Mentha spp. are indispensable in the food, cosmetic and pharmaceutical sectors due to their aromatic and bioactive properties. The spectral energy distribution of light in mint cultivation is crucial for the composition of secondary metabolites, however, its potential remains underexploited. Spectral adaption through light-emitting diode technology allows to biochemically modify the composition of secondary metabolites. To evaluate the effect of spectral tuning on the biosynthesis of non-volatile metabolites, five Mentha genotypes of different varieties were cultivated under light spectra dominated by either red (600–700 nm) or blue (400–500 nm) wavelengths. Polyphenols, chlorophylls and carotenoids were analyzed by LC-MS. In a cultivar-specific manner, light spectra influence the metabolic flux of polyphenol biosynthesis, directing it toward flavonoid production in ‘Fränkische Blaue’ or phenolic acid production in ‘Multimentha’. Growing Mentha in a blue-dominated light spectrum increases carotenoid contents, while the cultivation in a red-dominated spectrum leads to higher concentrations of polyphenols. • Red light significantly increases contents in flavonoids in ‘Fränkische Blaue’ • RAS is activated by wavelengths of 600–660 nm in ‘Multimentha’ • Chlorophyll contents of menthone-chemotypes were increased by blue-dominant light • Carotenoid content of carvone-chemotypes were increased under red-dominant light
Tsiaparas et al. (Sun,) studied this question.