Marijana Zovko Končić

University of Zagreb, Zagrabia, Grad Zagreb, Croatia

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Publications (25)37.11 Total impact

  • Mario Jug, Marijana Zovko Končić, Ivan Kosalec
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    ABSTRACT: This investigation was aimed to prepare solid propolis extracts by lyophilisation and to evaluate the efficiency of different extraction procedures (maceration/ultrasound extraction) and different types of extraction media used on extraction of phenolic compounds (TP), flavonoids (TF) and phenolic acids (TPA) from the raw poplar type propolis. Obtained lyophilised extracts were evaluated in terms of extraction yield, antioxidant potential and antimicrobial activity against selected bacterial/fungal stains. Those parameters varied significantly as a function of extraction parameters applied. In this regard, 80% ethanol was found to be the preferred extraction medium, allowing efficient extraction of TP and TF with high extraction yields. The resulting extracts were notable radical scavengers showing high antibacterial efficiency against Streptococcus mutans but were less efficient against Pseudomonas aeruginosa. Also, moderate antifungal activity against Candida albicans was observed. On the contrary, extracts prepared by aqueous extraction showed poor antimicrobial activity against tested stains but were active Fe2+ chelators. Ultrasound extraction showed comparable efficiency as maceration in extraction of bioactive compounds from the raw propolis, but offered additional advantages by ensuring the efficient extraction of phenolic compounds from propolis at rather low temperature (4 °C vs. 25/50 °C for maceration) in a short time (30 min vs. 24 h for maceration).
    Lebensmittel-Wissenschaft und-Technologie 07/2014; 57(2):530–537. · 2.55 Impact Factor
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    ABSTRACT: In this paper chemical composition of the essential oil (analysed by GC and GC-MS), the content of phenolic compounds (analysed by HPLC), quantity of total phenols and total flavonoids (analysed by UV/Vis spectrophotometer), antioxidant and antimicrobial activities of ethanolic extracts were investigated in endemic Teucrium arduini L. in population of Mt Biokovo (Croatia). The oil was characterized by a high concentration of sesquiterpene hydrocarbons (70.4%) of which β-caryophyllene (35.2%) and germacrene D (18.7%) being the major compounds. Three phenolic compounds (quercetin, ferulic acid and rosmarinic acid) were identified and quantified in ethanolic extract of T. arduini using HPLC. The results also showed that T. arduini is a source of polyphenolic and other antioxidants with radical-scavenging and chelating properties. The ethanol extracts prepared from the leaf of T. arduini showed broad spectrum of antimicrobial activity on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis, which are susceptible on concentration below or equal to 4.00 mg/mL, whilst Microsporum gypseum was resistant at investigated concentrations.
    Current drug targets 04/2013; · 3.93 Impact Factor
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    Marijana Zovko Koncic, Michał Tomczyk
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    ABSTRACT: As a society we are increasingly concerned about our physical appearance. For example, as much as 24% of people in developed countries admittedly exercise to improve their performance. Professional sportsmen and amateurs alike are in a constant search for new means that will enable them better sport results in shorter time. Among those means, a prominent place belongs to dietary supplements. However, the producers often advertise products whose use in sports is neither scientifically founded nor safe. This brings on an irrational use of herbal supplements which sometimes leads to unwanted side effects, but is more often of little use. Thus, the aim of this review will be to systematically evaluate some of the herbal supplements that are used as adaptogenic and ergogenic aids in sport. The review will include available data on Rhodiola rosea, Withania somnifera, Schisandra chinensis, Tribulus terrestris, Vitis vinifera, Citrus aurantium, and others. Their effects, active ingredients as well as possible adverse effects will be discussed with special focus on clinical studies.
