Identification and localization of hydroxycinnamoyl and flavonol derivatives from endive (Cichorium endivia L. cv. Geante Maraichere) leaves

Eight major phenolic compounds from endive (Cichorium endivia L.) leaves were separated and identified by analytical and semipreparative HPLC. An original enzymatic hydrolysis using hydroxycinnamoyl-quinate esterase is described for the characterization of five cinnamoyl esters. Three flavonoids were identified after acid hydrolysis. The acid-phenol, alcohol-acid, and sugar moieties released after enzymatic and acid hydrolysis were determined by using different HPLC methods. The cinnamoyl derivatives were shikimic, tartaric, and glucose esters, the phenol moiety of which was always caffeic acid. The flavonoids consisted of two kaempferol glycosides and one quercetin glycoside. After quantification in four fractions, e.g., foliar parenchyma and veins from either green or etiolated leaves, it was shown that caffeoyl esters represented more than 75% of the total phenolics. Among them, dicaffeoyltartaric esters were the major compounds (more than 50% of total phenolics). Foliar parenchyma fractions were richer in phenols than the vein fractions. Etiolation resulted in a large decrease in phenol content which was proportionately higher for the flavonol derivatives, mainly in the parenchyma fractions