Maria Anastasiadi

Agricultural University of Athens, Athínai, Attica, Greece

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Publications (11)25.09 Total impact

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    ABSTRACT: Grape stems constitute a scarcely investigated class of vinification byproducts with limited reports on their bioactive polyphenol content and/or industrial applications. Herein we present the outcome of our investigation on various grape stems extracts from native Greek grape varieties, concerning the assessment of their total polyphenolic content (TPC), the quantification of the individual bioactive polyphenols and the detailed evaluation of their antioxidant properties. Results obtained indicate that grape stems are particularly rich in flavonoids and stilbenes, with trans-resveratrol and epsilon-viniferin present in considerably high concentrations. They also exhibit significant antioxidant properties, which were determined by DPPH center dot radical scavenging and FRAP assays (modified to fit into a high throughput approach). Additional experiments concerning the inhibition of CuSO4-induced LDL oxidation and the reduction of intracellular reactive oxygen species (ROS) indicated that most extracts tested display an extreme capability to prevent the oxidation of LDL lipoprotein at very low concentrations and to reduce the intracellular ROS levels, exhibiting IC75 values between 10.4 mu g and 49.1 mu g per gram of extract. Results herein reveal that grape stems represent a rich source of high added value natural antioxidants, particularly stilbenes such as trans-resveratrol, which may be used by pharmaceutical, food and cosmetic industries.
    Lebensmittel-Wissenschaft und-Technologie 10/2012; 48(2):316-322. DOI:10.1016/j.lwt.2012.04.006 · 2.42 Impact Factor
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    ABSTRACT: Legumes are considered to have beneficial health implications, which have been attributed to their phytochemical content. Polyphenols are considered the most important phytochemical compounds extensively studied for their antioxidant properties. The aim of the present study was to examine the effects of potent antioxidant legume plant extracts on xanthine oxidase (XO), catalase (CAT) and superoxide dismutase (SOD) activities. XO exerts a dual role, as it is the major contributor of free radicals during exercise while it generates uric acid, the most potent antioxidant molecule in plasma. CAT and SOD are two of the main enzymes of the antioxidant defence of tissues. We demonstrate that the majority of the extracts inhibited XO activity, but they had no effect on CAT inhibition and SOD induction when used at low concentrations. These results imply that the tested extracts may be considered as possible source of novel XO inhibitors. However, we have shown that allopurinol administration, a known XO inhibitor, before exercise reduces performance and induces oxidative stress in rats. Considering the fact that the extracts examined had an inhibitory effect on XO activity, possibly posing a restriction in their characterization as antioxidants, phytochemical antioxidant administration before exercise should probably be reconsidered.
    Journal of physiology and biochemistry 03/2012; 68(1):37-45. DOI:10.1007/s13105-011-0117-z · 1.97 Impact Factor
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    ABSTRACT: A number of in vitro and in vivo studies have investigated the potential preventive activity of grape extracts against different diseases, and have mostly focused on their antioxidant properties. The present study examined the effects of 21 extracts from stem, skin and berry from Greek grape varieties on the activity of enzymes involved in regulation of oxidative stress, namely xanthine oxidase (XO), catalase (CAT) and superoxide dismutase (SOD). The effects of the extracts on the enzymatic activity of XO, CAT and SOD were studied spectrophotometrically. The tested extracts inhibited CAT and XO activity, while higher extract concentrations are required to induce SOD. However, stem and skin extracts exhibited a different inhibitory pattern against CAT and XO compared to berry extracts. The observed differences are possibly attributed to the extract polyphenolic composition. Although the induction of SOD activity suggests an antioxidant capacity, the inhibition of CAT and XO indicates a pro-oxidant action. In general, the extracts showed pro-oxidant activity, possibly dependent on both their polyphenolic composition and concentration.
    In vivo (Athens, Greece) 07/2011; 25(4):657-62. · 0.97 Impact Factor
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    ABSTRACT: The comparative quantization of main non-coloured polyphenols, the assessment of total polyphenolic content (TPC) and the detailed evaluation of the antioxidant activities of various grape-based products – from the harvest stage up to the production of the corresponding wines – are presented. The material studied consisted of grape tissues (berries, seeds and skins) of native Greek Vitis vinifera cultivars, which provided polyphenol-rich extracts via an optimized ultrasound extraction procedure, while the respective wine samples were condensed by a novel extraction procedure using XAD-4 adsorption resin column. The extraction methods accuracies were thoroughly validated and the polyphenolic content of extracts was assessed by HPLC–DAD and photometric methods. Their antioxidant properties were evaluated by following assays, modified to fit into a high throughput approach: DPPH radical scavenging, FRAP, inhibition of CuSO4-induced LDL oxidation and the reduction of intracellular reactive oxygen species (ROS) in smooth muscle cell cultures. Seed samples exhibited the highest TPC values, which are well correlated with their significant antioxidant properties in all assays performed. Of special interest is the significant capability of the tested extracts to prevent the LDL oxidation at very low concentrations. Furthermore, the good correlation between the antioxidant activities assessed for the LDL oxidation inhibition and the intracellular ROS assays is indicative of the possible in vivo antioxidant properties of the extracts. Results herein reveal the considerable antioxidant potential of the Greek grapevine production and exploits their vinification by-products as a potential inexpensive source of high added value antioxidants.
    Food Research International 04/2010; 43(3-43):805-813. DOI:10.1016/j.foodres.2009.11.017 · 2.82 Impact Factor
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    ABSTRACT: A sensitive and simple method was developed for the classification of wines according to variety, geographical origin, and vintage using NMR-based metabonomics. Polyphenol-rich extracts were prepared from 67 varietal wines from the principal wine-producing regions of Greece, using adsorption resin XAD-4. 1D (1)H NMR spectra obtained from the corresponding extracts were segmented, integrated, and normalized, and the data were subjected to principal component analysis. The chemometric classification of wines according to their phenolic profile allows discrimination between wines from different wineries of the same wine-producing zone and between different vintages for wines of the same variety.
    Journal of Agricultural and Food Chemistry 11/2009; 57(23):11067-74. DOI:10.1021/jf902137e · 2.91 Impact Factor
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    ABSTRACT: The quantitation of the main polyphenols and the assessment of the total polyphenolic content (TPC) in polyphenol-rich extracts of grape berries and vinification byproducts, obtained from Vitis vinifera cultivars of the Greek islands, are presented. The results indicated that seed extracts contain high concentrations of flavan-3-ols and their derivatives, whereas pomace and stem extracts consist of significant amounts of flavonoids, stilbenes, and phenolic acids. In particular, stemsa scarcely studied class of grape byproductwere also characterized by high trans-resveratrol and epsilon-viniferin content. The evaluation of their in vitro antilisterial activities revealed as most potent the seed and stem extracts of the red variety Mandilaria. Their minimum inhibitory concentrations (MICs) were assessed using a Malthus apparatus by two methods, a plate count technique and an automated technique that combines the conductance measurements with the common dilution method. The results revealed the usefulness of the conductance method as an alternative rapid means for the MIC estimation, whereas the respective values (0.26 and 0.34 for seeds and stems) indicated that both extracts represent an inexpensive source of potent natural antilisterial mixtures, which may be incorporated in food systems to prevent the growth of Listeria monocytogenes .
    Journal of Agricultural and Food Chemistry 01/2009; 57(2):457-63. DOI:10.1021/jf8024979 · 2.91 Impact Factor
  • M Anastasiadi · H Pratsinis · D Kletsas · A Papras · A Panagiotou · SA Haroutounian ·

