Influence of LED Light Spectra on Morphogenesis, Secondary Metabolite Production and Antioxidant Potential in Eucomis autumnalis Cultured In Vitro

Eucomis autumnalis is a bulbous ornamental species with ethnobotanical relevance. In vitro cultures offer a sustainable tool for biomass propagation and metabolite production. This study investigates the effects of nine LED light spectra: red (R), blue (B), red–blue (RB), RB with green (RBG), yellow (RBY), far-red (RBfR), ultraviolet (RBUV), white (WLED), and fluorescent light (Fl, control), on the morphogenesis, polyphenol production, and antioxidant potential of E. autumnalis shoot cultures. Cultures were maintained on MS medium with 5 µM BA and 0.5 µM NAA. HPLC-DAD analysis identified 11 phenolic acids and 4 flavonoids, including eucomic acid, characteristic of the genus. Light quality impacted compound-specific accumulation and antioxidant activity, with responses varying among compounds and treatments. R and B light increased catechin, gentisic acid and hesperidin (289, 195, 245 mg/100 g DW), while UV suppressed flavonoids by ca. 2-fold for catechin and flavanones compared to other lights. RBG and RBfR induced the highest eucomic acid accumulation (424 mg/100 g DW), ferulic acid and epicatechin, correlating strongly with ABTS•+ activity (18–19% higher than other lights; r > 0.6–0.8). These findings highlight LED spectral modulation as a tool to enhance the phytochemical quality of E. autumnalis in vitro and provide a foundation for future biotechnological applications.