The protective effect of caffeoyl derivatives (echinacoside, chlorogenic acid, chicoric acid, cynarine, and caffeic acid, typical constituents of Echinacea species) on the free radical-induced degradation of Type III collagen has been investigated. The macromolecule was exposed to a flux of oxygen radicals (superoxide anion and hydroxyl radical) generated by the xanthine/xanthine oxidase/Fe2+/EDTA system and its degradation assessed qualitatively by SDS-PAGE and quantitatively as the amount of soluble peptides (according to the 4-hydroxyproline method) released from native collagen after oxidative stress. The SDS-PAGE pattern of native collagen is markedly modified by free radical attack, with formation of a great number of peptide fragments with molecular masses below 97 kDa: in the presence of mu M concentrations of echinacoside, there is a complete recovery of the native profile. Collagen degradation was, in fact, dose-dependently inhibited by all the compounds, with the following order of potency: echinacoside approximate to chicoric acid > cynarine approximate to caffeic acid > chlorogenic acid, with IC50 ranging from 15 to 90 mu M. These results indicate that this representative class of polyphenols of Echinacea species protects collagen from free radical damage through a scavenging effect on reactive oxygen species and/or C-, N-, S-centered secondary radicals, and provide an indication for the topical use of extracts from Echinacea species for the prevention/treatment of photodamage of the skin by UVA/UVB radiation, in which oxidative stress plays a crucial role.
|Titolo:||Echinacoside and caffeoyl conjugates protect collagen from free radical-induced degradation: A potential use of Echinacea extracts in the prevention of skin photodamage|
|Parole Chiave:||asteraceae; caffeoyl derivatives; collagen degradation; Echinacea; free radicals; protective effect; skin photodamage|
|Settore Scientifico Disciplinare:||Settore CHIM/08 - Chimica Farmaceutica|
|Data di pubblicazione:||1995|
|Digital Object Identifier (DOI):||10.1055/s-2006-959359|
|Appare nelle tipologie:||01 - Articolo su periodico|