Quantitative structure-retention relationship study of steroidal tetraoxanes by thin-layer chromatography and multivariate chemometric methods

У оквиру овог рада испитиван је утицај структуре различитих класа биолошки активних стероидних тетраоксана на њихово ретенционо понашање у условима реверзно-фазне танкослојне хроматографије. Као стационарне фазе коришћени су RP-18 силика-гел и CN- силика-гел. Ретенција испитиваних стероидних тетраоксана се заснива на њиховим неспецифичним хидрофобним интеракцијама са неполарном стационарном фазом. На основу добијених резултата одређена је липофилност бис-стероидних и мешовитих тетраоксана преко параметара RM 0, b, C0 и PC1. На основу статистички значајних линеарних корелација између ових параметара и израчунатих logKоw вредности, утврђено је да се параметри RM 0, b, C0 и PC1 могу успешно применити за процену липофилности бис-стероидних тетраоксана, док се за процену липофилности мешовитих тетраоксана могу користити параметри RM 0, b и PC1. За изналажење дескриптора који на најбољи начин описују ретенционо понашање стероидних тетраоксана и квантификацију њиховог утицаја примењене су мултиваријантне хемометријске методе као што су анализа главних компонената, кластерска анализа, метода делимичних најмањих квадрата и вишеструка линеарна регресија. На основу добијених резултата предложени су најважнији структурни дескриптори који утичу на понашање и својства стероидних тетраоксана у примењеним хроматографским условима. За обе групе стероидних тетраоксана процењено је да највећи утицај на ретенцију имају структурни дескриптори који се односе на поларност молекула и њихове протон-донорске и акцепторске способности. На овај начин су утврђени статистички значајни модели који даље могу да се примене за предвиђање хроматографског понашања и липофилности нових сродних молекула. Модели који се односе на зависности биолошких активности бис-стероидних и мешовитих тетраоксана нису статистички значајни. На квалитативном нивоу указују на значај величине и облика молекула, поларности и протон-донорских својстава на антипролиферативну активност бис-стероидних тетраоксана. Насупрот томе, на антималаријску активност мешовитих тетраоксана највећи утицај имају дескриптори који уједно имају и највећи утицај на њихову ретенцију.The main focus of this PhD thesis was an investigation of the structure of different classes of biologically active steroidal tetraoxanes on their retention behavior applaying the reversed-phase thinlayer chromatography. As the stationary phases were used unpolar RP-18 silica and CN-silica with moderate polarity. The hydophobic interactions of the investigated substances with non-polar sorbents were proposed as interaction determining retention under RP conditions. Four chromatographic descriptors, RM 0, b, C0 and PC1 were used for assessing the lipophilicity of bis-steroidal and mixed tetraoxanes. On the basis of statisticaly significant linear correlations between these parameters and calculated logKоw values, it was found that all of them are suitable for lipophilicity estimation of bis-steroidal tetraoxanes, while for lipophilicity estimation of mixed tetraoxanes parameter C0 can be considered as the unfavorable. Chemometric methods such as principal component analysis, cluster analysis, partial least square and multiple linear regression, were performed to identify the molecular descriptors that best describe the chromatographic behavior of the investigated compounds, and to quantify their influences. For both classes of steroidal tetraoxanes the highest influence on retention have structural descriptors which describe the polarity of molecules and their hydrogen bond donating and accepting abbilities. In this way statistical significant models that can be used for prediction of chromatographic behavior and lipophilicity of a newly synthesized molecules are identified. Models based on biological activities and structural descriptors of both classes of steroidal tetraoxanes are statistically insignificant. On qualitative level, the most prominent factors affecting antiproliferative activity of the investigated bis-steroidal tetraoxanes are those relating to the size and shape of a molecule and those regarding to their polarity and the ability of hydrogen bodning. Contrary to that, the most prominent factors affecting antimalarial activity of mixed tetraoxanes are the same as the factors affecting their retention

Supplementary data for article: Šegan, S.; Božinović, N.; Opsenica, I.; Andrić, F. Consensus-Based Comparison of Chromatographic and Computationally Estimated Lipophilicity of Benzothiepino[3,2-c]Pyridine Derivatives as Potential Antifungal Drugs. Journal of Separation Science 2017, 40 (10), 2089–2096. https://doi.org/10.1002/jssc.201601442

Supporting information for: [https://doi.org/10.1002/jssc.201601442]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2462]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3076

