Quantitative Relationships Between Structure, Aggregation Properties and Antimicrobial Activity of Quaternary Ammonium Bolaamphiphiles

1995 ◽  
Vol 60 (7) ◽  
pp. 1213-1228 ◽  
Author(s):  
Magdaléna Pavlíková ◽  
Ivan Lacko ◽  
Ferdinand Devínský ◽  
Dušan Mlynarčík

QSAR analysis employing Kubinyi's bilinear model was applied to examine the relationship between the structure (characterized by the lengths of the terminal hydrocarbon chain, m, and of the hydrocarbon spacer chain, y), lipophilicity (characterized by the chromatographic parameter Rm and aggregation properties expressed through the critical micellar concentration cK), and antimicrobial activity (characterized by the minimum inhibition concentration, MIC) of quaternary ammonium bolaamphiphiles. The log cK = f(m) dependence was found to be linear whereas the log (1/MIC) = f(m), log (1/MIC) = f(y), log (1/MIC) = f (log cK) and log (1/MIC) = f(Rm) dependences were nonlinear. The effect of the hydrophobic terminal chains (m) and of the hydrophobic spacer chain (y) on the aggregation properties and on the biological activity of the substances was studied.

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 459 ◽  
Author(s):  
Dobrawa Kwaśniewska ◽  
Ying-Lien Chen ◽  
Daria Wieczorek

Besides their positive role, microorganisms are related to a number of undesirable effects, including many diseases, biodeterioration and food spoilage, so when their presence is undesired, they must be controlled. Numerous biocides limiting the development of microorganisms have been proposed, however, in this paper the biocidal and inhibitory activity of quaternary ammonium salts (QASs) and their zwitterionic derivatives is addressed. This paper presents the current state of knowledge about the biocidal activity of QAS and their derivatives. Moreover, the known mechanisms of antimicrobial activity and the problem of emerging resistance to QAS are discussed. The latest trends in the study of surfactants and their potential use are also presented.


1979 ◽  
Vol 34 (5-6) ◽  
pp. 485-486 ◽  
Author(s):  
Ivan Lacko ◽  
Ferdinand Devínsky ◽  
Ľudovít Krasnec ◽  
Dušan Mlynarčik

Abstract N,N-Dialkyl Ammonium Salts of Saturated Heterocyclic Amines, Antimicrobial Activity Antimicrobial activity of N-alkyl-N-dodecylpiperidinium bromides and N-ethyl-N-dodecylheterocycloalkyl ammonium bromides (pyrrolidine, morpholine, perhydroazepine) deter­ mined on grampositive and gramnegative bacteria, yeasts and moulds, presented as minimum inhibition concentration (MIC). Comparison of the effect of change of structure: lenghtening of alkyl chain, change of heterocyclic ring. Change in the lenght of alkyl chain markedly affects the antimicrobial activity, change of heterocyclic ring has no substantial effect. The most active compounds were N-heptyl-and N-hexyl-N-dodecylpiperidinium bromides.


2020 ◽  
Vol 17 (34) ◽  
pp. 403-411
Author(s):  
Konul Farrukh BAKHSHALIYEVA ◽  
Nizami Rza NAMAZOV ◽  
Arzu Rasul HASANOVA ◽  
Fidan Rasim MAMMADOVA ◽  
Panah Zulfigar MURADOV

In the carried out of the research, Xylotroph macromycetes have been researched as a perspective producer of bıologıcal actıve substances used for various purposes today in world practice which spread in Azerbaijan and some of their features (the biological activity of synthesized metabolites, toxicity, antimicrobial activity and dynamics of biomass formation ). It became clear that fungi such as Ganoderma lucidum (Curtis) P. Karst., Laetiporus sulphureus (Bull.) Murrill, Pleurotus ostreatus (Jacq.) P. Kumm, Schyzophyllum commune Fr and Trametes versicolor (L.) Lloyd considered as a perspective producer of bıologıcal actıve substances is widely spread in the forests of Azerbaijan, and some of them are even dominant species of xylomicobiot inherent in the nature of Azerbaijan. As a result of studies with isolated strains of these fungi, it was shown that both in the culture solution (CS) and in the vegetative mycelia (VB), there are metabolites with biological activity. The result of research also became clear that antimicrobial activity of CS in all cases is higher than in water or alcohol extracts of dry biomass (1,1-1,2 times), although it defines the overall biological activity of VB extracts to the relationship of Paramecium caudatum gives a higher increase effect. In addition, the selected active strains do not lag behind the known strains in terms of the amount of biomass formed (up to 8.7 g/l in 7 days) and manifestations of forms of biological activity. This gives a serious basis to realize the production of biologically active substances for different (food, feed, medical and other) purposes on their basis.


