Browsing by Author "Todorov P."
Now showing 1 - 20 of 22
Results Per Page
Sort Options
Item Additive Anticonvulsant Profile and Molecular Docking Analysis of 5,5′-Diphenylhydantoin Schiff Bases and Phenytoin(2023-11-01) Tchekalarova J.; Todorov P.; Rangelov M.; Stoyanova T.; Todorova N.Four 5,5′-diphenylhydantoin Schiff bases possessing different aromatic species (SB1–SB4) were recently synthesized and characterized using spectroscopic and electrochemical tools. The present study aimed to ascertain the anticonvulsant activity of the novel phenytoin derivatives SB1-Ph, SB2-Ph, SB3-Ph, and SB4-Ph, containing different electron-donor and electron-acceptor groups, and their possible mechanism of action. The SB2-Ph exhibited the highest potency to suppress the seizure spread with ED50 = 8.29 mg/kg, comparable to phenytoin (ED50 = 5.96 mg/kg). While SB2-Ph did not produce neurotoxicity and sedation, it decreased locomotion and stereotypy compared to control. When administered in combination, the four Schiff bases decreased the phenytoin ED50 by more than 2× and raised the protective index by more than 7× (phenytoin+SB2-Ph). The strongest correlation between in-vivo and docking study results was found for ligands’ interaction energies with kappa and delta receptors. These data, combined with the worst interaction energies of our ligands with the mu receptor, suggest that the primary mechanism of their action involves the kappa and delta receptors, where the selectivity to the kappa receptor leads to higher biological effects. Our findings suggest that the four Schiff bases might be promising candidates with potential applications as a safe and effective adjuvant in epilepsy.Item Ammonium hydrogen (RS)-[(5-methyl-2-oxo-1,3-oxazolidin-3-yl)methyl]phospho- nate(2010-01-22) Todorov P.; Naydenova E.; Nikolova R.; Shivachev B.In the title compound, NH4+·C 5H9NO5P-, the five-membered methyl-oxazolidin-2-one unit is disordered over two positions, the major component having a site occupancy of 0.832 (9). A three-dimensional network of O-H⋯O and N-H⋯O hydrogen bonds stabilizes the crystal structure.Item Balance modeling of the process for SiCaV alloy producing from waste vanadium catalyst(2014-02-25) Petrov P.; Marinov M.; Todorov P.; Alexandrova R.; Paunova R.The modern steel industry is characterized by continual improving the quality of the produced steel with constantly increasing range and quantity of deoxidation and alloying alloys. Among them falls SiCa with vanadium. Consider the absence in the Republic of Bulgaria of raw materials containing vanadium for example, the needs of metallurgy are provided mainly by imports of ferro-alloys. At the same time our country has an active chemical and metallurgical industries where significant polluting quantities of vanadium catalyst drop from production of sulfuric acid, which contains Si and V. Both material and heat balance models are developed for carbothermal producing of SiCa with a high content of vanadium. Vanadium waste, metallurgical lime and metallurgical coke are the raw material. The elements in the alloy after the carbothermal reduction are: V - 9.09 %, Fe - 9.06 %, Si - 66.45 %, Ca - 12.26 %, P - 0.02 %, S - 0.04 %, C - 0.21 %, Al - 2.83 % u Mn - 0.03 %. The main contributor into the alloy of V, Si and Fe is the waste vanadium catalyst. The relative consumption of electricity according to the heat balance model is 11505 kWh/ton alloy.Item Behavioral Effects and Analgesic Profile of Hemoglobin-Derived Valorphin and Its Synthetic Analog in Rodents(2023-10-01) Todorov P.; Assenov B.; Angelov D.; Dzhambazova E.; Pechlivanova D.Valorphin (V1) is a naturally occurring peptide derived from hemoglobin that has been found to have an affinity for opioid receptors and exhibits antinociceptive and anticonvulsant activity. Some of its synthetic analogs containing an aminophosphonate moiety show structure-dependent potent antinociceptive effects. This study aimed to reveal a detailed picture of the antinociceptive mechanisms and behavioral effects of V1 and its recently synthesized phosphopeptide analog V2p in rodents using a range of methods. The studied peptides significantly reduced acute (mean V1–9.0, V2p–5.8 vs. controls–54.1 s) and inflammatory (mean V1–57.9 and V2p–53.3 vs. controls–107.6 s) nociceptive pain in the formalin test, as well as carrageenan-induced hyperalgesia (mean V1–184.7 and V2p–107.3 vs. controls–61.8 g) in the paw pressure test. These effects are mediated