Correlation of structure and chromatographic behavior of the polioxygenated steroids by the means of thin-layer chromatography

U okviru ove doktorske disertacije detaljno je proučavan uticaj supstituenata vezanih za A prsten na hromatografsko ponašanje serije polioksigenovanih steroida u uslovima tankoslojne hromatografije. U cilju proučavanja uticaja polarnosti sorbenta na retenciju ispitivanih jedinjenja upotrebljena su dva veoma različita sorbenta: polarni nemodifikovani silika-gel i nepolarni C-18 modifikovani silika-gel. Posebna pažnja posvećena je razmatranju uticaja sastava primenjenih mobilnih faza na retenciju radi što boljeg razumevanja odnosa hromatografskog ponašanja i lipofilnosti ispitivanih jedinjenja. Uzimajući u obzir svojstva sorbenta kao i korišćenih mobilnih faza, retenciono ponašanje je izučavano u uslovima normalno-fazne i reverzno-fazne hromatografije. Kao tipični normalnofazni sistemi upotrebljeni su polarni silika-gel kao stacionarna faza i manje polarni rastvarači (aceton, heksan, acetonitril, dihlormetan) kao mobilna faza. Reverzno-fazni sistemi sastojali su se od smeše voda ˗ organski rastvarač (aceton, metanol ili acetonitril) i oktadecil modifikovanog silika-gela kao stacionarne faze. U uslovima normalno-fazne hromatografije sistem aceton/nheksan se pokazao kao pogodan za ispitivanje uticaja sastava mobilne faze na hromatografsko ponašanje polioksigenovanih steroidnih jedinjenja. U uslovima reverzno-fazne hromatografije najbolja selektivnost je postignuta primenom mobilne faze metanol - voda. U okviru ovog rada proučena je i mogućnost primene tankoslojne hromatografije za brzo i jednostavno određivanje lipofilnosti kao važnog parametra biološke aktivnosti ispitivanih steroida. Utvrđeno je da postoji linearna zavisnost između retencionih parametara ispitivanih jedinjenja i sastava dvokomponetnih mobilnih faza. Ispitivanjem korelacije između hromatografski određenih parametara lipofilnosti i teorijski izračunatih logP vrednosti utvrđeno je da je reverzno-fazna hromatografija pogodnija za procenu lipofilnosti ispitivanih jedinjenja.Takođe pokazano je da ispitivani polioksigenovani steroidi sa supstituisanim A prstenom predstavljaju kongenernu seriju. Primenom višestruke linearne regresije (multiple linear regression, MLR) i metode parcijalne regresije najmanjih kvadrata (partial least squares, PLS) proučavane su moguće zavisnosti između hromatografskog ponašanja i molekulskih svojstava analita. Na osnovu statističkih parametara dobijenih za tri reverzno-fazna hromatografska sistema najbolje korelacije između RM 0 i deskriptora bile su u sistemu C-18 / metanol-voda što izdvaja ovaj hromatografski sistem kao najpogodniji za određivanje lipofilnosti analita. Na osnovu regresionih modela određeni su deskriptori koji najbolje opisuju ponašanje analita u odnosu na utvrđene retencione parametre. Dobijeni su statistički značajni modeli kvantitativnog odnosa strukture i retencije (QSRR). Izračunata lipofilnost izražena kao XlogP, površinski napon (ST) i Hansenovo vodonično vezivanje (HHB) su deskriptori koji najbolje opisuju QSRR i u višestrukoj linearnoj regresiji i u parcijalnoj regresiji najmanjih kvadrata.The framework of this thesis was to thoroughly investigate influence of structural moiety attached to A ring on chromatographic behavior of series polyoxigenated steroids under thin-layer chromatography conditions. In order to examine the effect of sorbent polarity on retention behavior of the investigated substances, two different sorbents were selected: polar unmodified silica gel and non-polar C-18 modified silica. In addition, influence of the mobile phase composition was discussed with view to determine relationship between chromatographic behavior and lipophilicity. Taking into account the nature of both sorbents and chromatographic solvents used, the chromatographic behavior of the substances was investigated under normal- and reversed-phase conditions. Polar silica gel with less polar solvents was used as typical normal-phase systems, whereas alkyl modified silica gel (RP-18 silica) in combination with polar water–organic mobile phases (methanol, acetone or acetonitrile) - for typical reversed-phase separation. It was found that in normal-phase chromatography acetone/n-hexane was more suitable for studying relationship between chromatographic behavior of the polioxigenated steroids and mobile phase composition. Under reversed-phase condition the best selectivity was achieved by the use of methanol-water mobile phase. An additional goal of this thesis was to investigate possibility of application of thin-layer chromatography for rapid and simple determination of lipophilicity as parameter of special importance for biologically active substances. A linear relationship between retention parameters of the investigated compounds and composition of the binary mobile phase used was established. On the basis of correlation between chromatographically determined lipophilicity and calculated logP values it was found that reversed-phase chromatography is useful method for lipophilicity estimation. In addition, it is appear that investigated polyoxigenated steroids represent a congeneric series of compounds. Chromatographically determined parameters of lipophilicity (RM 0) were used for developing appropriate models for structure-retention relationships by multivariate statistical analysis. The retention data for system methanol-water on C-18 silica phase has the most significant correlation between RM 0 and descriptors indicating this chromatographic system as most suitable for lipophilicity determination of the studied compounds. Retention data were correlated to molecular characteristics of the analytes with view to examine possible relationships by the means of multiple linear regression and partial least square regression. On the basis of comparison of the statistical parameters obtained for both multiple linear regression and partial least square regression models, descriptors best describing the analyte behavior were selected. Statistically significant and physically meaningful structure-retention relationships were obtained. Calculated lipophilicity expressed as XlogP as well surface tension and Hansen hydrogen bonding was included in both multiple linear regression and partial least square regression models

