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Research on natural compounds is increasingly focused on their effects on human health. In this study, we were interested in the evaluation of nutritional value expressed as content of total phenolic compounds and antioxidant capacity of new apricot (Prunus armeniaca L.) genotypes resistant against Plum pox virus (PPV) cultivated on Department of Fruit Growing of Mendel University in Brno. Fruits of twenty one apricot genotypes were collected at the onset of consumption ripeness. Antioxidant capacities of the genotypes were determined spectrometrically using DPPH• (1,1-diphenyl-2-picryl-hydrazyl free radicals) scavenging test, TEAC (Trolox Equivalent Antioxidant Capacity), and FRAP (Ferric Reducing Antioxidant Power)methods. The highest antioxidant capacities were determined in the genotypes LE-3228 and LE-2527, the lowest ones in the LE-985 and LE-994 genotypes. Moreover, close correlation (r = 0.964) was determined between the TEAC and DPPH assays. Based on the antioxidant capacity and total polyphenols content, a clump analysis dendrogram of the monitored apricot genotypes was constructed. In addition, we optimized high performance liquid chromatography coupled with tandem electrochemical and spectrometric detection and determined phenolic profile consisting of the following fifteen phenolic compounds: gallic acid, 4-aminobenzoic acid, chlorogenic acid, ferulic acid, caffeic acid, procatechin, salicylic acid, p-coumaric acid, the flavonols quercetin and quercitrin, the flavonol glycoside rutin, resveratrol, vanillin, and the isomers epicatechin, (–)- and (+)- catechin.

We used carbon paste electrodes and a standard potentiostat to detect silver ions. The detection limit (3 Signal/Noise ratio) was estimated as 0.5 μM. A standard electrochemical instrument microanalysis of silver(I) ions was suggested. As a working electrode a carbon tip (1 mL) or carbon pencil was used. Limits of detection estimated by dilution of a standard were 1 (carbon tip) or 10 nM (carbon pencil). Further we employed flow injection analysis coupled with carbon tip to detect silver(I) ions released in various beverages and mineral waters. During first, second and third week the amount of silver(I) ions releasing into water samples was under the detection limit of the technique used for their quantification. At the end of a thirteen weeks long experiment the content of silver(I) ions was several times higher compared to the beginning of release detected in the third week and was on the order of tens of nanomoles. In subsequent experiments the influence of silver(I) ions (0, 5 and 10 μM) on a plant model system (tobacco BY-2 cells) during a fourday exposition was investigated. Silver(I) ions were highly toxic to the cells, which was revealed by a double staining viability assay. Moreover we investigated the effect of silver(I) ions (0, 0.3, 0.6, 1.2 and 2.5 μM) on guppies (Poecilia reticulata). Content of Ag(I) increased with increasing time of the treatment and applied concentrations in fish tissues. It can be concluded that a carbon tip or carbon pencil coupled with a miniaturized potentiostat can be used for detection of silver(I) ions in environmental samples and thus represents a small, portable, low cost and easy-to-use instrument for such purposes.

Neurodegenerative disorders (NDD) have become the common global health burden over the last several decades. According to World Health Organization (WHO), a staggering 30 million people will be affected by Alzheimer’s disease in Europe and the USA by 2050. Effective therapies in this complex field considering the multitude of symptoms associated with NDD indications, have not been found yet. Based on the results of NDD related studies, prevention appears to be the promise alternative. Antioxidative and anti-inflammatory properties are hypothesized for natural phenolics, a group of plant secondary products that may positively impact neurodegenerative diseases. In these studies, phenolic-rich extracts from less common fruit species: Blue honeysuckle (Lonicera edulis, Turcz. ex. Freyn), Saskatoon berry (Amelanchier alnifolia Nutt.), and Chinese hawthorn (Crateagus pinnatifida Bunge) were obtained and analyzed to detect neuroprotective substances content and establish a potential therapeutic value. High performance liquid chromatography with electrochemical detection was optimized and further applied on analysis of the extracts of less common fruit species. It was observed that Chinese hawthorn and Blue honeysuckle extracts are potent source of neuroprotective phenolic antioxidants. In accordance the results, it appears that the fruit or formulated products may have the potential for the prevention of neurodegenerative diseases.