by activation of opioid receptors with a predominance of kappa in V1 antinociception and by delta, kappa, and mu receptors in V2p-induced antinociception. Both peptides did not change the levels of TNF-alpha and IL-1-beta in blood serum. V1 induces depression-like behavior, and V2p shows a tendency toward anxiolysis and short-term impairment of motor coordination without affecting exploratory behavior. The results characterize valorphin and its derivative as promising analgesics that exert their effects both centrally and peripherally, without causing severe behavioral changes in experimental animals. These encouraging data are a foundation for future studies focusing on the effects of hemorphins after long-term treatment.Item Chemical Behavior and Bioactive Properties of Spinorphin Conjugated to 5,5′-Dimethyl- and 5,5′-Diphenylhydantoin Analogs(2024-06-01) Georgieva S.; Todorov P.; Tchekalarova J.; Subaer S.; Peneva P.; Chakarov K.; Hartati H.; Faika S.The discovery of new peptides and their derivatives is an outcome of ongoing efforts to identify a peptide with significant biological activity for effective usage as a possible therapeutic agent. Spinorphin peptides have been documented to exhibit numerous applications and features. In this study, biologically active peptide derivatives based on novel peptide analogues of spinorphin conjugated with 5,5′-dimethyl (Dm) and 5,5′-diphenyl (Ph) hydantoin derivatives have been successfully synthesized and characterized. Scanning electron microscopy (SEM) and spectral methods such as UV-Vis, FT-IR (Fourier Transform Infrared Spectroscopy), CD (Circular Dichroism), and fluorimetry were used to characterize the microstructure of the resulting compounds. The results revealed changes in peptide morphology as a result of the restructuring of the aminoacidic sequences and aromatic bonds, which is related to the formation of intermolecular hydrogen bonds between tyrosyl groups and the hydantoin moiety. Electrochemical and fluorescence approaches were used to determine some physicochemical parameters related to the biological behavior of the compounds. The biological properties of the spinorphin derivatives were evaluated in vivo for anticonvulsant activity against the psychomotor seizures at different doses of the studied peptides. Both spinorphin analog peptides with Ph and Dm groups showed activity against all three phases of the seizure in the intravenous Pentylenetetrazole Seizure (ivPTZ) test. This suggests that hydantoin residues do not play a crucial role in the structure of spinorphin compounds and in determining the potency to raise the seizure threshold. On the other hand, analogs with a phenytoin residue are active against the drug-resistant epilepsy test (6-Hz test). In addition, bioactivity analyses revealed that the new peptide analogues have the potential to be used as antimicrobial and antioxidant compounds. These findings suggest promising avenues for further research that may lead to the development of alternative medicines or applications in various fields beyond epilepsy treatment.Item Comparative Analysis of Anticonvulsant Activity of Trans and Cis 5,5′-Diphenylhydantoin Schiff Bases(2023-11-01) Tchekalarova J.; Todorov P.; Stoyanova T.; Atanasova M.Recently, the four 5,5′-diphenylhydantoin Schiff bases, possessing different aromatic species (SB1-Ph, SB2-Ph, SB3-Ph and SB4-Ph) were synthesized, characterized, and evaluated for anticonvulsant activity in combination with phenytoin. In the present study, the SB1-Ph and SB4-Ph compounds were selected, based on their anticonvulsant potency, and compared with their cis isomers, prepared after a one-hour exposure to the UV source, for their anticonvulsant potency in the maximal electroshock (MES) test and the kainate (KA)-induced status epilepticus (SE) test in mice. In the MES test, the cis SB1-Ph compound exhibited superior to phenytoin and trans isomer activity in the three tested doses, while the cis SB4-Ph compound entirely suppressed the electroshock-induced seizure spread at the highest dose of 40 mg/kg. Pretreatment with the cis SB1-Ph compound and the cis SB4-Ph at the doses of 40 mg/kg, respectively, for seven days, significantly attenuated the severity of KA SE compared to the matched control group pretreated with a vehicle, while phenytoin was ineffective in this test. The cis SB4-Ph but not the cis SB1-Ph demonstrated an antioxidant effect against the KA-induced SE in the hippocampus. Our