    Current Drug Targets 04/2013; 14:1079-1092. · 3.85 Impact Factor
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    ABSTRACT: Effects of flavonoids quercetin and chrysin on lipid peroxidation and histopathological changes in liver of diabetic mice were studied and compared with the antioxidant and reducing ability of quercetin and chrysin and their ability to chelate Fe(2+) ions in vitro. Diabetes was induced in Swiss albino mice with a single intravenous injection of alloxan (75 mg kg(-1)). Two days after alloxan injection, flavonoid preparations (50 mg kg(-1) per day) were given intraperitoneally for 7 days in diabetic mice. The lipid peroxidation was evaluated by measuring the malondialdehyde production using the 2-thiobarbituric acid test. Administration of quercetin and chrysin to diabetic mice resulted in a significant decrease in lipid peroxidation level in liver tissue. Treatment of diabetic mice with flavonoids solutions results in decreased number of vacuolated cells and degree of vacuolization of the liver tissue. The protective role of flavonoids against the reactive oxygen species-induced damages in diabetic mice gives a hope that they may exert similar protective action in humans.
    Human & Experimental Toxicology 01/2013; · 1.31 Impact Factor
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    ABSTRACT: The quantity of phenols, as well as antioxidant and antimicrobial activities, were investigated in bark of Rhamnus alaternus L., R. fallax Boiss., R. intermedia Steud. et Hochst., and R. pumila Turra from natural stands in Croatia. The most abundant anthraquinones in the investigated extracts were chrysophanol in R. alaternus (3.14mg/g), emodin in R. pumila (0.339mg/g), and physcion in R. fallax (2.70mg/g) and R. intermedia (0.285mg/g). The species exhibiting the highest antioxidant activity were R. fallax and R. pumila. A positive correlation was observed between total phenolic and flavonoid levels of the extracts and antioxidant activity in some of the assays. All species showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Aspergillus niger and Microsporum gypseum with minimal inhibitory concentrations equal to or below 2.500mg/mL. The results indicate that the investigated Rhamnus species are a source of anthraquinones and other phenols, which act as multifunctional antioxidants with antimicrobial activity.
    Food Chemistry 01/2013; 136(2):335-41. · 3.33 Impact Factor
  • M.Z. Končić, M. Tomczyk
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    ABSTRACT: Cited By (since 1996):2, Export Date: 18 October 2014
    Current Drug Targets. 01/2013; 14(9):1079-1092.
  • M.Z. Koncic, R. Petlevski, Z. Kalodera
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    ABSTRACT: Export Date: 18 October 2014
    International Journal of Food Properties 01/2013; 16(5):964-973. · 0.88 Impact Factor
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    ABSTRACT: Frangula rupestris and Frangula alnus are deciduous shrubs distributed in Balkan Peninsula. While the bark of F. alnus is medicinally widely used, little is known about chemical and biological properties of F. rupestris. In the present study, F. rupestris and F. alnus bark were evaluated for their reducing power, DPPH radical scavenging and chelating activity, as well as antioxidant activity in β-carotene-linoleic acid assay. In addition, phenolic content, anthraquinone profile and antimicrobial activity of F. rupestris and F. alnus bark were determined. The most represented anthraquinone derivatives in F. rupestris and F. alnus bark were physcion (0.11mg/g) and emodin (2.03mg/g), respectively. Both species demonstrated excellent antioxidant and antimicrobial activities with MIC values equal or lower than 2.5mg/mL. The presented research indicates that both species may have health benefits as natural antioxidants and antimicrobial agents for use in functional foods or medicine.
    Food Chemistry - FOOD CHEM. 04/2012;
  • Marijana Zovko Koncic, Roberta Petlevski, Zdenka Kalođera
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    ABSTRACT: Ethanolic and aqueous extract of Ipomoea batatas (L.) Lam leaf grown in Croatia were prepared. Antioxidant activity of the extracts, as well as their effect on intracellular glucose-induced oxidative stress was determined. Antioxidant activity was assayed by DPPH radical scavenging activity, reducing power, activity in β-carotene-linoleic acid assay and superoxide dismutase-like activity. In addition to being richer in phenols and flavonoids than aqueous extract, ethanolic extract also demonstrated superior antioxidant activity in all the assays. In concentration of 10 μg/ml, both extracts were able to significantly increase intracellular glutathione levels.
