Enhancing polyphenol yield in Salvia viridis L. shoot culture through liquid medium optimization and light spectrum manipulation

Salvia viridis, cultivated in Europe as an ornamental plant, has been used for centuries in folk medicine in its natural habitat in the areas of Iran and Turkey. The aim of the study was to obtain a S. viridis shoot culture that can provide high amounts of raw material rich in bioactive compounds at the lowest possible cost in a short time. It investigated the effect of different light spectra (including blue, red, mixed i.e. R:B 7:3 and white LEDs, and fluorescent lamps), and different liquid media systems (liquid agitated medium, liquid stationary medium without support, and with nanocellulose or polyurethane as support) on culture growth and polyphenol production. The phenolic compounds in 80% methanolic extract were quantified by ultra-high performance liquid chromatography (UPLC). It was found that among the LED treatments, the blue light had the most beneficial effect on shoot regeneration (proliferation factor of 4.56), shoot biomass (17-fold increase in fresh weight, 15-fold increase in dry weight), and polyphenol level (15.24 mg/g dry weight). Additionally, a liquid system with nanocellulose as a supporting material turned out to be beneficial for the cultivation of S. viridis. In these conditions, about 8.4 new buds/shoots were obtained from a single explant, fresh weight increased about 40-fold, and dry weight 30-fold. The liquid culture system with cellulose yielded 38.5 mg/g DW polyphenol content: twice as high as the shoots on the solid medium.

Liquid system with nanocellulose and blue LEDs result in efficient biomass and total polyphenol accumulation in Salvia viridis shoots.