Perica Vasiljević

Chemical composition of three Parmelia lichens and antioxidant, antimicrobial and cytotoxic activities of some their major metabolites.

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia caperata, P. saxatilis and P. sulcata and antioxidant, antimicrobial and anticancer activities of some their major metabolites. The phytochemical analysis of acetone extracts of three Parmelia lichens were determined by HPLC-UV method. The predominant phenolic compounds in these extracts were protocetraric and usnic acids (P. caperata) and depsidone salazinic acid (other two species). Besides these compounds, atranorin and chloroatranorin, were also detected in some of these extracts. Antioxidant activity of their isolated metabolites was evaluated by free radical scavenging, superoxide anion radical scavenging and reducing power. As a result of the study salazinic acid had stronger antioxidant activity than protocetraric acid. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. Both compounds were highly active with minimum inhibitory concentration values ranging from 0.015 to 1mg/ml. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. Salazinic acid and protocetraric acid were found to be strong anticancer activity toward both cell lines with IC(50) values ranging from 35.67 to 60.18μg/ml. The present study shows that tested lichen compounds demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggest that these lichens can be used as new sources of the natural antimicrobial agents, antioxidants and anticancer compounds.

Phytochemical and antioxidant studies of Laurera benguelensis growing in Thailand

The aim of this study was to investigate metabolites of the lichen Laurera benguelensis. A high-performance liquid chromatographic (HPLC) method has been developed for the characterization of xanthones and anthraquinones in extracts of this lichen. Lichexanthone, secalonic acid D, norlichexanthon, parietin, emodin, teloschistin and citreorosein were detected in the lichen samples, which were collected from two places in Thailand. Components of the lichen were identified by relative retention time and spectral data. This is the first time that a detailed phytochemical analysis of the lichen L. benguelensis was reported and this paper has chemotaxonomic significance because very little has been published on the secondary metabolites present in Laurera species. Some of the metabolites were detected for the first time in the family Trypetheliaceae. The results of preliminary testing of benzene extract and its chloroform and methanol fractions showed that all samples showed a weak radical scavenging activity. The chloroform extract showed the highest antioxidant activity.

Chemical Composition, Antioxidant, and Antimicrobial Activities of Lichen Umbilicaria cylindrica (L.) Delise (Umbilicariaceae)

The phytochemical analysis of methanol and chloroform extracts of Umbilicaria cylindrica was determined by HPLC-UV method. The predominant phenolic compound in both extracts was depsidone, salazinic acid (1). Besides salazinic acid, the tested extracts of U. cylindrica contain norstictic acid (2), methyl-β-orcinol carboxylate (3), ethyl haematommate (4), atranorin (5), and usnic acid (6), in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity, and inhibitory activity towards lipid peroxidation. The lichen extracts demonstrated important antimicrobial activity against eight strains with MIC values from 15.62 to 62.50 μg/mL. This is the first report of the detail chemical composition and antioxidant activity of the lichen Umbilicaria cylindrica, and the results suggest that this lichen can be used as a new source of the natural antioxidants and the substances with antimicrobial features.

Biological Activities of Toninia candida and Usnea barbata Together with Their Norstictic Acid and Usnic Acid Constituents

The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC50 values of 12.72 and 15.66 μg/mL.

Chemical composition and antioxidant activity of lichen Toninia candida

In the present investigation, methanol, chloroform and petrol ether extracts from the lichen Toninia candida (Weber) Th. Fr, Catillariaceae, were assayed for their antioxidant activity. The phenolic composition of the extracts was determined by HPLC-UV analysis. The predominant phenolic compound in all the extracts was depsidone, norstictic acid. All the tested extracts of T. candida contain, besides norstictic acid, atranorin, stictic, protocetraric and usnic acid, but in different amounts and relations. The lichen extracts showed comparable and strong antioxidant activity, exhibited higher DPPH and hydroxyl radical scavengings, chelating activity and inhibitory activity towards lipid peroxidation. This is the first report of chemical composition and antioxidant antimicrobial activity of the lichen Toninia candida.

