[Formation of a depside-caffeine complex during cold conservation of coffee leaf samples in a hydro-ethanolic medium. Methodologic implications for the extraction of depsides].
The depsides present in coffee leaves are not apparent upon extraction with ethanol if the plant material has been fixed in boiling ethanol then maintained at - 25 degrees C. A complex formed with cafein prevents the extraction and this artefact from cold conservation concerns chlorogenic acid and its isomers. A treatment with chloroform can break the complex and allows the depsides to be dosed. The complex does not seem to exist in living tissues.
D000812:Anhydrides / Q000302:isolation & purification; D002110:Caffeine / Q000302:isolation & purification; D003069:Coffee / Q000032:analysis; D003080:Cold Temperature; D004355:Drug Stability; D000431:Ethanol; D008722:Methods; D010944:Plants / Q000032:analysis*; D014867:Water
D000812:Anhydrides; D003069:Coffee; D014867:Water; D002110:Caffeine; D000431:Ethanol
Sur la formation d'un complexe "depside-caféine" lors de la conservation, au froid, en milieu hydro-éthanolique, d'échantillons foliares de caféiers. Implications méthodologiques pour l'extraction des depsides.