Biosynthesis of Acridone Alkaloids. A Cell-Free System from Ruta graveolens Cell Suspension Cultures

Abstract

A cell-free extract of Ruta graveolens cell suspension cultures, strain R-20, was prepared which synthesizes 1,3-dihydroxy-N-methylacridone from N-methylanthranilic acid and malonylcoenzyme A. The reaction is strongly dependent on the presence of ATP. After adding of coenzyme A to the assay mixtures a second compound X2 is accumulated to a considerable extent. The structure of this substance has not yet been clarified. Apparently X2 is a precursor of 1,3-dihydroxy-N-methylacridone, the key intermediate in the pathway leading to more complex acridones.