Jacek Łuczyński

Antifungal activity of gemini quaternary ammonium salts.

A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations. None of the tested compounds were cytotoxic and mutagenic. Cationic gemini surfactants poorly reduced the adhesion of microorganisms to the polystyrene plate, but inhibited the filamentation of Candida albicans. One of the tested compounds eradicated C. albicans and Rodotorula mucilaginosa biofilm, what could be important in overcoming catheter-associated infections. It was also shown that gemini surfactants enhanced the sensitivity of C. albicans to azoles and polyenes, thus they might be potentially used in combined therapy against fungi.

Hemolysis of erythrocytes and erythrocyte membrane fluidity changes by new lysosomotropic compounds.

This work contains the results of studies on the influence of newly synthesized lysosomotropic substances (lysosomotropes) on human erythrocytes. Six homologous series of the compounds differing in the alkyl chain length and counterions were studied. They were found to hemolyse erythrocytes and to change their osmotic resistance. The observed hemolytic effects were dependent both on the compound’s structure (polar head dimension and alkyl chain length of compound) and its form (the kind of the counterion). In parallel, the influence of lysosomotropes on fluidity of the erythrocyte membrane was studied. Three different fluorescent probes were used; 1,6-diphenyl-1,3,5-hexatriene (DPH), 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene, p-toluenesulfonate (TMA-DPH) and 6-dodecanoyl-2-dimethylaminonaphthalene (laurdan). Their anisotropy (DPH and TMA-DPH) or general polarization (laurdan) values after incorporation into ghost erythrocyte membranes were measured. The results obtained show that fluidity changes accompanied the effects observed in hemolytic experiments both quantitatively and qualitatively.

Gemini ester quat surfactants and their biological activity

Cationic gemini surfactants are an important class of surface-active compounds that exhibit much higher surface activity than their monomeric counterparts. This type of compound architecture lends itself to the compound being easily adsorbed at interfaces and interacting with the cellular membranes of microorganisms. Conventional cationic surfactants have high chemical stability but poor chemical and biological degradability. One of the main approaches to the design of readily biodegradable and environmentally friendly surfactants involves inserting a bond with limited stability into the surfactant molecule to give a cleavable surfactant. The best-known example of such a compound is the family of ester quats, which are cationic surfactants with a labile ester bond inserted into the molecule. As part of this study, a series of gemini ester quat surfactants were synthesized and assayed for their biological activity. Their hemolytic activity and changes in the fluidity and packing order of the lipid polar heads were used as the measures of their biological activity. A clear correlation between the hemolytic activity of the tested compounds and their alkyl chain length was established. It was found that the compounds with a long hydrocarbon chain showed higher activity. Moreover, the compounds with greater spacing between their alkyl chains were more active. This proves that they incorporate more easily into the lipid bilayer of the erythrocyte membrane and affect its properties to a greater extent. A better understanding of the process of cell lysis by surfactants and of their biological activity may assist in developing surfactants with enhanced selectivity and in widening their range of application.

Porous terpolymers: poly(acrylonitrile-co-ethyl/butyl/acrylate-co-divinylbenzene)

Abstract A series of terpolymers was prepared from acrylonitrile, ethyl or butyl acrylate and divinylbenzene (10 wt%). The terpolymers were obtained by suspension polymerization with inert diluents. They had a porous structure unless the amount of acrylate exceeded 50 mol%. The porous structure, however, was not permanent. By heating the copolymers above T g or treating with solvents, a porosity as high as 40% could be made to disappear. The inverse gas chromatography (i.g.c.) measurements revealed that the segmental motion of terpolymer chains appeared in the temperature ranges where the segmental mobility of poly(acrylonitrile) is observed (∼95, 120–160°C). It may be concluded from the values of Kovats indices that the hydrophilicity of the surface area of terpolymers is higher than that of acrylonitrile-divinylbenzene copolymers.

Hydrolysis driven surface activity of esterquat surfactants

HYPOTHESIS Surface activity of selected cleavable esterquat cationic surfactants is determined by the synergistic effect of surface active products of their hydrolysis. EXPERIMENTS Interfacial behavior of two classes of esterquat surfactants, quaternary alkylammmoniumesters and amino acid betaine (trimethylglycine) esters of fatty acids were examined both experimentally and theoretically. The surface tension measurements at air/water interface were performed by the pendant drop shape analysis method, then the obtained isotherms were theoretically described by the model of adsorption of ionic/non-ionic surfactants mixtures taking into account the presence of surface active products of surfactant hydrolysis. FINDINGS We found that surface activity of the mixture of surface active compounds resulting from the esterquat basic hydrolysis increases with time and it is higher when the ester carbonyl group is connected with the quaternary amine by bridging oxygen than in the inverted (betaine ester type) arrangement. That is, in the first case, the consequence of strong synergistic effect between the cationic esterquat surfactant and the anionic product of its hydrolysis - dodecanoate ion, while in the second case, the non-ionic hydrolysis product - dodecanol exhibits much weaker synergy. The addition of side CH3 group into the esterquat head-group slows down the hydrolysis that leads to the lower surface activity of the resulting mixture.

Aminoethyl esters of fatty acids as model lysosomotropic substances.

