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In this work phytochemical characterization of two medicinal plants from Lamiaceae family, Mentha rotundifolia and Satureja calamintha, has been carried out. Extracts obtained with different solvents were screened for different plant secondary metabolites and were biologically characterized by defining their antiradical and antibacterial activities. Phytochemical screening of M. rotundifolia and S. calamintha confirmed their richness in different secondary metabolites. The determination of phenolic compounds revealed high polyphenols contents in water: methanol (30:70) extracts with concentrations of 20.64±1.74 mg EAG/g DW and 13.45±0.91 mg EAG/g DW for M. rotundifolia and S. calamintha, respectively. These extracts were also characterized by high concentrations of flavonoids (Mentha rotundifolia 12.33±1.58 mg EQ/g DW, Satureja calamintha 7.11±0.02 mg EQ/g DW). Furthermore, the water: methanol (30:70) extract of M. rotundifolia was the most effective in inhibiting free radicals. Recorded inhibition diameters for both plant samples and tested microbial strains ranged from 6.66 mm to 13.66 mm. Presented results confirmed that tested indigenous Algerian plants are favorable sources of polyphenols with antioxidant and antimicrobial properties.

Ephedra alata, Ononis angustissima, and Genista saharae are endemic Algerian plants with pharmacological potential, used for centuries in traditional medicine. Herein the efficiency of subcritical water extraction (SWE) of phenols and flavonoids from these plants was evaluated by spectrophotometric assays. The most important operational parameters of the technique (temperature, pressure, time) were optimized for each plant based on phenols yield. At defined optimal extraction conditions (140ºC for E. alata, 155ºC for O. angustissima and G. saharae, 50 bars, 15min), maximum contents of phenols in the extracts were 16.13, 18.33, and 21.12 mg GAE/g dry weight, for E. alata, O. angustissima, and G. saharae, respectively. Considering the safety of the used solvent, excellent yields of phenols and short extraction time, subcritical water extraction can efficiently be used in exploitation of pharmacological potentials of the studied plants.

The work focuses on the study of two brown algae Dictyota dichotoma and Dictyopteris membranacea. Extracts obtained by different organic solvents (dichloromethane, hexane, acetone, methanol, chloroform) were screened for their DPPH antiradical activity, whereas essential oils obtained by steam distillation were chemically characterized by GC-MS. Steam distillation yielded 0.07 and 0.095% of the essential oils for Dictyota dichotoma and Dictyopteris membranacea, respectively. The chemical screening of the essential oils of Dictyopteris membranacea and Dictyota dichotoma showed similar chemical profiles. Namely, trans-anethole showed to be the main component in both studied oils, yielding 12.28% and 10.70% for Dictyopteris membranacea and Dictyota dichotoma, respectively. Antioxidant activity of extracts was expressed by IC50 values and was in the range 0.375-1.72 mg/ml.

In this work, anti-atherogenic and anti-hyperlipidemic effects of a herbal mixture, rich in polyphenols, and composed of 35% of buckthorn bark (Frangulae cortex), 20% of mint leaves (Menthae piperita folium), 20% of caraway fruit (Carvi fructus) and 25% of parsley fruit (Petroselinum fructus) were studied by monitoring biochemical parameters in experimental animals. Experimental animals (Wistar rats) were subjected to five different feeding regimes. Plasma levels of total cholesterol, triglycerides, cholesterol bound to high-density lipoproteins (HDL) and cholesterol linked to low-density lipoproteins (LDL) were monitored in different time periods. The feces of experimental animals was analysed for seven bile acids, as well as for total cholesterol. Simultaneously, the activities of alanine aminotranferase (ALT) and aspartate aminotransferase (AST) were measured. The introduction of herbal mixture into fatty food did not have significant influence on enzyme activities; however, the effect on induced hyperlipidemia was significant. Total atherogenic index was reduced by 43.3%, whereas total cholesterol and cholesterol bound to low density lipoproteins were reduced by 18.2% and 18.8%, respectively. Total bile acids concentrations dropped by 13.2%, whereas cholesterol was reduced by 33%. [Projekat Ministarstva nauke Republike Srbije: Functional products of cereal for persons with metabolic disorders]

The relationships between the contents of various metals (Cu, Ni, Pb and Al) in 38 different milk chocolate samples were studied using a chemometric approach. The chemometric expressions were generated using a training set of 25 chocolate samples and the predictive ability of the resulting models was evaluated against a test set of 13 chocolate samples. The chemometric analysis was based on the application of multiple linear regression analysis (MLR). MLR was performed in order to select the significant models for predicting the metal contents. The MLR equations that represent the content of one metal as a function of the contents of other metals were established. High agreement between experimental and predicted values, obtained in the validation procedure, indicated the good quality of the models. It enables the researchers to establish reliable relationships between the contents of various metals which can be used for their prediction in different types of chocolate prior to their analysis. This can reduce the trial-and-error element and experimental costs in the production.[Projekat Ministarstva nauke Republike Srbije, br. 31055, br. 172012 i br. 172014]

Arsenic is a naturally occurring toxic and carcinogenic element. The degree of the toxicity depends on its chemical form and the concentration. Application of a sensitive, selective, simple and rapid method for detection and monitoring of different oxidation states of arsenic in waters is of great importance because main route of population exposure is through drinking water. In this work chronopotentiometric stripping analysis (CSA) was used for the determination of As(III) and As(V) in tap, well, river and rain waters from Vojvodina (Serbia). Gold film electrode on the glassy carbon support was used as the working electrode. The experimental parameters of the technique were investigated and optimized. Detection limit of the method for the electrolysis time of 600 s was 2 μg/dm3 of As(III).

Polycyclic aromatic hydrocarbons (PAHs) were determined in soil samples from forty different locations in Vojvodina. The samples were Soxhlet extracted cleaned-up and analyzed using gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode (SIM). Each PAH was separately quantified using an eight-point calibration of mixed standard solutions in the range between 0.25 and 10 μg/cm3. The sum of the 16 US Environmental Protection Agency PAHs analyzed in the soil samples varied from 0.043 to 1.362 mg/kg of dry soil.

The limit of detection (LOD) and the limit of quantitation (LOQ) for 16 individual PAHs from the Environmental Protection Agency (EPA) list (naphthalene, acenaphthylene, acenaphtene, fluorene, phenanthrene antrachene, fluoranthene, pyrene, benzo(a)anthracene, chrysene benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h) anthracene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene) were determined by Gas Chromatography – Mass Spectrometry (GC-MS). Determination was performed by SCAN (digital linear scanning) and SIM (selected ion monitoring) techniques preceded by the optimization of the experimental factors. The limit of detection obtained by the SCAN technique was in the range of 0.179 – 15.236 ng, and the quantitation limit in the range of 1.017 – 50.788 ng. SIM technique enabled LOD and LOQ in the range of 0.036 – 13.886 pg and 0.119 – 46.287 pg respectively.

The influence of the most important experimental factors in chronopotentiometric stripping analysis (CSA) of selenium( IV) using mercury film working electrode was examined. Interferences of copper, iron and lead were investigated as well. The possibility of avoiding prolonged deaeration of the solution was examined by applying medium exchange modification of the technique, where the dissolution of the deposit was performed in calcium-chloride solution. Detection limits obtained for the modification of the CSA with prior deaeration and medium exchange modification were 0.4 μg/dmJ and 1.15μg/dmJ, respectively. Accuracy of the defined techniques has been confirmed by analysing reference material (RM 8436) -wheat durum flour. The results obtained by applying both modifications of the technique showed a very good agreement of total selenium content with declareted value.