    International Journal of Food Properties 01/2012; · 0.88 Impact Factor
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    ABSTRACT: Cited By (since 1996):8, Export Date: 18 October 2014
    BMC Complementary and Alternative Medicine 01/2012; 12. · 2.08 Impact Factor
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    Marijana Zovko Končič, Branka Zorc, Predrag Novak
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    ABSTRACT: Two hydrosoluble conjugates of 17β-estradiol (ED) and estradiol-17β-valerate (EV) with polyaspartamide polymer were prepared and characterized. ED and EV were first chemically modified and bound to poly[α,β-(N-2-hydroxyethyl-DL-aspartamide)]-poly[α,β-(N-2-aminoethyl-DL-aspartamide)] (PAHA), a hydrosoluble polyaspartamide-type copolymer bearing both hydroxyl and amino groups. ED was first converted to 17-hemisuccinate (EDS) and then bound to PAHA. In the resulting conjugate PAHA-EDS, the estradiol moiety was linked to the polymer through a 2-aminoethylhemisuccinamide spacer. On the other hand, EV was first converted to estradiol-17β-valerate-3-(benzotriazole-1-carboxylate), which readily reacted with amino groups in PAHA affording the polymer-drug conjugate PAHA-EV. In the prepared conjugate PAHA-EV, the estradiol moiety was covalently bound to the polyaspartamide backbone by carbamate linkage, through an ethylenediamine spacer. The polymer-drug conjugates were designed and prepared with the aim to increase water-solubility, bioavailability and to improve drug delivery of the lipophilic estrogen hormone.
    Acta Pharmaceutica 12/2011; 61(4):465-72. · 1.16 Impact Factor
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    ABSTRACT: The anthraquinone profile, antioxidant and antimicrobial activities as well as the total phenol and total flavonoid contents were determined in methanol extracts of the barks of Rhamnus catharticus L. and R. orbiculatus Bornm. The most abundant anthraquinone derivatives in R. catharticus were physcion (67.8%) and emodin (26.2%), while R. orbiculatus contained mostly physcion (81.3%) and chrysophanol (14.6%). R. catharticus displayed better activity in the beta-carotene-linoleic acid assay, as well as chelating activity, whereas its activity in the reducing power assay was significantly lower than that of R. orbiculatus. Both methanol extracts showed antimicrobial activity against all microbial species tested (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Aspergillus niger, Microsporum gypseum) with MIC values either equal to or lower than 2.50 mg/mL. R. catharticus and R. orbiculatus contained several anthranoid aglycones and their bark extracts demonstrated notable antioxidant and antimicrobial properties. The results obtained indicate the medicinal potential of these two species.
    Natural product communications 09/2011; 6(9):1275-80. · 0.96 Impact Factor
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    Marijana Zovko Končić, Monika Barbarić, Ivana Perković, Branka Zorc
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    ABSTRACT: Reactive oxygen species, along with reactive nitrogen species, may play an important role in the pathogenesis and progress of many diseases, including cancer, diabetes and sickle cell disease. It has been postulated that hydroxyurea, one of the main treatments in sickle cell disease, achieves its activity partly also through its antioxidant properties. A series of hydroxyurea derivatives of L- and D-amino acid amides and cycloalkyl-N-aryl-hydroxamic acids was synthesized and investigated for their radical scavenging activity, chelating properties and antioxidant activity. All the compounds showed exceptional antiradical activities. For example, free radical scavenging activities of investigated hydroxyureas were higher than the activity of standard antioxidant, butylated hydroxyanisole (BHA). Moreover, most of the investigated hydroxamic acids were stronger Fe²⁺ ion chelators than quercetin. In addition, the investigated compounds, especially hydroxamic acids, were proven to be excellent antioxidants. They were as effective as BHA in inhibiting β-carotene-linoleic acid coupled oxidation. It is reasonable to assume that the antioxidant activity of the investigated compounds could contribute to their previously proven biological properties as cytostatic and antiviral agents.