Conclusions1.The activity of the DM-n compounds is chain length and pH dependent; the highest activity being observed for 11–13 carbon atoms chain.2.The highest biological activity was observed at pH above 7, which is characteristic for lysosomotropic agents.3.Hemolytic experiments conformed the lysosomotropic character of DM-n. The free amine (DMF-11) can pass through membranes and at lower pH can interact with the vacuolar membrane.4.In yeast, DM-n mobilized respiration of endogenous substrates.5.In yeast protoplasts treated with DM-n, temporary increase in Ca2+ uptake (characteristic for apoptosis) takes place. This indicates that the compounds have a killing effect.

N-substituted aminoethylesters of fatty acid as lysosomotropic substances

[1] SUBIK J., KOLAROV J., KOVA(~ L.: BiochemBiophys.Res.Commun. 49, 192-198 (1972). [2] HAPALA 1.: Biochem.Biophys.Res.Commun. 159, 612-617 (1989). [3] HAPALA I., HUNAKOVA A., GERZANIt~OVA G., BUTKO P.: Biochim.Biophys.Acta 1190, 40-42 (1994). [4] DRGO~q T., ~ABOVA L., NELSON N., KOLAROV J.: FEBS Lett. 289, 159-162 (1991). [5l HAPALA 1,, HUNAKOVA A.: Folia Microbiol. 41, 95-96 (1996). [6] ZINSER E., PALTAUF F., DAUM G.: J.Bacteriol. 175, 2853-2858 (1993).

Antioxidative activity of new N-oxides of tertiary amines: membrane model and chromogen studies.

Potential antioxidative activities of three series of newly synthesized N-oxides were studied. Individual components in each of the series differed in the lipophilicities and number of free radical scavenging groups. Various methods were used to determine their antioxidative efficiencies: Prevention of erythrocyte membrane lipid oxidation induced by UV irradiation and chromogen experiments in which antioxidative efficiencies of compounds were compared to that of the standard antioxidant Trolox (a water-soluble vitamin E analogue). Additionally, some hemolytic (pig erythrocytes) and differential scanning calorimetry (DSC) measurements were performed to determine a mechanism of the interaction between membranes and N-oxides. It was found that N-oxides, especially those of long alkyl chains (> C12H25), readily interacted with both, erythrocyte and liposomal membranes. No marked differences were found in their protection of erythrocytes against oxidation. In most cases inhibition of oxidation changed between 15% and 25%. Still, it was far better than in chromogen experiments where suppression of free radicals reached 20% in the best case. It may be concluded that antioxidative capabilities of N-oxides are moderate. Studies on the interaction mechanism showed that incorporation of particular compounds into model membranes varied. Hemolysing activities of compounds increased with the elongation of the alkyl chain but differed for corresponding compounds of particular series indicating that lipophilicity of compounds is not the only factor determing their interaction with erythrocyte membranes. DSC experiments showed that N-oxides, upon incorporation into 1,2-dipalmitoyl-3-snphosphatidylcholine liposomes, shifted the subtransition (Tp) and the main transition (Tm). The shifts observed depended on the alkyl chain length. The effects differed for each series. It seems that in the case of long alkyl chain compounds the domain formation may take place. Generally, the decrease of Tm was greatest for the same compounds that exhibited the best hemolytic efficacy. The same conclusion concerns the decrease of cooperativity of the main transition and the observed changes suggest an increase in membrane fluidity. Both, erythrocyte and DSC experiments seem to indicate that compounds of particular series incorporate in a somewhat different way into membranes.

Plasma membrane H+-ATPase activity in wild type and mutants ofSaccharomyces cerevisiae treated by some lysosomotropic drugs

Conclusions(1)The aminoesters inhibit glucose-stimulated proton extrusion by yeast cells.(2)The inhibitory activity depends on aliphatic carbon chain length.(3)The inhibition of proton extrusion is concentration-dependent.(4)The aminoesters stimulate quinacrine accumulation in vacuoles of yeast cells so they should possess affinities for lysosomes.

Effects of Interaction of Gemini Ester Quat Surfactants with Biological Membranes

Abstract The aim of the study was to determine the relation between the biological activity of two homologous series of cationic gemini surfactants, which are quaternary ammonium salts, and their structure. The measure of the biological activity of the compounds was assumed to be the effects they exert on the membrane of erythrocytes, treated as a simple model of the biological membrane. In particular, it was determined the effects of the compounds on hemolysis and the osmotic resistance of erythrocytes and the fluidity of erythrocyte membrane, and the packing arrangement of the polar heads of membrane lipids. The results have shown that surfactants affect the osmotic resistance of erythrocytes to various degrees, and at sufficiently high concentrations operate destructively on their membrane, eventually causing hemolysis, modify the fluidity of erythrocyte membrane and affect the arrangement of polar heads of membrane lipids. Additionally, the results showed that that activity depends on a surfactants chemical structure, in particular, on the length of its alkyl chain and structure of the polar head group that determines the spacing between the chains. In both used new series the compounds containing 10, 12 and 14 carbon atoms in a chain possess a high biological activity. In addition, the surfactants with larger spaces between the chains are more active than those with smaller spacing. The investigations have revealed a high activity of compounds with longer chains and bigger polar heads. The results of the study may find application when designing a molecular structure and synthesizing new compounds of specific, desired activity.