Intracellular distribution and origin of pentacyclic triterpenes in Calendula officinalis leaves

In Calendula officinalis leaves the cyclization of squalene to β-amyrin and its further oxidation to oleanolic acid as well as the biosynthesis of all derivatives of oleanolic acid 3-glucoside and some derivatives of oleanolic acid 3-glucuronoside occur in the microsomal fraction. The final metabolites of oleanolic acid 3-glucoside series i.e. pentaglycosides, are translocated from this fraction, one to the cell wall and plasmalemma fraction and the other to the cytosol. The derivatives of oleanolic acid 3-glucoronoside are synthesized partially in other fractions and accumulate in the different membraneous structures of the cell.