Enhanced rosmarinic acid biosynthesis in Solenostemon scutellarioides culture: a precursor-feeding strategy

The aim of this study was to employ precursor-feeding strategy for the improved production of rosmarinic acid (RA) in Solenostemon scutellarioides in vitro. The cultures were fed with precursors, namely L-phenylalanine (Phe), L-tyrosine (Tyr) and cucumber juice (CJ), at different concentrations. Phe (100 mg L-1) and Tyr (400 mg L-1) caused similar to 1.5-and 2.1-fold increase in RA accumulation within 48 h. CJ (50 mg L-1) feeding displayed highest RA content (similar to 1.6-fold) in 72 h. In this study, we focused on the function of individual precursor on key enzymes involved in RA biosynthesis. The phenylalanine ammonia lyase activity was significantly upregulated after Phe (100 mg L-1) feeding, while tyrosine aminotransferase and hydroxyphenylpyruvate reductase activities were improved with Tyr (400 mg L-1) treatment. However, rosmarinic acid synthase activity was significantly enhanced by all three precursors. In synergy study, Phe (100 mg L-1) + Tyr (400 mg L-1) could enhance (similar to 3.1-fold) RA biosynthesis within 48 h.