Effect of differential exposure of UV-C and melatonin stress on the therapeutic potential of bioactive compounds in Moringa oleifera.

• Moringa oleifera , known as a miracle tree, possesses a rich repository of bioactive metabolites and nutraceuticals. • In vitro derived callus cultures of M. oleifera were subjected to different UV-C exposure durations and various melatonin concentrations to assess their combined impacts on biomass, secondary metabolite synthesis, and antioxidant ability. • Melatonin significantly raised biomass accumulation. • Optimum phenolic and flavonoid contents were produced by UV-C treatment. • HPLC analysis showed maximum accumulation of major phytochemicals in melatonin. Moringa oleifera, widely recognized as a miracle tree, boasts a rich repository of bioactive metabolites and nutraceuticals. This study explores a biotechnological approach utilizing UV-C and melatonin elicitation for enhancing pharmaceutically significant secondary metabolites in M. oleifera callus cultures. callus cultures were exposed to different UV-C exposure durations and various melatonin concentrations to assess their combined impacts on biomass, secondary metabolite synthesis, and antioxidant ability. Biomass yields for fresh weight (F.W) were measured for 10 μM melatonin (176. 18 g/L) and UV-C 60 min (172.17 g/L). Total phenolic production (TPP: 25.83 mg/L D.W) and total flavonoids production (TFP: 157.07 mg/L D.W) peaked at 15 μM melatonin. High-performance liquid chromatography facilitated metabolite quantification. Significant increases in total phytochemical production were observed, reaching 12.98 mg g-1 D.W with 15 μM melatonin—an approximately 2.5-fold rise. UV-C exposure for 60 min yielded a two-fold increase (10.847 mg g-1 D.W) compared to the control (5.155 mg g-1 D.W). Metabolic profiling identified four phytochemicals (p-coumaric acid, chlorogenic acid, rutin, and apigenin) through HPLC. Melatonin at 15 μM demonstrated superior DPPH free radical scavenging activity (93.32 %) compared to the control (82.05 %). Additionally, FRAP (382.52 TAEC μM) and ABTS (535.8 TAEC μM) exhibited maximum values under 15 μM melatonin concentration. This study provides a comprehensive approach for enhanced phytochemical production, offering insights into the comparative impacts of UV-C and melatonin elicitation on secondary metabolite pathways in M. oleifera callus cultures. [ABSTRACT FROM AUTHOR]