Effects of exogenous salicylic acid on metabolic and biochemical properties of Spirulina platensis

• Spirulina platensis is considered as a valuable source for bioactive compounds and minerals. • Different concentrations of salicylic acid alter the amount of superoxide anion, and antioxidant enzymes activities in S. platensis in a time-dependent manner. • Salicylic acid treatments caused alterations in the profiles of phytopigments such as chlorophyl a/b, carotenoids, phycocyanin, phycoerythrin, and allophycocyanin. • Salicylic acid induced phytohormones production and minerals accumulation in S. platensis in a time-dependent manner. Spirulina platensis is an alternative source of several invaluable compounds, particularly phytopigments, and minerals. The present work investigated how different concentrations of salicylic acid (SA) affect metabolic and physiological changes in the culture of S. platensis . Thus, S. platensis was cultured in a Zarrouk media exposed to SA concentrations (0, 100, 250, and 500 µM) at various time points. There was a significant increase in biomass yield in S. platensis exposed to SA. The formation of superoxide anion, and the actions of peroxidase, and catalase were induced in S. platensis exposed to SA. The levels of SA significantly stimulated total chlorophyll, chlorophyll a, chlorophyll b, carotenoids, and astaxanthin during a time-course study. A significant induction in total protein, proline, and ascorbate composition occurred in S. platensis exposed to SA elicitation. SA had a positive impact on total phenolics, flavonoids, and DPPH antioxidant capacity during a time-course study. There was an induction in the content of phycocyanin (1.94-fold) and phycoerythrin (1.85-fold) in cultures treated with 250 µM SA after seven days, while the content of allophycocyanin was significantly induced at 250 and 500 µM SA after seven days. The profile of important phytohormones such as SA, zeatin, kinetin, and melatonin was increased by SA treatment. Based on ICP analysis, the composition of minerals like K, P, S, Ca, Mn, Fe, Mg, and Cu were induced under SA treatment. In conclusion, SA affects oxidative status and phytohormones reprogramming toward accumulating valuable bioactive compounds and minerals in S. platensis .