Plant polyphenols in cell-cell interaction and communication

Abstract

Plant polyphenols including flavonoids and tannins are important constituent of our everyday diet and medical herbals. It is broadly accepted that polyphenols may protect us from toxins, carcinogens and pollutants though the mechanisms of the polyphenols action is still not clear. Here we discuss the ability of polyphenols and especially gallate rich compounds like tannins and catechin gallates to interact with proteins and lipids, establish binding between adjacent bilayer surfaces and initiate membrane aggregation. This phenomena discovered in model experiments could also influence lateral segregation and compartmentalization of cell surface compounds and assist the cell-cell interaction and signal transduction. The involvement of plant polyphenols in communication between cells could be an important factor responsible for anticarcinogenic, vascular and cardioprotective activity of these compounds and speculated to be implicated in the evolution of human brain and intelligence.Plant polyphenols including flavonoids and tannins are present on our daily diet. The opinion on their influence on the human health is contradictory and ranges widely from positive to skeptic and even to alarming. [1][2][3] Obviously the processes of their functioning in our body should be studied in more details.The polyphenols are know not only as patent antioxidants but also as cell metabolism regulators. 4 The biological functioning of these compounds begins from their interaction with the cell surface and penetration through the plasma membrane into the cytoplasm. They can influence various physical properties of membrane lipids including diffusion, melting temperature, detergent solubility, osmotic stability, permeability to water soluble compounds 5-7 and general parameters of lipid packing and intrinsic bilayer curvature related to membrane interaction and fusion. Their penetration through the lipid bilayer inversive correlates with the number of hydroxyl groups and accordingly with the hydrophobicity of molecules.The background of polyphenols functioning is attributed to the ability of these compounds to interact with proteins, lipids and polynucleotides through electrostatic, hydrophobic, and even covalent binding. [6][7][8][9] The polyphenolic compounds are generally not very active chemically and only electrostatic and hydrophobic forces are responsible for their interaction within cells. However, after oxidation of catechol and gallate 10 moieties to quinones (Fig. 1) in presence of peroxidases, polyphenol oxidases, alkaline pH, or transition metals they could be involved in reactions with free nucleophilic functional groups such as sulfhydryl, amine, amide, indole and imidazole substituents; 11 and result in covalent binding with different residues including lysine, methionine, cysteine and tryptophane. 8,12 We expect that terminal amino groups of phosphatidylethanolamines or sulfolipids of biological membranes can also participate in covalent binding with quinones. The consequence of chemical derivatization of proteins ma...

Stabilization of erythrocytes against oxidative and hypotonic stress by tannins isolated from sumac leaves (Rhus typhina L.) and grape seeds (Vitis vinifera L.)

“…For hydrolysable tannins, increasing fluidity in the internal region of the lipid bilayer has been shown, but no changes were found on the surface of the membrane of the Chinese hamster cell line B14 [50]. It is known that the binding of tannins to the membrane surface of cells may induce cluster and raft formation [34]. It may prevent erythrocytes swelling and release of hemoglobin.…”

“…Furthermore, there are data showing that erythrocytes bind polyphenols and may increase the capacity of blood to scavenge oxidants. It has been shown that polymerized polyphenols are bound by proteins on the cell surface rather than intracellular structures and that erythrocyte-polyphenol complexes may serve as potent "sinks" for RONS [34][35][36]. We used HClO and ONOO -as oxidants that can also be transformed into other radicals, which can lead to different damage of biomolecules.…”

The Emergence of Polyphenols in the Potentiation of Treatment Modality in Cystic Fibrosis

“…Despite their low bioavailability, these compounds can act as signaling molecules that can induce endogenous antioxidant defense pathways as well as modulate many intracellular signaling processes associated with oxidative stress and inflammation. In that regard, the health-promoting benefits of polyphenol parent compounds and their microbial metabolites have been related to translocation into the nucleus of nuclear factor erythroid 2-related factor 2 (Nrf2) and induction of Nrf2-antioxidant response element signaling pathway [7], suppression of nuclear factor κB (NF-κB) and activator protein 1 (AP-1) [8], induction of glutathione conjugates [9] and glutathione S-transferase [10], caspase-3 activation [11], c-jun NH 2 -terminal kinase [12] and P38 activation [13], and modulation of mitogenactivated protein kinases [14] and the phosphoinositide-3 kinase/Akt protein kinase B pathway [15].…”

Influence of aggregation on the antioxidative capacity of milk peptides

“…2 suggested that genistein could alter the aggregation nature of milk peptides by interfering with the electrostatic and hydrophobic interactions of peptide macroaggregates. The interactions within the associated aggregates may be due to the ionic interactions between the p electrons in the phenol ring of genistein and the NH 3 þ group of amino acid side chains (Tarahovsky, 2008).…”