Various berries and fruit types of less common fruit species are known to contain antioxidants. Consumption of high amounts of antioxidant flavonoids, which display a variety of biological properties, including antiproliferative and anti-inflammatory activity, may have a positive impact on human health, particularly for the prevention of cancer and other inflammatory diseases. In these studies, based on the hypothesis that the fruit extract with the highest content would possess significantly higher health benefits, flavonoid-rich extracts were obtained from some less common fruit species – Blue Honeysuckles (Lonicera Kamtschatica and Lonicera edulis, Turcz. ex. Freyn), Saskatoon berry (Amelanchier alnifolia Nutt.) and Chinese Hawthorn (Crataegus pinnatifida BUNGE) – grown from germplasm held at the Mendel University of Agriculture and Forestry in Brno, Czech Republic and then characterized in terms of biological value based on the results from a relative antioxidant capacity assessment. The antioxidant content evaluation was based on the total flavonoid amount, determined by liquid chromatography with electrochemical detection (HPLC-ED). A DPPH• test was applied as a reference. The antioxidant content measured in Chinese Hawthorn fruit extract identified it as a potent source of flavonoid antioxidants, with a content 9-fold higher than that seen in Amelanchier fruit. The multifunctional HPLC-ED array method coupled with a DPPH• reference appears to be the optimal analytical progress, accurately reflecting the nutritivetherapeutic properties of a fruit.

Vitamin C (ascorbic acid, ascorbate, AA) is a water soluble organic compound that participates in many biological processes. The main aim of this paper was to utilize two electrochemical detectors (amperometric – Coulouchem III and coulometric – CoulArray) coupled with flow injection analysis for the detection of ascorbic acid. Primarily, we optimized the experimental conditions. The optimized conditions were as follows: detector potential 100 mV, temperature 25 °C, mobile phase 0.09% TFA:ACN, 3:97 (v/v) and flow rate 0.13 mL·min-1. The tangents of the calibration curves were 0.3788 for the coulometric method and 0.0136 for the amperometric one. The tangent of the calibration curve measured by the coulometric detector was almost 30 times higher than the tangent measured by the amperometric detector. Consequently, we coupled a CoulArray electrochemical detector with high performance liquid chromatography and estimated the detection limit for AA as 90 nM (450 fmol per 5 μL injection). The method was used for the determination of vitamin C in a pharmaceutical preparations (98 ± 2 mg per tablet), in oranges (Citrus aurantium) (varied from 30 to 56 mg/100 g fresh weight), in apples (Malus sp.) (varied from 11 to 19 mg/100 g fresh weight), and in human blood serum (varied from 38 to 78 μM). The recoveries were also determined.

About biological affecting of flavonoids on animal organisms is known less,thus we selected flavonoids, flavanones and flavones, and their glycosides, which wereexamined as potential inducers of cytochrome(s) P450 when administrated by gavages intoexperimental male rats. The study was focused on induction of CYP1A1, the majorcytochrome P450 involved in carcinogen activation. The data obtained demonstrate thenecessity of taking into account not only ability of flavonoids to bind to Ah receptor(induction factor) but also to concentrate on their distribution and metabolism (includingcolon microflora) in the body. After that we examined certain flavonoids as potential inducers of cytochrome P450, we wanted to suggest and optimize suitable electrochemical technique for determination of selected flavonoids (quercetin, quercitrin, rutin, chrysin and diosmin) in body liquids. For these purposes, we selected square wave voltannetry using carbon paste electrode. Primarily we aimed on investigation of their basic electrochemical behaviour. After that we have optimized frequency, step potential and supporting electrolyte. Based on the results obtained, we selected the most suitable conditions for determination of the flavonoids as follows: frequency 180 Hz, step potential 1.95 mV/s and phosphate buffer of pH 7 as supporting electrolyte. Detection limits (3 S/N) of the flavonoids were from units to tens of nM except diosmin, where the limit were higher than μM. In addition, we attempted to suggest a sensor for analysis of flavonoids in urine. It clearly follows from the results obtained that flavonoids can be analysed in the presence of animal urine, because urine did not influence much the signals of flavonoids (recoveries of the signals were about 90 %).

Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of the methods utilized for detection ofurease are based on analysis of its enzyme activity – the hydrolysis of urea. The aim of thiswork was to detect urease indirectly by spectrometric method and directly by voltammetricmethods. As spectrometric method we used is called indophenol assay. The sensitivity ofdetection itself is not sufficient to analyse the samples without pre-concentration steps.Therefore we utilized adsorptive transfer stripping technique coupled with differential pulse voltammetry to detect urease. The influence of accumulation time, pH of supporting electrolyte and concentration of urease on the enzyme peak height was investigated. Under the optimized experimental conditions (0.2 M acetate buffer pH 4.6 and accumulation time of 120 s) the detection limit of urease evaluated as 3 S/N was 200 ng/ml. The activity of urease enzyme depends on the presence of nickel. Thus the influence of nickel(II) ions on electrochemical response of the enzyme was studied. Based on the results obtained the interaction of nickel(II) ions and urease can be determined using electrochemical methods. Therefore we prepared Ni nanoelectrodes to measure urease. The Ni nanoelectrodes was analysed after the template dissolution by scanning electron microscopy. The results shown vertically aligned Ni nanopillars almost covered the electrode surface, whereas the defect places are minor and insignificant in comparison with total electrode surface. We were able to not only detect urease itself but also to distinguish its native and denatured form.

Despite very intensive research in the synthesising of new cytostatics, cisplatin isstill one of the most commonly used anticancer drugs. Therefore, an investigation ofinteractions of cisplatin with different biologically important amino acids, peptides andproteins is very topical. In the present paper, we utilized flow injection analysis coupledwith electrochemical detection to study and characterize the behaviour of various forms ofglutathione (reduced glutathione – GSH, oxidized glutathione – GSSG and S-nitrosoglutathione – GSNO). The optimized conditions were as follows: mobile phase consistedof acetate buffer (pH 3) with a flow rate of 1 mL min-1. Based on results obtained we chose850 mV as the optimal potential for detection of GSH and 1,100 mV as the optimalpotential for detection of GSSG and GSNO. The detection limits of GSH, GSSG andGSNO were 100 pg mL-1, 50 ng mL-1 and 300 pg mL-1, respectively. Further, the optimized technique was used for investigation of interactions between cisplatin and GSH. We were able to observe the interaction between GSH and cisplatin via decrease in the signal corresponding to glutathione. Moreover, we evaluated the formation of the complex by spectrometry. The spectrometric results obtained were in good agreement with electrochemical ones.

This study reported on the possibility of intoxications of non-target wild animalsassociated with use of bromadiolone as the active component of rodenticides withanticoagulation effects. A laboratory test was done with earthworms were exposed tobromadiolone-containing granules under the conditions specified in the modified OECD207 guideline. No mortality of earthworms was observed during the fourteen days longexposure. When the earthworms from the above test became a part of the diet of commonvoles in the following experiment, no mortality of consumers was observed too. However,electrochemical analysis revealed higher levels of bromadiolone in tissues fromearthworms as well as common voles compared to control animals. There were determinedcomparable levels of bromadiolone in the liver tissue of common voles after primary(2.34±0.10 μg/g) and secondary (2.20±0.53 μg/g) intoxication. Therefore, the risk ofsecondary intoxication of small mammalian species feeding on bromadiolone-containing earthworms is the same as of primary intoxication through baited granules. Bromadiolone bio-accumulation in the food chain was monitored using the newly developed analytical procedure based on the use of a liquid chromatography coupled with electrochemical detector (HPLC-ED). The HPLC-ED method allowed to determine the levels of bromadiolone in biological samples and is therefore suitable for examining the environmental hazards of this substance.

