[Biotransformation and pharmacokinetics of grandiflorenic acid [kauradien-9(11),16-oic acid-18] / 2nd communication (author's transl)].

6 metabolites are formed by incubation of grandiflorenic acid (GFA) with rat liver microsomes. 79% of GFA are metabolized after i.p. application to rats; 11 biotransformation products are found in faeces, the main excretion way. They are conjugated to glucuronic acid. Gut microflora is involved in these metabolic reactions. The structure of three metabolites is proved by IR-, MS- and NMR-spectroscopies.