Apatite formation on nanomaterial calcium phosphate/poly-dL-lactide-co-glycolide in simulated body fluid

Simulated body fluid (SBF) is an artificial fluid which has ionic composition and ionic concentration similar to human blood plasma. Purpose This paper compares the interaction between the nanomaterial containing calcium phosphate/poly-DL-lactide-co-glycolide (N-CP/PLGA) and SBF, in order to investigate whether and to what extent inorganic ionic composition of human blood plasma leads to the aforementioned changes in the material. Methods N-CP/PLGA was incubated for 1, 2, 3, and 5 weeks in SBF. The surface of the material was analyzed on SEM-EDS and FTIR spectrometer, while SBF was subjected to pH and electrical conductivity measurement. Results Our results indicate that dissolution of the polymer component of the material N-CP/PLGA and precipitation of the material similar to hydroxyapatite on its surface are based on the morphologic changes seen in this material. Conclusions The mechanism of the apatite formation on the bioceramic surface was intensively studied and was considered crucial in designing the new biomaterials. The results obtained in this work indicate that N-CP/PLGA may be a good candidate for application to bone regeneration.

PHENOLIC AND FLAVONOID CONTENT AND ANTIOXIDANT ACTIVITY OF DAPHNE BLAGAYANA GROWING IN SERBIA

ABSTRACT Th e aim of this study was to examine the phenolic and flavonoid contents and antioxidant activities of methanol and chloroform extracts of leaves and twigs of Daphne blagayana. Th e total phenolic content in the chloroform extract of plant twigs (90.26 ± 0.69 mg GA/g) was higher than that of the other extracts (from 76.56±0.89 to 77.45±0.43 mg GA/g). In the case of flavonoids, a greater value was also obtained for the chloroform extract of twigs (35.24±0.55 mg RU/g). Several diff erent methods were used to determine the antioxidant activity of the tested extracts, including total antioxidant capacity, metal chelating activity, hydroxyl radical scavenging activity and inhibitory activity against lipid peroxidation. Our results showed that although secondary metabolites of the plants may contribute significantly to their antioxidant activities, those antioxidant activities were not directly related to the phenolic and flavonoid amounts. Th e results of the present analysis demonstrated, for the first time, that Daphne blagayana leaves and twigs possess high phenolic and flavonoid contents, as well as potential antioxidant activity. Th is study suggests that Daphne blagayana twigs and leaves may potentially be used as an accessible source of natural antioxidants. SAŽETAK Cilj ovog rada je bio da se ispita fenolni i flavodnoidni sadržaj, kao i antioksidativna aktivnost metanolskih i hloroformskih ekstrakta lišća i grančica biljke Daphne blagayana. Ukupan sadržaj fenola u hloroformskom ekstraktu grančica (90.26±0.69 mg GA/g) bio je veći od sadržaja u ostalim ekstraktima (od 76.56±0.89 do 77.45±0.43 mg GA/g). U slučaju flavonoida, maksimalna vrednost je takođe zabeležena kod hloroformskog ekstrakta grančica (35.24±0.55 mg RU/g). Nekoliko različitih metoda su korišćeno za određivanje antioksidantne aktivnosti testiranih ekstrakata uključujući ukupan antioksidantni kapacitet, metal helacionu aktivnost, aktivnost hidroksi radikala i inhibitornu aktivnost prema lipidnoj peroksidaciji. Naši rezultati su pokazali da, iako sekundarni metabolite biljaka mogu značajno doprineti antioksidantnim aktivnostima, ove aktivnosti nisu bile uvek direktno povezane sa količinom fenola i flavonoida u ekstraktima. Rezultati ovih ispitivanja su pokazali, po prvi put, da grančice i lišče biljke Daphne blagayana poseduju visok sadržaj fenola i flavonoida i potencijalno antioksidantno delovanje. Ova studija je pokazala da se lišće i grančice ove biljke mogu potencijalno koristiti kao pristupačan izvor prirodnih antioksidanasa.

