Antioxidative Effect of Quercetin and Its Equimolar Mixtures with Phenyltin Compounds on Liposome Membranes

• Published in: Journal of agricultural and food chemistry 2006-10, Vol.54 (20), p.7735-7746
• Main Authors: Gabrielska, Janina, Soczyńska-Kordala, Monika, Hładyszowski, Jerzy, Żyłka, Romuald, Miśkiewicz, Janusz, Przestalski, Stanisław
• Format: Article
• Language: English
• Subjects: antioxidant activity; antioxidants; Antioxidants - pharmacology; Biological and medical sciences; chemical reactions; Chromans; diphenyltin dichloride; DPPH radical; Electron Spin Resonance Spectroscopy; Food industries; free radicals; Fundamental and applied biological sciences. Psychology; Glycerophospholipids; Lipid Peroxidation - drug effects; Liposomes; liposomes (artificial); Models, Molecular; organotin compounds; Organotin Compounds - chemistry; Organotin Compounds - pharmacology; phenolic compounds; phenyltin compounds; phosphatidylcholines; quercetin; Quercetin - chemistry; Quercetin - pharmacology; triphenyltin chloride
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf060720a

Our earlier studies have shown that the compounds diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) in the presence of UVC radiation enhanced the degree of phosphatidylcholine liposome membrane oxidation (J. Agric. Food Chem. 2005, 53, 76−83). The prooxidative behavior of the compounds has now been confirmed with the electron paramagnetic resonance method, which proved the possibility that the studied compounds can exist in free radical forms. The present work investigates the possibility of the protective action of quercetin on phosphatidylcholine liposome membranes exposed to the prooxidative action of DPhT and TPhT induced by UV radiation (λ = 253.7 nm). The concentrations of quercetin and its equimolar mixtures with DPhT and TPhT were determined (and compared with well-known antioxidants as standardstrolox and butylated hydroxytoluene, also in the presence of phenyltins) as those that induce 50% inhibition in oxidation of liposomes radiated with UV. They are 5.1 ± 0.10, 2.9 ± 0.12, and 1.9 ± 0.08 μM (differences between the values are statistically significant), constituting the following sequence of antioxidative activity:  quercetin:TPhT > quercetin:DPhT > quercetin. This relation is confirmed by the results on the antiradical ability of quercetin and its mixtures with DPhT and TPhT toward the free radical 1,1-diphenyl-2-pricrylhydrazil. Similar sequences obtained in both studies suggest a possible mechanism of the antiradical action of the mixtures as free radical scavengers. We suggested that (i) quercetin's ability, documented by spectrophotometric, infrared attenuated total reflectance spectroscopy, 1H NMR, and molecular modeling methods, to form complexes with phenyltins indicates a possible way of protection against the peroxidation caused by the free radical forms of phenyltins and (ii) the differentiation in the action of the quercetin/TPhT and quercetin/DPhT associates (statisticaly significant) may result from a different localization in the liposome membrane, which is indicated by the results of the fluorimetric studies. Keywords: Quercetin; phenyltin; antioxidants; complexes; fluidity; liposomes; molecular modeling