Acetylsalicylic acid (AcSA), or aspirin, was introduced in the late 1890s and hasbeen used to treat a variety of inflammatory conditions. The aim of this work was to suggestelectrochemical sensor for acetylsalicylic detection. Primarily, we utilized square wavevoltammetry (SWV) using both carbon paste electrode (CPE) and of graphite pencilelectrode (GPE) as working ones to indirect determination of AcSA. The principle ofindirect determination of AcSA bases in its hydrolysis on salicylic acid (SA), which isconsequently detected. Thus, we optimized both determination of SA and conditions forAcSA hydrolysis and found out that the most suitable frequency, amplitude, step potentialand the composition and pH of the supporting electrolyte for the determination of SA was260 Hz, 50 mV, 10 mV and Britton-Robinson buffer (pH 1.81), respectively. The detectionlimit (S/N = 3) of the SA was 1.3 ng/ml. After that, we aimed on indirect determination ofAcSA by SWV CPE. We tested the influence of pH of Britton-Robinson buffer andtemperature on yield of hydrolysis, and found out that 100% hydrolysis of AcSA wasreached after 80 minutes at pH 1.81 and 90°C. The method for indirect determination ofAcSA has been utilized to analyse pharmaceutical drug. The determined amount of AcSA in the pharmaceutical drug was in good agreement with the declared amounts. Moreover, weused GPE for determination of AcSA in a pharmaceutical drug. Base of the results obtainedfrom stationary electrochemical instrument we used flow injection analysis withelectrochemical detection to determine of salicylates (SA, AcSA, thiosalicylic acid, 3,5-dinitrosalicylic acid and 5-sulfosalicylic acid – SuSA). We found out that we are able todetermine all of detected salicylates directly without any pre-treatment, hydrolysis and so onat units of femtomoles per injection (5 μl).

Naphthoquinones are one of the groups of secondary metabolites widespread innature, where they mostly appear as chromatic pigments. They embody broad-range ofbiological actions from phytotoxic to fungicidal. An anticancer effect of naphthoquinonesstimulates an interest in determination and characterization of single derivatives of 1,2- and1,4-quinones in biological samples. The main aim of this work was to suggest a techniquesuitable to determine lawsone, juglone and/or plumbagin in biological samples and to studyof their influence on BY-2 tobacco cells. The BY-2 tobacco cells were cultivated in thepresence of the naphthoquinones of interest (500 μg.l-1) for 24 h and then the morphologicalchanges were observed. We found out that naphthoquinones triggered the programmed celldeath at BY-2 cells, which can be confirmed by the apoptotic bodies in nucleus. After thatwe suggested and optimized different electrochemical techniques such differential pulsevoltammetry (DPV) coupled with hanging mercury drop (HMDE) and carbon pasteelectrode, micro flow device coupled with carbon screen printed electrodes and flowinjection analysis coupled with Coulochem III detector to determine them. The detectionlimits of naphthoquinones of interest were expressed as 3S/N and varied from units tohundreds of ng per millilitres according to methods used. Moreover, we utilized DPVcoupled with HMDE and micro flow device to determine content of juglone in leavesPersian walnut (Juglans regia). We determined that the leaves contained juglone tenths of gper 100 g of fresh weight. The results obtained show the convincing possibilities of using ofthese methods in analysis of plant secondary metabolites.

Apples are known to be a rich source of phenolic compounds, however detailed studies about their content in the individual parts of apple trees are reported rarely. For this purpose, we tested various stationary phases for the determination of phenolic compounds in leaves, bark, and buds. Phloridzin, phloretin, chlorogenic acid, rutin, and quercitrin were analyzed with high performance liquid chromatography coupled with diode array detection. A YMC Triart C18-ExRS 150 × 4.6 mm, 5 µm particle size analytical column with multilayered particle technology was used. The separation was performed with a mobile phase that consisted of acetonitrile and 0.1% phosphoric acid, according to the gradient program, at a flow rate of 1 mL/min for 12.50 min. The concentration of phenolic compounds from 13 cultivars was in the range of 64.89–106.01 mg/g of dry weight (DW) in leaves, 70.81–113.18 mg/g DW in bark, and 100.68–139.61 mg/g DW in buds. Phloridzin was a major compound. The total antioxidant activity was measured using flow analysis and the correlation with the total amount of phenolic compounds was found. This finding can lead to the re-use of apple tree material to isolate substances that can be utilized in the food, pharmaceutical, or cosmetics industries.