Dragana Č. Dabić

Analysis and characterisation of phytochemicals in mulberry (Morus alba L.) fruits grown in Vojvodina, North Serbia

In this study, the polyphenolic profile of 11 Morus alba fruits grown in the Vojvodina region was investigated. Ultra high performance liquid chromatography (UHPLC) coupled with Linear Trap Quadrupole and OrbiTrap mass analyzer, and UHPLC coupled with a diode array detector and a triple-quadrupole mass spectrometer were used for the identification and quantification of the polyphenols, respectively. A total of 14 hydroxycinnamic acid esters, 13 flavonol glycosides, and 14 anthocyanins were identified in the extracts with different distributions and contents according to the sampling. The total phenolic content ranged from 43.84 to 326.29 mg GAE/100g frozen fruit. The radical scavenging capacity (50.18-86.79%), metal chelating ability (0.21-8.15%), ferric ion reducing power (0.03-38.45 μM ascorbic acid) and superoxide anion radical scavenging activity (16.53-62.83%) were assessed. The findings indicated that mulberry polyphenolics may act as potent superoxide anion radical scavengers and reducing agents.

Phenolic profile and antioxidant activity of Serbian polyfloral honeys.

A total of 58 polyfloral honey samples from different regions in Serbia were studied to determine their phenolic profile, total phenolic content and antioxidant capacity. UHPLC-LTQ OrbiTrap MS made possible the identification of 36 compounds: 24 flavonoids, two abscisic acids, and 10 phenolic acids and their derivatives. Quantification was done using 14 available standards. Data on phenolics and abscisic acids allowed the discrimination and classification of honeys in accordance to their geographical origin, using pattern recognition techniques, principal component analysis and partial least squares discriminant analysis. Samples originated from Vojvodina and Zlatibor region were clearly distinguished from those from the rest of Serbia because of the presence of dicaffeoylquinic acid, ellagic acid, caffeic acid phenethyl ester, and chlorogenic acid, among others. A good correlation (r = 0.865) was observed between total phenolic content and radical-scavenging activity. Total phenolic content ranged from 0.03 to 1.39 mg GAE/g and radical scavenging activity ranged from 1.31% to 25.61%.

Chemical composition of two different extracts of berries harvested in Serbia.

Total phenolic content (TPC), total anthocyanin content (TAC), free and total ellagic acid content, sugars, minerals, and radical-scavenging activity were determined in nine berries harvested in Serbia. More than 30 phenolic compounds were identified; among them, 11 polyphenols and cis,trans-abscisic acid were quantified using UHPLC coupled with an LTQ-Orbitrap XL mass analyzer. For the first time chrysin, naringenin, pinocembrin, and galangin were quantified in some of the investigated berry species. The extraction efficiency of the two extraction systems, methanol and acetone, was investigated. It was found that acetone is a better extracting solvent for TPC, whereas more TAC was extracted by methanol. TPC in acetone extracts ranged from 177.51 to 459.71 mg gallic acid equiv/100 g frozen weight. TAC ranged from 5.39 to 96.94 mg cyanidin-3-glucoside/100 g frozen weight in methanol extracts. The amounts of both free and total ellagic acid were found to be higher in the acetone extract in comparison to the methanol extract.

Physicochemical, Antioxidant and Sensory Properties of Peach Wine Made from Redhaven Cultivar

Physicochemical, sensory, and health-related characteristics of peach wine produced from Redhaven variety and selected white wines produced from various grape varieties were determined and compared. The alcohol content, titratable acidity, and total extract of peach wine was significantly lower compared with that of white wines, while its pH value was higher. The content of total phenolics (TPC) and flavonoids (TFC) of peach wine (402.53 mg/L GAE and 332.67 mg CAE/L, respectively) have been found significantly higher in comparison with that of white wines (TPC range 243.67-319.00 mg/L GAE, TFC range 129.67-175.17 mg CAE/L). The main phenolic compounds found in peach wine were chlorogenic acid, caffeic acid, and catechin (3.59, 0.87, and 0.60 mg/L, respectively). Antioxidant capacities were strongly correlated with total phenolics with correlation coefficients over 0.99. The highest antioxidant capacity was ascribed to peach wine. The results of sensory analysis indicated that the peach wine was very well accepted by the regular consumers of wine and can be a very interesting product in the market.

Quantitative structure–retention relationship of new N‐substituted 2‐alkylidene‐4‐oxothiazolidines

A quantitative structure-retention relationship (QSRR) was built to investigate the relationship between the structural descriptors of 23 newly synthesized N-substituted 2-alkylidene-4-oxothiazolidines and their chromatographic retention. Retention was investigated by means of the reversed-phase thin-layer chromatography (RP-TLC) on the C(18) and CN stationary phases, using methanol, acetonitrile, and tetrahydrofuran as organic modifiers. Full geometry optimization based on the Austin Model 1 (AM1) semi-empirical molecular orbital method was carried out and a set of physicochemical molecular descriptors was calculated from the optimized structures. QSRR was built by means of multiple linear regression (MLR) and partial least squares regression (PLS). The best MLR and PLS models were chosen, on the basis of comparison of the statistical parameters (squared correlation coefficient (R(2)), cross-validated coefficient (R(cv)(2)), and Fischer significance value (F) were used for MLR and the square of the multiple correlation coefficients for the calibration objects (R(2)Y (cum)) and the square of the multiple correlation coefficients for the cross-validation segments (Q(2)Y (cum)) were used for PLS models). Statistically significant and physically meaningful QSRR provided better insight on understanding the retention behavior of the new series of compounds. Lipohilicity (expressed as log P) was included in all MLR and PLS models.

