Localization and interactions of melatonin in dry cholesterol/lecithin mixed reversed micelles used as cell membrane models.
The state of melatonin confined in dry cholesterol/lecithin mixed reversed micelles dispersed in CCl4 was investigated using 1H-NMR and FT-IR spectroscopies as a function of the melatonin to lecithin molar ratio (R(MLT)) and of the cholesterol to lecithin molar ratio (R(CHL)). An analysis of experimental results leads to the hypothesis that, independent of R(MLT) and as a consequence of anisotropic melatonin/lecithin, melatonin/cholesterol and cholesterol/lecithin interactions, melatonin is totally solubilized in reversed micelles. Melatonin is mainly located in and oriented in the nanodomain constituted by the hydrophilic groups of cholesterol and lecithin. A competition of melatonin and cholesterol for the hydrophilic binding sites of the reversed micelles was observed by changing the R(CHL). Some possible biological implications of the specific interactions governing the solubilization process, the preferential location and the peculiar properties of melatonin confined in cholesterol/lecithin mixed reversed micelles are discussed.
Bongiorno
David
D
Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, Palermo, Italy.
Ceraulo
Leopoldo
L
Ferrugia
Mirella
M
Filizzola
Felice
F
Ruggirello
Angela
A
Liveri
Vincenzo Turco
VT
D002462:Cell Membrane; D002784:Cholesterol / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008550:Melatonin / Q000737:chemistry*; D008823:Micelles; D008954:Models, Biological; D010713:Phosphatidylcholines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D008823:Micelles; D010713:Phosphatidylcholines; D002784:Cholesterol; D008550:Melatonin