Flavonoid interactions

Circular Dichroism in Studies of Molecular Flavonoid Interaction.117... 

MS. This section will rather briefly concentrate on some of the more recent applications of UV absorption spectroscopy in the flavonoid field. It will mainly cover online UV absorption spectroscopy in chromatography (Section 2.5.1). Because of the current importance of UV Vis in the study of anthocyanins, some more UV Vis spectral details have been included related to this pigment group (Section 2.5.2). Section 2.5.3 indicates the recent use of this technique in studies of flavonoids interacting with other compounds. 

Brown, J.E., IChodr, H., Hider, R.C., and Rice-Evans, C.A., Structural dependence of flavonoid interactions with Cu ions implications for their antioxidant properties, Biochem. J., 330, 1173, 1998. 

Consequences of Flavonoid Interactions on Membrane-Associated Processes 122... 

Flavonoids bear different degrees of hydroxylation, polymerization, and methylation that define both specific and nonspecific interactions with membrane lipids. Molecule size, tridimensional structure, and hydrophili-city/hydrophobicity are chemical parameters that determine the nature and extent of flavonoid interactions with lipid bilayers. The hydrophilic character of certain flavonoids and their oligomers endows these molecules with the ability to bind to the polar headgroups of lipids localized at the water-lipid interface of membranes. On the other hand, flavonoids with hydrophobic character can reach and cross the lipid bilayer. In this section, we will discuss current experimental evidences on the consequences of flavonoid interactions with both the surface and the hydrophobic core of the lipid bilayer. 

Flavonoids can also interact with membrane proteins, such as those functioning as receptors, transporters, channels, and enzymes, and potentially affect their biological activities. A summary of recent advances on the study of flavonoid interactions with plasma membrane proteins is presented in Table 4.2. 

CONSEQUENCES OF FLAVONOID INTERACTIONS ON MEMBRANE-ASSOCIATED PROCESSES... 

The affinity of flavonoids for phospholipid membranes has been unequivocally demonstrated by many authors. Many biological functions of these compounds are also believed to be the result of flavonoid interactions with cell membranes. Partition coefficients for a large group of flavonoids between water and olive oil were determined, and it was shown that the hydrophobic-ity of the compounds is inversely proportional to the number of OH groups. 

Among flavonoid interaction processes, copigmentation has been extensively studied for a review see Brouillard and Dangles (1993). 

Snijman PW, Swanevelder SJ, Joubert E, Green IR, Gelderblom WCA (2007) The antimutagenic activity of the major flavonoids of rooibos (Aspalathus linearis) some dose-response effects on mutagen activation-flavonoid interactions. Mutat Res 631 111... 

Flavonoids interact with the major enzymatic scavengers of ROS within the cytosol such as catalase, superoxide dismutase (SOD), ascorbate peroxidase (APX), and with several enzymes involved in maintaining reduced antioxidant pool such as glutathione reductase (GR) (Fig. 6.8). Depending on their structure, some flavones and flavonols activate CAT from bovine liver. Isoflavones and flavanones exhibit weak antioxidative activities against... 

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