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Γεροθανάσης Ιωάννης

 

 

 

 

 

Professor Ioannis P. Gerothanassis

University of Ioannina

Department of Chemistry

Section of Organic Chemistry and Biochemistry

45110, Ioannina, Greece

tel. 26510 08389

fax: 26510 08799

e-mail: igeroth@cc.uoi.gr

 

Biographical Sketch

  • 1974 (1975: year of award): BSc Degree in Chemistry, Aristotle Univ. of Thessaloniki.
  • 1974-1977: Military service.
  • 1977: 3 years fellowship from the Greek Scholarship Foundation for postgraduate studies in England.
  • 1978 (1979: year of award): MSc degree in Chemical Spectroscopy in the School of Chemical Sciences, University of East Anglia. Title: Natural Abundance Oxygen-17 Fourier Transform NMR Studies, pp.1-196.
  • 1980 (1981: year of award): PhD thesis, School of Chemical Sciences, University of East Anglia. Title: Studies of 17O NMR Spectroscopy, pp.1-259.
  • 1980: Postdoctorate fellowship from the “Swiss Fond National” for NMR Biophysical Research in the University of Lausanne, Institute of Organic Chemistry.
  • 1981-1984: “Premier Assistant”, University of Lausanne, Institute of Organic Chemistry.
  • 1984: Lecturer, Section of Physical Chemistry, Department of Chemistry, School of Natural Sciences, University of Ioannina, Greece.
  • 1986: Assistant Professor, Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Greece.
  • 1990: Associate Professor in the same Department.
  • October 1994: Honorary Research Fellow of the Queen Mary College, Univ. of London.
  • September 1997: Full Professor, Department of Chemistry, University of Ioannina.
  • September 1997-August 2000: Head of the Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina.
  • September 1998-August 2000: Vice Chairman of the Department of Chemistry.
  • September 2000-August 2004: Chairman of the Department of Chemistry.
  • September 2003-August 2006: Vice Rector of the University of Ioannina.
  • September 2006-August 2010: Rector of the University of Ioannina.
  • September 2010-today: Member of the Hellenic Quality Assurance Agency for Higher Education (HQAA).
  • July 2011: DSc, University of East Anglia.

Fellowships and Awards

  1. September 1977-July 1980: Greek Scholarship Foundation, University of East Anglia, England.
  2. March 1979: Price for the best MSc thesis submitted in Chemical Spectroscopy in the School of Chemical Sciences, University of East Anglia, England.
  3. July 1980-September 1980: NATO Research Fellowship, University of East Anglia, England.
  4. September 1980-June 1981: Research Postdoctorate Fellowship, Swiss Scientific Research Council, University of Lausanne, Switzerland.
  5. June 1984-August 1984: EMBO Short Term Fellowship, University of Lausanne, Switzerland.
  6. July 1985-September 1985: EMBO Short Term Fellowship, CNRS, Nancy, France.
  7. June 1986-August 1986: EMBO Short Term Fellowship, CNRS, Nancy, France.
  8. June 1987-September 1987: FEBS Short Term Fellowship, CNRS, Nancy, France.
  9. June 1988: EEC Short Term Fellowship, Institute Curie, Orsay, France.
  10. July 1988-August 1988: EMBO Short Term Fellowship, CNRS, Nancy, France.
  11. July 1989-September 1989: DAAD Short Term Fellowship, Max Planck Institut, Mülheim, a.d. Ruhr, Germany.
  12. July 1990-August 1990: FEBS Short Term Fellowship, Max Planck Institut, Mülheim, a.d. Ruhr, Germany.
  13. November 1990-April 1991: Welcome Trust Fellowship, National Institute of Medical Research, London, England.
  14. Summer 1992, 1993, 1994: NATO Collaborative Grant, Institut Curie, Section de Biologie, Orsay, France.
  15. Summer 1995, 1996: EEC Grant, QMW College, London, England.
  16. Summer 1999, 2000, 2001: Collaborative Greece-Italy Program and NATO Grant, University of Florence, Italy.
  17. September 2011: Grant from the Greek Ministry of Education and DAAD, University of Leipzig, Germany.