results suggest that trans–cis conversion of 5,5′-diphenylhydantoin Schiff bases has potential against seizure spread in the MES test and mitigated the KA-induced SE. The antioxidant potency of cis SB4-Ph might be associated with its efficacy in mitigating the SE.Item DEVELOPMENT OF VOLTAMMETRIC METHOD FOR DETERMINATION OF TRACE OF Cu(II) IN THE PRESENCE OF Fe(III) IN WATER USING 5,5'-DIPHENYLIMIDAZOLIDINE-2,4-DIONE DERIVATIVE(2021-01-01) Georgieva S.; Todorov P.; Bezfamilnyi A.A new cyclic voltammetric method has been developed for the determination of Cu(II) in the presence of Fe(III) in tap and surface water samples using complexing properties of 5,5'-diphenylimidazolidine-2,4-dione derivative. In acetate buffer solution (0.1 mol L-1; pH 5.25 ± 0.01) containing minimum ten-fold excess of imidazolidine derivative, copper metal ion was determined as complex compound following redox process into the working hanging mercury drop electrode (HMDE) versus Ag/AgCl, 3 mol L-1 KCl using as a reference electrode. Limits of detection as low as 0.0415 mg L-1 Cu(II) was achieved. The interfering effect of various cations as K(I), Na(I), Mg(II), Ca(II), Al(III), Zn(II), Fe(II), Fe(III) and anions: Cl-, NO3-, SO42-, PO43-, most common in surface and tap water samples, were also assessed.Item Investigation of electrochemical behavior of new hemorphin-5 analogue(2019-01-01) Georgieva S.; Todorov P.; Peneva P.A biologically active VV-hemorphin-5 (Valorphin: Val-Val-Tyr-Pro-Trp-Thr-Gln) analogue was characterized electrochemically. In this regard the oxidation and adsorption reactions of the peptide on an electrode surface in a phosphate buffer solution have been studied and compared with those of valorphin and polarographic active tryptophan and tyrosin. For investigation of the interfacial behavior of the VV-hemorphin-5 derivative (H2) voltamperometry with platinum electrode as working electrode, with Ag/AgCl, (3 mol L-1) KCl electrode as a reference electrode, and a carbon electrode as an auxiliary electrode, have been used. The redox potentials were determined under various mode of sweep - differential pulse (DP) and cyclic voltamperometry (CV). Analysis of the wave shape, pH dependence, and concentration dependence of the oxidation process leads to the conclusion that the valorphin derivative is adsorbed on the Pt-electrode. The detection of a low concentration (2x10-5 mol L-1) leads to the conclusion for possible application of the voltamperometry as a method for determination of low concentrations from this class peptides.Item Metal–Peptide Complexes with Antimicrobial Potential for Cotton Fiber Protection(2023-02-01) Georgieva S.; Todorov P.; Staneva D.; Grozdanov P.; Nikolova I.; Grabchev I.A study of the formation of copper (II) complexes with hemorphin peptide motifs in alkalic water solutions is presented. The effect of the peptide ligand on the complexing properties of the Cu (II) ion was quantified by giving the stoichiometry and stability of the complex compounds in the medium in which they are formed using voltammetric (cyclic) and spectral (UV-Vis and fluorimetric) analytical techniques. The resulting complexes were examined via IR spectroscopy to detect M-N and M-O oscillations and using the EPR approach in solution and in the solid phase to view the coordination and ligand binding regime. The possibility of the synergistic action of copper ions in the antivirus protection processes of cotton fibers coated in the same solvent with the newly obtained complex compounds was also investigated. One of the advantages is the formation of the complexes in an environment where the immobilization takes place, which contributes to increasing the efficiency of the process. The obtained results may serve as an aid for future more detailed biological studies of structure–activity relationships (SARs).Item METHODS FOR MODIFICATION OF COTTON FABRICS WITH GELATIN - GLUTARALDEHYDE AND ZNO NANOPARTICLES(2022-01-01) Zheleva D.; Koleva M.; Angelova D.; Grabcheva D.; Todorov P.Cotton fabrics have good water absorption properties, air permeability, non-toxicity, but microorganisms easily damage them. Collagen is a commonly used biomaterial that has properties such as biocompatibility, biodegradability, non-toxicity, but with poor mechanical properties. Glutaraldehyde is the main cross-linking agent for collagen and characterized by antimicrobial properties. ZnO nanoparticles exhibiting antibacterial, antifungal, anticorrosive and