Supplementary data for the article: Andrić, F.; Šegan, S.; Dramićanin, A.; Majstorović, H.; Milojković-Opsenica, D. Linear Modeling of the Soil-Water Partition Coefficient Normalized to Organic Carbon Content by Reversed-Phase Thin-Layer Chromatography. Journal of Chromatography A 2016, 1458, 136–144. https://doi.org/10.1016/j.chroma.2016.06.063

Supplementary material for: [https://doi.org/10.1016/j.chroma.2016.06.063]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2288]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3561

Kvantitativna analiza arbutina i hidrokinona u listovima obične planike (Arbutus unedo L., Ericaceae) plinskokromatografskom metodom uz detekciju masenim spektrometrom

The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 μg mL-1), as well as good precision (RSD0,9987) u ispitivanom koncentracijskom rasponu (0,5-200 μg mL-1), kao i dobru preciznost (RSD<5 %), analitički povrat (96,2-98,0 %) i osjetljivost (granica detekcije=0,009 μg mL-1 za arbutin i 0,004 μg mL-1 za hidrokinon). Rezultati dobiveni validiranom GC-MS metodom u dobroj su suglasnosti s rezultatima dobivenim metodom tekućinske kromatografije visoke učinkovitosti (HPLC). Predložena metoda je primijenjena za određivanje sadržaja arbutina i hidrokinona u metanolnom ekstraktu lišća. Sadržaj arbutina određen u lišću obične planike prikupljenom na otoku Koločepu (6,82 mg g-1 suhe mase) bio je veći u usporedbi sa sadržajem arbutina u lišću prikupljenom na otoku Malom Lošinju (2,75 mg g-1 suhe mase). Hidrokinon nije detektiran ni u jednom uzorku. Analitičke značajke predložene GC-MS metode pokazale su da se arbutin i hidrokinon mogu alternativno određivati plinskom kromatografijom. S obzirom na široki koncentracijski raspon, metoda je pogodna za analizu arbutina i hidrokinona, ne samo u lišću obične planike, nego također i u lišću biljaka drugih porodica (Rosaceae, Lamiaceae, itd.)

Kvantitativna analiza arbutina i hidrokinona u listovima obične planike (Arbutus unedo L., Ericaceae) plinskokromatografskom metodom uz detekciju masenim spektrometrom

The phenolic glycoside arbutin and its metabolite with uroantiseptic activity hydroquinone occur naturally in the leaves of various medicinal plants and spices. In this study, an extraction procedure coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine arbutin and hydroquinone content in strawberry tree (Arbutus unedo L., Ericaceae) leaves. The method showed good linearity (R2>0.9987) in the tested concentration range (0.5-200 μg mL-1), as well as good precision (RSD0,9987) u ispitivanom koncentracijskom rasponu (0,5-200 μg mL-1), kao i dobru preciznost (RSD<5 %), analitički povrat (96,2-98,0 %) i osjetljivost (granica detekcije=0,009 μg mL-1 za arbutin i 0,004 μg mL-1 za hidrokinon). Rezultati dobiveni validiranom GC-MS metodom u dobroj su suglasnosti s rezultatima dobivenim metodom tekućinske kromatografije visoke učinkovitosti (HPLC). Predložena metoda je primijenjena za određivanje sadržaja arbutina i hidrokinona u metanolnom ekstraktu lišća. Sadržaj arbutina određen u lišću obične planike prikupljenom na otoku Koločepu (6,82 mg g-1 suhe mase) bio je veći u usporedbi sa sadržajem arbutina u lišću prikupljenom na otoku Malom Lošinju (2,75 mg g-1 suhe mase). Hidrokinon nije detektiran ni u jednom uzorku. Analitičke značajke predložene GC-MS metode pokazale su da se arbutin i hidrokinon mogu alternativno određivati plinskom kromatografijom. S obzirom na široki koncentracijski raspon, metoda je pogodna za analizu arbutina i hidrokinona, ne samo u lišću obične planike, nego također i u lišću biljaka drugih porodica (Rosaceae, Lamiaceae, itd.)

