Metabolism and excretion of methylproscillaridin by man

Summary

0.5 mg³H-proscillaridin-4-methylether was administered orally to 5 healthy males. Maximum plasma levels of total radioactivity were reached after one to two hours. In two subjects a second peak was observed between 6 and 12 hours. The plasma half life of total radioactivity was 51 hours. 20% and 56% respectively of the dose were eliminated in urine and faeces during the following 7 days. 55% of the total radioactivity in plasma, 80% in urine and 20% in faeces consisted of CHCl₃-insoluble compounds. 50 – 60% of the latter in plasma and urine could be hydrolysed by β-glucuronidase. More than 90% of the split products were identified as conjugates of methylproscillaridin. TLC-separation of the CHCl₃-soluble fractions of plasma and urine yielded two unidentified metabolites, P₂ and P₃, as the main compounds, besides methylproscillaridin, proscillaridin and scillarenin. In faeces more than 90% of the non-polar fraction was identified as methylproscillaridin. Shortly after administration of³H-methylproscillaridin, the radioactivity in plasma consisted mainly of CHCl₃-in-soluble conjugates and of the metabolite P₂.