Phenolic Content, and Antioxidant and Antimicrobial Activities of Crataegus Oxyacantha L (Rosaceae) Fruit Extract from Southeast Serbia

Purpose: The aim of this work was to determine the content of total phenols, total flavonoids, anthocyanins, as well as antioxidant and antimicrobial activities of hawthorn (Crataegus oxyacantha L.) alcohol, hydroalcohol and aqueous extracts.Methods: The content of total phenols, flavonoids and anthocyanins of the alcohol, hydroalcohol and aqueous extracts of hawthorn were determined using spectrophotometric methods. Antioxidant assay was based on the measurement of DPPH absorbance at 517 nm caused by the reaction of DPPH with the test sample. Antimicrobial activity was evaluated by measuring the zone of inhibition against selected test microorganisms: Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonasaeruginosa, and Salmonella abony while antifungal activity was tested against two organisms: Aspergillus niger and Candida albicans.Results: The results of spectrophotometric investigations indicate that the content of total phenol compounds in the investigated extracts varied from 2.12 to 30.63 mg GAE g-1 of fresh hawthorn sample. The content of anthocyanins ranged from 0.3207 to 3.168 mg of cyanidin-3-O-glucoside g-1 of fresh hawthorn fruit. The fruit extracts showed high antioxidant activity with DPPH radical transformation value as high as 89.9 % in the methanol-water (50/50, v/v%)) extract. The ethanol extract exhibited antimicrobial activity against all test microorganisms except two, Bacillus subtilis and Staphylococcus aureus, and one species of fungi, Aspergillus niger. Flavonoid structure influenced the extract’s selectivity towards Gram-positive and Gram negative bacteria.Conclusion: Extracts of the fruit of Crataegus oxyacantha L. can be used as natural antioxidant and antimicrobial preparations.Keywords: Crataegus oxyacantha L.; Natural phenolic compounds; Antioxidant and antimicrobial activity, Southeast Serbia

Levels of Major and Minor Elements in Some Commercial Fruit Juices Available in Serbia

Purpose: To evaluate the macro- and micro-nutrient elements of some commercially available fruit juices in Serbia.Methods: Inductively coupled plasma optical emission spectrometry (ICP-OES) technique was employed for determination of the major and minor elements in samples of two different types of fruit juices - clear and cloudy.Results: Among macro-nutrient elements, potassium (K) had the highest content of 230.17 μg/g in samples of multivitamine cloudy juice. The content of K was higher in cloudy fruit juices than in clear fruit juices. The content of iron, which is among the group of trace elements, ranged from 2.237 to 5.911 μg/g in clear juices and 3.55 to 10.05 μg/g in cloudy fruit juices. Other trace elements followed the descending order copper > zinc > nickel in terms of their content. The presence of aluminum and cadmium in the tested samples of fruit juices can be toxic since they have no nutritional value, and hence may be treated as potential contaminants in these beverages.Conclusion: All the tested juices had some nutritional value for human health and the juices could be use as an additional source of these elements. The content of aluminium and cadmium are below levels permitted by national regulations.Keywords: Elements, Fruit juice, Inductively-coupled plasma optical emission spectrometry

Development and Application of Ligand-Exchange Reaction Method for the Determination of Clonazepam

Purpose: This paper presents an improved kinetic-spectrophotometric procedure for determining clonazepam (CZP) in pharmaceutical formulations and human serum.Methods: The method is based on ligand-exchange reaction. The reaction was followed spectrophotometrically by measuring the rate of change of absorbance at 425 nm in ethanolic sodium hydroxide solution.Results: The optimum operating conditions for reagent concentrations and temperature were established. Linear calibration curve was obtained in the range of 0.32 - 4.10 μg mL-1. The optimized conditions yielded a theoretical detection limit of 0.24 μg mL-1 based on the 3.3So criterion, where S0 is standard deviation of the calibration line. The interference of certain drugs, foreign ions and amino acids on the reaction rate were studied in order to assess the selectivity of the method.Conclusion: The developed method is sensitive, accurate and reproducible and could be used for routine anlysis of clonazepam in pharmaceutical preparations and serum samples.Keywords: Clonazepam, Ligand-exchange reaction, Kinetic spectrometry, Validation, Pharmaceutical preparation, Human seru

Impact of Clonal Variability on Phenolics and Radical Scavenging Activity of Grapes and Wines: A Study on the Recently Developed Merlot and Cabernet Franc Clones (<i>Vitis vinifera</i> L.)

<div><p>In this study, grapes and corresponding wines of Merlot /No 022, 025 and 029/ and Cabernet Franc /No 02, 010 and 012/ clones (recently developed) were evaluated regarding the total phenolic content, total anthocyanin content, and radical scavenging activity, aiming to better understand their quality and market potential. The nineteen individual polyphenols were quantified in studied grape samples using UHPLC coupled to a triple-quadrupole mass spectrometer. The mother grapes and wines were used as the relevant standards. In the grape, studied characteristics were monitored at three stages of berry development: green berry, véraison and mature berry. The mature grape of clones presented high values of total phenolics (3.81–10.89 g gallic acid equivalent kg^-1 frozen weight), anthocyanin content (359.00–1668.18 mg malvidin-3-<i>O</i>-glucoside kg^-1 frozen weight) and the radical scavenging activity (41.37–80.48 mmol trolox equivalent kg^-1 frozen weight) depending on the clone. Grapes and wines of Merlot No 025 and Cabernet Franc No 010 stood out with the highest values of all three parameters. Generally, the high correlation was observed between TPC and RSA values for green berries and mature grapes, as well as for wine samples. The most abundant phenolics in both Merlot and Cabernet Franc grapes were gallic acid, <i>p</i>-hydroxybenzoic acid, ferulic acid, catechin, epicatechin, gallocatechin gallate, catechin gallate, and rutin. Catechin, epicatechin, epigallocatechin, and catechin gallate, typical for the ripe grape of Merlot and Cabernet Franc clones, showed significant correlation with RSA values. Concentrations of individual polyphenols varied depending on the sample being studied and berry development stages. Merlot No 025 and Cabernet Franc No 010 grapes showed particularly interesting attributes for the production of high quality wines.</p></div