Current Research Interests

Bioorganic Chemistry, Medicinal Chemistry and Structural Biology

  1. Multinuclear and multidimensional NMR studies in solution of: a) the angiotensin converting enzyme (ACE) and synthetic polypeptide model compounds; b) Myelin Basic Protein Epitopes (MBP); c) Mapping of protein-ligand and ligand-receptor interactions through flexible docking calculations (implications to ACE and angiotensin II- AT1 receptor).
  2. Determination of the three dimensional structures of peptide hormones in solution by the use of NMR and molecular dynamics calculations-investigation of solvation-hydration phenomena of cis/trans amides, model peptides and peptide hormones - origin of cis isomer stabilization in proteins.
  3. Multidisciplinary approach for decoding the chemoprevention mechanism of biophenols from plant natural products: isolation, structure analysis and biological evaluation.

NMR Structural Studies and Analytical Applications in Natural Products Chemistry and Food Chemistry

  1. Identification and quantitative evaluation of natural products in complex plant extracts of Greek flora, and of the lipid fraction of milk and cheese by the use of high resolution one- and two- dimensional NMR (COSY, TOCSY, NOESY, ROESY), Mass Spectrometry and HPLC methods.
  2. Development of hyphenated (coupled) methodologies of HPLC and NMR Spectroscopy and Chemically Induced Dynamic Nuclear Polarization (CIDNP) NMR Spectroscopy.
  3. Rapid NMR and multidimensional fingerprint identification and quantification of crude edible plant extracts of Greek flora.

Publications in International Journals

One hundred fourteen (114) publications, with a total impact factor of the journals of ~400 and a mean impact factor per journal of ~3.71. Total number of references over 1640 (web of science), 1260 without self citations, h-factor: 22.

Publications in Proceeding of International Conferences

Fifty two (52) publications.

Author/Editor of Books

  1. “Spectroscopy of Organic Compounds”, I.P. Gerothanassis, Greek Open University, pp. 1-122 (2000), in Greek.
  2. “Natural Anioxidant Phenols. Sources, Structure, Structure – Activity Relationship, Current Trends in Analysis and Characterization”. D. Boskou, I.P. Gerothanassis and P. Kefalas (Eds), Research Signpost: Kerala, India, 2006.

Reviewer- Advisory Board

Reviewer of more than thirty (30) international journals. Member of Editorial Advisory Board of the journals:

  1. “The Open Natural Products Journal”, Benthum Open, ISSN, 187A-8481.
  2. “International Journal of Green Pharmacy”, Med. Know.

Supervision of PhD and MSc Students-Current Research Group

Ten (10) PhD students and nine (9) MSc students have completed their thesis under my supervision. Three (3) of my former PhD students followed an academic career (one of them is Associate Professor in USA). My current research group consists of:

  1. Dr. V. Exarchou, Specific teaching laboratory staff (NMR Centre) of the University of Ioannina.
  2. Dr. C. Tsiafoulis, Specific technical-administrative staff (NMR Centre).
  3. Dr. V.G. Kontogianni, Postdoctorate researcher.
  4. P. Charisiadis (MSc), PhD student.
  5. A. Primikiri (MSc), PhD student.

Committees (in the last five (5) years)

  1. Coordination Committee of the National Postdoctorate Program “PYTHAGORAS”, Greek Ministry of Education & Religious Affairs (2005-2006).
  2. National Representative of Greece in the Marie Curie Actions European Communities (2005-2006).
  3. Member of the Committee of the Greek Rectors Conference for the evaluation of the new Law for Research and Development, Greece (2007).
  4. Member of the Greek National Plenary Council for Research & Technology (2008-2009).
  5. Member of the Greek National Committee for the “Institutional Framework for Research and Technology”, General Secretariat of Research & Technology (2009).
  6. Chairman of the Greek Supreme Chemistry Council (2005-2009).
  7. Chairman of the Committee of Physics-Chemistry-Materials of the Greek General Secretariat for Research & Technology (2008-2009).
  8. Chairman of the Committee of National Strategic Reference Framework (MSRF) 2007-2013 of the Greek Rectors Conference (2007-2010).
  9. Chairman of the Committee of “Nanotechnology” in the frame of National Reference Framework (NCRF) of GGSR (2008-2009).
  10. National Representative of Greece in the European Community for “Site issue Working Groups” (2009).

List of Most Significant Publications

A.     17O NMR Spectroscopy: Development of Experimental Methods and Applications to Molecules of Biological Interest

1a.     “Methods of Avoiding the Effects of Acoustic Ringing in Pulsed FT NMR Spectroscopy”, I.P. Gerothanassis, Progr. NMR Spectrosc. 19, 267-329 (1987).

