Comparative role of oxidative balance, alkaloid production, and metabolites in exposure to red-to-blue light in Catharanthus roseus

Light quality is a critical regulator of plant morphology and physiological metabolism, with spectral optimization emerging as a key strategy for enhancing bioactive compound production in medicinal plants. Catharanthus roseus , valued for its alkaloid content, exhibits significant metabolic plasticity in response to light conditions. This study examined the effects of two red-to-blue light ratios [2:1 (R2B1) and 7:1 (R7B1)] on morphophysiological responses, metabolite profiles, and alkaloid accumulation in C. roseus , using white light as a control. Both R2B1 and R7B1 altered plant morphology and enhanced alkaloid synthesis. R2B1 notably increased antioxidant enzyme activity, while R7B1 boosted non-enzymatic antioxidants and phenolic compounds. The Integrative Biomarker Response version 2 analysis identified R7B1 as the optimal treatment for promoting the accumulation of bioactive compounds. Untargeted metabolomics revealed that R7B1 enhanced sugar levels and induced tissue-specific changes in organic acid metabolism. Correlation analysis suggested that red-to-blue light promotes alkaloid biosynthesis by modulating antioxidant systems and key metabolic pathways. These findings highlight the potential of red-to-blue light optimization to enhance alkaloid production in C. roseus , providing valuable insights into the regulation of secondary metabolism and practical strategies for improving bioactive compound yields in medicinal plants.