    Planta Medica 07/2008; 74(09). DOI:10.1055/s-0028-1084896 · 2.15 Impact Factor
  • M Anastasiadi · H Pratsinis · D Kletsas · SA Theotokatos · SA Haroutounian ·

    Planta Medica 07/2008; 74(09). DOI:10.1055/s-0028-1084865 · 2.15 Impact Factor
  • M Anastasiadi · H Pratsinis · D Kletsas · AL Skaltsounis · SA Haroutounian ·

    Planta Medica 07/2008; 74(09). DOI:10.1055/s-0028-1084864 · 2.15 Impact Factor

  • Planta Medica 07/2008; 74(09). DOI:10.1055/s-0028-1084866 · 2.15 Impact Factor
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    I S Boziaris · P N Skandamis · M Anastasiadi · G-J E Nychas ·
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    ABSTRACT: The fate of Listeria monocytogenes Scott A, was studied in broth, at different a(w)s (by adding NaCl or KCl from 0.0 to 1.4 mol l(-1)), pHs (from 4.0 to 7.3 by adding lactic acid), and nisin concentrations (from 0 to 100 IU ml(-1)). Increasing salt and nisin concentrations and decreasing pH resulted in lower growth rates and extended lag phases. At pH 4.5 no growth was observed while in presence of nisin and/or 1 mol l(-1) salts of both kinds, L. monocytogenes Scott A was inactivated. Equal-molar concentrations of NaCl or KCl (similar a(w)), exerted similar effects against L. monocytogenes in terms of lag phase duration, growth or death rate. The growth boundaries of L. monocytogenes Scott A at 5 degrees C were also estimated by growth/no growth turbidity data, modeled by logistic polynomial regression. The concordance of logistic models, were 99.6 and 99.8% for NaCl and KCl, respectively. The growth interfaces derived by both NaCl and KCl models were almost identical. Hence, NaCl can be replaced by KCl without risking the microbiological safety of the product. Increasing nisin concentrations markedly affected the interface resulting in a more inhibitory environment for L. monocytogenes Scott A. Low to medium salt concentrations (0.3-0.7 mol l(-1) of either NaCl or KCl) provided a protective effect against inhibition of L. monocytogenes Scott A by nisin. Modelling the growth boundaries not only contributes to the development of safer food by providing useful data, but can also be used to study interactions between factors affecting initiation of growth of pathogenic micro-organisms.
    Journal of Applied Microbiology 04/2007; 102(3):796-805. DOI:10.1111/j.1365-2672.2006.03117.x · 2.48 Impact Factor