White-rot fungal pretreatment of wheat straw: effect on enzymatic hydrolysis of carbohydrate polymers

The aim of the study was the comparative analysis of degradation of wheat straw lignin by white-rot fungi and its implications on the efficiency of enzymatic hydrolysis of holocellulose. Peroxidases were found to be predominantly responsible for lignin degradation, even though high laccase activities were detected, especially in the initial stages of fungal culturing. The studied fungal species showed various ability to degrade lignin in wheat straw, which further affected the release of reducing sugars during enzymatic saccharification. The highest rate of lignin, hemicelluloses and cellulose degradation was noticed in the sample pretreated with Irpex lacteus. Among all the tested species, only Ganoderma resinaceum was found as a suitable lignin degrader, with 2-fold higher hydrolysis yield (51.1 ± 4.7%) than in the control. A key mechanism that enhances convertibility of carbohydrates is the selective lignin removal from biomass. Operating time, holocellulose loss and unpredictable fungal response to culturing conditions are the main challenges in fungal pretreatment of lignocellulosic feedstock

Comparison of Sugar Profile between Leaves and Fruits of Blueberry and Strawberry Cultivars Grown in Organic and Integrated Production System

The objective of this study was to determine and compare the sugar profile, distribution in fruits and leaves and sink-source relationship in three strawberry ('Favette', 'Alba' and 'Clery') and three blueberry cultivars ('Bluecrop', 'Duke' and 'Nui') grown in organic (OP) and integrated production systems (IP). Sugar analysis was done using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). The results showed that monosaccharide glucose and fructose and disaccharide sucrose were the most important sugars in strawberry, while monosaccharide glucose, fructose, and galactose were the most important in blueberry. Source-sink relationship was different in strawberry compared to blueberry, having a much higher quantity of sugars in its fruits in relation to leaves. According to principal component analysis (PCA), galactose, arabinose, and melibiose were the most important sugars in separating the fruits of strawberries from blueberries, while panose, ribose, stachyose, galactose, maltose, rhamnose, and raffinose were the most important sugar component in leaves recognition. Galactitol, melibiose, and gentiobiose were the key sugars that split out strawberry fruits and leaves, while galactose, maltotriose, raffinose, fructose, and glucose divided blueberry fruits and leaves in two groups. PCA was difficult to distinguish between OP and IP, because the stress-specific responses of the studied plants were highly variable due to the different sensitivity levels and defense strategies of each cultivar, which directly affected the sugar distribution. Due to its high content of sugars, especially fructose, the strawberry cultivar 'Clery' and the blueberry cultivars 'Bluecrop' and 'Nui' could be singled out in this study as being the most suitable cultivars for OP

