[Pharmacokinetic studies of the propolis constituent pinocembrin in the rat (author's transl)].

The present investigation into the pharmacokinetic behaviour of the propolis constituent pinocembrin which produces a relatively good antimicrobial effect in vitro, points to possible causes of its therapeutical failure when mice infected with Candida albicans were used as a model. The biological half-life periods for the phases of invasion and elimination were 26 and 268 min, respectively. The biological availability was 25%. Almost 15% of pinocembrin are excreted unchanged in faeces and urine. Even in case of oral application of doses of up to 500 mg/kg, the serum pinocembrin concentrations did not equal the MIC (minimal inhibitor concentration) values required in vitro. A considerable first-pass effect and accelerated processes of elimination are discussed as possible causes. It appears from the present findings that pinocembrin may be utilizable only for the external treatment of stomatomycoses.