Rosmarinic acid production from Lavandula angustifolia HEMUS and Lavandula x intermedia var. Super A species

Plants produce large amounts of secondary metabolites as a response to biotic and abiotic factors to create a defense mechanism. Today, they are used in many industries such as pharmaceuticals, pesticides, flavorings, fragrances, cosmetics, colorants and food additives. Rosmarinic acid (RA) is an important secondary metabolite especially for the pharmaceutical and cosmetic industry since RA is effective in many biological activities such as antimicrobial, antioxidant and antiviral. Its production has traditionally been based on harvesting plants from the field but it has many disadvantages such as low yield and seasonal variations. Therefore, plant cell suspension culture has been developed as an alternative method for the RA production regardless of the environmental changes. Secondary metabolite production can be further increased by applying different strategies such as selection of cell lines with higher metabolite production by using a selective agent. In this study, plant cell suspension cultures from two lavender species (Lavandula angustifolia Hemus and Lavandula x intermedia var. Super A) were established using 4 yearold callus cell lines in order to provide RA production, and increase the yield with resistant cell lines. Growth parameters were measured based on the fresh weight, pH of the media, and extraction of RA over time. RA extraction was optimized with different volumes (2 and 5 ml) of extraction solvent and resuspension solvent types (water and 70 per cent ethanol). Furthermore, a selection strategy was performed in order to obtain cell lines with higher RA production by using m-f-D,L-phenylalanine (MPHE) in different concentrations (0.4 mM, 0.6 mM, 0.8 mM). The effect of cell density (inoculation size) on cell growth and RA production was examined as well. Use of cell suspension culture for the selection was found to be the best method. The suspension cells which were resistant to MPHE demonstrated significantly higher RA production (0.399 g/L) compared to non-selected cells. In addition, the production of RA decreased when the resistant cells were maintained in the absence of MPHE. Finally, from the resistant cells of both lavender species, the expression of the LaAT1 gene, a role in the formation of RA, was quantified by using qPCR. The resistant Hemus cell lines under 0.6 mM MPHE selection showed higher LaAT1 gene expression levels. This study will be a base for the production of RA in Lavender species in further studies.