Leaf Soluble Sugars and Free Amino Acids as Important Components of Abscisic Acid-Mediated Drought Response in Tomato

Water deficit has a global impact on plant growth and crop yield. Climate changes are going to increase the intensity, duration and frequency of severe droughts, particularly in southern and south-eastern Europe, elevating the water scarcity issues. We aimed to assess the contribution of endogenous abscisic acid (ABA) in the protective mechanisms against water deficit, including stomatal conductance, relative water potential and the accumulation of osmoprotectants, as well as on growth parameters. To achieve that, we used a suitable model system, ABA-deficient tomato mutant, flacca and its parental line. Flacca mutant exhibited constitutively higher levels of soluble sugars (e.g., galactose, arabinose, sorbitol) and free amino acids (AAs) compared with the wild type (WT). Water deficit provoked the strong accumulation of proline in both genotypes, and total soluble sugars only in flacca. Upon re-watering, these osmolytes returned to the initial levels in both genotypes. Our results indicate that flacca compensated higher stomatal conductance with a higher constitutive level of free sugars and AAs. Additionally, we suggest that the accumulation of AAs, particularly proline and its precursors and specific branched-chain AAs in both, glucose and sucrose in flacca, and sorbitol in WT, could contribute to maintaining growth rate during water deficit and recovery in both tomato genotypes

Supplementary data for the article: Waisi, H.; Janković, B.; Nikolić, B.; Dragičević, V.; Panić, I.; Tosti, T.; Trifković, J. Influence of Various Concentrations of 24-Epibrassinolide on the Kinetic Parameters during Isothermal Dehydration of Two Maize Hybrids. South African Journal of Botany 2018, 119, 69–79. https://doi.org/10.1016/j.sajb.2018.08.006

Supplementary material for: [https://doi.org/10.1016/j.sajb.2018.08.006]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/342

The Polyphenols as Potential Agents in Prevention and Therapy of Prostate Diseases.

In recent years, the progress of science and medicine greatly has influenced human life span and health. However, lifestyle habits, like physical activity, smoking cessation, moderate alcohol consumption, diet, and maintaining a normal body weight represent measures that greatly reduce the risk of various diseases. The type of diet is very important for disease development. Numerous epidemiological clinical data confirm that longevity is linked to predominantly plant-based diets and it is related to a long life; whereas the western diet, rich in red meat and fats, increases the risk of oxidative stress and thus the risk of developing various diseases and pre-aging. This review is focused on the bioavailability of polyphenols and the use of polyphenols for the prevention of prostate diseases. Special focus in this paper is placed on the isoflavonoids and flavan-3-ols, subgroups of polyphenols, and their protective effects against the development of prostate diseases

Preliminary investigation of aromatic fraction composition indust extract from the Library of the Facility of Chemistry in Belgrade

