Abstract
After oral administration of 100 mg/kg b. w. (235.8 µmol/kg) salicortin to
Wistar rats, peak serum concentrations of 1.43 mg/L (13.0 µM) catechol were
detected after 0.5 h in addition to salicylic acid by HPLC-DAD after serum
processing with β-glucuronidase and sulphatase. Both metabolites
could also be detected in the serum of healthy volunteers following oral
administration of a willow bark extract (Salicis cortex, Salix spec.,
Salicaceae) corresponding to 240 mg of salicin after processing with both
enzymes. In humans, the cmax (1.46 mg/L, 13.3 µM) of catechol was
reached after 1.2 h. The predominant phase-II metabolite in humans and rats
was catechol sulphate, determined by HPLC analysis of serum samples
processed with only one kind of enzyme. Without serum processing with
glucuronidase and sulphatase, no unconjugated catechol could be detected in
human and animal serum samples. As catechol is described as an
anti-inflammatory compound, these results may contribute to the elucidation
of the mechanism of the action of willow bark extract.
Key words
Salix
- Salicaceae - catechol - salicortin - metabolism - conjugates - salicylic acid - pharmacokinetic study -
in vivo
