Influence of silybin on biophysical properties of phospholipid bilayers1

Authors

  • Olga WESOŁOWSKA,

    Corresponding author
    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • Barbara ŁANIA-PIETRZAK,

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • Micha KUŻDŻAŁ,

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
    2. Division of Biochemistry, Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, ul Wybrzeze Wyspianskiego 27, 50–370 Wroclaw, Poland
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  • Kamila STAŃCZAK,

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • Daniela MOSIĄDZ,

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • Piotr DOBRYSZYCKI,

    1. Division of Biochemistry, Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, ul Wybrzeze Wyspianskiego 27, 50–370 Wroclaw, Poland
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  • Andrzej OŻYHAR,

    1. Division of Biochemistry, Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroclaw University of Technology, ul Wybrzeze Wyspianskiego 27, 50–370 Wroclaw, Poland
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  • Małgorzata KOMOROWSKA,

    1. Institute of Physics, Wroclaw University of Technology, ul Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland skiego 27, 50–370 Wroclaw, Poland
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  • Andrzej B HENDRICH,

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • Krystyna MICHALAK

    1. Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50–368 Wroclaw, Poland
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  • 1

    This work was supported by the Polish Committee for Scientific Research, funds for Wroclaw Medical University. This project was realized partially in the frames of COST European Programme Action P15 “Advanced paramagnetic resonance methods in molecular biophysics”.

5Correspondence to Dr Olga WESOŁOWSKA.
Phn 48-71-784-1415.
Fax 48-71-784-0088.
E-mail olawes@biofiz.am.wroc.pl

Abstract

Aim: Silybin (silibinin) is major biologically active flavonolignan extracted from milk thistle (Sylibum marianum). Its biological activities include hepato-protection, anticancer properties, and antioxidant- and membrane-stabilizing functions. Although membranes are postulated to be one of the cellular targets for silybin, little is known about its interaction with phospholipid bilayers. Methods: In the present work, the interactions of silybin with phosphatidylcholine bilayers were studied in detail using fluorescence spectroscopy, microcalorimetry and electron spin resonance techniques. Results: The results showed that silybin interacted with the surface of lipid bilayers. It affected the generalized polarization of the fluorescent probe Prodan, while not influencing the more deeply located Laurdan. Silybin lowered the main phospholipid phase transition temperature as judged by microcalorimetry, and caused the immobilization of spin probe Tempo-palmitate located on the surface of membranes. The mobility of spin probes 5- and 16-doxyl stearic acid was not affected by silybin. Silybin-induced quenching of 1,6-diphe-nyl-1,3,5-hexatriene fluorescence indicated that some flavonoid molecules partitioned into the hydrophobic region of membranes, which did not change significantly the biophysical properties of the deeper membrane regions. Conclusion: Such a behavior of silybin in membranes is in accordance with its postulated biological functions and neglectable side effects of therapies using silybin.

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