Anti-proliferative potential and oxidative reactivity of thermo-oxidative degradation products of stigmasterol and stigmasteryl esters for human intestinal cells.

Stigmasterol in free and esterified form is incorporated in LDL cholesterol-lowering food products, intended for direct consumption and cooking, baking, and frying. Under thermal treatment, stigmasterol compounds may constitute a source of thermo-oxidative degradation products and oxyderivatives with potentially adverse health effects. This study aimed to analyze the anti-proliferative potential and genotoxicity of thermo-oxidatively treated stigmasterol (ST), stigmasteryl linoleate (ST-LA), and oleate (ST-OA). The effects on cell viability and proliferation, cell cycle progression, intracellular reactive oxygen species (ROS) generation, and DNA damage were analyzed in normal human intestinal cells. The mutagenic potential was assessed in a bacterial reverse mutation test using Salmonella enterica serovar Typhimurium strains involving metabolic activation. Stigmasteryl esters showed a significantly lower potential to affect intestinal cell viability and proliferation than non-esterified ST, regardless of heating. Thermo-oxidatively treated ST suppressed intestinal cell proliferation by arresting the cell cycle in the G2/M phase and DNA synthesis inhibition. The enhanced intracellular ROS generation and caspase 3/7 activity suggest targeting intestinal cells to the apoptosis pathway. Also, heated ST-LA intensified ROS production and elicited pro-apoptotic effects. Thermo-oxidative derivatives of ST and ST-LA may evoke harmful gastrointestinal effects due to their high oxidative reactivity towards intestinal cells.

Ruthenium(II) and Platinum(II) Complexes with Biologically Active Aminoflavone Ligands Exhibit In Vitro Anticancer Activity.

Continuing our studies on the mechanisms underlying the cytotoxicity of potential drugs, we have described several aspects of the in vitro anticancer activity of ruthenium(II) and platinum(II) complexes with bioactive, synthetic aminoflavone ligands. We examined the mechanism of proapoptotic activity of cis-dichlorobis(3-imino-2-methoxyflavanone)ruthenium(II), cis-dichlorobis(3-imino-2-ethoxyflavanone)ruthenium(II), and trans-dichlorobis(3-aminoflavone)platinum(II). Cisplatin was used as a reference compound. The cytotoxicity was investigated by MTT assay. The mechanism of proapoptotic activity of the tested compounds was investigated by evaluation of caspase-8 activity, cytometric analysis of annexin-V positive cells, and mitochondrial potential loss measurement. The results showed that ruthenium compounds break partially or completely the cisplatin resistance by activating the caspase 8-dependent apoptosis pathway and loss of mitochondrial membrane potential. Platinum compounds also have a cytostatic effect, but their action requires more exposure time. Potential mechanisms underlying drug resistance in the two pairs of cancer cell lines were investigated: total glutathione content, P-glycoprotein activity, and differences in the activity of DNA repair induced by nucleotide excision. Results showed that cisplatin-resistant cells have elevated glutathione levels relative to sensitive cells. Moreover, they indicated the mechanisms enabling cells to avoid apoptosis caused by DNA damage. Pg-P activity has no effect on the development of cisplatin resistance in the cell lines described.

Acyl moiety and temperature affects thermo-oxidative degradation of steryl esters. Cytotoxicity of the degradation products.

Phytosterols and their esters are often used as functional ingredients in food products due to its lowering blood cholesterol properties. Products containing phytosterols and its esters are recommended for direct consumption, cooking, baking and frying, however during food preparation it is possible thermo-oxidative degradation is possible. Unsaturation of fatty acid present in steryl ester may further stimulates degradation. Free stigmasterol degraded faster than its esters, even with linoleic acid attached. The highest amount of degradation products was observed for free stigmasterol, followed by esters with linoleic and oleic acids. Polar dimers were fund in all heated samples, although for free stigmasterol heated at 60 °C were not detected. Whereas non-polar dimers were observed only in heated stigmasterol. Degradation of esterified stigmasterol generated degradation products with lower cytotoxicity.

New Look on 3-Hydroxyiminoflavanone and Its Palladium(II) Complex: Crystallographic and Spectroscopic Studies, Theoretical Calculations and Cytotoxic Activity.

This work presents the synthesis, spectroscopic properties and single-crystal X-ray examination of the structure of 3-hydroxyiminoflavanone and its palladium complex. It presents the results of NMR (Nuclear Magnetic Resonance) spectroscopy, electron-density studies based on X-ray wavefunction refinement and theoretical calculations combined with QTAIM (Quantum Theory of Atoms in Molecules) and ELI-D (Electron Localizability Indicator) analyses. These offer an interesting new insight into the structures and behavior of flavanone and its complex, in solid state and in solution. The study also examines the cytotoxicity of the ligand and its complex against three human ovarian and lung cancer cell lines.

Proapoptotic activity in vitro of two novel ruthenium(II) complexes with flavanone-based ligands that overcome cisplatin resistance in human bladder carcinoma cells.

In this study we examined their proapoptotic activity of cis-dichloridobis(3-imino-2-methoxyflavanone)ruthenium(II)3H(2)O (1) and cis-dichloridobis(3-imino-2-ethoxyflavanone)ruthenium(II)2H(2)O (2) towards human bladder carcinoma cell line EJ and its cisplatin resistant subline EJcisR. On the basis of the experiments we carried out, it may be concluded, that: CDDP (cis-diamminedichloridoplatinum) resistance of EJcisR cells is probably based on partial loss of apoptotic pathway activating caspase-8 and increased resistance to DNA strand breaks and/or alkali-labile sites. Increased glutathione levels, as well as activity of P-gp transporter seems to be not relevant in this case. The proapoptotic activity of the ruthenium compounds is higher than that of cisplatin. Higher proapoptotic activity of 1 and 2 when compared to CDDP may be due to the presence of large, lipophilic flavanone-based ligands that may facilitate their trans-membrane transport and their redox activity. 1 and 2 induce apoptosis apparently in more than one way. Although caspase-8 activation and DNA strand breaks and/or alkali-labile sites are caused by the compounds, their ability to cause the oxidative stress in the cells may also participate in apoptosis induction.

Synthesis, single-crystal and solution structure analysis and in vitro cytotoxic activity of two novel complexes of ruthenium(II) with in situ formed flavanone-based ligands.

Synthesis, structure and properties of two new flavanone complexes of Ru(ii) are described. The new complexes form during the reaction of ruthenium(iii) chloride with 3-aminoflavone (3-af) dissolved in an aliphatic alcohol. The formed products depend on the alcohol used and were found to be: cis-dichloridobis(3-imino-2-methoxyflavanone)ruthenium(ii)·3H(2)O (1) from a methanolic solution and cis-dichloridobis(3-imino-2-ethoxyflavanone)ruthenium(ii)·2H(2)O (2) from an ethanolic solution, in which the original ligand 3-af had been converted by dehydrogenative alcoholysis to an entirely new ligand. This paper presents the X-ray structure and detailed (1)H-NMR analysis of both new compounds, as well as the study of their antiproliferative activity. The coordination of Ru(ii) is octahedral with [RuCl(2)N(2)O(2)] chromophores, having trans chlorides and common Ru-L distances. Both 1 and 2 are highly cytotoxic towards the cisplatin resistant EJ and L1210 cell lines, and both complexes are as active as cisplatin in the sensitive cell lines. They display the ability to overcome cisplatin resistance in the drug resistant sub-lines EJcisR and L1210R. The present evidence suggests that the mechanism of biological activity may be different for these ruthenium compounds compared to cisplatin.