Effect of illumination on growth and phytochemical profile of Salvia yangii grown in vitro

Plant in vitro cultures are a feasible system for testing influence of single environmental factor on biosynthesis of medicinally relevant compounds. Light spectrum and intensity can be simple means to stimulate production of specialized metabolites. Our aim was to examine the influence of different types of light on the morphogenetic response and the production of terpenoids and phenylpropanoids in Salvia yangii B.T.Drew (syn. Perovskia atriplicifolia Benth.) in vitro cultures. Shoots were illuminated with white, PAR (photosynthetic active radiance), red, blue, and mixed red/blue LED, as well as cool-fluorescent light of different intensities. Phytochemical analysis was performed using HSPME-GC-MS for volatile compounds and LC-MS for polyphenols and abietane diterpenoids. Among volatiles, hydrocarbon monoterpenes (camphene, 3-carene, limonene,

α-pinene), oxidized monoterpenes (eucalyptol, camphor, borneol), monoterpene ester (bornyl acetate) and sesquiterpenes (β-caryophyllene, isocaryophyllene), and from the non-volatile compounds, rosmarinic and carnosic acids were examined. Higher light intensity corresponded to differences in the chlorophyll and polyphenol content. The largest differences in the essential oils constituents were between PAR and red light. In case of rosmarinic and carnosic acids, the red light was most efficient. Light used in controlled conditions of in vitro cultures modified morphogenesis and influenced the content of selected metabolites. This can be used obtaining pharmacologically active compounds, such as carnosic acid, which in nature is produced in relatively small amounts.