Rafts making and rafts braking: how plant flavonoids may control membrane heterogeneity

Abstract

Plant flavonoids are not only known as powerful antioxidants, but also as cell metabolism regulators. It has been postulated that they are able to control cell signal pathways by targeting receptors on the cell surface or by intercalating the lipid bilayer of membranes. Some flavonoids can increase lipid viscosity and decrease the cooperativity of hydrocarbon chain melting, while others can considerably decrease the lipid melting temperature, thus providing additional freedom for lipid diffusion. Here we discuss the ability of flavonoids to influence phase transition and lateral segregation of lipids, responsible for the formation of membrane compartments known as lipid rafts. The thermodynamic parameters of the bilayer determined by lipid packing characteristics and by lateral segregation of the bilayer are expected to depend on the location of flavonoid molecules in the bilayer. Flavonoid molecules preferably located in the hydrophobic region of the bilayer can initiate formation of raft-like domains (raft-making effect), while the molecules located in the polar interface region of the bilayer can fluidize membranes (raft-breaking effect), or initiate formation of interdigitated or micellar structures. Accordingly, we expect that in cellular membranes flavonoids can influence the appearance and development of rafts or raft-like membrane domains and thus influence the lateral diffusion of lipid molecules. Because rafts participate in cellular signal transduction, endocytosis and transmembrane translocation of different compounds, flavonoids may control cell metabolism by modulating the bilayer state.

Antioxidants in Thai Herb, Vegetable and Fruit Inhibit Hemolysis and Heinz Body Formation in Human Erythrocytes

“…It was showed that the T 50 mins were longer than 3 and a half hours. Plant polyphenols are membrane-active antioxidant agents (Saija et al, 1995) and are the cell metabolism regulators by modulating the fluidity of lipid bilayer, since they have been demonstrated to control cell signal pathways by targeting receptors on the cell surface or by intercalating the lipid bilayer of membranes (Tarahovsky et al, 2008). Polyphenols interact with the surface of bilayer through hydrogen bonding have been shown to reduce the accessibility of oxidants, thus protecting the structure and function of membranes (Oteiza et al, 2005).…”

Application of the DSC and spectroscopy methods in the analysis of the protective effect of extracts from the blueberry fruit of the genus Vaccinium in relation to the lipid membrane

“…Changes in the lipid organization indicate changes in the physicochemical properties of the cell lipid bilayer membrane by, e.g., reduction in hydrophobicity of the lipid membrane interior, change in organization and fluidity of the bilayer and disorders of the lipid asymmetry and depolarization of the membrane [19][20][21]. As a consequence of those changes, an inhibition of the activity of the enzyme and transport of proteins and loss of membrane integrity may occur, leading to cell's death.…”

Antioxidant effects of anthocyanins-rich extract from black sticky rice on human erythrocytes and mononuclear leukocytes

“…The results showed that RBCs were resistant to AAPH-induced oxidation when ARE in the 100 -600 mg/L concentration range were supplemented. Flavonoids may regulate cell metabolism by modulating the bilayer state since they have been demonstrated to control cell signal pathways by targeting receptors on the cell surface or by intercalating the lipid bilayer of membranes (Tarahovsky et al, 2008). In addition, interactions of flavonoids at the surface of bilayer through hydrogen bonding have been shown to be crucial in reducing the accessibility of oxidants, thus protecting the structure and function of membranes (Oteiza et al, 2005).…”