Biological activities and chemical composition of lichens from Serbia.

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia arseneana and Acarospora fuscata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and gyrophoric acid isolated from A. fuscata. The HPLC-UV method was used for the identification of secondary metabolites. Stictic acid, norstictic acid, gyrophoric acid, usnic acid, atranorin and chloroatranorin were identified in the A. fuscata. In P. arseneana, we detected stictic acid, norstictic acid, usnic acid and atranorin, while gyrophoric acid was not identified. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic compounds in extracts. As a result of the study, gyrophoric acid was found to have the largest DPPH radical scavenging activity with an IC50 value of 105.75 µg/ml. Moreover, the tested samples had an effective superoxide anion radical scavenging and reducing power. The total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also gyrophoric acid, with minimum inhibitory concentration values ranging from 0.019 to 1.25 mg/ml. Anticancer activity was tested against LS174 (human colon carcinoma cell line), A549 (human lung carcinoma cell line), Fem-x (malignant melanoma cell line), and a chronic myelogeneous leukaemia K562 cell line using the MTT method. Extract of P. arseneana expressed the strongest anticancer activity against all cell lines with IC50 values ranging from 11.61 to 47.06 µg/ml.

PHYTOCHEMICAL AND ANTIMICROBIAL SCREENING OF LEAVES AND STEMS OF BALKAN ENDEMIC SPECIES DAPHNE MALYANA BLEČIĆ

ABSTRACT Daphne malyana Blečić (Thymelaeaceae) is an endemic species of the western part of the Balkan Peninsula. No previous detailed studies exist on D. malyana Blečić. The aim of this study was to provide information on the anatomy of the leaf and stem as well as to perform phytochemical screening and to assay the antimicrobial activity of methanol extracts of the leaves and stems of D. malyana Blečić. The phytochemical analysis showed that coumarins and flavonoids are the major classes of secondary metabolites in both leaves and stems. The antimicrobial activity of the methanol extracts from leaves and stems of D. malyana was also evaluated against six Gram-positive and six Gram-negative bacteria by employing both microdilution and disc diffusion methods. The results from the well-diffusion assay showed significant antimicrobial activity at all tested concentrations of the extracts. The results showed that methanol extracts of leaves and twigs have similar chemical compositions and similar antimicrobial activity. To our knowledge this is the first report on the phytochemistry and antimicrobial activity of this plant species.

THE INFLUENCE OF LONG-TERM INTAKE OF COPPER AND CHROMIUM COMPOUNDS ON REPRODUCTIVE ABILITY AND DEVELOPMENT OF DROSOPHILA MELANOGASTER

ABSTRACT The aim of this work was to compare the effect of solitary and combined presence of copper (II) and chromium (VI) in food medium, on the reproductive ability and development of the fruit fly Drosophila melanogaster. We used copper (II) sulfate penta-hydrate (CuSO4×5H2O) and potassium-dichromate (K2Cr2O7), which were added at the same concentrations of 500mg/L to the food medium. The flies were exposed to the mentioned compounds during the two generations. The results of the research showed that the average number of adult offspring per one female of the flies exposed only to the influence of copper (II) sulfate or only to potassium-dichromate were on the control level. The flies cultured on the medium containing both tested compounds, had a significantly lower number of offspring compared to the control group (p<0.001). The reproductive period duration in the control and all experimental groups was the same, but the maximum value of this parameter was lower in the group where both heavy metals were present in the food medium. The combined effect of copper and chromium compounds induced a significant prolongation of the development on average for 2.16 days (p< 0.001). The combined effect of both copper and chromium compounds show synergistic toxicity, that is manifested by significant decrease in the reproductive ability and prolongation of developmental time.