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Proceedings Paper

Production and laser-induced fluorescence spectroscopy (L.I.F.S.) of different Hypericum perforatum L. extracts
Author(s): Dimitris Skalkos; George Filippidis; Dimitris Kapsokalyvas; Heiko Meyer; Theodore Papazoglou; Eleni Karentzou; Heleni Dimitriou; M. Kalmanti
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Paper Abstract

We are reporting elsewhere, the promising photodynamic effect of Hypericum perforatum L. extract (PMF) against T24, NBT-II tumor bladder cells, and HL-60 leukemic cells (using 630nm, and 530nm laser light respectively). The main advantages of the extract as a photosensitizer are its low cost, extensive availability, adequate solubility, minimal toxicity, and use with a range of wavelengths. Extraction of dry herb with methanol yields the methanolic extract (ME) in 11%, which is then fractionated using liquid / liquid extraction, yielding the polar methanolic fraction (PMF) in 9,9% overall yield. Hypericin, a photosensitizing ingredient of the herb, was found in these extracts in concentrations as low as 0,51%, and 0,57% respectively. Laser induced fluorescence spectra from the ME and PMF were recorded in order to evaluate their photodiagnostic capacity. An Argon-ion laser was employed for the excitation of the samples. It was shown that the extracts resulted in different fluorescence spectra related both to their intensity, and shape. The intensities of these spectra were only 8 times less compared to the fluorescence of pure hypericin. The dependence of the signal on the pH of the medium of pure hypericin and of PMF was also investigated in order to determine specific spectra variations. According to the results hypericin fluorescence signal fades smoothly in highly acidic medium, while it decreases sharply in highly basic environment. On the contrary PMF gives a slow decrease of fluorescence in both acidic and basic medium. These data suggest that PMF-induced fluorescence is highly sensitive in basic and acidic environment.

Paper Details

Date Published: 8 April 2005
PDF: 8 pages
Proc. SPIE 5689, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIV, (8 April 2005); doi: 10.1117/12.587484
Show Author Affiliations
Dimitris Skalkos, Univ. of Ioannina (Greece)
George Filippidis, IESL, Foundation for Research and Technology-Hellas (Greece)
Dimitris Kapsokalyvas, IESL, Foundation for Research and Technology-Hellas (Greece)
Heiko Meyer, IESL, Foundation for Research and Technology-Hellas (Greece)
Theodore Papazoglou, IESL, Foundation for Research and Technology-Hellas (Greece)
Eleni Karentzou, Univ. General Hospital of Ioannina (Greece)
Heleni Dimitriou, Medical School/Univ. of Crete (Greece)
M. Kalmanti, Medical School/Univ. of Crete (Greece)

Published in SPIE Proceedings Vol. 5689:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XIV
David Kessel, Editor(s)

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