CHOLERETIC AND ANTICHOLESTATIC ACTIVITIES OF FLAVONOIDS OF ARTICHOKE (CYNARA CARDUNCULUS L. SUBSP. SCOLYMUS (L.) HAYEK)

High-dose extracts from artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hayek) leaves are known to induce choleresis in man by yet unknown mechanisms. Using fluorescent cholephilic compounds the secretion of which into newly formed bile canaliculi in primary cultures of rat hepatocytes was analyzed by fluorescence microscopy in conjunction with computerized image processing, the effect of the extracts on biliary secretion could be directly demonstrated in vitro. Furthermore, taurolithocholate-induced cholestasis was strikingly reversed by the extracts as detected on the level of secretion as well as on the ultrastructural level. In both cases, flavonols such as luteolin and, to a lesser extent, luteolin-7-O-glucoside proved to be responsible for this influence, while artichoke-specific polyphenols such as caffeic acid or chlorogenic acid were almost ineffective. These results support the choleretic influence and suggest an anticholestatic effect of artichoke leaf extracts most probably due to the flavonol content of these extracts.