protective properties against UV, is widely applicable in medicine. The combination of all these components in one biocomposite with potential antimicrobial properties and healing effect can find application in medical practice. In this study, an attempt was made to improve the properties of cotton fabric by impregnating it with gelatin hydrogel cross-linked with glutaraldehyde and containing ZnO nanoparticles. Three methods of modification were applied, varying the mixing regimes of the components and the conditions. The composite materials were investigated by means of SEM, FTIR, and fluorescence analysis. The morphological analyzes of the samples modified by different methods show that the spher ical particles of ZnO have changed into a flower-like structures; the particles are covered by the collagen film; and dispersed and agglomerated in certain places. FTIR analyzes prove interactions between the organic and inorganic components. This is also confirmed by the observed fluorescent properties, which are of different intensity. All these observations suggest good antibacterial properties that will be the subject of future research.Item OPTICAL PROPERTIES OF PAZO POLYMER COMPOSITE FILMS DOPED WITH PARTICLES OF A NOVEL COPPER HYDANTOIN COMPLEX(2021-01-01) Lilova V.; Trifonova Y.; Stoilova A.; Georgieva S.; Todorov P.In this work the transmittance coefficient (T), the reflectance coefficient (R), the refractive index (n), the extinction coefficient (k), the optical absorption coefficient (a) and the optical band gap (Eof thin (poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]), shortly PAZO, azopolymer films with embedded particles of Cu(II) 3-amino-5,5‘-dimethylhydantoin at three different concentrations have been determined. The influence of the dopants concentration on the optical performance of the composite films has been discussed.Item Photoinduced birefringence in pazo polymer nanocomposite films with embedded particles of biologically active metal complexes(2019-01-01) Mateev G.; Stoilova A.; Nazarova D.; Nedelchev L.; Todorov P.; Georgieva S.; Trifonova Y.; Lilova V.The composite materials based on azo polymers doped with metal particles attract considerable attention due to their advantageous electrical and optical properties. The present communication reports results from measuring the photoinduced birefringence in composite films of the azopolymer (poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]), shortly PAZO, doped with metal complexes of Cu(II) 3-amino-5,5'-dimethylhydantoin (CLP) and Ni(II) 3-amino-5,5'-dimethylhydantoin (NLP) of different concentrations. The thin film materials are prepared via spin coating. The thickness of the samples is in the range between 500 nm and 800 nm. The photoinduced birefringence is measured by a classical polarimetric setup, where a vertically polarized He-Cd laser emitting at ? = 442 nm is used as a pump laser, while a DPSS laser emitting at = 635 nm is used as a probe laser. The influence of the dopants concentration on the maximal induced birefringence and the time of response are discussed.Item (R)-Methyl {[(2-carb-oxy-bicyclo-[2.2.2]octan-1-yl)-ammonio]-methyl}-phos- phon-ate dichloro-methane 0.25-solvate(2011-08-01) Todorov P.; Calmes M.; Shivachev B.L.; Nikolova R.P.The carb-oxy-lic acid mol-ecule of the title compound, C 11H 20NO 5P·0.25CH 2Cl 2, exists as a zwitterion with the H atom of the phospho-nate group being transferred to the imine N atom. In the asymmetric unit, there are two crystallographically independent acid molecules adopting the same absolute configuration and differing slightly in their geometrical parameters. In each mol-ecule, the imino and carboxyl groups are connected via an intra-molecular N - H⋯O hydrogen bond. Inter-molecular O - H⋯O and N - H⋯O hydrogen bonds induce the formation of layers parallel to the ab plane. The dichloro-methane solvent mol-ecule, with a site occupancy of 0.5, is located between the layers.Item Recent Synthesis, Characterization, and Pharmacological Evaluation of Multifunctional Hemorphins Containing Non-Natural Amino Acids with Potential Biological Importance(2022-11-01) Todorov P.; Georgieva S.; Tchekalarova J.The endogenous hemorphins are bioactive peptides with activity on opioid receptors. They are extensively studied and summarized in numerous reviews. During the last decade, several research teams have synthesized, characterized, and pharmacologically evaluated synthetic hemorphin analogs