Rosmarinic acid production in Coleus cell cultures.

TLDR: Cell suspension cultures of Coleus blumei Benth have been found to accumulate 8–11% of their dry weight as rosmarinic acid (α-O-caffeoyl-3,4-dihydroxyphenyl-lactic acid) and this high rate of synthesis coincides with an increase in phenylalanine ammonia-lyase specific activity.

Abstract: Rosmarinic acid, or α-0-caffeoyl-3,4-dihydroxyphenyllactic acid (Fig. 1), is a representative of a major class of plant secondary metabolites, the ester- or amide-linked conjugates of hydroxycinnamic acids. These compounds, along with the flavonoid tannins, are believed to serve as the substrates for peroxidases and polyphenol oxidases during the browning of damaged plant tissues and the hypersensitive response to pathogen attack (Tomiyama et al. 1967). Auto-oxidation and enzymic oxidation convert the hydroxycinnamoyl moiety to various reactive species which can readily couple covalently with electron-deficient centers in proteins, nucleic acids and other metabolites (Pierpoint et al. 1977; Igarashi and Yasui 1985). Since this process can rapidly destroy the functional integrity of a cell, hydroxycinnamoyl conjugates in living cells must normally be sequestered in a cellular compartment which isolates them from oxidative enzyme catalysis. The limited evidence on this point indicates that the soluble conjugates are normally stored within the central vacuole (Chaprin and Ellis 1984). There is also a pool of insoluble conjugates associated with the cell wall (El-Basyouni et al. 1964), but their metabolic relationship to the soluble conjugates remains unknown.