational analysis of the ligand and the complex. The calculated NPA charges, Fukui functions and MEP values of the anionic ligand in solution pointe...
Article
Full-text available
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Article
Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies
Article
While cancer remains a major killer in the developed world, a broad spectrum of novel and exciting approaches are being developed and tested. The importance of metal compounds in medicine is undisputed, as can be judged by the use of many metal-based compounds in the treatment of various diseases. In terms of anti-tumour activity, a wide range of c...
Article
Full-text available
FT-IR spectrum of 2-chloro-6-methyl benzonitrile in the region 400-4000 cm-1 has been recorded in KBr pellet technique with a Bruker IFS-66 Fourier transform spectrometer. FT-Raman spectrum in powder form has been recorded in the region 50-4000 cm"' on a Bruker IFS 66 optical bench with an FRA 106 Raman module attachment interfaced to a microcomput...
Article
New La(III) and Dy(III) complexes of deprotonated 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (Acenocoumarol) were synthesized and characterized using FT-IR, FT-Raman, (1)H NMR spectra, and elemental analyses. The ligand and its lanthanide(III) complexes were tested for their cytotoxic/cytostatic activity against two tumor cell...
Article
Density functional calculations (DFT) by various methods were performed to clarify wavenumber assignments of the experimental observed bands. A comparison with the molecule of uracil was made, and specific scale factors were deduced and employed in the predicted wavenumbers of 5-IU. Comparisons were also performed with other halo-uracil derivatives...
Article
Full-text available
The laser Raman (0-3500 cm-1) and FTIR (200-4000 cm -1) spectra (Nujol, KBr, liquid and vapour) of 2-chloro-5- nitrobenzonitrile have been recorded. A zero-order normal coordinate analysis has been made for the molecule using force constants derived earlier. On the basis of potential energy distributions and eigen vectors unambiguous vibrational as...
Article
New Sm(III) and Gd(III) complexes of deprotonated 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (Acenocoumarol) were synthesized and characterized using FT-IR, FT-Raman, NMR spectra, and elemental analyses. The vibrational study gave evidence for the coordination of ligand to lanthanide ions. The ligand and its lanthanide(III) com...
Article
Full-text available
New La(III) and Dy(III) complexes of 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (Acenocoumarol) were characterized using FT-IR, FT-Raman spectral analyses. The infrared and Raman spectra of the ligand were predicted theoretically from the calculated intensities using B3LYP density functional theory (DFT) methods. The DFT calcul...
Article
The FT-IR and FT-Raman spectra of sodium salt of 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (acenocoumarol sodium salt) in solid phase have been recorded and analyzed. The optimization geometry, intramolecular hydrogen bonding, and harmonic vibrational wavenumbers of acenocoumarol sodium salt have been investigated with the hel...
Article
Complexes of cerium(III), lanthanum(III) and neodymium(III) with 3,5-pyrazoledicarboxylic acid (H3pdc) were synthesized and their compositions determined by elemental analysis. To identify the binding of Ce(III), La(III) and Nd(III) with H3pdc, detailed vibrational analysis was performed comparing experimental vibrational spectra of the ligand and...
Article
Full-text available
The complexation ability and the binding mode of the ligand coumarin‐3‐carboxylic acid (HCCA) to La(III), Ce(III), Nd(III), Sm(III), Gd(III) and Dy(III) lanthanide ions (Ln(III)) are elucidated at experimental and theoretical level. The complexes were characterized using elemental analysis, DTA and TGA data as well as 1H NMR and 13C NMR spectra. FT...
Article
The cerium (III), lanthanum (III) and neodymium (III) complexes of 5-aminoorotic acid were synthesized and their structures were determined by means of theoretical study, spectral and physicochemical analysis. Significant differences in the spectra of the complexes were observed as compared to the spectra of the ligand. The ligand and the complexes...
Article
The gadolinium(III) and dysprosium(III) complexes of 3, 5-pyrazoledicarboxylic acid (H3pdc) were synthesized and characterized. The structures of the final complexes were determined by means of FTIR and FTRaman spectral analyses. To help the binding mode elucidation in the new Gd(III) and Dy(III) complexes of h3pdc, detailed vibrational analysis wa...
Article
Angiogenesis, the development of new blood vessels from the existing vasculature, is essential in normal developmental processes. Uncontrolled angiogenesis is a major contributor to a number of disease states such as inflammatory disorders, obesity, asthma, diabetes, cirrhosis, multiple sclerosis, endometriosis, AIDS, bacterial infections and autoi...
Article
The new cerium(III), lanthanum(III) and neodymium(III) complexes were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, (1)H NMR, (13)C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of compa...
Article
Complexes of cerium(III) with bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-pyridin-2-yl-methane, bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-pyridin-3-yl-methane and bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-pyridin-4-yl-methane were synthesized by reaction of cerium(III) salt and the ligands, in amounts equal to metal-ligand molar ratio of 1:2. The cerium(III) comple...
Article
Full-text available
The cerium (III), lanthanum (III) and neodymium (III) complexes of 5-aminoorotic acid were synthesized and their structures were determined by means of theoretical study, spectral and physicochemical analysis. Significant differences in the spectra of the complexes were observed as compared to the spectra of the ligand. The ligand and the complexes...
Article
Coumarins have attracted intense interest in recent years because of their diverse pharmacological properties. Among these properties, their anticancer effect was most extensively examined. In this review, their broad range of effects on the tumours as shown by various in vitro and in vivo experiments as well as clinical investigations is discussed...
Article
The complexes of gadolinium(III) and dysprosium(III) were synthesized by reaction of the respective inorganic salts with 3,5-pyrazoledicarboxylic acid in amounts equal to metal to ligand molar ratio of 1 : 2. The structures of the final complexes were determined by means of spectral and elemental analyses. To help further the binding mode elucidati...
Article
Considerable progress has been made in recent years in the field of drug development against HIV. Many different kinds of natural products, including coumarins, have been found to be active in anti-HIV models and are thus undergoing further investigation. This review demonstrates the variety of coumarins with unique mechanisms of action in the diff...
Article
The complex of lanthanum(III) was synthesized by reaction of lanthanum(III) nitrate with sodium salt of orotic acid in amounts equal to metal:ligand molar ratio of 1:2. The structure of the final complex was determined by means of vibrational (IR and Raman) spectra and elemental analysis. Significant differences in the IR and Raman spectra of the c...
Article
New complexes of cerium(III) and neodymium(III) with coumarin-3-carboxylic acid (HCCA) were synthesized and characterized. The elemental, DTA and TGA analyses showed the general formula, Ln(CCA)2(NO3)(H2O) (Ln=Ce, Nd). To suggest the binding mode of HCCA a detail vibrational investigation based on Raman, FTIR and DFT/B3LYP/SVP studies of HCCA, its...
Article
Complexes of cerium(III), lanthanum(III) and neodymium(III) with coumarin-3-carboxylic acid (HCCA) were synthesized by mixing of equimolar amounts of the respective metal nitrates and coumarin-3-carboxylic acid in ethanol. The complexes were characterized and identified by elemental analysis, IR and Raman spectroscopy. DTA and TGA were applied to s...
Article
Full-text available
The complex of La(lll) with coumarin-3-carboxylic acid (HCCA) has been synthesized and characterized with different physicochemical data, elemental analysis, DTA and TGA data, IR, Raman, 1H NMR and 13C NMR spectra. B3LYP method with 6-31G(d) and 6-31++G(d,p) basis sets was successfully applied to study the molecular, electronic and vibrational stru...