title: Interaction of flavonoids with red blood cell membrane lipids and proteins: antioxidant and antihemolytic effects.
abstract: Plant flavonoids are emerging as potent therapeutic drugs effective against a wide range of free radical mediated diseases. Hence their interactions with cell membranes, which generally serve as targets for lipid peroxidation, are of enormous interest. Here we report in vitro studies, via absorption and fluorescence spectroscopy, on the effects of several flavonoids (namely fisetin, quercetin, chrysin, morin, and 3-hydroxyflavone, 3-HF) in goat RBC membranes. Owing to the presence of functionally relevant membrane protein components embedded in the lipid bilayer RBC ghosts provide a more realistic system for exploring drug actions in biomembranes than simpler membrane models like phosphatidylcholine liposomes used in our previous studies [e.g. B. Sengupta, A. Banerjee, P.K. Sengupta, FEBS Lett. 570 (2004) 77-81]. Here, we demonstrate that binding of the flavonoids to the RBC membranes significantly inhibits lipid peroxidation, and at the same time enhances their integrity against hypotonic lysis. Interestingly, the antioxidant and antihemolytic activities are found to be crucially dependent on the locations of the flavonoids in the membrane matrix as revealed by fluorescence studies. Furthermore, we observe that FRET (from membrane protein tryptophans to flavonoids) occurs with significant efficiency indicating that the flavonoid binding sites lie in close proximity to the tryptophan residues in the ghost membrane proteins.
authors.affiliation: Biophysics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India.
authors.forename: Sudip
authors.initials: S
authors.lastname: Chaudhuri
authors.forename: Anwesha
authors.initials: A
authors.lastname: Banerjee
authors.forename: Kaushik
authors.initials: K
authors.lastname: Basu
authors.forename: Bidisa
authors.initials: B
authors.lastname: Sengupta
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Sengupta
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects* / Q000378:metabolism*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D031541:Fluorescence Resonance Energy Transfer; D006041:Goats; D006461:Hemolysis / Q000187:drug effects; D007038:Hypotonic Solutions; D066298:In Vitro Techniques; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014783:Viscosity
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D007038:Hypotonic Solutions; D008563:Membrane Lipids; D008565:Membrane Proteins; D017392:Thiobarbituric Acid Reactive Substances