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Nowadays, climate changes induce deviations in the composition of honey varieties characteristic of a specific geographic region. Therefore, according to Codex Alimentarius for honey, the slight variations in values of determined parameters cannot be strictly regarded as a sign of its adulteration. Here, modified methods are presented for preparing honey samples for inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and the high-performance liquid chromatography (HPLC) method to use them as fast and reliable methods in the food industry. ICP-OES analysis suggested that all analysed honey samples are natural, and HPLC-DAD (diode-arrray detection) analysis on the flavonoids showed that one sample is probably not natural. Invertase activity showed an overlap with this HPLC-DAD finding but suggested more samples as possibly adulterated, which can be neglected due to possible thermal treatment of those natural samples, causing a decrease in invertase activity. Therefore, results obtained from the analyses of investigated honey samples based on the mineral content, number, and quantity of flavonoids, together with the invertase activity, indicated that the combination of analyses could be a reliable tool for determining the quality of honey samples.

Since ancient times, medicinal plants and pharmacologically active products obtained from different natural sources play an important role in human health. Plants belonging to the genus Artemisia possess a great biological potential and it is a well-studied genus in the fields such as systematics (including molecular phylogenetics) and genome organization. Many species of the genus (e.g., A. absinthium, A. annua, A. vulgaris, A. abrotanum, A. arborescens) are widely exploited, because of their high economic value as medicines, food and ornamentals. Withal, in such a large genus, some hiatus must inevitably exist, concerning attainments and potentials that individual species possess. Most of the studies are focused on bioactivity and pharmacology of sesquiterpene lactones. Lignans are unjustly neglected, even though they as well exhibit a wide range of bioactivities. Motivated by that fact, we tried to consolidate findings on bioactive lignans accumulated through the years, with the logical perspectives on further work on isolation and identification of new bioactive lignans and the exploitation of lignans as substances of potential pharmacological interest. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172047]

A simple, rapid, sensitive and selective kinetic spectrophotometric method for determination of Fe(III) traces was elaborated in this paper. It is based on the catalytic effect of Fe(III) ions on oxidation of potassium salt of disulphonated hydroquinone (K2S2Hy) by hydrogen peroxide in acidic media, at a constant ionic strength. At the working temperature of 20°C and the wavelength of 450.0 nm, optimal conditions for determination of iron were found so that iron (III) can be determined by the proposed method in the concentration range of 1.87 to 18.7 ng cm-3. Corresponding RSD values were determined to be in the range 4.22 to 10.33 %. The limit of detection (LOD) calculated in two ways was found to be 1.07 ng cm-3 i.e. 1.11 ng cm-3 Fe(III). In order to assess the selectivity of the method effects of different ions on the reaction rate were also determined. It was found that presence of oxalates and citrates in the w/w ratio to Fe(III) 1:1 under selected experimental conditions interferes with determination of iron. Then the method was applied for determination of Fe(III) traces in white radish juice. The results agreed well with those obtained by atomic absorption spectrometry.

The aim of this work was to assess phenomena occurring during AgNP transport from nanocomposite Ag/alginate hydrogels under conditions relevant for potential biomedical applications as antimicrobial soft tissue implants. First, we have studied AgNP migration from the nanocomposite to the adjacent alginate hydrogel mimicking soft tissue next to the implant. AgNP deposition was carried out by the initial burst release lasting for ∼24 h yielding large aggregates on hydrogel surfaces and smaller clusters (∼400 nm in size) inside. However, the overall released content was low (0.67%) indicating high nanocomposite stability. In the next experimental series, release of AgNPs, 10–30 nm in size, from Ag/alginate microbeads in water was investigated under static conditions as well as under continuous perfusion mimicking vascularized tissues. Mathematical modeling has revealed AgNP release by diffusion under static conditions with the diffusion coefficient within the Ag/alginate hydrogel of 6.9x10–19 m2 s–1. Conversely, continuous perfusion induced increased AgNP release by convection with the interstitial fluid velocity estimated as 4.6 nm s–1. Overall, the obtained results indicated the influence of hydrodynamic conditions at the implantation site on silver release and potential implant functionality, which should be investigated at the experimentation beginning using appropriate in vitro systems. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45019]

