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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:36 |
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Conference: Bucharest University Faculty of Physics 2005 Meeting
Section: Electricity and Biophysics
Title:
New approaches of hypericin blood transport and neuronal uptake
Authors:
Beatrice Macri*, Maria-Luiza Flonta*, Adela Bonoiu**, Gheorghe Stoian**
Affiliation:
*Department of Animal Physiology and Biophysics, and **Department of Biochemistry, Faculty of Biology, University of Bucharest, Splaiul Independentei, 91-95
E-mail
beatrice_macri@yahoo.com
Keywords:
hypericin, high density lipoproteins, gradient electrophoresis, cellular uptake
Abstract:
Hypericin interacts with serum albumins and low density lipoproteins, with binding constants of 0.15 mg/ml and 2.82 mg/ml, respectively (Siboni et al., 2002). Uptake parameters of hypericin into carcinoma cells depend on the presence of albumins (1.63 mg/ml) and LDL (2.22 mg/ml) in the medium (Siboni et al., 2002). The goals of our study were to investigate the possible serum fractions that bind hypericin and to evidence the neuronal uptake of this compound. We confirmed the formation of the hypericin-albumin complex, by hypericin post-incubation of SDS-PAGE gels containing albumins; once stained, gels maintained for several days the fluorescence of the hypericin-albumin complex. The UV-VIS spectrum of the hypericin-albumin complex has a similar profile to that of hypericin in DMSO, but very different from the spectrum of hypericin in aqueous solution, pointing out the albumin role for solubilization during blood transport. Beside the LDL, we evidenced hypericin binding to HDL using continuous and discontinuous gradient electrophoresis; hypericin clearly binds HDL2 and HDL3, but other lipoproteins can be taken into account. Differences of hypericin binding to several serum fractions of male and female mice have been observed. We also performed studies of fluorescence microscopy in order to evidence the neuronal uptake of hypericin at different concentrations (250 nM – 1 microM). This cellular uptake is concentration and incubating time – dependent. In conclusion, our study proves hypericin binding to high density lipoproteins and evidences the neuronal cytoplasmic localisation of hypericin.
Siboni, G., H. Weitman, D. Freeman, Y. Mazur, Z. Malik, and B. Ehrenberg. 2002. Photochem Photobiol Sci 1(7): 483-491
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