Using biotechnology to improve the production of rosmarinic acid from rosemary plants

Rosemary (Rosmarinus officinalis) is a very important medical herb containing secondary products in its leaves. It belongs to the mint family (Lamiaceae), and is native to the Mediterranean region. Rosmarinic acid (RA) is a very strong antioxidant produced in rosemary leaves and used to protect plant tissues against free radicals and lipid peroxidation caused by stress. Also it is used in medicine, food preservatives and cosmetics. The objectives of my study was to (1) Measure the concentration of RA in leaves and callus of 5 different rosemary genotypes (Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill and Arp). (2) Increase the RA concentration in callus produced from leaf tissues by increasing the medium osmotic pressure using different sucrose concentrations or through enhancing the RA biosynthetic pathway (Increasing L-proline and L-phenylalanine in medium). (3) Measure the stress gene (PAL) expression in leaves of the five genotypes and its effect on RA production. It was found that the best genotypes for RA production from leaf tissues were Pine Scented and Majorca during the spring. While for RA extraction from callus it is preferred to use genotype Rosmarinus officinalis or Madeline Hill in the second subculture. Dark treatment and high sucrose concentration increased the RA content in callus tissues (0.0755 mg RA/gm fw callus) reaching level higher than the RA concentration inside leaf tissues. It is preferred to use sucrose concentration at 4% for Rosmarinus officinalis and 3% sucrose for Madeline Hill in the dark condition. Combination of L-proline (4 mM) and L-phenylalanine (0.8 gm/L) enhanced RA production in callus of Madeline Hill. It is preferred to extract the RA from callus tissues since in callus there is no tissue specific regulation which causes different PAL gene expression inside plant tissues due to exogenous and endogenous stimuli. Also it will enable the production of high amount of RA in relatively small areas; this approach potentially will save agricultural lands for the production of essential food crops.