containing unusual amino acids, D-amino acids, α-aminophosphonic acids, and their derivatives. The present review summarizes the current studies on short-chain synthetic hemorphin peptide derivates containing non-natural amino acids. This review focuses on the structure–activity relationship analysis, details on specific methods for their characterization, and the advantage of synthetic hemorphin analogs compared to endogenous peptides as potent biologically active compounds with a complex mechanism of action.Item Spectroscopic and voltamperometric studies of Cu(II) complex with 3-amino-5,5-diphenylhydantoin(2018-01-01) Georgieva S.; Todorov P.New copper(II)-aminohydantoin complexes ([CuAPh2Cl2(OH2)2]; [CuAPh2(NH3) (OH2)2], where APh is 3-amino-5,5-diphenylhydantoin), were synthesized and analyzed by means of elemental analysis, atomic absorption spectroscopy, UV-Vis spectroscopy and voltamperometric method. The complex forming processes in the Cu(II)- aminophenytoin (APh) system are studied by differential pulse polarography (DPP). The experiments are carried out at temperature of 20±1°C in ammonia buffer solution (pH = 8.2±0.1) at ionic strength I = 0.1. The reversibility of the reduction of the peak is proved and the equations of De Ford and Hume and these of Leden to DPP data are applied. The mean ligand number n of the complexes formed is found from the slopes of the straight lines of r ΔEpr = f(lgCAPh) function. The existence of two complexes (n =1 and 2) is proved in the presence of high ligand concentration (CAPh = 2.10-4 - 3.10-3 mol l-1) and the values of its conditional and total stability constants are found. It was found that the values of the total constants are lg CuβAPh = 8.0, lgβCuAPh2 =10.9 (I = 0.1). A satisfactory good coincidence between the results obtained by the procedure proposed and the literature data is observed. The atomic absorption spectroscopy and elemental analysis confirm the compounds stoichiometry. The IR and UV/Vis spectra show that APh act as bidentate ligands with the coordination involving the carbonyl oxygen and the nitrogen atom of amino group.Item Structure, conformation and hydrogen bonding of two amino-cycloalkanespiro-5-hydantoins(2009-01-09) Todorov P.; Petrova R.; Naydenova E.; Shivachev B.The crystal structures of 3-amino-cycloheptanespiro-4′- imidazolidine-2′,5′-dione (I) {systematic name: 3-amino-1,3-diazaspiro[4.6] undecane-2,4-dione} and 3-amino-cyclooctanespiro-4′- imidazolidine-2′,5′-dione (II) {systematic name: 3-amino-1,3-diazaspiro[4.7] dodecane-2,4-dione}, have been determined. In both compounds the polar hydantoin groups cause molecules to aggregate via N-H⋯O and N-H⋯N interactions, forming a layer structure, in which the cycloalkane rings project outwards from the central, more polar, region. The observed molecular structure is compared with that calculated by density functional theory methods. © Versita Warsaw and Springer-Verlag Berlin Heidelberg 2009.Item Study of Novel Peptides for Antimicrobial Protection in Solution and on Cotton Fabric(2022-08-01) Todorov P.; Georgieva S.; Staneva D.; Peneva P.; Grozdanov P.; Nikolova I.; Vasileva-Tonkova E.; Grabchev I.Some new N- and C-modified biomolecular peptide analogues of both VV-hemorphin-5 and VV-hemorphin-7 with varied amino acids (Cys, Glu, His), 1-adamantanecarboxylic acid, and niacin (nicotinic acid) were synthesized by solid-phase peptide synthesis—Fmoc (9-fluorenylmethoxy-carbonyl) chemistry and were characterized in water solutions with different pH using spectroscopic and electrochemical techniques. Basic physicochemical properties related to the elucidation of the peptide structure at physiological pH have been also studied. The results showed that the interaction of peptide compounds with light and electricity preserves the structural and conformational integrity of the compounds in the solutions. Moreover, textile cotton fibers were modified with the new compounds and the binding of the peptides to the surface of the material was proved by FTIR and SEM analysis. Washing the material with an alkaline soap solution did not show a violation of the modified structure of the cotton. Antiviral activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5), the antimicrobial activity against B. cereus and P. aeruginosa used as model bacterial strains and cytotoxic effect of the peptide derivatives and modified cotton textile material has been evaluated. Antimicrobial tests showed promising