2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Peter Nemeček ◽  
Tatiana Ďurčeková ◽  
Ján Mocák ◽  
Karel Waisser

AbstractThis study gives a quantitative structure-activity relationship (QSAR) correlation of the 72 N-benzylsalicylamide derivatives properties with their antimycobacterial activity. The antimycobacterial activity was measured as the minimal inhibition concentration (MIC) determined for four strains of mycobacterium (M. avium, M. kansasii, M. kansasii clin.-clinically isolated form, and M. tuberculosis) after 14 days and after 21 days of cultivation. The objective was to identify the factors most closely defining biological activity of N-benzylsalicylamides, in order to enable QSAR prediction of new derivatives with high antimycobacterial activity. Optimal properties for the QSAR analysis were selected from several physicochemical properties, including lipophilicity parameter log P, molecular mass M, molar refraction MR, NMR chemical shifts, polarizability, etc. Many of the considered properties are different from those typically used in traditional QSAR. Selection of the most important properties was performed by one-way Analysis of Variance (ANOVA) and correlation analysis using the significance coefficients and the correlation coefficients, respectively. The chosen variables were further used in artificial neural networks (ANN) for predicting biological activity in the form of-log(MIC).


2021 ◽  
Vol 72 (1) ◽  
pp. 70-79
Author(s):  
Aleksandra Bogdanović ◽  
Anita Lazić ◽  
Slavica Grujić ◽  
Ivica Dimkić ◽  
Slaviša Stanković ◽  
...  

Abstract In this study we screened twelve newly synthesised N-(substituted phenyl)-2-chloroacetamides for antimicrobial potential relying on quantitative structure-activity relationship (QSAR) analysis based on the available cheminformatics prediction models (Molinspiration, SwissADME, PreADMET, and PkcSM) and verified it through standard antimicrobial testing against Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Candida albicans. Our compounds met all the screening criteria of Lipinski’s rule of five (Ro5) as well as Veber’s and Egan’s methods for predicting biological activity. In antimicrobial activity tests, all chloroacetamides were effective against Gram-positive S. aureus and MRSA, less effective against the Gram-negative E. coli, and moderately effective against the yeast C. albicans. Our study confirmed that the biological activity of chloroacetamides varied with the position of substituents bound to the phenyl ring, which explains why some molecules were more effective against Gram-negative than Gram-positive bacteria or C. albicans. Bearing the halogenated p-substituted phenyl ring, N-(4-chlorophenyl), N-(4-fluorophenyl), and N-(3-bromophenyl) chloroacetamides were among the most active thanks to high lipophilicity, which allows them to pass rapidly through the phospholipid bilayer of the cell membrane. They are the most promising compounds for further investigation, particularly against Gram-positive bacteria and pathogenic yeasts.


1998 ◽  
Vol 51 (7) ◽  
pp. 581 ◽  
Author(s):  
Tim W. Davey ◽  
Alan R. Hayman

Several members of a novel class of w-substituted asymmetric bolaform surfactants have been synthesized in order to investigate their surfactant and biological properties. The ω-hydroxy trialkylammonium and pyridinium surfactants have significant antimicrobial and antifungal activity relative to their conventional analogues. For conventional quaternary ammonium alkyl surfactants, increasing the hydrocarbon chain length causes a decrease in the surfactant monomer solubility and a corresponding decrease in the biological activity. No such trend is observed for the ω-hydroxy quaternary ammonium bromide series.


Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2254 ◽  
Author(s):  
Sarka Salajkova ◽  
Marketa Benkova ◽  
Jan Marek ◽  
Radek Sleha ◽  
Lukas Prchal ◽  
...  

