Do in vitro cultures hold the key? Exploring cultivation systems, hormonal composition and LED elicitation in enhancing shoot biomass and phenolic profiles of Lychnis flos-cuculi

Abstract Lychnis flos-cuculi L. is a valuable plant species with recognized medicinal properties. In vitro culture methods provide a sustainable approach to biomass production and secondary metabolite accumulation. This study aimed to enhance shoot biomass production and the accumulation of bioactive compounds in L. flos-cuculi through the application of different cultivation systems, plant growth regulators, and LED light elicitation. Shoot cultures were cultured on Murashige and Skoog medium with various supplementation regimens, including meta-topolin (TOP), indole-3-acetic acid (IAA), gibberellic acid (GA 3 ). Cultivation was performed using agitated shoots in liquid media, agitated shoots on support bridges in liquid media, and temporary-immersion bioreactors (RITA ® ). LED light elicitation was tested using different wavelengths, along with dark and natural light exposure. Biomass growth parameters were assessed, and secondary metabolite content, including phenolic acids and flavonoids, was quantified using HPLC-DAD. The highest biomass growth rate and shoot multiplication were observed in agitated liquid cultures supplemented with TOP, IAA, and GA₃. RITA bioreactors demonstrated enhanced shoot proliferation compared to other systems. Light elicitation significantly influenced secondary metabolite accumulation, with white LED light yielding the highest phenolic acid content and mixed red-blue LED light stimulating flavonoid biosynthesis. The use of RITA bioreactors and LED light elicitation provides promising strategies for enhancing the accumulation of phenolic acids and flavonoids.