Salvia lavandulifolia Vahl., a species native to the Western Mediterranean, is valued for its bioactive compounds and beneficial biological properties. Commonly propagated in greenhouses, it may benefit from exposure to tailored light-emitting diode (LED) light to enhance antioxidant defense and metabolite production. This study examined the effects of various spectra on two S. lavandulifolia ecotypes from southeastern Spain. Plants were propagated in vitro and grown for 30 days under white, red, blue, red/blue (70:30), white/blue, or white/red LED light, under a 16/8 h light/dark photoperiod (light intensity of 115 µmol m⁻² s⁻¹). Photosynthetic pigments, enzymatic antioxidants (superoxide dismutase and catalase), non-enzymatic antioxidants (tocopherols and polyphenols), antioxidant capacity (FRAP and DPPH^•), and lipid peroxidation (MDA) were assessed. In ecotype 1, red LED light significantly increased the content of photosynthetic pigments and non-enzymatic antioxidants while reducing enzymatic antioxidant activity. In contrast, ecotype 2 showed higher catalase and non-enzymatic antioxidant activity under white/blue light, without changes in pigment content. In both ecotypes, these treatments increased α-tocopherol and hydroxycinnamic acid derivative content, strengthening antioxidant defenses without inducing oxidative damage. Overall, the results highlight the need to customize LED light spectra for each ecotype, as genetic background may significantly influence plant responses.

This study investigated how different spectral ranges of LED light affect the synthesis of photosynthetic pigments and antioxidant systems in Thymus mastichina L., focusing on two ecotypes with distinct chemotypes: linalool and eucalyptol. The ecotypes were exposed to white, red, blue, red-blue (70:30), white-blue, or white-red light for 30 days under a 16/8 h light/dark cycle (115 μmol/m²s). Photosynthetic pigment content, lipid oxidative damage, antioxidant capacities, and both enzymatic (SOD, CAT) and non-enzymatic (tocopherols and polyphenols) antioxidant systems were assessed. For the linalool chemotype, red-blue light significantly increased carotenoid content, antioxidant capacity, and catalase activity, while elevating levels of plastochromanol-8 and phenolic compounds such as salvianolic acid B, rosmarinic acid, and 6-OH-apigenin-7-hexoside, thereby reducing oxidative stress. In contrast, for the eucalyptol chemotype, pure red light produced the most significant enhancements in carotenoid synthesis and antioxidant defenses, substantial increases in key compounds such as salvianic, neochlorogenic, rosmarinic, and lithospermic acids, and salvianolic acids E and B, and higher levels of plastochromanol-8. Additionally, both SOD and CAT activities increased, providing greater protection against lipid oxidation. These findings highlight the importance of customizing light treatments not only based on plant species but also according to chemotype to obtain optimal biochemical and physiological outcomes.

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.