    Molecules 01/2011; 16(8):6232-42. · 2.43 Impact Factor
  • Marijana Zovko Končić, Mario Jug
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    ABSTRACT: Antioxidant and bioadhesive properties of onion, garlic, leek, and ramsons, processed under low pH conditions were investigated. For investigation of antioxidant activity DPPH free radical scavenging activity and reducing power were used. The most active radical scavenger (EC50 = 2.07 mg/ml) and reductant was the ethanolic extract of leek leaf. Positive correlation between antioxidant activity and phenol content in the extracts (P < 0.01) was found. To determine bioadhesive properties of the extracts, tensile studies were performed and work of adhesion (Wa) was measured. The most pronounced bioadhesive properties were determined for garlic and ramsons bulbs extracts (Wa > 8 μJ).
    International Journal of Food Properties 01/2011; 14(1):92-101. · 0.88 Impact Factor
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    ABSTRACT: Novel primaquine conjugates with non-steroidal anti-inlammatory drugs (PQ-NSAIDs, 4a-h) were prepared, fully chemically characterized and screened for radical scavenging and antioxidant activities. The synthetic procedure leading to twin drugs 4a-h involved two steps: i) preparation of NSAID benzotriazolides 3a-h from the corresponding NSAID (ibuprofen, ketoprofen, fenoprofen, ketoprofen hydroxy and methylene analogues, diclofenac or indomethacin) and benzotriazole carboxylic acid chloride (BtCOCl, 1), ii) reaction of intermediates 3a-h with PQ. The prepared PQ-NSAIDs exerted moderate activities in the DPPH free radical test and β-carotene-linoleic acid assay. Moreover, ketoprofen derivatives 4d and 4b demonstrated a notable Fe2+ chelating ability as well. On the other hand, negligible antiproliferative and antituberculotic effects of conjugates 4a-h were observed.
    Acta Pharmaceutica 09/2010; 60(3):325-37. · 1.16 Impact Factor
  • Planta Medica 08/2010; 76(12). · 2.35 Impact Factor
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    ABSTRACT: Antioxidant and antimicrobial activities as well as the quantity of phenolic substances (total phenol, flavonoid and phenolic acid contents) were determined in aqueous extracts of leaves, stems and flowers of Moltkia petraea (Tratt.) Griseb. from two mountainous localities (Sveti Jure and Snijeznica) in Croatia. In addition, the profile of phenolic acids was analyzed by UPLC-MS/MS. Antioxidant activities of all extracts in different test systems, namely the DPPH radical scavenging, reducing power assay and chelating activity, increased with extract concentration. Activity of the extracts from Snijeznica in beta-carotene-linoleic acid assay did not differ from the activity of standard, BHA. The leaf extracts from Snijeznica demonstrated superior antioxidant activity in most of the assays, while the stem extract from the same locality was the most effective Fe(2+) ion chelator. In general, the extracts from Snijeznica were more effective antioxidants than the corresponding extracts from Sveti Jure. The aqueous extracts of M. petraea did not show antimicrobial activity against bacteria and fungi tested in the diffusion and dilution assays.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 03/2010; 48(6):1537-42. · 2.99 Impact Factor
  • M Zovko Koncić, D Kremer, K Karlović, I Kosalec
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    ABSTRACT: Antioxidant activities of the ethanolic extracts of roots, twigs and leaves of common barberry (Berberis vulgaris L.) and Croatian barberry (Berberis croatica Horvat) were studied. All the extracts were found to possess some radical-scavenging and antioxidant activities, as determined by scavenging effect on the DPPH free radical, reducing power and beta-carotene-linoleic acid model system. With the exception of the beta-carotene-linoleic acid test, antioxidant activity correlated well with the content of main plant antioxidants, phenols and flavonols, which suggests an important role of these compounds in overall antioxidant activity of investigated plant organs. The antioxidant activity varied mostly in relation to the organ, while no significant statistically differences were found between B. vulgaris and B. croatica.
    Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2010; 48(8-9):2176-80. · 2.99 Impact Factor
  • Planta Medica - PLANTA MED. 01/2010; 76(12).
  • Planta Medica - PLANTA MED. 01/2010; 76(12).