Choleretic effects of curcuminoids on an acute cyclosporin-induced cholestasis in the rat

Former studies have shown that curcumin, which can be extracted from differ ent Curcuma species, is able to stimulate bile flow in rats, whereas bisdem ethoxycurcumin, which is mainly found in rhizomes of Curcumca longo, is bel ieved to inhibit bile flow To reevaluate this observation we investigated t he influence of both curcuminoids on bile flow, bile acid concentration and excretion over a time period of 180 min in the bile fistula model in rats. Furthermore, we tested the ability of both curcuminoids to reduce cyclospo rin-induced cholestasis. 30 min after intravenous injection of 25 mg/kg of curcumin and bisdemethoxycurcumin bile flow was enhanced from 500 mu l/kg/1 5 min (100 %) to 180 % and to 220 %, respectively. The choleretic effect of bisdemethoxycurcumin lasted longer than that of curcumin. Following intrav enous injection of 30 mg/kg of cyclosporin, which reduced bile flow, bile a cid concentration (15 mmol/l) and excretion (12.5 mu mol/kg/15 min) to 40 % of the initial value, administration of curcumin and bisdemethoxycurcumin transiently increased bile flow to 100% and to 125% of the starting value, respectively. However, only bisdemethoxycurcumin statistically significantl y attenuated cyclosporin-induced reduction of bile acid excretion. We concl ude that: the beneficial properties of curcuminoids for the therapy of cycl osporin-induced cholestasis still remain to be proven.