Production of Phenolic Acids Improved in Callus Cultures of Lactuca undulata by Ultraviolet-B Irradiation

As a valuable industrial compound, cichoric acid has antiviral, antioxidant, and anti-inflammatory properties. It is effectively used in obesity prevention and for neuroprotective purposes. Here, we aimed to compare the effects of plant growth regulators and UV-B radiation on the induction of cichoric acid production under tissue culture conditions. For this purpose, Lactuca undulata, an herbaceous medicinal plant, was used as a new source of cichoric acid. Leaf explants were initially cultured on ½ MS (Murashige and Skoog) medium containing 0.1, 1 mg/L Kinetin (Kin) and 2,4-Dichlorophenoxyacetic acid (2,4-D). The callus was then exposed to different UV-B exposure times (0, 20, 40, and 60 min) and was harvested after 5, 10, and 15 days. The highest amounts of total phenol, cichoric acid, chlorogenic acid, and caffeic acid were achieved in callus samples that were treated with 20 and 40 minutes of UV-B radiation for 10 days. Cichoric acid content reached an amount of 6.15±0.292 mg/g DW after 20 min of radiation. Pearson’s correlation coefficient analysis (PCC) showed that Phenylalanine Ammonia Lyase (PAL) activity did not correlate with the production of caffeic acid derivatives. These results suggested that UV-B irradiation can be used as an elicitor to induce the production of cichoric acid in Lactuca undulata callus cultures.