Optimized production of bioactive secondary metabolites in Balanites aegyptiaca callus cultures: The synergistic effects of precursors and elicitors

Secondary metabolites derived from plants, including Balanites aegyptiaca (L.) Delile, exhibit substantial potential for applications across the pharmaceutical, agricultural, and industrial sectors. These bioactive compounds serve as critical precursors for drug development, biopesticides, and other high-value bioproducts. This study investigated the optimization of callus biomass and secondary metabolite production in B. aegyptiaca through the strategic manipulation of precursors and elicitors. Calli were treated with varying concentrations of L-phenylalanine, L-tryptophan, and glutamine (5-40 mg L-1) as precursors, alongside chitosan (5-40 mg L-1), yeast extract (0.25-4.0 g L-1), and salicylic acid (5-40 mg L-1) as elicitors, in the presence of 2.0 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D). Our findings indicate a positive correlation between increasing precursor concentrations and enhanced fresh callus weight, as well as the accumulation of total polyphenols, flavonoids, and saponins. Notably, glutamine at 40 mg L-1 was identified as the most effective precursor for maximizing both biomass and biosynthetic yield. Among the elicitors, salicylic acid consistently enhanced antioxidant activity and the total content of total flavonoids and phenolics. Furthermore, the highest concentrations of yeast extract and salicylic acid significantly promoted saponin biosynthesis. These results demonstrate that the integrated application of optimized precursors and elicitors can substantially augment secondary metabolite yields in B. aegyptiaca callus cultures, providing a viable framework for future industrial-scale bioproduction.