The Fate of Curcumin in the Rat
Curcumin, the colouring principle of turmeric, is one of the few colours remaining on the Swedish list of food additives and its increased use may be assumed. Further studies on the fate of curcumin in the body therefore become important for an assessment of its possible toxicity. In experiments on isolated rat liver perfused with semi-synthetic human blood it was found that 1 to 15% of the curcumin added to the blood appeared in the bile within 3 h. Altogether about 20% of the added curcumin could be recovered from bile and liver in these experiments. Incubation of isolated liver microsomes or hepatocytes with curcumin, in conc:s up to 10 μg/ml, showed that roughly 80% of the added curcumin disappeared in 30 min at 37°C.
In experiments on bile duct cannulated rats, anaesthesized with Nembutal (50 mg/kg bw), 0.4 to 5% of intravenously injected curcumin appeared in the bile within 3 h. Curcumin was also accumulated in the liver, kidneys and body fat. When added to the perfused liver, or intravenously injected, curcumin stimulated the bile production, and in the latter case also increased the excretion of cholesterol and bilirubin.
After oral administration of 1 g/kg bw of curcumin only about 0.001% was excreted in the bile during 3 h, and plasma levels remained close to zero.
Six rats, given 1 g/kg bw of curcumin orally, excreted 65 to 85% of the substance unchanged in the faeces and less than 0.1% in the urine during 72 h, at which time the excretion was virtually complete. In an acute toxicity study there was no mortality or gross effects 72 h after oral doses of curcumin up to 5 g/kg bw.