Marko N. Živanović

Vanillic Mannich bases: synthesis and screening of biological activity. Mechanistic insight into the reaction with 4-chloroaniline

One-step multi-component Mannich reaction of vanillin, aromatic amines (aniline and 4-chloroaniline), and cyclohexanone was successfully catalyzed by three chloroacetate ethanolamine based ionic liquids: diethanolammonium chloroacetate, and newly synthesized ethanolammoniumchloroacetate and N,N-diethylethanolammoniumchloroacetate. These reactions were performed in ethanol at room temperature. Mechanistic aspects of the reaction with 4-chloroaniline were considered by using density functional theory. The yield of obtained Mannich bases (MB-Cl and newly synthesized MB-H) was very good, while diastereoselectivity was excellent. These compounds were evaluated for their in vitro antioxidative activity by DPPH free radical scavenging assay. It was shown that both bases exhibit high activity against DPPH. In vitro cytotoxic and antioxidative effects of MB-Cl and MB-H against human breast carcinoma MDA-MB-231 and human colon carcinoma HCT-116 cell lines were also determined. The investigated Mannich bases show moderate or very weak cytotoxic effect on HCT-116 cells, while no cytotoxic effect was observed in the case of MDA-MB-231 cells. On the other hand, the tested substances induced oxidative stress in the treated cancer cell lines.

Chelate N,O-palladium(II) complexes: synthesis, characterization and biological activity

Four trans chelate N,O-palladium(II) complexes were synthetized starting from salicylaldehyde anil Schiff bases, as ligands. Their structures were elucidated using experimental and theoretical tools. The structures of the theoretically possible cis isomers are examined using the DFT method. The biological activity, in vitro cytotoxic and prooxidative effects against human breast carcinoma MDA-MB-231, human colon carcinoma HCT-116, and human fibroblast healthy MRC-5 cell lines of investigated compounds were determined. Schiff bases show a moderate or weak cytotoxic effect. On the other hand, complexes Pd-1 and Pd-6 show a significant cytotoxic effect on all three cell lines, with IC50 values in the range of 0.6 to 17.1 μM on HCT-116 cells, 7.2 to 55.6 μM on MDA-MB-231 cells and 34.5 to 48.1 μM on MRC-5 cells. Also, Pd-1 and Pd-6 induce extreme oxidative stress in the all treated cell lines. At this stage of investigation, Pd-1 and Pd-6 showed no selectivity towards cancer cells, i.e. they were also cytotoxic to MRC-5 cells to a similar extent. Taking into account these facts, it could be further investigated how the most active substances impact on the type of cell death (apoptotic and/or necrotic pathways).

Novel seleno-hydantoin palladium(II) complex - antimigratory, cytotoxic and prooxidative potential on human colon HCT-116 and breast MDA-MB-231 cancer cells.

Selenium and palladium containing compounds separately exert multifunctional effects on cells. While selenium containing compounds usually exert antioxidative properties, palladium(II) containing compounds are cytotoxic and prooxidative. Here we investigated biological effects of bicyclic seleno-hydantoin cis-7a-ethyl-5-methyl-5-phenylselanylmethyl-tetrahydro-pyrrolo[1,2-c]imidazole-1,3-dione (Hid-Se), and its palladium(II) complex, trans-bis-(cis-7a-ethyl-5-methyl-5-phenylselanylmethyl-tetrahydro-pyrrolo[1,2-c]imidazole-1,3-dionato) palladium(II) chloride ((Hid-Se)2Pd) on human colon HCT-116 and breast MDA-MB-231 cancer cell lines. Hid-Se and (Hid-Se)2Pd showed prooxidative and cytotoxic character. In all performed experiments (Hid-Se)2Pd proved to be more active, i.e. this substance exerted greater prooxidative effect, cytotoxicity and influence on cell migration potential. Even though Hid-Se and (Hid-Se)2Pd enhanced migration of HCT-116 cells, very important feature of these substances is the strong antimigratory potential on metastatic MDA-MB-231 cells.

Study of the structure, prooxidative, and cytotoxic activity of some chelate copper(II) complexes

The six chelate N,O-copper(II) complexes were synthesised starting from salicylaldehyde anil Schiff bases, as ligands. Their structure is elucidated using experimental and theoretical tools. In vitro biological activities, i.e. cytotoxic and prooxidative effects against human epithelial mammary gland/breast metastatic carcinoma MDA-MB-231, epithelial colorectal carcinoma HCT-116, and foetal lung fibroblast healthy MRC-5 cell lines of investigated compounds are also determined. Complexes Cu-1, Cu-6, and especially Cu-7 showed significant cytotoxic effects, with IC50 values comparable with effects of positive control CisPt. In addition, investigated complexes induced extreme oxidative and nitrosative stress in all treated cell lines. The most prominent effect is observed on HCT-116 cells, and on MRC-5 cells, while MDA-MB-231 cells showed higher resistance to the investigated cell lines, giving us direction towards the substances with more specific selectivity.