Usled modernog načina života ljudi provode oko 90 % vremena u zatvorenim prostorijama, kao što su kuće/stanovi, kancelarije, automobili itd. Prašina je sve prisutna u svim pomenutim sredinama i nalazi se kao čestice suspendovane u vazduhu ili istaložena na površinama. Čestice prašine se mogu lako udahnuti i mogu da oštete respiratorni sistem i pluća. Pored toga, čestice prašine akumuliraju hemikalije iz zatvorenih prostorija i predstavljaju važan put izlaganja ljudi tim jedinjenjima. U kućnoj prašini se mogu naći ftalati, policiklični aromatični ugljovodonici i ostala poluisparljiva jedinjenja. Ftalati se često koriste kao plastifikator u proizvodnji polivinil hlorida (PVC-a) i predmeta opšte upotrebe kao što su građevinski materijal, dečije igračke i nameštaj, ali i u proizvodnji podnih obloga, veštačke kože, lepkova, tepiha, maziva, cevi, žica, sredstava za čišćenje kuće, proizvoda za negu tela (fiksatori mirisa, proizvodi za negu kože, pene i šamponi) i ambalaže za namirnice. Primena ftalata zavisi od njihove molekulske mase. Ftalati male molekulske mase, kao što su di-metil-ftalat (DMP), di-etil-ftalat (DEP), di-propil-ftalat (DPP), di-izobutil-ftalat (DiBP), di-n-butil ftalat (DBP), di-n-pentil-ftalat (DNPP) i benzil- butil-ftalat (BBP), se koriste u rastvaračima, lepkovima, voskovima, mastilu, lekovima, kozmetici i insekticidima.Visokomolekulski ftalati, kao di-2-etilheksil-ftalat (DEHP), di- ciklo-heksil-ftalat (DCHP) i di-izo-nonil-ftalat (DiNP), su plastifikatori u PVC proizvodima i predmetima od opšte upotrebe. Estri ftalata su povezani sa velikim brojem zdravstvenih problema kod ljudi. Pre svega, ftalati deluju kao endokrini disruptori i doprinose stvaranju varijacija u reprodukcionom sistemu kao što su opadanje broja spermatozoida, oštećenje DNK u spermatozoidima, prevremeni razvoj dojki i promena u reproduktivnim hormonima. Ftalati utiču na pojavu astme, alergija i poremećaja funkcije nervnog sistema. Pored toga, DEHP je okarakterisan kao 2b kancerogena supstanca, tj. kao potencijalno kancerogen za ljude, od strane IARC-a (Međunarodna agencija za istraživanje raka, eng. International Agency for Research on Cancer). Treba napomenuti da su pojedini metaboliti ftalata često toksičniji od samih nepromenjenih ftalata. Ljudi mogu biti izloženi ftalatima inhalacijom, ingestijom i apsorpcijom preko kože. Oko 1 g istaložene prašine je sakupljen iz biblioteke Hemijskog fakulteta u Beogradu, sa visine iznad 1m od poda. Uzorci su odmereni, ekstrahovani, prečišćeni i aromatična frakcija je snimljena metodom gasne hromatografije, povezanom sa masenim spektrometrom. Lokacija uzorkovanja i hromatogram aromatične frakcije je prikazan na slici 1. Dobijeni rezultati ukazuju na to da, pored prirodnih proizvoda kao što su metil estri masnih kiselina (koje su najverovatnije znatno obilnije u alifatičnoj frakciji), uzorak sadrži 3,5-di- terc-butil-4-hidroksibenzaldehid, metabolit 2,6-di-terc-butil-4-methilfenola, koji se koristi kao antioksidans u namirnicama i kozmetičkim proizvodima [3]. Najzastupljenija jedinjenja u aromatičnoj frakciji su DiBP), DBP i DEHP. Interesantno je primetiti da se detektovani ftalati koriste u dve različite svrhe, kao aditivi u plastici i drugim proizvodima (DiBP i DBP) i kao plastifikatori u polimerima (DEHP). Kao što je prethodno pomenuto, DEHP je klasifikovan kao potencijalno kancerogena supstanca za ljude. Pored toga, primena DiBP, DBP i DEHP je ograničena od strane Evropske komisije. Zbog prisustva ftalata koji imaju veliki uticaj na ljudsko zdravlje u ekstraktu prašine, potrebno je izvršiti dodatna ispitivanja na većem broju uzoraka i uraditi detaljnu kvantifikaciju i procenu rizika po ljudsko zdravlje.Постерска презентација представљена је на 9. симпозијуму Хемија и заштита животне средине ENVIROCHEM2023 са међународним учешћем у Кладову, Србија у периоду од 04. до 07. јуна 2023. године

Supplementary material for the article: Mesarović, J.; Trifković, J.; Tosti, T.; Fotirić Akšić, M.; Milatović, D.; Ličina, V.; Milojković-Opsenica, D. Relationship between Ripening Time and Sugar Content of Apricot (Prunus Armeniaca L.) Kernels. Acta Physiologiae Plantarum 2018, 40 (8). https://doi.org/10.1007/s11738-018-2731-7

Supplementary material for: [https://doi.org/10.1007/s11738-018-2731-7]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2193

