Synthesis and cytotoxicity of (R)- and (S)-ricinoleic acid amides and their acetates.

An environment-friendly, free of solvent, process for the synthesis of (R)- and (S)-ricinoleic acid amides has been developed. Starting from methyl ricinoleates and pyrrolidine or ethanolamine, the corresponding amides were obtained with yields ranging from 83-88%. Among 12 synthesized derivatives of ricinoleic acid, including the starting methyl esters, amides, and their acetates, nine compounds were obtained and tested for the first time.

Studies on the cytotoxicity of diamond nanoparticles against human cancer cells and lymphocytes.

Detonation nanodiamonds (DND) are a widely studied group of carbon nanomaterials. They have the ability to adsorb a variety of biomolecules and drugs onto their surfaces, and additionally their surfaces may be subjected to chemical functionalization by covalent bonds. We present a procedure for the purification and surface oxidation of diamond nanoparticles, which were then tested by spectroscopic analysis such as ATR-FTIR, Raman spectroscopy, and thermogravimetric analysis.

Nitroxides protect against peroxynitrite-induced nitration and oxidation.

Nitroxides are promising compounds for prevention of undesired protein modifications. The aim of this study was to compare the efficiency of 11 nitroxides, derivatives of 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO) and 2,2,5,5-tetramethylpirrolidine-1-oxyl (PROXYL) in prevention of nitration and oxidation of model compounds and human serum albumin (HSA). Most nitroxides were very efficient in preventing loss of fluorescein fluorescence induced by peroxynitrite (PN) (IC50 in the nanomolar range) and preventing HSA nitration.

Effect of functionalized and non-functionalized nanodiamond on the morphology and activities of antioxidant enzymes of lung epithelial cells (A549).

The development of nanotechnology opens up new ways for biomedical applications of unmodified and modified diamond nanoparticles which are one of the most popular nanomaterials used in biology, biotechnology, medicine, cosmetics and engineering. They have been applied as diagnostic and therapeutic agents because they can be targeted to and localized in cells causing apoptosis and necrosis. The problem of biocompatibility of nanodiamonds at higher concentrations is thus of primary importance.

Intracellular transport of nanodiamond particles in human endothelial and epithelial cells.

During the recent years nanodiamonds have been the subject of interest as possible means of targeted delivery of anticancer substances. Detonation nanodiamonds are attractive candidates for intracellular studies due to their synthesis methods, low cost, good biocompatibility and facile surface functionalizability. Our previous study, in which we used nanoparticles obtained by different methods showed the significance of size and way of production of nanodiamonds in their cellular effects.

Cytotoxicity of nitroxyl (HNO/NO-) against normal and cancer human cells.

Nitroxyl (HNO/NO(-)) is a molecule which results from one-electron reduction of nitric oxide (NO). It is considered to be a pharmacologically important particle because of its cardiovascular effects and potential anticancer activity. Due to molecule instability studies on nitroxyl biological activity require the use of donor compounds.

Ethoxyquin: An Antioxidant Used in Animal Feed.

Ethoxyquin (EQ, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline) is widely used in animal feed in order to protect it against lipid peroxidation. EQ cannot be used in any food for human consumption (except spices, e.g.

Modulation of ethoxyquin genotoxicity by free radical scavengers and DNA damage repair in human lymphocytes.

N-tert-butyl-alpha-phenylnitrone (PBN) and its new derivative N-(Pyridine-4-ylmethylidene)-2-carboxy-tert-butylamine N-oxide (PBNC) were synthesized and used to modulate ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, EQ) genotoxicity. Ethoxyquin, an antioxidant used mainly as a preservative in animal feeds, was shown to cause DNA breaks in human lymphocytes. The aim of the study was to evaluate the involvement of free radicals in the genotoxicity of EQ and its modulation by cellular repair systems.

Genotoxic and antioxidant activities of ethoxyquin salts evaluated by the comet assay.

Four newly synthesized salts of ethoxyquin (EQ: 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline), an antioxidant used in animal feeds, were evaluated with the use of the comet assay performed on human lymphocytes: ethoxyquin ascorbate, ethoxyquin hexanoate, ethoxyquin salicylate and ethoxyquin salt of Trolox C (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid). In the study the abilities of these compounds to cause DNA fragmentation and to protect against H2O2-induced DNA damage were analysed. The obtained results were compared with those noted earlier for EQ.

