Enhanced rosmarinic acid accumulation and rosmarinic acid synthase gene expression under drought stress in thyme (Thymus vulgaris)

Rosmarinic acid (RA) is the ester of 3,4-dihydroxyphenyllactic acid and caffeic acid and widely occurs in the Lamiaceae. It has numerous biological effects such as antiviral, antibacterial, anti-inflammatory and antioxidant activity. In an earlier study RA accumulation correlated with the expression of rosmarinic acid synthase (RAS) gene in in vitro lemon balm (Melissa officinalis L.) cell cultures [1].