Chemical Characterization of Fruit Wine Made from Oblačinska Sour Cherry

This paper was aimed at characterizing the wine obtained from Oblačinska, a native sour cherry cultivar. To the best of our knowledge, this is the first paper with the most comprehensive information on chemical characterization of Oblačinska sour cherry wine. The chemical composition was characterized by hyphenated chromatographic methods and traditional analytical techniques. A total of 24 compounds were quantified using the available standards and another 22 phenolic compounds were identified based on the accurate mass spectrographic search. Values of total phenolics content, total anthocyanin content, and radical scavenging activity for cherry wine sample were 1.938 mg gallic acid eqv L−1, 0.113 mg cyanidin-3-glucoside L−1, and 34.56%, respectively. In general, cherry wine polyphenolics in terms of nonanthocyanins and anthocyanins were shown to be distinctive when compared to grape wines. Naringenin and apigenin were characteristic only for cherry wine, and seven anthocyanins were distinctive for cherry wine.

ESTIMATION OF LIPOPHILICITY OF N-SUBSTITUTED 2-ALKYLIDENE-4-OXOTHIAZOLIDINES BY MEANS OF REVERSED-PHASE THIN-LAYER CHROMATOGRAPHY

The chromatographic behavior of 23 new 2-alkylidene-4-oxothiazolidine derivatives was investigated by means of the reversed-phase thin-layer chromatography (RP TLC) on the C18 and CN stationary phases. Binary mixtures of methanol-water, acetonitrile-water, and tetrahydrofuran-water were used as mobile phases. Linear relationships between the volume fraction of the organic mobile phase modifier and the RM values were established for each solute with high correlation coefficient values (r > 0.99). The investigated 4-oxothiazolidines are a congeneric set of compounds, and significant correlations were obtained between the chromatographically determined and m values. The lipophilicity parameters obtained from the reversed-phase experiments were compared with the calculated log P values. Some of these correlations offer very good predicting models, which are important for a better understanding of the relationships between chemical structure and retention, and can prove helpful in the structure-activity studies as well. Finally, our investigation was focused on chemometric processing of the retention data in different chromatographic systems. To this effect, Principal Component Analysis (PCA) was performed, yielding the results helpful in interpretation of interactions among investigated substances, binary mobile phases, and the two different stationary phases.

Polyphenolic Profile of Pear Leaves with Different Resistance to Pear Psylla (Cacopsylla pyri)

The European pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious arthropod pests of pear. Since proper control of this pest is essential, better understanding of the complex plant-pest relationship is mandatory. This research deals with constitutive polyphenolic profiles in leaves of 22 pear cultivars of diverse origin (P. communis, P. pyrifolia, and P. pyrifolia × P. communis) and different resistance to psylla. The study was designed to show which differences in the polyphenolic profile of leaves from resistant and susceptible pear cultivars could be utilized as information in subsequent breeding programs. The results demonstrated that the leaves of Oriental pear cultivars contained much higher amounts of p-hydroxybenzoic acid, ferulic acid, aesculin, and naringin, that, together with detected 3-O-(6″-O-p-coumaroyl)-hexoside, apigenin, apigenin 7-O-rutinoside, and hispidulin, indicated a clear difference between the species and might represent phenolics responsible for psylla resistance.

Structure-retention relationship study of polyoxygenated steroids.

The chromatographic behavior of 31 newly synthesized polyoxygenated steroids was investigated by the means of reversed-phase planar chromatography. Retention data were correlated to molecular characteristics of the analytes with view to examine possible relationships by the means of multiple linear regression (MLR) and partial least square (PLS) regression. On the basis of comparison of the statistical parameters obtained for both MLR and PLS 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 MLR and PLS models.

Identification of Phenolic Compounds from Seed Coats of Differently Colored European Varieties of Pea (Pisum sativum L.) and Characterization of Their Antioxidant and In Vitro Anticancer Activities

ABSTRACT To date little has been done on identification of major phenolic compounds responsible for anticancer and antioxidant properties of pea (Pisum sativum L.) seed coat extracts. In the present study, phenolic profile of the seed coat extracts from 10 differently colored European varieties has been determined using ultrahigh-performance liquid chromatography–linear trap quadrupole orbitrap mass spectrometer technique. Extracts of dark colored varieties with high total phenolic content (up to 46.56 mg GAE/g) exhibited strong antioxidant activities (measured by 2,2-diphenyl-1-picrylhydrazyl or DPPH assay, and ferric ion reducing and ferrous ion chelating capacity assays) which could be attributed to presence of gallic acid, epigallocatechin, naringenin, and apigenin. The aqueous extracts of dark colored varieties exert concentration-dependent cytotoxic effects on all tested malignant cell lines (human colon adenocarcinoma LS174, human breast carcinoma MDA-MB-453, human lung carcinoma A594, and myelogenous leukemia K562). Correlation analysis revealed that intensities of cytotoxic activity of the extracts strongly correlated with contents of epigallocatechin and luteolin. Cell cycle analysis on LS174 cells in the presence of caspase-3 inhibitor points out that extracts may activate other cell death modalities besides caspase-3-dependent apoptosis. The study provides evidence that seed coat extracts of dark colored pea varieties might be used as potential cancer-chemopreventive and complementary agents in cancer therapy.