Comparative analysis of cytotoxic, genotoxic and antioxidant effects of 2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline and ethoxyquin on human lymphocytes.

2,2,4,7-Tetramethyl-1,2,3,4-tetrahydroquinoline (THQ) is a new synthetic compound with potential antioxidant activity. In this study, cytotoxic, genotoxic and antioxidant activities of THQ were studied on human lymphocytes with the use of the trypan blue exclusion assay, the TUNEL method, the comet assay and the micronucleus test. The activities of THQ were compared with those of a structurally similar compound-ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, EQ), which is used in animal feeds as a preservative.

Synthesis and studies on antioxidants: ethoxyquin (EQ) and its derivatives.

In our study ethoxyquin (EQ) and its two complexes with flavonoids were obtained from ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline, EQ) and quercetin (EQ-Q, 1:1) or rutin (EQ-R, 1:1). Cytotoxicity of the tested compounds was studied using the trypan blue exclusion method and the properties of the studied compounds were also analyzed with the TUNEL method evaluating their ability to induce apoptosis. It was shown that EQ induced apoptosis in cultured human lymphocytes, especially at 0.

Apoptosis and cytotoxicity caused by ethoxyquin and two of its salts.

In our study, we analyzed the cytotoxicity of ethoxyquin (EQ) and its two salts, ethoxyquin hydrochloride (EQ-HCL) and ethoxyquin phosphate (EQ-P). It was shown that EQ was the most cytotoxic compound (IC(50) = 0.09 mM), while the lowest cytotoxic effect was observed for EQ-P (IC(50) = 0.

Gibbs monolayers at the air/water interface: surface partitioning and lateral mobility of an electrochemically active surfactant.

Monolayer films of a water-soluble surfactant, 4-octaneamido-2,2,6,6-tetramethyl-1-piperidinyloxy (C8-TEMPO) were investigated at the air/water interface. An electrochemical, horizontal touch method was developed to measure the equilibrium surface concentrations (gamma) of C8TEMPO. The dependence of gamma on the solution concentration followed a Langmuir isotherm and yielded the partition constant K = (2.

Cytotoxicity, cytoprotection and neurotoxicity of novel deprenyl-related propargylamines, stable nitroxide free radicals, in vitro and in vivo.

Since novel synthesized deprenyl-related derivatives of nitroxides, named "JSAKs", have been shown to possess antioxidative properties, their cytotoxicity on neuronal-like PC-12 cells line was examined. The antiproliferative effect of two selected JSAKs was examined and expressed as IC10, IC50 and IC90, and compared with those of the parent nitroxide (Nx-640), model nitroxide TEMPO and deprenyl. There were substantial differences in the dose-dependence of all the observed antiproliferative and cytotoxic effects.

Antioxidant properties of newly synthesized N-propargylamine derivatives of nitroxyl: a comparison with deprenyl.

In our search for novel, low-toxic, cell-penetrable and neuroprotective antioxidants, we have designed a number of novel N-propargylamine derivatives of nitroxyl, named "JSAKs". The reactivity and antioxidative potency of two selected JSAKs and their parent nitroxyl against reactive oxygen species (ROS) were examined in vitro, in a cell-free gamma-radiolysis and in model Fenton-type reaction systems and compared with those of deprenyl, the investigated member of adjunct therapies in clinical neurology. The efficiency of JSAKs to suppress the oxidative degradation of a model target (deoxyribose), deprenyl and dopamine, caused by hydroxyl radical (*OH) was also investigated.

Pro-oxidative activity of nitroxides in their reactions with glutathione.

Nitroxides are unreactive towards glutathione in vitro. Interaction of nitroxides with peroxynitrite does not lead to a significant loss of their electron paramagnetic resonance (EPR) signal. However, addition of peroxynitrite to a solution containing glutathione and nitroxides induces an irreversible disappearance of EPR signal of nitroxides and augmentation of glutathione oxidation which is a pro-oxidant effect of these compounds.

Synthesis and antioxidant activity evaluation of novel antiparkinsonian agents, aminoadamantane derivatives of nitroxyl free radical.

Two new analogues of the antiparkinsonian drug 1-aminoadamantane: 4-(1-adamantylamino)-2,2,6,6-tetramethylpiperidine-1-oxyl and 4-(1-adamantylammonio)-1-hydroxy-2,2,6,6-tetramethylpiperidinium dihydrochloride have been synthesized. Their antioxidant activity towards reactive oxygen species (ROS: (z.rad;)OH and O(2)(z.