Content of pigments and secondary metabolites in basil leaves (Ocimum basilicum L. and O. × citriodorum) under light culture conditions

Relevance. LED lighting enables targeted control of primary and secondary metabolite biosynthesis, enhancing the nutritional and pharmacological value of plants. Basil is a valuable essential-oil crop rich in bioactive compounds. However, the regulation of LED spectral composition for directed stimulation of growth and biosynthesis of specific components remains underexplored. Materials and Methods. The effects of four LED regimes (Blue:White:Red:Deep Pink, %: 25:70:25:25; 50:80:25:50; 50:60:50:25; 50:70:25:25; photon flux density 126–149 µmol/0.5 m²/s) were studied on basil chemotypes: “citral” (O. × citriodorum Vis. Kapriz), “linalool” (Ocimum basilicum L. Luchano), “methyl cinnamate” (Ocimum basilicum L. № 232/21). Chlorophylls, carotenoids, phenolic compounds (PC), and flavonols were quantified spectrophotometrically. Essential oil was obtained by hydrodistillation and analysed by GC-MS. Data were processed by two-way ANOVA (Tukey test, p < 0.05). Results. In Kapriz, chlorophyll and carotenoid levels were highest where PC (including flavonols) were lowest, and vice versa. In Luchano, photosynthetic pigments peaked in regimes where they declined in Kapriz and № 232/21. Sample № 232/21 showed the least change in PC accumulation; its essential oil consisted of 87 % methyl cinnamate. Kapriz plants were most stress-sensitive, while № 232/21 was the most resilient. Conclusion. The 50:60:50:25 regime boosted photosynthetic pigments, whereas 50:70:25:25 enhanced PC via phenylpropanoid pathway activation under photo-oxidative stress. The proposed LED regimes enable targeted modulation of basil’s biochemical profile – delivering either high antioxidant activity or maximum essential-oil yield.