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Search Results: 1 - 10 of 117900 matches for " Manojlovi? Nedeljko T. "
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The isolation, analytical characterization by HPLC-UV and NMR spectroscopy, cytotoxic and antioxidant activities of baeomycesic acid from Thamnolia vermicularis var. subuliformis
ManojloviNedeljko T.,Vasiljevi? Perica J.,Nikoli? Dragan,Bogdanovi?-Du?anovi? Gordana
Hemijska Industrija , 2011, DOI: 10.2298/hemind110414035m
Abstract: The aim of this work was the analytical characterization of the β-orcinol depside, baeomycesic acid in lichens extracts. The extract of Thamnolia vermicularis var. subuliformis was analyzed by the two different methods, namely HPLC-UV and 1H NMR analysis. The results showed that baeomycesic acid was the most abundant depside in the lichens. These results could be of use for rapid identification of this metabolite in other lichen species. Besides baeomycesic acid, three depsides and one monocyclic phenolic compound were isolated from the lichen extract on the chromatographic column. The structure of baeomycesic acid was confirmed by HPLC-UV and spectroscopic methods. In addition, antioxidant and cytotoxic activities of baeomycesic acid were determined. The result of the testing showed that baeomycesic acid exhibited a moderate radical scavenging activity (IC50 = 602.10 ± 0.54 μg/mL) and good cytotoxic activity. This is the first report of detailed analytical characterization, isolation, as well as antioxidant and cytotoxic activities of baeomycesic acid from Thamnolia vermicularis. These results may be helpful in future industrial production of herbal medicines that include this important natural product.
Phytochemical screening and biological activity of extracts of plant species Halacsya sendtneri (Boiss.) D rfl.
Ma?kovi? Pavle Z.,ManojloviNedeljko T.,Mandi? Anamarija I.,Mi?an Aleksandra ?.
Hemijska Industrija , 2012, DOI: 10.2298/hemind110828068m
Abstract: This study is aimed at examining total polyphenol, flavonoid, gallotannin and condensed tannins content in acetone, chloroform, ethyl acetate and petroleum ether extracts of Halacsya sendtneri (Boiss.) D rfl., their antimicrobial and antioxidant activities, as well as identifying and quantifying the phenolic components. The antioxidant activity is consistent with the results of total quantity of phenolic compound. The results showed that the acetone extract of plant species Halascya sendtneri (Boiss.) D rfl. possessed the highest antioxidant activity. IC50 values were determined: 9.45±1.55 μg/mL for DPPH free radical scavenging activity, 13.46±1.68 μg/mL for inhibitory activity against lipid peroxidation, 59.11±0.83 μg/mL for hydroxyl radical scavenging activity and 27.91±0.88 μg/mL for ferrous ion chelating ability. The antimicrobial activity was tested using broth dilution procedure for determination of the minimum inhibitory concentration (MIC). The MICs were determined for 8 selected indicator strains. All of the extracts showed strong to moderate strong antimicrobial activity. The phenolic composition of Halacsya sendtneri extracts was determined by the HPLC method. The dominant phenolic compound in acetone, chloroform and ethyl acetate extract is rosmarinic acid. Ethyl acetate extract was also abundant in p-hydroxybenzoic acid and ferulic acid. The main compounds in petrol ether extract were chlorogenic acid and quercetin.
HPLC, UV-Vis and NMR spectroscopic and DFT characterization of purpurin isolated from Rubia tinctorum L.
Markovi? Zoran S.,ManojloviNedeljko T.,Jeremi? Svetlana R.,?ivi? Miroslav
Hemijska Industrija , 2013, DOI: 10.2298/hemind120419058m
Abstract: Purpurin (1,2,4-trihidroxyanthraquinone), a naurally occuring anthraquinone pigment present in the root of Rubia tinctorum (Mull. Arg.) Zahlbr. was isolated from the plant, purified and characterized by HPLC chromatography, UV-Vis and NMR spectroscopy. The geometries of the purpurin conformers were optimized using the B3LYP/6-311+G(d,p) level of theory. It was found that all conformations have similar energies and that the corresponding purpurin radicals are planar. In spite of their planarity, there is no significant electron delocalization over the A and C rings. The antioxidant properties of purpurin were investigated using the colorimetric assay as Trolox-equivalent antioxidant capacity, and theoretical BDE (Bond Dissociation Enthalpy). Both methods revealed that purpurin has strong antioxidant capacity.
