Exogenous addition of methyl jasmonate and salicylic acid in immobilized cell cultures of Thevetia peruviana: effect on the biomass, phenolic compounds and cardiac glycosides production

Abstract Thevetia peruviana is an ornamental shrub with ethnobotanical uses related to secondary metabolites, including cardiac glycosides (CG), phenolic compounds (PC), and flavonoids (Fv). Known for its cardiac, antioxidant, anticancer, and antimicrobial activities, this study aimed to culture T. peruviana cells immobilized in calcium alginate and evaluate the effects of exogenous methyl jasmonate (MeJA) and salicylic acid (SA) on biomass and metabolite production. Immobilization was performed with 3% (w/v) sodium alginate and 100 mM CaCl₂ in Schenk and Hildebrandt medium. Cultures were maintained for 20 days, reaching a maximum biomass concentration of 7.45 ± 0.49 g DW/L on day 10, compared to 13.92 ± 0.34 g DW/L in free cell cultures. Immobilization reduced biomass concentration but increased the production of secondary metabolites at 10–11 days. This suggests that the alginate matrix acts as an abiotic stress factor, directing carbon consumption and energy flow toward the biosynthesis of PC, Fv, and CG. Additionally, treatment with SA (300 µM) and MeJA (3 µM) during the exponential phase increased metabolite secretion at 48–72 h post-elicitation. SA-treated cultures showed PC, Fv, and CG levels 2.24, 1.66, and 1.37 times higher than controls, respectively, while MeJA increased these levels by 1.24, 1.83, and 1.25 times. Exogenous SA and MeJA stimulate the biosynthesis of secondary metabolites in calcium alginate-immobilized T. peruviana cells; and facilitate the diffusion of metabolites into the extracellular medium. However, further studies are needed to validate this hypothesis. Graphical abstract