ABSTRACT
Photoreactions of 8-methoxypsoralen (8-MOP) in the presence of synthetic lecithins esterified at the beta-position with linoleic/oleic and gamma-palmitic acid (PCd2/d1pal) have been studied. Following UV-A (320-400 nm) irradiation, the photoproducts separated by thin-layer chromatography are analysed by UV absorption spectroscopy, nuclear magnetic resonance and mass spectroscopy. The new isolated products are lecithin double cyclobutane adducts, PC-(8-MOP)2, fatty acid-8-MOP split adducts from phosphatidylcholine and lecithin adducts with photo-oxidized 8-MOP. The photolysis performed in the presence of 8-MOP is related to the previously reported lecithin cyclobutane adducts with psoralen. A hypothetical scheme of lecithin photolysis under PUVA (psoralen + UV-A) treatment is proposed. We suggest that photolysis of lecithin may have a significant role in the chain of reactions triggered in cell membrane submitted to PUVA treatment.
Subject(s)
Methoxsalen/chemistry , Phosphatidylcholines/chemistry , Ultraviolet Rays , Chromatography, Thin Layer , Magnetic Resonance Spectroscopy , Mass Spectrometry , Methoxsalen/radiation effects , Models, Chemical , Phosphatidylcholines/radiation effects , Photolysis , SpectrophotometryABSTRACT
Photochemotherapy using psoralens and UVA is a treatment used widely in some skin diseases, in cutaneous lymphomas and in autoimmune diseases. This review has selected recent publications dealing with the photochemical processes triggered in the cells by UVA radiation and psoralen treatment. The photochemical changes initiated in the cell membranes were described.
Subject(s)
Furocoumarins/therapeutic use , PUVA Therapy , Cell Membrane/drug effects , Cell Membrane/radiation effects , Furocoumarins/pharmacologyABSTRACT
The formation of cyclobutane (cb) photoadducts of psoralen with a model lecithin has been shown. The adducts are formed both in ethanol solution and in micellar suspension in water. In spite of their sensitivity to various factors such as light, temperature, air, etc., they are isolated by thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC) and characterized by mass spectrometry, NMR and UV absorption spectroscopy. The NMR analysis indicates the similarity of isomeric forms of cb adducts in lecithin to those formed with free oleic acid.
