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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.

In this study, a two-level factorial design was used to evaluate the significant extraction parameters in achieving higher recovery yield of Cu, Fe, Mn, and Zn contents from Melissa officinalis leaves. The independent parameters were solid-to-solvent ratio, extraction temperature, and duration of extraction. The experimental data obtained were fitted to a first-order polynomial equation using multiple regression analysis and studied by appropriate statistical methods (ANOVA). The optimum extraction conditions were as follows: solid-to-solvent ratio 1:15 g/mL, extraction temperature 100°C, and extraction time 80 min. Under these conditions, the experimental concentrations were in close agreement with the value predicted by the model. The correlation coefficients of 0.9947, 0.9966, 0.9939, and 0.9957 observed between the predicted and actual values for the response variables are evidence that the regression model can represent the experimental data well. Minerals present in the extracts may be maximized when process conditions are carefully adjusted within the reported values.

Objectives: This study was conceived with the aim of translating the experience and knowledge of the research group into the design and creation of multi-active phytocomplex cocktails from lyophilised winery by-products (Grape Pomace—GP) and weeds (Sambucus ebulus L., Dwarf Elder—DE). Methods: Quantification of bioactive molecules was performed by high-performance liquid chromatography (HPLC) method. Results: In the extract obtained from lyophilised GP, the most dominant component that was quantified was petunidin-3-glucoside. Prominent compounds that were quantified in DE extract were cyanidin derivatives. The total number of microorganisms in lyophilisates is low, but some of them still survive lyophilisation. Antibacterial activity was determined by microdilution, the minimum inhibitory concentration (MIC) of the tested bacteria ranged from 0.78 mg/mL to 25.00 mg/mL. Antibacterial susceptibility testing (AST) revealed that Klebsiella spp. and Acinetobacter baumannii complex are extensively drug-resistant (XDR). Conclusions: The GP + DE cocktail showed very strong AB power against both tested XDR bacteria. The total phenolic content and antioxidative effect (determined spectrophotometrically) indicate their linear correlation. [ABSTRACT FROM AUTHOR]

The extract of the plant species Satureja hortensis L. (often used as traditional ethno-therapy and in food processing) was prepared using the ultrasonic extraction technique, and contains a large quantity of secondary metabolites, with scientific evidence for antioxidant, antimicrobial, sedative, antispastic and antidiarrheal activities. Process optimization was carried out using a mathematical–statistical method (response surface methodology—RSM), which models and examines the effects of three levels and three variables on the observed response. The investigated responses were the content of total phenolic components (TPC) and total flavonoids (TFC), as well as tests of antioxidant activity at the level of radicals. The independent variables were ethanol concentration (40–80%), temperature (40–80 °C) and the liquid–solid ratio (10–30 mL/g). Results from this study were entered into a second-degree polynomial with multiple non-linear regression. Analysis of variance (ANOVA) was applied to find the most favorable environment for assessing the model's performance and effectiveness with an ethanol concentration of 20%, temperature of 80 °C and LSR of 21.4 mL/g. ANOVA assessed the model's significance, and a second-order polynomial model described the relationships between variables and responses. Diagnostic plots confirmed the model's adequacy and reliability. The estimated values were 4.11 mg chlorogenic acid equivalents per gram of dry weight (CEA/g), 2.18 mg of rutin equivalents per gram of dry weight (RE/g), and 0.030 mg/mL and 0.030 mg/mL for TPC, TFC, IC50 and EC50, respectively. High-Performance Liquid Chromatography with diode array detection (HPLC-DAD) examination revealed that the prominent substance in the tested extract is rosmarinic acid (46,172 µg/mL), followed by chlorogenic acid (1519 µg/mL). [ABSTRACT FROM AUTHOR]