2a.     “17O-NMR Spectroscopy as a Tool for Studying Synthetic Oxygen Carriers Related to Biological Systems: Application to a Synthetic Single-face Hindered Iron Porphyrin-dioxygen Complex in Solution”, I.P. Gerothanassis* and M. Momenteau, J. Am. Chem. Soc. 109, 6944-6947 (1987).

3a.     “17O-NMR Studies of the Conformational and Dynamic Properties of Enkephalins in Aqueous and Organic Solutions Using Selectively Labeled Analogues”, C. Sakarellos, I.P. Gerothanassis, N. Birlirakis, T. Karayannis, M. Sakarellos-Daitsiotis and M. Marraud, Biopolymers 28, 15-26 (1989).

4a.     “Hydrogen-Bond Stabilization of Dioxygen, Conformation Excitation, and Autoxidation Mechanism in Hemoprotein Models as Revealed by 17O-NMR Spectroscopy”, I.P. Gerothanassis*, M. Momenteau* and B. Loock, J. Am. Chem. Soc. 111, 7006-7012 (1989).

5a.     “17O- and 14N-nmr Studies of Leu-enkephalin and Enkephalin-related Fragments in Aqueous Solution”.

          T. Karayannis, I.P. Gerothanassis*, M. Sakarellos-Daitsiotis, C. Sakarellos and M. Marraud, Biopolymers 29, 423-439 (1990).

6a.     “17O-NMR and FT-IR Study of the Ionization State of Peptides in Aprotic Solvents. Application to Leu-enkephalin”, I.P. Gerothanassis*, N. Birlirakis, T. Karayannis, V. Tsikaris, M. Sakarellos-Daitsiotis, C. Sakarellos, B. Vitoux and M. Marraud, FEBS Letters 298, 188-190 (1992).

7a.     “Structural Differences of the Iron-Dioxygen Moiety of Haemoprotein Models with and without Axial Hindered Base as Revealed by 17O NMR and FTIR Spectroscopy in Solution”, I.P. Gerothanassis*, B. Loock and M. Momenteau*, J. Chem. Soc., Chem. Commun. 598-600 (1992).

8a.     “Hydration of Gly-2 and Gly-3 Peptide Oxygens of Leu-5-enkephalin in Aqueous Solution as Revealed by the Combined Use of 17O-NMR and Fourier- Transform Infrared Spectroscopy”, I.P. Gerothanassis*, N. Birlirakis, T. Karayannis, M. Sakarellos-Daitsiotis, C. Sakarellos*, B. Vitoux and M. Marraud, Eur. J. Biochem. 210, 693-698 (1992).

9a.     “Solvation State of the Tyr Side-chain in Peptides. An FT-IR and 17O-NMR Approach”, I.P. Gerothanassis*, Ν. Birlirakis, C. Sakarellos* and M. Marraud, J. Am. Chem. Soc. 114, 9043-9047 (1992).

10a.   “Multinuclear and Multidimensional NMR Methodology for Studying Individual Water Molecules Bound to Peptides and Proteins in Solution: Principles and Applications”, I.P. Gerothanassis, Progr. NMR Spectrosc. 26, 171-237 (1994).

11a.   “17O NMR Studies of Hemoproteins and Synthetic Model Compounds in the Solution and Solid State”, I.P. Gerothanassis, Progr. NMR Spectrosc. 26, 239-292 (1994).

12a.   “17O NMR Chemical Shifts as a Tool to Study Specific Hydration Sites of Amides and Peptides - Correlation with the IR Amide I Stretching Vibration”, I.P. Gerothanassis* and C. Vakka, J. Org. Chem. 59, 2341-2348 (1994).

13a.   “17O NMR Studies of the Solvation State of Cis/Trans Isomers of Amides and Model Protected Peptides”, I.P. Gerothanassis*, C. Vakka and A. Troganis, J. Magn. Reson. B 111, 220-229 (1996).

14a.   “Carbon-13 and Oxygen-17 Chemical Shifts, (16O/18O) Isotope Effects on 13C Chemical Shifts, and Vibrational Frequencies of Carbon Monoxide in Various Solvents and of the Fe-C-O Unit in Carbonmonoxy Heme Proteins and Synthetic Model Compounds”, C.G. Kalodimos, I.P. Gerothanassis*, R. Pierattelli and B. Ancian, Inorg. Chem. 38, 4283-4293 (1999).

