THE BIOSYNTHESIS OF ROSMARINIC ACID IN SUSPENSION-CULTURES OF COLEUS-BLUMEI

Suspension cultures of Coleus blumei accumulate very high amounts of r osmarinic acid, an ester of caffeic acid and 3,4-dihydroxyphenyllactat e, in medium with elevated sucrose concentrations. Since the synthesis of this high level of rosmarinic acid occurs in only five days of the culture period, the activities of the enzymes involved in the biosynt hesis are very high. Therefore all the enzymes necessary for the forma tion of rosmarinic acid from the precursors phenylalanine and tyrosine could be isolated from cell cultures of Coleus blumei: phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, hydroxycinnamoyl:CoA ligas e, tyrosine aminotransferase, hydroxyphenylpyruvate reductase, rosmari nic acid synthase and two microsomal 3- and 3'-hydroxylases. The main characteristics of these enzymes of the proposed biosynthetic pathway of rosmarinic acid will be described.