Supplementary data for the article: Šegan, S.; Opsenica, I.; Zlatović, M.; Milojković-Opsenica, D.; Šolaja, B. Quantitative Structure Retention/Activity Relationships of Biologically Relevant 4-Amino-7-Chloroquinoline Based Compounds. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences 2016, 1012–1013, 144–152. https://doi.org/10.1016/j.jchromb.2016.01.033

Supplementary material for: [https://doi.org/10.1016/j.jchromb.2016.01.033]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2059

Supplementary data for article: Aleksić, I.; Šegan, S.; Andrić, F.; Zlatović, M.; Moric, I.; Opsenica, D. M.; Senerovic, L. Long-Chain 4-Aminoquinolines as Quorum Sensing Inhibitors in Serratia Marcescens and Pseudomonas Aeruginosa. ACS Chemical Biology 2017, 12 (5), 1425–1434. https://doi.org/10.1021/acschembio.6b01149

Supporting information for: [https://doi.org/10.1021/acschembio.6b01149]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2461]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3089

Hydrophilic Interaction Liquid Chromatography for the Analysis of Pharmaceutical Formulations

For a long time, Reversed-Phase Liquid Chromatography (RPLC) was the most dominant technique for the analysis of pharmaceutical compounds, but with poor efficiency in the separation of small polar molecules. From the efforts to solve the problem of insufficient retention of these molecules, during the last decades, a mode of liquid chromatography named Hydrophilic Interaction Liquid Chromatography (HILIC) has experienced vast expansion. It is based on the use of a highly hydrophilic stationary phase along with an aqueous mobile phase with high organic modifier content. In this review, the characteristics of stationary and mobile phases used in HILIC are described, and corresponding separation mechanisms are discussed. An overview of recently published papers dealing with the application of HILIC in analyzing pharmaceuticals in biological and non-biological samples is provided. Besides, the application of HILIC systems in the determination of the physicochemical properties of compounds is described

Novel Quorum Quenching YtnP Lactonase From Bacillus paralicheniformis Reduces Pseudomonas aeruginosa Virulence and Increases Antibiotic Efficacy in vivo

Bacterial infections have become increasingly difficult to treat due to the occurrence of antibiotic-resistant strains. A promising strategy to increase the efficacy of therapy is to combine antibacterials with agents that decrease pathogen virulence via the modulation of the quorum sensing (QS). Lactonases inhibit acylated homoserine lactone (AHL)-mediated QS in Gram-negative bacteria, including the leading nosocomial pathogen Pseudomonas aeruginosa. Here we describe the characteristics of heterologously expressed YtnP lactonase from Bacillus paralicheniformis ZP1 (YtnP-ZP1) isolated from agricultural soil using the culture enrichment method. Purified YtnP-ZP1 hydrolyzed different AHLs with preference to substrates with long acyl residues as evaluated in assays with biosensors and HPLC. The enzyme showed good thermostability and activity in a wide temperature range. YtnP-ZP1 in 50 μg mL–1 concentration reduced the amount of P. aeruginosa-produced long-chain AHLs by 85%, while it hydrolyzed 50% of short-chain AHLs. Incubation of P. aeruginosa PAO1 with YtnP-ZP1 reduced its swarming motility and elastolytic activity without bactericidal effect. YtnP-ZP1 caused the inhibition of biofilm formation and disintegration of mature biofilms in P. aeruginosa PAO1 and multiresistant clinical strain BR5H that was visualized by crystal violet staining. The treatment with YtnP-ZP1 in concentrations higher than 25 μg mL–1 improved the survival of P. aeruginosa PAO1-infected zebrafish (Danio rerio), rescuing 80% of embryos, while in combination with tobramycin or gentamicin survival rate increased to 100%. The treatment of P. aeruginosa PAO1 biofilms on infected zebrafish tail wounds with 50 μg mL–1 YtnP-ZP1 and 2 × MIC tobramycin led to infection clearing in 2 days. The extensive toxicity studies proved YtnP-ZP1 was non-toxic to human cells and zebrafish. In conclusion, novel YtnP-ZP1 lactonase with its effective anti-virulence activity could be used to increase the efficacy of clinically approved antibiotics in clearing both systemic and biofilm-associated P. aeruginosa infections

Supplementary data for the article: Selaković, Z.; Soloveva, V.; Gharaibeh, D. N.; Wells, J.; Šegan, S.; Panchal, R. G.; Šolaja, B. A. Anti-Ebola Activity of Diazachrysene Small Molecules. ACS Infectious Diseases 2016, 1 (6), 264–271. https://doi.org/10.1021/acsinfecdis.5b00028

Supporting information for: [https://doi.org/10.1021/acsinfecdis.5b00028]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2035