15a.   “The 17O-NMR Shielding Range and Shielding Time Scale and Detection of Discrete Hydrogen-Bonded Conformational States in Peptides”, Ι.P. Gerothanassis, Biopolymers 59, 125-130 (2001).

16a, “Oxygen - 17 NMR Spectroscopy: Basic Principles and Applications (Part I)”, I.P. Gerothanassis, Progr. NMR Spectrosc. 56, 95-197 (2010); 

17a. “Oxygen - 17 NMR Spectroscopy: Basic Principles and Applications (Part II)”, I.P. Gerothanassis, Progr. NMR Spectrosc. 57, 1-110 (2010).

 

B.      Multinuclear NMR Studies of Molecules of Biological Interest

1b.    “Hydrogen Bonding Effects on 31P NMR Shielding in the Pyrophosphate Group of NADPH Bound to L.Casei Dihydrofolate Reductase”, I.P. Gerothanassis*, B. Birdsall and J. Feeney, FEBS Letters 291, 21-23 (1991).

2b.    “31P Solid-State NMR Measurements Used to Detect Interactions Between NADPH and Water and to Determine the Ionization State of NADPH and a Protein-Ligand Complex Subjected to Low-level Hydration”, I.P. Gerothanassis*, P.J. Barrie, B. Birdsall and J. Feeney*, Eur. J. Biochem. 235, 262-266 (1996).

3b.    “Observation of Large Solvent Effects on the 31P Shielding Tensor of a Cyclic Nucleotide”, I.P. Gerothanassis*, P.J. Barrie* and C. Tsanaktsidis, J. Chem Soc., Chem. Commun. 2639-2640 (1994).

4b.    “Solvation Properties of N-Substituted Cis and Trans Amides are not Identical: Significant Enthalpy and Entropy Changes are Revealed by the Use of Variable Temperature 1H NMR in Aqueous and in Chloroform Solutions and Ab Initio Calculations”. A. Troganis, E. Sicilia, K. Barbarossou, I.P. Gerothanassis* and N. Russo*, J. Phys. Chem. A. 109, 11878-11884 (2005).

5b.     “Is the Iron-Carbon-Oxygen Moiety Linear or Bent in Heme Model Compounds? Evidence for Non-Axially Symmetric Shielding Tensors from Carbon-13 CP MAS NMR Spectroscopy”, I.P. Gerothanassis*, M. Momenteau, G.E. Hawkes and P.J. Barrie, J. Am. Chem. Soc. 115, 9796-9797 (1993).

6b.    “Solid State 13C NMR Evidence for a Large Deviation from Linearity of the Fe-C-O Unit in the CO Complex with Myoglobin”, I.P. Gerothanassis*, P.J. Barrie*, M. Momenteau and G.E. Hawkes, J. Am. Chem. Soc. 116, 11944-11949 (1994).

7b.    “13C CP/MAS NMR Studies of Hemoprotein Models With and Without an Axial Hindered Base: 13C Shielding Tensors and Comparison With Hemoproteins and X-Ray Structural Data”, I.P. Gerothanassis*, M. Momenteau*, P.J. Barrie, C.G. Kalodimos and G.E. Hawkes, Inorg. Chem. 35, 2674-2679 (1996).

8b.     “Carbon-13 Nuclear Shieldings as a Novel Method in Estimating Porphyrin Ruffling in Hexacoordinated Superstructured Heme Model Compounds in Solution”, C.G. Kalodimos and I.P. Gerothanassis*, J. Am. Chem. Soc. 120, 6407-6408 (1998).

9b.    “The Effects of Atropisomerism and Porphyrin Deformation on 57Fe Shieldings in Superstructured Hemoprotein Models” I.P. Gerothanassis*, C.G. Kalodimos, G.E. Hawkes and P. Haycock, J. Magn. Reson. 131, 163-165 (1998).

10b.  “Iron-57 Nuclear Shieldings as a Quantitative Tool for Estimating Porphryrin Ruffling in Hexacoordinated Carbonmonoxy Heme Model Compounds in Solution”. C.G. Kalodimos, I.P. Gerothanassis*, E. Rose, G.E. Hawkes and R. Pierattelli, J. Am. Chem. Soc., 121, 2903-2908 (1999).