HPLC analysis, antimicrobial and antioxidant activities of Daphne cneorum L.
ManojloviNedeljko T.,Ma?kovi? Pavle Z.,Vasiljevi? Perica J.,Jeli? Ratomir M.
Hemijska Industrija , 2012, DOI: 10.2298/hemind120114029m
Abstract: The present study describes in vitro antimicrobial and antioxidant activities of the methanol extracts which were obtained from the leaves and twigs of the plant Daphne cneorum L. The antimicrobial activity of these extracts was tested against human pathogenic microorganisms using a minimum inhibitory concentration (MIC) values. Total phenolics and flavonoids, as well as the antioxidant activity of the extracts were determined. The two tested extracts showed good antimicrobial and antioxidant activities. The results of a high performance liquid chromatographic (HPLC) method showed that 7,8-dihydroxycoumarin is one of the most abundant secondary metabolite in the tested extracts. The results of this study clearly indicated that the extracts of D. cneorum could be used as a potential source of natural antioxidant and antimicrobial agents.
Biological Activities of Toninia candida and Usnea barbata Together with Their Norstictic Acid and Usnic Acid Constituents
Branislav Rankovi?,Marijana Kosani?,Tatjana Stanojkovi?,Perica Vasiljevi?,Nedeljko Manojlovi
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms131114707
Abstract: 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 IC 50 values of 12.72 and 15.66 μg/mL.
Synthesis of C7-C16-alkyl maltosides in the presence of tin(IV) chloride as a Lewis acid catalyst
Zoran Markovi , Jasmina Predojevic, Nedeljko T. Manojlovic
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: The synthesis of C7- to C16-alkyl maltosides in the presence of tin(IV) chloride as Lewis acid catalyst was performed. The characterization of the products and theoretical investigation of the crucial step in the synthesis were carried out. The preparation of the β-maltosides required reaction time of 1 h, and that of the α-maltosides was 72 h. The side products were the α-D-maltosidechloride and 2-hydroxy-β-maltoside, respectively. The PM3 calculation confirmed the formation of the kinetically controlled β-product. KEY WORDS: Maltose, Synthesis of maltosides, Tin(IV) chloride, PM3 Bull. Chem. Soc. Ethiop. 2011, 25(1), 83-90.
Synthesis of C7-C16-alkyl maltosides in the presence of tin(IV) chloride as a Lewis acid catalyst
Zoran Markovi?,Jasmina Predojevic,Nedeljko T. Manojlovic
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: The synthesis of C7- to C16-alkyl maltosides in the presence of tin(IV) chloride as Lewis acid catalyst was performed. The characterization of the products and theoretical investigation of the crucial step in the synthesis were carried out. The preparation of the β-maltosides required reaction time of 1 h, and that of the α-maltosides was 72 h. The side products were the α-D-maltosidechloride and 2-hydroxy-β-maltoside, respectively. The PM3 calculation confirmed the formation of the kinetically controlled β-product.
Chemical composition and antioxidant activity of lichen Toninia candida
Manojlovic, Nedeljko T.;Vasiljevic, Perica J.;Maskovic, Pavle Z.;
Revista Brasileira de Farmacognosia , 2012, DOI: 10.1590/S0102-695X2011005000184
Abstract: 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.
Phytochemical and antioxidant studies of Laurera benguelensis growing in Thailand
Nedeljko T Manojlovic,Perica J Vasiljevic,Wandee Gritsanapan,Roongtawan Supabphol
Biological Research , 2010,
Abstract: 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 identifed by relative retention time and spectral data. This is the frst time that a detailed phytochemical analysis of the lichen L. benguelensis was reported and this paper has chemotaxonomic signifcance because very little has been published on the secondary metabolites present in Laurera species. Some of the metabolites were detected for the frst 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 and antioxidant activity of lichen Toninia candida
Nedeljko T. Manojlovic,Perica J. Vasiljevic,Pavle Z. Maskovic
Revista Brasileira de Farmacognosia , 2012,
Abstract: 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.
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