Real-time monitoring of cytotoxic effects of electroporation on breast and colon cancer cell lines.

PURPOSE To study the effects of electroporation on different cell lines. MATERIAL The effects of electroporation on human breast cancer (MDA-MB-231), human colon cancer (SW-480 and HCT-116), human fibroblast cell line (MRC-5), primary human aortic smooth muscle cells (hAoSMC) and human umbilical vein endothelial cells (HUVEC) were studied. Real-time technology was used for cell viability monitoring. Acridine orange/ethidium bromide assay was applied for cell death type determination. A numerical model of electroporation has been proposed. RESULTS Electroporation induced inhibition of cell viability on dose (voltage) dependent way. The electroporation treatment 375-437.5Vcm-1 caused irreversible electroporation of cancer cells and reversible electroporation of healthy cells. The application of lower voltage rating (250Vcm-1) led to apoptosis as the predominant type of cell death, whereas the use of higher voltage (500Vcm-1) mainly caused necrosis. CONCLUSION Electroporation represents a promising method in cancer treatment. Different cancer cell lines had different response to the identical electroporation treatment. Electroporation 375-437.5Vcm-1 selectively caused permanent damage of cancer cells (SW-480), while healthy cells (MRC-5, hAoSM and HUVEC) recovered after 72h. The type of cell death is dependent of electroporation conditions. The proposed numerical model is useful for the analysis of phenomena related to electroporation treatment.

Spectroscopic and theoretical investigation of the potential anti-tumor and anti-microbial agent, 3-(1-((2-hydroxyphenyl)amino)ethylidene)chroman-2,4-dione

The coumarin-orthoaminophenol derivative was prepared under mild conditions. Based on crystallographic structure, IR and Raman, 1H and 13C NMR spectra the most applicable theoretical method was determined to be B3LYP-D3BJ. The stability and reactivity parameters were calculated, in the framework of NBO, QTAIM and Fukui functions, form the optimized structure. This reactivity was then probed in biological systems. The antimicrobial activity towards four bacteria and three fungi species was examined and activity was proven. In vitro cytotoxic effects, against human epithelial colorectal carcinoma HCT-116 and human healthy lung MRC-5 cell lines, of the investigated substance are also tested. Compound showed significant cytotoxic effects on HCT-116 cells, while on MRC-5 cells showed no cytotoxic effects. The effect of hydroxy group in ortho-position on the overall reactivity of molecule was examined through molecular docking with Glutathione-S-transferases.

Proapoptotic and Antimigratory Effects of Pseudoevernia furfuraceae and Platismatia glauca on Colon Cancer Cell Lines

SUMMARY The aim of this study is to investigate cytotoxic, proapoptotic, antimigratory and pro-antioxidant effects of methanol, acetone and ethyl acetate extracts of lichens Pseudevernia furfuracea and Platismatia glauca on colorectal cancer (HCT-116 and SW-480) cell lines. We compared the cytotoxic effects on colorectal cancer cells with the effects obtained from normal human fibroblast (MRC-5) cell line. Tetrazolium (MTT) test evaluated the cytotoxic effects, Transwell assay evaluated cell migration, acridine orange/ethidium bromide (AO/EB) fluorescent method followed the apoptosis, while prooxidant/antioxidant effects were determined spectrophotometrically through concentration of redox parameters. The tested extracts showed considerable cytotoxic effect on cancer cells with no observable cytotoxic effect on normal cells. Ethyl acetate and acetone extract of P. furfuracea induced the highest cytotoxicity (IC50=(21.2±1.3) µg/mL on HCT-116, and IC50=(51.3±0.8) µg/mL on SW-480 cells, respectively, after 72 h), with noteworthy apoptotic and prooxidant effects, and antimigratory potential of methanol extract. P. glauca extracts induced cytotoxic effects on HCT-116 cells after 72 h (IC50<40 μg/mL), while only methanol and acetone extracts had cytotoxic effects on SW-480 cells after 24 h, with proapoptotic/necrotic activity, as a consequence of induced oxidative stress. In conclusion, lichen extracts changed to a great extent cell viability and migratory potential of colorectal cancer cell lines. HCT-116 cells were more sensitive to treatments, P. furfuracea had better proapoptotic and antimigratory effects, and both investigated lichen species might be a source of substances with anticancer activity.

Optimization of Parameters for Electrochemical Detection: Computer Simulation and Experimental Study

It has been shown that for each electrochemical measurement it is necessary first to optimize all the parameters that influence the obtained electrochemical signal. This is a time-consuming process and that is why in this study we focused on the computer simulation of the influence of multiparameters on the electrochemical signal. Herein we used a model system of the electroreduction of ruthenium(III) salt on gold electrode in phosphate buffer solution. Ru3+ is often used as redox probe for detection and understanding of nucleic acid hybridization on the electrodes. This study should reveal some new aspects of using the computer simulations in determining the optimal measuring conditions for detection of RNA/PNA hybridoms on the gold surface.