activity of the newly synthesized compounds against the used Gram-positive and Gram-negative bacteria. The compounds C-V, H-V, AC-V, and AH-V were found slightly more active than NH7C and NCH7. The activity has been retained after the deposition of the compounds on cotton fibers.Item Synthesis of new modified with rhodamine b peptides for antiviral protection of textile materials(2021-11-01) Todorov P.; Georgieva S.; Staneva D.; Peneva P.; Grozdanov P.; Nikolova I.; Grabchev I.Here we report on the synthesis and characterization of three new N-modified analogues of hemorphin-4 with rhodamine B. Modified with chloroacetyl, chloride cotton fabric has been dyed and color coordinates of the obtained textile materials were determined. Antiviral and virucidal activities of both the peptide-rhodamine B compounds and the dyed textile material were studied. Basic physicochemical properties (acid-base behavior, solvent influence, kinetics) related to the elucidation of structural activity of the new modified peptides based on their steric open/closed ring effect were studied. The obtained results lead to the conclusion that in protic solvent with change in pH of the environment, direct control over the dyeing of textiles can be achieved. Both the new hybrid peptide compounds and the modification of functionalized textile materials with these bioactive hemorphins showed virucidal activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5) for different time intervals (30 and 60 min) and the most active compound was Rh-3.Item Synthesis, Characterization and Biological Investigation of New N-Modified Spinorphin Analogs(2022-10-01) Todorov P.; Georgieva S.; Tchekalarova J.; Subaer S.; Peneva P.; Hartati H.The emergence of diverse peptide derivatives has been due to constant efforts to find a specific peptide with pronounced biological activity for effective application as a therapeutic. Spinorphin-peptide products have been reported to possess various applications and properties. In the present study, spinorphin peptides with a rhodamine residue and a modification in the amino acid backbone were synthesized by a solid-phase method using Fmoc chemistry. The results obtained from the spectral and electrochemical techniques used: Scanning electron microscopy (SEM), UV-vis, fluorescence, infrared spectroscopy (IR), and voltammetry were used to elucidate the structural characteristics and some physicochemical properties to gain insight into their behavior in the solid state and in aqueous solutions with different pHs. Both Rh-S5 and Rh-S6 had compound anticonvulsant effect comparable to Rh-S against psychomotor seizures at the highest dose of 20 μg. Furthermore, Rh-S6 showed a strong ability to inhibit seizure propagation and had a similar threshold to Rh-S against the intravenous pentylenetetrazol induced clonic seizure in mice; one of the three hybrid spinorphin analogs tested when screened for anticonvulsant activity. Biological tests against several bacterial pathogens such as Staphylococcus aureus, Escherichia coli, and Bacillus cereus showed similar results to negative control of the new peptide derivatives. The compounds also showed weak activity against Candida albicans fungus. The antioxidant testing results revealed more than 50% activity by reviewing the radical deterrence capabilities of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results are indicative of the ongoing search for universal antimicrobial agents with pronounced synergism when used simultaneously as anticonvulsant, antibacterial, and antifungal agents.Item Synthesis, characterization and cytotoxic activity of novel Cu(II) and Co(II) complexes with 3-amino-5, 5-dimethylhydantoin(2014-01-01) Georgieva S.; Todorov P.; Wesselinova D.Novel mixed complexes of copper (II) and cobalt (II) with 3-amino-5,5-dimethylhydantoin were synthesized and their in vitro anticancer activity was investigated. The structures of the compounds were confirmed by IR, UV-Vis spectrometry, voltammetry and elemental analysis. The cytotoxic effects of novel complexes of copper (II) and cobalt (II) with 3-amino-5,5-dimethylhydantoin were tested against a panel of human tumor cell lines. All of the compounds investigated exhibited different concentration-dependent antiproliferative effects against the HT29, MDA-MB-231, HepG2 and HeLa cell lines after 24 h of treatment. The most sensitive cells were the HepG2 cells at various concentrations of both tested compounds followed by HT29.