11b.  “On the Molecular Basis of the Recognition of Angiotensin II (AII). NMR Structure of AII in Solution Compared with the X-ray Structure of AII bound to the mAb Fab131”, A.G. Tzakos, A.M. Bonvin, A. Troganis, P. Cordopatis, M.L. Amzel, I.P. Gerothanassis*, and N.A. van Nuland, Eur. J. Biochem. 270, 849-860 (2003).

12b.  “Domain-Selective Ligand-Binding Modes and Atomic Level Pharmacophore Refinement in Angiotensin I Converting Enzyme (ACE) Inhibitors”, A.G. Tzakos and I.P. Gerothanassis*, ChemBioChem. 6, 1089-1103 (2005).

13b.  “The Molecular Basis for the Selection of Captopril cis and thans Conformations by Angiotensin I Converting Enzyme”, A.G. Tzakos, N. Naqvi, K. Comporozos, R. Piarattelli, V. Theodorou, A. Husain* and I.P. Gerothanassis*, Bioorg. Med. Chem. Lett. 16, 5084-5087 (2006).

14b.  “NMR and Molecular Dynamics Studies of an Autoimmune Myelin Basic Protein Peptide and its Antagonist. Structural Implications for the MHC II (1-A4) – Peptide Complex through Docking Calculations”, A.G. Tzakos, P. Fuchs, N.A.J. van Nuland, A. Troganis, T. Tselios, J. Matsoukas, I.P. Gerothanassis* and A.M.J. Bonvin, Eur. J. Biochem. 271, 3399-3413 (2004).

 

C.      NMR Analytical Applications of Complex Natural Extracts

1c.     “Methodology for Identification of Phenolic Acids in Complex Phenolic Mixtures by High-Resolution Two- Dimensional Nuclear Magnetic Resonance. Application to Methanolic Extracts of Two Oregano Species”, I.P. Gerothanassis*, V. Exarchou, V. Lagouri, A. Troganis, M. Tsimidou and D. Boskou*, J. Agric. Food Chem. 46, 4185-4192 (1998).

2c.     “Identification and Quantification of Caffeic and Rosmarinic Acid in Complex Plant Extracts by the Use of Variable-Temperature Two-Dimensional Nuclear Magnetic Resonance Spectroscopy”, V. Exarchou, A. Troganis, I.P. Gerothanassis*, M. Tsimidou and D. Boskou, J. Agric. Food Chem. 49, 2-8 (2001).

3c.     “LC-UV-Solid Phase Extraction-NMR-MS Combined with a Cryogenic Flow Probe and its Application to the Identification of Compounds Present in Greek Oregano”, V. Exarchou*, M. Godejohann, T.A. Van Beek, I.P. Gerothanassis and J. Vervoort, Anal. Chem. 75 6288-6294 (2003).

4c.     “Identification of the Major Constituents of Hypericum Perforatum by LC/SPE/NMR and/or LC/MS”, E.C. Tatsis, S. Boeren, V. Exarchou, A.N. Troganis, J. Vervoort and I.P. Gerothanassis*, Phytochemistry, 68 (2007) 383-393.

5c.     “1H-NMR Determination of Hypericin and Pseudohypericin in Complex Natural Mixtures by the Use of Strongly Deshielded OH Groups”, E. Tatsis, V. Exarchou, A. Troganis and I.P. Gerothanassis*, Anal. Chim. Acta, 607, 219-226 (2008).

6c.     “Rapid and Novel Discrimination and Quantification of Oleanolic and Ursolic Acids in Complex Plant Extracts using Two-Dimensional  Nuclear Magnetic Resonance Spectroscopy-Comparison with HPLC Methods”, V.G. Kontogianni, V. Exarchou, A. Troganis and I.P. Gerothanassis*, Anal. Chim. Acta 635, 188-195 (2009).

7c.    “Exploring the “Forgotten”- OH NMR Spectral Region in Natural Products”, P. Charisiadis, V. Exarchou, A.N. Troganis and I.P. Gerothanassis*, Chem.Commun. 46, 3589-3591 (2010).