Physicochemical analysis and phenolic profile of polyfloral and honeydew honey from Montenegro

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3828

Kromatografsko profiliranje primarnih metabolita kao alat za kemotaksonomsku klasifikaciju uzoraka sjemenki bobičastog voća

Research background. Considering the importance of consumption of berry fruits with proven health-beneficial properties and difficulties in quality control of products of specific botanical and geographic origin, a fingerprint method was developed, based on advanced data analysis (pattern recognition, classification), in order to relate the variability of nutrients in the selected cultivars to primary metabolite profile. Experimental approach. Forty-five samples of genuine berry fruit cultivars (strawberry, raspberry, blackberry, black currant, blueberry, gooseberry, chokeberry, cape gooseberry and goji berry) were characterized according to chromatographic profiles of primary metabolites (sugars, lipids and fatty acids) obtained by three chromatographic techniques (high-performance thin-layer chromatography, gas chromatography coupled to mass spectrometry, and high-performance anion-exchange chromatography with pulsed amperometric detection). Results and conclusions. Comprehensive analysis allowed monitoring and identification of metabolites belonging to polar lipids, mono-, di- and triacylglycerols, free fatty acids, free sterols, sterol esters, mono- to heptasaccharides and sugar alcohols. Chemical fingerprint of berry seeds showed the uniformity of primary metabolites within each fruit species, but revealed differences depending on the botanical origin. All three chromatographic methods provided a discriminative, informative and predictive metabolomics methodology, which proved to be useful for chemotaxonomic classification. Novelty and scientific contribution. A novel methodology for the identification of bioactive compounds from primary metabolites of natural products was described. The proposed untargeted metabolite profiling approach could be used in the future as a routine method for tracing of novel bioactive compounds. The knowledge of metabolite composition obtained in this study can provide a better assessment of genotypic and phenotypic differences between berry fruit species and varieties, and could contribute to the development of new breeding programs.Pozadina istraživanja. Imajući u vidu značaj konzumiranja bobičastog voća dokazanog blagotvornog učinka na organizam, ali i teškoće u kontroli kvalitete proizvoda specifičnog botaničkog i geografskog podrijetla, u radu je predložena metodologija zasnovana na kemijskom profiliranju i naprednoj analizi podataka (prepoznavanje obrazaca i klasifikacija), koja bi se mogla koristiti za procjenu autentičnosti određenih vrsta na osnovu njihovog profila primarnih metabolita. Eksperimentalni pristup. Ukupno je okarakterizirano 45 uzoraka različitih sorata bobičastog voća (jagoda, malina, kupina, crni ribiz, borovnica, ogrozd, aronija, peruanska jagoda i goji) na osnovu kemijskih profila primarnih metabolita (šećera, lipida i masnih kiselina) dobivenih pomoću triju kromatografskih tehnika (tankoslojnom kromatografijom velike učinkovitosti, plinskom kromatografijom spregnutom s masenom spektrometrijom i ionskom kromatografijom s pulsnom amperometrijskom detekcijom). Rezultati i zaključci. Sveobuhvatnom kemijskom analizom identificirane su različite klase metabolita: polarni lipidi, mono-, di- i triacilgliceroli, slobodne masne kiseline, slobodni steroli, sterolni esteri, mono- do heptasaharidi i šećerni alkoholi. Rezultati pokazuju da uzorci koji pripadaju istoj biljnoj vrsti imaju sličan kemijski profil, a različite vrste imaju različit sastav primarnih metabolita. Sve tri kromatografske metode pružaju diskriminativnu, informativnu i prediktivnu metabolomičku metodologiju primjenjivu u kemotaksonomskoj klasifikaciji. Novina i znanstveni doprinos. Opisana je nova metodologija identifikacije bioaktivnih spojeva iz primarnih metabolita prirodnih proizvoda. Predloženi pristup neciljanog profiliranja metabolita mogao bi se koristiti kao rutinska metoda pronalaska novih bioaktivnih spojeva. Poznavanje sastava metabolita omogućuje bolju procjenu genotipskih i fenotipskih razlika između sorata bobičastog voća, što može pridonijeti razvoju novih programa oplemenjivanja