Abstract
The medicinal properties of curcumin obtained from Curcuma longa L. cannot be utilised because of poor bioavailability due to its rapid metabolism
in the liver and intestinal wall. In this study, the effect of combining piperine,
a known inhibitor of hepatic and intestinal glucuronidation, was evaluated on the
bioavailability of curcumin in rats and healthy human volunteers. When curcumin was
given alone, in the dose 2 g/kg to rats, moderate serum concentrations were achieved
over a period of 4 h. Concomitant administration of piperine 20 mg/kg increased the
serum concentration of curcumin for a short period of 1-2h post drug. Time to maximum
was significantly increased (P<0.02) while elimination half life and clearance significantly
decreased (P<0.02), and the bioavailability was increased by 154%. On the other hand
in humans after a dose of 2g curcumin alone, serum levels were either undetectable
or very low. Concomitant administration of piperine 20 mg produced much higher concentrations
from 0.25 to 1h post drug (P<0.01 at 0.25 and 0.5h; P < 0.001 at 1 h), the increase
in bioavailability was 2000%. The study shows that in the dosages used, piperine enhances
the serum concentration, extent of absorption and bioavailability of curcumin in both
rats and humans with no adverse effects.
Key words
Curcumin - piperine - pharmacokinetics -
Curcuma longa
- Zingiberaceae