8c.    “Contribution of Flavonoids to the Overall Radical Scavenging Activity of Olive (Olea Europea 1.) Leaf Polar Extracts”, V. Goulas, V.T. Papoti, V. Exarchou, M.Z. Tsimidou* and I.P. Gerothanassis*, J. Agric. Food Chem. 6, 3303-3308 (2010)]

9c.    “Novel Determination of the Total Phenolic Contents in Crude Plant Extracts by the Use of 1H NMR of the –OH Spectral Region”, A.A. Neratzaki, C.G. Tsiafoulis*, P. Charisiadis, V.G. Kontogianni and I.P. Gerothanassis*, Anal. Chim. Acta 688, 54-60 (2011).

10c.  “Unprecendented Ultra High Resolution –OH 1H NMR Spectral Region in the Analysis of Complex Plant Extracts”, P. Charisiadis, A. Primikyri, V. Exarchou, A. Tzakos and I.P. Gerothanassis*, J. Nat. Prod., 2011, in press.

 

Significant Research Achievements in the Last 10 Years

NMR and Computational Studies of Angiotensin II, Angiotensin Converting Enzyme (ACE) and ACE Inhibitors

Angiotensin II (AII), the main effector octapeptide hormone of the rennin-angiotensin system exerts a variety of actions via specific receptors designated AT1 and AT2. AII has been extensively investigated in solution during the last 40 years with a variety of techniques. The results have been interpreted in terms of various models such as a α-helix, β-turn, cross-β-forms I, γ-turn, random coil side chain ring cluster etc. It is evident that several of the reported models are not consistent with each other and that there is no general consensus on the solution conformation of AII. The high resolution 3D NMR structures of the octapeptide hormone angiotensin II (AII) in aqueous solution have been obtained [On the Molecular Basis of the Recognition of Angiotensin II (AII). NMR Structure of AII in Solution Compared with the X-ray Structure of AII bound to the mAb Fab131”, A.G. Tzakos, A.M. Bonvin, A. Troganis, P. Cordopatis, M.L. Amzel, I.P. Gerothanassis*, and N.A. van Nuland, Eur. J. Biochem. 270, 849-860 (2003)]. These data were interpreted in terms of a biological ‘nucleus’ conformation of the hormone in solution which requires a limited number of structural rearrangements for receptor-antigen recognition and binding. Putative structural models have been generated for the interactions of several ACE inhibitors with both the ACE_C and the ACE_N domains which might provide an improved basis for structure-base rational design, domain selective inhibitors [“Domain-Selective Ligand-Binding Modes and Atomic Level Pharmacophore Refinement in Angiotensin I Converting Enzyme (ACE) Inhibitors”, A.G. Tzakos and I.P. Gerothanassis*, ChemBioChem. 6, 1089-1103 (2005)]. Further, in order to shed light on the recognition process in the case of human angiotensin I converting enzyme (hACE) and its inhibitor captopril, we have established a novel combinatorial approach exploiting solution NMR, flexible docking calculations, mutagenesis, and enzymatic studies [“The Molecular Basis for the Selection of Captopril cis and trans Conformations by Angiotensin I Converting Enzyme”, A.G. Tzakos, N. Naqvi, K. Comporozos, R. Piarattelli, V. Theodorou, A. Husain* and I.P. Gerothanassis*, Bioorg. Med. Chem. Lett., 16, 5084-5087 (2006)].

 

NMR Analytical Applications of Complex Natural Extracts

Analysis of natural products is an attractive research area which is based on tedious and time-consuming techniques. Typically, their study includes fractionation of the complex mixture, separation and isolation of the individual components with liquid chromatography, and structure elucidation using various spectroscopic methods (UV, IR, MS and NMR). The traditional use of NMR spectroscopy in natural products analysis, therefore, is the determination of the structure of various components isolated from plant extracts. The objective of this research project was two-fold:

  1. The development of NMR methodologies that can be successfully applied for the analysis of various constituents of complex plant extracts without any previous separation and isolation of the individual components. For the analysis of the extremely complex 1H NMR spectra, particular emphasis has been given: (a) to two dimensional (2D) homonuclear NMR (COSY, TOCSY) and variable temperature heteronuclear 1H-13C HSQC and HMBC NMR experiments “Identification and Quantification of Caffeic and Rosmarinic Acid in Complex Plant Extracts by the Use of Variable-Temperature Two-Dimensional Nuclear Magnetic Resonance Spectroscopy”, V.I. Exarchou, A. Troganis, I.P. Gerothanassis*, M. Tsimidou and D. Boskou, J. Agric. Food Chem. 49, 2-8 (2001); “Rapid and Novel Discrimination and Quantification of Oleanolic and Ursolic Acids in Complex Plant Extracts using Two-Dimensional Nuclear Magnetic Resonance Spectroscopy-Comparison with HPLC Methods”, V.G. Kontogianni, V. Exarchou, A. Troganis and I.P. Gerothanassis*, Anal.Chim. Acta 635, 188-195 (2009)] and, for the first time, to the use of the strongly deshielded OH protons in the region of 8-15 ppm [“1H-NMR Determination of Hypericin and Pseudohypericin in Complex Natural Mixtures by the Use of Strongly Deshielded OH Groups”, E. Tatsis, V. Exarchou, A. Troganis and I.P. Gerothanassis*, Anal. Chim. Acta, 607, 219-226 (2008); “Novel Determination of the Total Phenolic Contents in Crude Plant Extracts by the Use of 1H NMR of the –OH Spectral Region”, A.A. Neratzaki, C.G. Tsiafoulis*, P. Charisiadis, V.G. Kontogianni and I.P. Gerothanassis*, Anal. Chim. Acta 688, 54-60 (2011)]. The use of the significantly enhanced resolution of the “forgotten” –OH NMR spectral region and the application of 2D 1H-13C HMBC techniques [“Exploring the “Forgotten”- OH NMR Spectral Region in Natural Products”, P. Charisiadis, V. Exarchou, A.N. Troganis and I.P. Gerothanassis*, Chem. Commun. 46, 3589-3591 (2010); “Unprecedented Ultra High Resolution –OH 1H NMR Spectral Region in the Analysis of Complex Plant Extracts”, P. Charisiadis, A. Primikyri, V. Exarchou, A. Tzakos, I.P. Gerothanassis*, J. Nat. Prod., 2011, in press] will open new avenues in structure analysis of complex natural extracts with phenol –OH groups.

(ii) The development, for the first time, of coupled on-line solid-phase extraction (SPE) in LC-NMR for peak storage after the liquid chromatography (LC) separation prior to NMR analysis [“LC-UV-Solid Phase Extraction-NMR-MS Combined with a Cryogenic Flow Probe and its Application to the Identification of Compounds Present in Greek Oregano”, V. Exarchou*, M. Godejohann, T.A. Van Beek, I.P. Gerothanassis and J. Vervoort, Anal. Chem. 75 6288-6294 (2003)] and application to several extracts from natural plants [“Identification of the Major Constituents of Hypericum Perforatum by LC/SPE/NMR and/or LC/MS”, E.C. Tatsis, S. Boeren, V. Exarchou, A.N. Troganis, J. Vervoort and I.P. Gerothanassis*, Phytochemistry  68, 383-393 (2007); “Contribution of Flavonoids to the Overall Radical Scavenging Activity of Olive (Olea Europea L.) Leaf Polar Extracts”, V. Goulas, V.T. Papoti, V. Exarchou, M.Z. Tsimidou* and I.P. Gerothanassis*, J. Agric. Food Chem. 6, 3303-3308 (2010)].

Distinctions-Awards

  1. Medal of the Ministry of Education of Ukraine, 2009.
  2. DSc, University of East Anglia, 2011.

Plenary Research Lectures in International Conferences

1.   “ΝΜR Detection of Antioxidants”, I.P. Gerothanassis, in 1st International Advance Course: Chemistry and Biochemistry of Antioxidants, Wageningen, Netherlands, November (2000).

2.   “NMR Detection of Antioxidants”, I.P. Gerothanassis, in 2nd International Advanced Course: Chemistry and Biochemistry of Antioxidants, Wageningen, Netherlands, November (2001).

3.   “NMR Detection of Antioxidants”, I.P. Gerothanassis, in 3rd International Advanced Course: Chemistry and Biochemistry of Antioxidants, Wageningen, Netherlands, November (2002).

4.   “NMR Detection of Antioxidants”, I.P. Gerothanassis, in 4th International Advanced Course: Chemistry and Biochemistry of Antioxidants, Wageningen, Netherlands, November (2003).

5.   “NMR Methods for Investigating Antioxidants”, I.P. Gerothanassis, in 5th International Advanced Cource: Chemistry and Biochemistry of Antioxidants-Antioxidants in Health, Disease and Food Safety – Practical Assessment Wageningen, Netherlands, November (2004).

