Light Quality as a Non-Chemical Elicitor of Polyphenol Accumulation in Rosemary (Salvia rosmarinus Spenn.) Cell Suspension Cultures

Salvia rosmarinus Spenn. is a valuable source of phenolic compounds, but their production is affected by environmental and seasonal variability. Addressing these limitations, plant cell suspension cultures provide a controlled platform for secondary metabolite production, with elicitation offering a strategy to enhance metabolite accumulation and biosynthetic efficiency. In this context, our study investigated the effects of LED light as a physical elicitor on the growth and phenolic profile of rosemary cell suspension cultures. Suspension cells were exposed to five different light conditions: darkness, white light (WL), a mixture of blue, red, and far-red light (B+R+FR), blue light (B) and red combined with far-red light (R+FR) over 2 weeks. Growth parameters, phenolic profile, and antioxidant activity were evaluated. We found that, while B produced the highest packed cell volume, the R+FR combination significantly enhanced biomass accumulation. Regarding phenolic content, the B+R+FR treatment led to the highest production of salvianic and rosmarinic acids. This combination of wavelengths showed a strong correlation with improved antioxidant capacity. These findings suggest that tailored LED spectra, particularly the B+R+FR combination, have good potential to improve the phytochemical quality of rosemary in vitro, supporting the development of a sustainable platform for the production of high-value bioactive compounds.