The objective of the present study was to investigate the correlation between the radical-scavenging properties (measured by evaluating the quenching of the stable 2,2-diphenyl-1-picrylhydrazil radical) of Serbian, Macedonian and Montenegran red wine Vranac of different geographical origins, and their contents of total phenolics, total flavonoids and polyphenol profile. All tested Vranac wines samples showed a high antioxidant activity ranging from 13.00 to 15.02 mmol/L, while the total polyphenolic content was between 3478.70 and 3935.19 mg/L. The predominant anthocyanin was malvidin-3-glucoside (179.04-281.31 mg/L), predominant flavonol was quercetin-3-glucoronide (5.88-11.78 mg/L), predominant flavan-3-ol was catechin (24.43 - 76.78 mg/L) and predominant hydroxicinnamic acid was t-caftaric acid (13.46-38.56 mg/L). Generally, red wines Vranac produced from Balkan regions are a rich source of phenolics, which the evident antioxidant capacity showed. [Projekat Ministarstva nauke Republike Srbije, br. 174007 i br. TR31060]

The absorption and fluorescence emission spectra of cyanidin and cyanidin 3-O-β-glucopyranoside (Cy3Glc) at pH 5.5 in aqueous solution have been studied. The most effective fluorescence excitations of cyanidin were at the UV absorption maxima at 220 and at 230 nm and at higher wavelengths at 270 and at 280 nm. Cyanidin exhibits fluorescence emission maxima at 310 nm and in the visible range at 615 nm. For the Cy3Glc most effective fluorescence excitation was at 220 and at 230 nm and at higher wavelengths at 300 and at 310 nm. Cy3Glc has fluorescence emission spectra with the maximum at 380 nm and does not show fluorescence emission in the visible range. If compare fluorescence emission spectra of cyanidin and Cy3Glc it can be seen that fluorescence emission intensity for cyanidin is significantly higher than that for Cy3Glc. These results reveals the impact of 3-glucosidic substitution at C-3 of aglycone (to form Cy3Glc) on the significantly decrease in fluorescence emission intensity, and disappearance of the fluorescence emission in visible wavelength range.

The colour variation, colour intensity and stability at various pH values (2.0, 4.0, 7.0 and 9.0) of cyanidin 3-O-β-glucopyranoside (Cy3Glc) and its aglycone cyanidin was investigated during a period of 8 hours storage at 25ºC. Our data showed that pH of aqueous solution had impact on spectroscopic profile of cyanidin and Cy3Glc. Beginning with the most acidic solutions, increasing the pH induce bathochromic shifts of absorbance maximum in the visible range for all examined pH values (with the exception pH 4.0 for cyanidin), while the presence of the 3-glucosidic substitution induce hypsochromic shift. Compared to cyanidin, Cy3Glc has higher colour intensity and higher stability in the whole pH range, except at pH 7.0. The 3-glucosidic substitution influences on the colour intensity of Cy3Glc in the alkaline region. After 8-hour incubation of Cy3Glc and cyanidin at pH 2.0 and 25 ºC, 99% of Cy3Glc and only 27% of cyanidin remained unchanged.

Blackthorn (Prunus spinosa L.) is commonly used in food industry and phytotherapy. The contents of phenols, flavonoids, anthocyanins and antioxidative activity in extracts of blackthorn fruit were determined using spectrophotometric methods. The content of total phenol compounds varies from 15.33 to 20.94 mg GAE g-1 of fresh fruit. The content of total flavonoids is very low, and ranges from 0.419 to 1.31 mg QE g-1 of fresh fruits. Anthocyanins content lies between 0.112 mg cyanidin 3-glucoside/g of fresh sample in ethanol extract and 0.265 mg of cyanidin 3-glucoside g-1 of fresh blackthorn fruit in methanol-water 50/50 (v/v) extract. The differences in total phenol compounds content depend on used extraction medium as a consequence of different polarity of used organic solvents and their mixtures, which selectively extract individual compounds. All explored extracts exhibited strong scavenging activity against DPPH radicals, which ranges from 32.05 to 89.10%. Phenolic acids (neochlorogenic and caffeic acids), flavonoids (quercetin and myricetin) and anthocyanins (cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside) were identified in investigated ethanol extracts by HPLC analysis. Ethanol extract shows significant antimicrobial activity against Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Salmonella abony NCTC 6017 and antifungal activity against Candida albicans ATCC 10231. Blackthorn fruit extract exhibits a high phenolic content and a high antioxidant activity, and can be used as an antioxidant in food and pharmaceutical industries.[Projekat Ministarstva nauke Republike Srbije, br. 172047]

