title: Influence of silybin on biophysical properties of phospholipid bilayers.
abstract: OBJECTIVE
  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-diphenyl-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.
  
  
  CONCLUSIONS
  Such a behavior of silybin in membranes is in accordance with its postulated biological functions and neglectable side effects of therapies using silybin.
authors.affiliation: Department of Biophysics, Wroclaw Medical University, ul Chalubinskiego 10, 50-368 Wroclaw, Poland. olawes@biofiz.am.wroc.pl
authors.forename: Olga
authors.initials: O
authors.lastname: Wesołowska
authors.forename: Barbara
authors.initials: B
authors.lastname: Łania-Pietrzak
authors.forename: Micha
authors.initials: M
authors.lastname: Kuzdzał
authors.forename: Kamila
authors.initials: K
authors.lastname: Stanczak
authors.forename: Daniela
authors.initials: D
authors.lastname: Mosiadz
authors.forename: Piotr
authors.initials: P
authors.lastname: Dobryszycki
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ozyhar
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Komorowska
authors.forename: Andrzej B
authors.initials: AB
authors.lastname: Hendrich
authors.forename: Krystyna
authors.initials: K
authors.lastname: Michalak
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005453:Fluorescence; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D010743:Phospholipids / Q000737:chemistry*; D000077385:Silybin; D012838:Silymarin / Q000737:chemistry / Q000494:pharmacology
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D012838:Silymarin; D015060:1,2-Dipalmitoylphosphatidylcholine; D000077385:Silybin; D004134:Dimyristoylphosphatidylcholine