Vanillic acid is used in the food industry and perfumery, and the optimization of its extraction process from the natural source is important for saving time and money. The presence of vanillic acid in pumpkin seeds was proven using HPLC analysis. Computational optimization of the extraction shows that for the concentration of ethanol 40% and solmodul: V/m=20, the optimum condition for the extraction of vanillic acid from pumpkin seeds was 100 min and 450C. The estimation of fitting for each kinetic model to the experimental kinetic data was performed using the root mean square, standard deviation, and the correlation coefficient. Ponomarev model was shown as the most suitable with the highest accuracy among the six considered kinetic models. The enthalpy and entropy changes were positive, while the Gibbs free energy was negative and decreased when temperature increased during the thermodynamic analysis. Therefore, the extraction of vanillic acid from pumpkin seeds was endothermic, spontaneous, and irreversible.

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 kinetic spectrophotometric method for determining residues of insecticide diflubenzuron 1(4-chlorphenyl)-3-(2,6-diflubenzoyl)urea (DFB) has been developed and validated. Kinetic method was based on the inhibitory effect of DFB on the oxidation reaction of sulfanilic acid (SA) by hydrogen peroxide in the presence of Co2+ ions in a phosphate buffer, which was monitored at 370 nm. DFB can be measured in the concentration interval 0.102 – 3.40 μg mL-1 and 3.40 – 23.80 μg mL-1. The detection and quantification limits of the method were calculated according to the 3σ criteria and found to be 0.077 μg mL-1 and 0.254 μg Ml-1, respectively. The relative standard deviations for five replicate determinations of 0.102, 1.70 and 3.40 μg mL-1 DFB were 2.08, 1.22 and 1.21 %, respectively, for the first concentration interval, and the recovery percentage values were from 94.12 to 97.35 %. HPLC method was used as a parallel method to verify results of the kinetic method. The kinetic method was successfully applied to determine diflubenzuron concentrations in spiked water and baby food samples after solid phase extraction of the samples. The F and t values at 95% confidence level are lower than the theoretical ones, confirming agreement of the developed and the HPLC method. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172061]

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]

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.

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]

In this study, the effect of various parameters such as solvent concentration (50 and 80%), extraction temperature (30, 40, and 50°C), and solvent/solid ratio (1:20, 1:25, and 1:30 g ml−1) on the extraction yield of apigenin-glycosides from parsley were investigated. The high-performance liquid chromatography analysis of parsley extracts confirms the presence of two apigenin-glycosides: apiin and malonyl-apiin. The kinetics of extraction was described using non-stationary diffusion model and Ponomarev's model. Models have a good fit to the experimental data (root mean square: RMS<±1.6%; standard deviation: SD<±1.5%; the coefficient of determination: R2 > 0.82). The effects of the process factors on the kinetic model parameters, equilibrium constant and Gibbs free energy change were assessed using the full factorial test plan 23. [ABSTRACT FROM AUTHOR]

The main goal was to optimize and establish the kinetics and the thermodynamics of the extraction process. Aninvestigation into the effects of ethanol concentration (0-100 %), liquid to solid ratio (30-60mLg-1), extraction temperature (25-65 °C), and extraction time (40-200 min) on the extraction of total phenols (TP) and total flavonoids (TF) from linden (Tilia cordata M.) flowers was performedusing single-factor experiments. Experimental results showed that extraction conditions had a significant effect on the extraction of phenolic compounds. The optimized conditions were 50%ethanol, liquid to solid ratio 60mLg-1 for 120 min at 55 °C, with values of 17.05 mg GAE g-1 dry weight (d.w.) for TP and 13.32 mg CE g-1 d. w. for TF. Extracted phenolic compounds were analyzed by HPLC. The antioxidant activity of the extracts was evaluated by DPPH and ABTS assays. The applicability of different mathematical models (model based for the unsteady diffusion through the plant material, model based on the film theory and model of Ponomaryov) to describe the kinetics of the extraction process of TP and TF from linden flowers was studied as well. The mathematical models applied showed a good agreement with the experimental results, which allows their application in modelling and optimizing the solid/liquid extraction process to extract TP and TF from linden flowers. [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]