The quality of some medicinal plants and their water extracts from South East Serbia is determined on the basis of metal content using atomic absorption spectrometry. The two methods were used for the preparation of water extracts, to examine the impact of the preparation on the content of metals in them. Content of investigated metals in both water extracts is markedly lower then in medicinal plants, but were higher in water extract prepared by method (I), with exception of lead content. The coefficients of extraction for the observed metal can be represented in the following order: Zn > Mn > Pb > Cu > Fe. Correlation coefficients between the metal concentration in the extract and total metal content in plant material vary in the range from 0.6369 to 0.9956. This indicates need the plants to be collected and grown in the unpolluted area and to examine the metal content. The content of heavy metals in the investigated medicinal plants and their water extracts is below the maximum allowable values, so they are safe to use.

The aim of this study is to evaluate the content of phenolics: the total phenols (TP), flavonoids (TF), anthocyanins (TA), as well as the total antioxidant capacity (TAC) in three sour cherry cultivars (Prunus cerasus L.) introduced to the southeast Serbia climate conditions. Among the researched sour cherries, ‘Oblacinska’ cultivar contained the highest amounts of all groups of phenolics, followed by ‘Cigancica’ > ‘Marela’. A significant difference were observed in the phenolic content among different cultivars and growing seasons (p

The content of phenolics: total phenols (TP), flavonoids (TF), anthocyanins (TA) and hydroxicinnamic acid as well as the total antioxidant capacity (TAC) in nine commercial red fruit juices (sour cherry, black currant, red grape) produced in Serbia were evaluated. The total compounds content was measured by spectrophotometric methods, TAC was determined using DPPH assays, and individual anthocyanins and hydroxycinnamic acids was determined using HPLC-DAD methods. Among the examined fruit juices, the black currant juices contained the highest amounts of all groups of the phenolics and exhibited strong antioxidant capacity. The amount of anthocyanins determined by HPLC method ranged from 92.36 to 512.73 mg/L in red grape and black currant juices, respectively. The anthocyanins present in the investigated red fruit juices were derivatives of cyanidin, delphinidin, petunidin, peonidin and malvidin. The predominant phenolic acid was neoclorogenic acid in sour cherry, caffeic acid in black currant, and p-coumaric acid in black grape juices. Generally, the red fruit juices produced in the Serbia are a rich source of the phenolic, which show evident antioxidant capacity.

The heavy metals (Fe, Cu, Zn and Mn) contents of selected plant species, grown in Southeast region of Serbia, that are traditionally used in alternative medicine were determined. Among the considered metals, iron content was the highest one and varied from 137.53 up to 423.32 mg/kg, while the contents of Cu, Zn and Mn were remarkably lower, and ranged from 8.91 to 62.20 mg/kg. In addition, an analysis of plants extracts showed a significant transfer of heavy metals during extraction procedure; therefore, the corresponding extraction coefficients reached values up to 88.8%. Those were especially high in the ethanol based extracts. Moreover, it is established that such coefficients mostly depend on the solvent nature and also on the treated plant species. The obtained results impose that medicinal plants from Southeast region of Serbia due to rather low content of heavy metals are appropriate for preparation of teas and medicinal extracts.

An accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantification of doxycycline hyclate in pharmaceutical samples has been developed and validated. The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm x 4.6 mm, 10 mm particle size) at 20°C with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous solution of oxalic acid (2:3:5, v/v/v). The flow rate was 1.25 ml min-1. A UV detector set at 350 nm was used to monitor the effluent. Each analysis required no longer than 4 min. The limits of detection and quantification were 1.15 and 3.84 µg ml-1, respectively. Recoveries for different concentrations ranged from 99.58 to 101.93%.

kinetic-spectrophotometric method is proposed for the determination of morin. The method is based on the inhibition effect of morin on the oxidation of C6H5COON aby hydrogen peroxide in the presence of the complex Fe(II)-AA(ascorbic acid),which acts as a catalyst. The concentration range for the determination of morin is one of the lowest achieved so far (a linear calibration graph was obtained for morin from 2.255–22.55 ng cm-3). The limit of detection of the method is 0.28 ng cm-3. The relative error ranges between 1.42 to 5.10% for the given concentration interval. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined in order to assess the selectivity of the method. The major advantages of this kinetic-spectrophotometric assay are its sensitivity, selectivity, reproducibility, speed and simplicity.

All investigated extracts of red mulberry (Morus rubra L.) contain a high content of total phenols. The highest content of total phenols was shown by red mulberry in the ethanolic extract (50%). Certain extracts of the fruit of red mulberry (aqueous, ethanolic 50%, acetonic 50% and acetonic) contain very small quantities of anthocyanins. Four phenolic acids were identified in the extracts of red mulberry: chlorogenic, neochlorogenic, cryptochlorogenic acid and caffeic acid, and four flavonoids using HPLC analysis: quercetin-3-O-rutinoside, quercetin-3-O-glucoside, quercetin-3-Orhamnoside, and kaempferol-3-O-rutinoside. Cyanidin-3-O-glucoside was identified in the methanolic extract of red mulberry. The content of heavy metals (Fe, Cu, Mn, Cd, Ni, Zn and Pb) was determined using atomic absorption spectroscopy in fruits and the extracts of red mulberry. Mulberry fruit has been shown the highest content of Fe and low content of toxic metals. The content of metals is the highest in the majority of cases in the extracts of acetone and acetone 50%. The methanolic extract of red mulberry shows the antimicrobial properties against all investigated bacteria except Staphylococcus aureus. Obtained results show that fresh fruits of red mulberry and its extracts can be used in nutrition and the preparation of pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the content of phenolic compounds (phenols, flavonoids and anthocyanins) of Morus alba L. fruit (white mulberry), Morus rubra L. (red mulberry) and Morus nigra L. fruit (black mulberry) by the HPLC analysis. In the extracts of white, red and black mulberry identified the four phenolic acids by HPLC analysis: chlorogenic, 4-caffeoylquinic, 5-caffeoylquinic and caffeic acid. 5-caffeoylquinic acid was identified in all tested extracts of white, red and black mulberry. 4-caffeoylquinic acids contain all the extracts except methanol extract of red mulberry. Caffeic and chlorogenic acid containing methanol extracts of white and red mulberry. [ABSTRACT FROM AUTHOR]

Solid-liquid extraction of total flavonoids (TF) from rosemary (Rosemarinus of Ucinalis) leaves was studied in the present work. The effects of type of solvent and its concentration, temperature and extraction time on amount of flavonoids as well as the effects of these parameters on the kinetics and thermodynamic parameters of extraction process were investigated. The effects of the process factors on the TF were assessed using the full factorial test plan 2³. Extraction using 50% ethanol in a 50 °C during 100 min, was the most suitable conditions to produce a extract with high content of flavonoids (32.428 mg catechin equivalents / g rosemary leaves). The following two-parametric models were analyzed: non-stationary diffusion model trough the plant material, model of Ponomarev and parabolic diffusion model. All models gave a good fit to the experimental data (root mean square, RMS<2%, coefficient of determination, R²>93%). The ΔG°, ΔS° and ΔH° values of the flavonoids extraction process were -4.89 - (-7.02) kJ/mol, 23.59 - 25.91 KJ/mol and 0.95 - 9.90 kJ/mol, respectively, indicating spontaneous, irreversible, and endothermic process. [ABSTRACT FROM AUTHOR]