Elicitor-induced activity of isorinic acid 3'-hydroxylase, an enzyme catalyzing the final step of rosmarinic acid biosynthesis in Lithospermum erythrorhizon cell suspension cultures

Isorinic acid 3′-hydroxylase (IA3′H) catalyzes a final step in the biosynthetic pathway leading to rosmarinic acid (RA). IA3′H activity was detected in a microsomal fraction prepared from cultured cells of Lithospermum erythrorhizon. Addition of yeast extract or methyl jasmonate to the cell suspension cultures drastically increased IA3′H activity in parallel with increased RA production, whereas addition of salicylic acid enhanced neither IA3′H activity nor RA production. These results are consistent with an integral role for IA3′H in biosynthesis of RA in response to elicitation with yeast extract or methyl jasmonate.