Phospholipid membranes, flavonoid

Interaction of Flavonoids with Model Phospholipid Membranes. 242... 

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. 

Fig. 6.2 Interactions between phospholipids, membrane proteins, and flavonoids. (a) In acidic and neutral conditions, flavonoids such as quercetin intercalate between phospholipids in the hydrophobic zone and initiate the formation of an ordered lipid phase. Flavonoids can also interact with membrane proteins, (b) In alkaline conditions, deprotonated flavonoids cover the polar head surface of phospholipids and interact with membrane proteins, (c) When phloretin replaces quercetin, the distance between the hydrocarbon chains is increased and lipids form a superordered lipid phase. Intercalation of phloretin between the polar heads of phospholipids induces micelle formation, (d) Outer and inner phospholipidic layers can be interdigitated when phospholipids are spaced by phloretin but not by quercetin (a and b). Modified from Tarahovsky et al. (2008).

Tammela P, Laitinen L, Galkin A et al. (2004) Permeability characteristics and membrane affinity of flavonoids and alkyl gallates in Caco-2 cells and in phospholipid vesicles. Arch Biochem Biophys 425 193-199... 

Immobilized artificial membrane (lAM) stationary phase consists of a monolayer of phospholipid covalently immobilized on an inert silica support. The lAM stationary phase mimics the lipid environment found in cell membranes, and it can be used for elucidating drug-membrane interactions. The interaction of catechins, flavones, flavonols, anthocyanidins, and anthocyanins with phosphatidylcholine was investigated by HPLC with an lAM colunm. The lAM partition coefficients of the flavonoids correlated well with the amounts flavonoids incorporation into the liposomes [42]. 

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