Invited Research Lectures in International Conferences

1.  “The Triad: NMR-Biomolecular Structure-Thermodynamics”, I.P. Gerothanassis, in 2nd Ηellenic Forum on Bioactive Peptides, University of Patras, April (2000).

2.  “Hydration Phenomena of Biomolecules in Solution and in the Solid as Revealed by the Triad: NMR-Structure-Thermodynamics”, I.P. Gerothanassis, XIX International Conference on Magnetic Resonance in Biological Systems, Florence, Italy, August (2000).

3.  “Hydration Phenomena of Molecules of Biological Interest: Structural and Thermodynamic Aspects as Revealed by the Use of Multinuclear and Multidimensional NMR”, I.P. Gerothanassis, 2nd International Conference of the Chemical Societies of the South-Eastern Countries, Chalkidiki, Greece (2000).

4.  “The Renin-Angiotensin System: NMR and Molecular Modeling Studies of Polypeptide Models of the Zn-active Site of the Angiotensin Converting Enzyme, Angiotensin II and Pοtential Analogues”, I.P. Gerothanassis, 4th User Meeting of the European Large-Scale Facilities for NMR, Frankfurt, Germany (2001).

5.  “Separation and Identification of the Major Constituents of Greek Hypericum Perforatum by LC – UV – Solid Phase Extraction NMR and LC-UV-MS/MS”, E.C. Tatsis, S. Boeren, V. Exarchou, A.N. Troganis, J. Vervoort, and I.P. Gerothanassis, 4th International Conference on Instrumental Methods of Analysis, Crete, Greece (2005).

6.  “Structure – Function Discrimination, Domain Selective Ligand – Binding Model and the Role of Chloride Anions of Angiotensin I Converting Enzyme”, I.P. Gerothanassis, HALCHEM III, Ioannina, Greece June (2006).

7.  “Myelin Basic Protein: Structural Disorder, Protein Partners and Diseases”, I.P. Gerothanassis, 5th International Greek Biotechnology Forum, Zappeio Megaro, Athens (2009).

Current Research Programmes

1.   “ΝΜR Studies of the Composition in Terpenoids of Natural Extracts from Plants from the Region of Epirus”. Coordinator: Prof. I.P. Gerothanassis, Foundation Joseph Ester Gani (2008-2009).

2.   “High Sensitivity Cryo-NMR and LC-SPE-cryo-NMR Studies and Investigation of Anti-proliferation and Anti-angiogenesis Properties of Natural Products”. Coordinator: Prof. I.P. Gerothanassis, HERACLETOS PhD Program, Greek Ministry of Education, Life Long Learning & Religious Affairs (2010-2013).

 

Research Infrastructure

NMR Center

The NMR Center is lodged in two specially tided up rooms, in the Department of Chemistry of the University of Ioannina. The instrumentation consists of:

  • A Brüker AV-250 spectrometer (resonance frequency of 1H 250 MHz), installed in 1999, updated in 2006.
  • A Brüker AV-400 spectrometer (resonance frequency of 1H 400 MHz), installed in 1994, updated in 2006, with the capabilities of obtaining high-resolution spectra in the liquid and solution state.
  • A Brüker AV-500 hyphenated with an LC-SPE system, the latter equipped with a solvent delivery pump, a DAD UV detector and a Prospect 2 solid phase extraction (SPE) unit. All individual components are connected in line to produce LC-SPE-UV-NMR hyphenation. This modern instrumentation was sponsored in 2005 by the Greek Community Support Framework III, Regional Operational Program of Epirus 2000–2006 (MIS 91629). Moreover the AV500 was equipped with a cryogenic platform and a cryo TXI -probe head. The latter can be easily converted to flow probe and work in flow mode after the necessary modification through the mounting of a flow inlet. The AV-500 is also equipped with an autosampler fully controlled by the Topspin suite (ICON-NMR).

All spectrometers have probes that are optimised for 1H applications and probes that are capable of multinuclear detection. The running cost of the instruments of the Center is about 16.900 € per year. The outlet of the fixed consumables (liquid He and liquid N2) and the repairing of the instruments are covered by the budget of the University of Ioannina.

Computational Facilities

Three workstations are available to the users for data manipulation. The two of them have the Topspin suite and the third has additionally the AMIX –Aurelia suite.

 

 

 

 

 

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