Marija Radojković

Free radical scavenging activity, total phenolic and flavonoid contents of mulberry (Morus spp. L., Moraceae) extracts

Mulberry (Morus spp. L., Moraceae) fruits, leaves, bark and branch have been used in traditional medicine as diuretic, hypoglycemic and hypotensive. The mechanism of their effects is correlated with the content of active components. Objective of this work was to evaluate and compare antioxidant properties of different extracts of two Morus species growing in Serbia: Morus alba L. (white mulberry) and Morus nigra L. (black mulberry). Potential antioxidant activity, content of antioxidant compounds (phenolics and flavonoids) and radical scavenging capacity, tested by DPPH method, were evaluated. The phenolic and flavonoid composition of different Morus extracts was determined by the HPLC method. The extracts prepared from fruits, leaves and roots of M. alba and M. nigra exhibited different characteristics. The highest extraction yield was achieved by M. alba leaves extraction (23.40%). M. nigra roots extract shown the highest total phenolics (186.30 mg CAE/g), while highest total flavonoids content (67.37 mg RE/g) was determined for M. nigra leaves extracts. In addition, black mulberry leaves extracts with the highest antioxidant activity had the highest phenolic acids contents. The dominant phenolic components in the samples were rutin and chlorogenic acid. All investigated mulberry dry extracts shown high content of phenolic compounds and significant antioxidant activity. This work contributes to knowledge of the antioxidant properties of Morus species. The obtained results may be useful in the evaluation of new dietary supplements and food products.

Fatty Acid Profiles of Four Wild Mushrooms and Their Potential Benefits for Hypertension Treatment

Mushrooms are useful in balancing human diet and treating different health problems. The main determinant of the fluidity of erythrocyte membranes and rheologic properties of blood is the lipid composition of the membrane, which directly depends on lipids present in the diet. Lipid profiles of 4 European wild edible mushrooms, as well as the ability of mushroom lipids to modify the fluidity of erythrocyte membrane, were examined by using gas chromatography-mass spectometry, gas chromatography-flame ionization detector, and electron paramagnetic resonance spin probing technique. Lipids from 2 species--Macrolepiota procera and Collybia platyphylla--provoked an increase in erythrocyte membrane fluidity. Therefore, introduction of these and other wild mushrooms with similar lipid profiles to the human diet could be very beneficial in the treatment of hypertension and other cardiovascular diseases related to decreased fluidity of erythrocyte membranes.

Biological activities of phenolic compounds and ethanolic extract of Halacsya sendtneri (Boiss) Dőrfler

The objective of this study was to evaluate the efficacy of the ethanolic extract of endemic plant Halacsya sendtneri in inhibiting the growing of the test fungi and bacteria as well as to determine its genotoxic potential and toxicity using the Allium anaphase-telophase assay. Minimum inhibitory concentrations (MIC) were determined for 15 indicator strains of pathogens, representing both bacteria and fungi. The highest susceptibility to the ethanolic extract of H.sendtneri was exhibited by Pseudomonas glycinea (FSB4), (MIC=0.09 mg/ml) among the bacteria, and by Phialophora fastigiata (FSB81), (MIC=1.95 mg/ml) among the fungi. The composition of H. sendtneri extracts was also determined using HPLC analysis. Rosmarinic acid was found to be the dominant phenolic compound. The Allium anaphase-telophase genotoxicity assay revealed that the ethanolic extract of H. sendtneri at concentrations of 31.5 mg/l and below does not produce toxic or genotoxic effects. This is the first report of chemical constituents, genotoxic and antimicrobial activities of the endemic species, H. sendtneri.

Biological activity and chemical profile of Lavatera thuringiaca L. extracts obtained by different extraction approaches

BACKGROUND Lavatera thuringiaca L. is herbaceous perennial plant from Malvaceae family, which is known for its biological activity and richness in polyphenolic compounds. Despite this, the information regarding the biological activity and chemical profile is still insufficient. PURPOSE Aim of this study was to investigate biological potential and chemical profile of Lavatera thuringiaca L., as well as influence of applied extraction technique on them. STUDY DESIGN AND METHODS Two conventional and four non-conventional extraction techniques were applied in order to obtain extracts rich in bioactive compound. Extracts were further tested for total phenolics, flavonoids, condensed tannins, gallotannins and anthocyanins contents using spectrophotometric assays. Polyphenolic profile was established using HPLC-DAD analysis. Biological activity was investigated regarding antioxidant, cytotoxic and antibacterial activities. Four antioxidant assays were applied as well as three different cell lines for cytotoxic and fifteen bacterial strain for antibacterial activity. RESULTS AND CONCLUSION Results showed that subcritical water extraction (SCW) dominated over the other extraction techniques, where SCW extract exhibited the highest biological activity. Study indicates that plant Lavatera thuringiaca L. may be used as a potential source of biologically compounds.

Fatty acid profile of stinging nettle leaves: application of modern analytical procedures for sample preparation and analysis

Stinging nettle is a perennial plant with significant biological activity and a long history of application in folk medicine and as food. Its activity is ascribed to its chemical composition. Its leaves contain different classes of compounds including fatty acids. This study deals with the isolation of fatty acids in stinging nettle leaves using a rapid extraction system for solid–liquid extraction (Soxtherm) with petroleum ether as the solvent. The obtained results indicate that the saturated fatty acids are more abundant than unsaturated fatty acids. The most abundant fatty acids are C12 : 0 (20.94%, 348.07 μg g−1), C16 : 0 (18.57%, 309.06 μg g−1), and C18 : 1 (13.16%, 219.44 μg g−1), whereas the fatty acid with the lowest content is C17 : 1 (0.13%, 2.20 μg g−1). Prior to analysis, the method is validated to obtain accurate and precise results. The limit of detection and limit of quantification are 0.012–0.038% and 1.67–7.03%, whereas the precision and accuracy are 83–126% and 1.67–7.03%, respectively. The validation parameters are >0.999, 0.011–0.032%, 0.012–0.038%, 1.67–7.03%, 83–126%, 0.22–5.24%, and 0.38–6.94% for linearity, limit of detection, limit of quantitation, precision, accuracy, inter-day precision, and intra-day precision, respectively, confirming the suitability of this method for fatty acid analysis.

The antioxidant properties of polypore mushroom Daedaleopsis confragosa

Daedaleopsis confragosa belong to a large and remarkable group of mushrooms called polypores. This type of mushroom could be easily said to be quite unexplored and unused when it comes to its antioxidant properties. Thus, in order to evaluate its antioxidant activity, the investigation had to include the total phenolics and flavonoide content, the content of Selenium, the content of Zinc, the scavenging capacity on DPPH· and OH· radicals, reducing power and capacity to remove lipid peroxidation. The investigated mushroom extract contained 54.17 mg GAE/g of total phenols and 48.46 mg CE/g of total flavonoides. Zinc and Selenium were detected and quantified by using inductively coupled plasma mass spectroscopy. The scavenging activity of the radicals was found to exhibit 50% of the inhibition value (IC50 value) at the extract concentration of 0.015±0.007 mg/ml for the investigated D. confragosa extract. By using electron paramagnetic resonant spectroscopy it was found that the investigated extract does not have a significant role in the prevention of lipid peroxidation. It was effective in scavenging on ·OH radical, RI was 56±2%.