Nosocomial infections, which greatly increase morbidity among hospitalized patients, together with growing antibiotic resistance still encourage many researchers to search for novel antimicrobial compounds. Picolinium salts with different lengths of alkyl chains (C12, C14, C16) were prepared by Menshutkin-like reaction and evaluated with respect to their biological activity, i.e., lipophilicity and critical micellar concentration. Picolinium salts with C14 and C16 side chains achieved similar or even better results when in terms of antimicrobial efficacy than benzalkoniums; notably, their fungicidal efficiency was substantially more potent. The position of the methyl substituent on the aromatic ring does not seem to affect antimicrobial activity, in contrast to the effect of length of the N-alkyl chain. Concurrently, picolinium salts exhibited satisfactory low cytotoxicity against mammalian cells, i.e., lower than that of benzalkonium compounds, which are considered as safe.


2019 ◽  
Vol 70 (10) ◽  
pp. 3603-3610
Author(s):  
Madalina Mihalache ◽  
Cornelia Guran ◽  
Aurelia Meghea ◽  
Vasile Bercu ◽  
Ludmila Motelica ◽  
...  

The three copper complexes having a-ketoglutaric acid (H2A) and 1- (o-tolyl) biguanide (TB) ligands have been synthesized and characterized. The proposed formulas for these complexes are: [Cu(TB)(HA)]Cl (C1), [Cu(TB)(HA)CH3COO]�H2O (C2) and [Cu(TB)(HA)](NO3) (C3) where HA represents deprotonated H2A. The complexes obtained were tested for antibacterial activity against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, antifungal activity on Candida albicans ATCC 10231 and antitumor activity on HeLa tumor cells. Due to the antitumor, antifungal, antimicrobial activity and inhibition of inert substrate adhesion, complexes synthesized could be used for potential therapeutic applications.


2020 ◽  
Vol 17 (2) ◽  
pp. 214-225 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek

Background: Nitro-derivatives of heterocyclic compounds were used as active agents against pathogenic microorganisms. A set of 4- and 5-nitroimidazole derivatives exhibiting antimicrobial activity was analyzed with the use of Quantitative Structure-Activity Relationships (QSAR) method. The study included compounds used both in documented treatment and those described as experimental. Objective: The purpose of this study was to demonstrate the common and differentiating characteristics of the above-mentioned chemical compounds alike physicochemically as well as pharmacologically based on the quantum chemical calculations and microbiological activity data. Methods: During the study PCA and MLR analysis were performed, as the types of proposed chemometric approach. The semi-empirical and ab initio level of in silico molecular modeling was performed for calculations of molecular descriptors. Results: QSAR models were proposed based on chosen descriptors. The relationship between the nitro-derivatives structure and microbiological activity data was able to class and describe the antimicrobial activity with the use of statistically significant molecular descriptors. Conclusion: The applied chemometric approaches revealed the influential features of the tested structures responsible for the antimicrobial activity of studied nitro-derivatives.


2020 ◽  
Vol 10 (1) ◽  
pp. 44-60
Author(s):  
Mohamed E.I. Badawy ◽  
Entsar I. Rabea ◽  
Samir A.M. Abdelgaleil

Background:Monoterpenes are the main constituents of the essential oils obtained from plants. These natural products offered wide spectra of biological activity and extensively tested against microbial pathogens and other agricultural pests.Methods:Antifungal activity of 10 monoterpenes, including two hydrocarbons (camphene and (S)- limonene) and eight oxygenated hydrocarbons ((R)-camphor, (R)-carvone, (S)-fenchone, geraniol, (R)-linalool, (+)-menthol, menthone, and thymol), was determined against fungi of Alternaria alternata, Botrytis cinerea, Botryodiplodia theobromae, Fusarium graminearum, Phoma exigua, Phytophthora infestans, and Sclerotinia sclerotiorum by the mycelia radial growth technique. Subsequently, Quantitative Structure-Activity Relationship (QSAR) analysis using different molecular descriptors with multiple regression analysis based on systematic search and LOOCV technique was performed. Moreover, pharmacophore modelling was carried out using LigandScout software to evaluate the common features essential for the activity and the hypothetical geometries adopted by these ligands in their most active forms.Results:The results showed that the antifungal activities were high, but depended on the chemical structure and the type of microorganism. Thymol showed the highest effect against all fungi tested with respective EC50 in the range of 10-86 mg/L. The QSAR study proved that the molecular descriptors HBA, MR, Pz, tPSA, and Vp were correlated positively with the biological activity in all of the best models with a correlation coefficient (r) ≥ 0.98 and cross-validated values (Q2) ≥ 0.77.Conclusion:The results of this work offer the opportunity to choose monoterpenes with preferential antimicrobial activity against a wide range of plant pathogens.


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