Bioactive Phytochemicals and Antioxidant Capacity of Wheatgrass Treated with Salicylic Acid under Organic Soil Cultivation

This study was undertaken to determine the influence of salicylic acid (SA) on the bioactive phytochemicals and antioxidant capacity of wheatgrass extract in the organic growing medium. Wheatgrass was cultivated in SA-enriched organic growing medium, obtained from acetylsalicylic acid (aspirin) of various concentrations (0 [control], 0.25, 0.50, 1.00, and 2.00 mM) in a plant growth chamber by controlling atmosphere (20/15 °C, day/night), light (14/10 h, light/dark; light intensity 150 μmol m⁻² s⁻¹, using quantum dot light-emitting diodes), and atmospheric moisture (60 %) for 10 d. The 0.25 mM SA-treatment showed the highest impact on germination rate, wheatgrass length, weight, yield, and chlorophyll content. Levels of bioactive phytochemicals, mainly phenolic compounds, flavonoids, β-carotene, and vitamin C, were the highest in the 1.00 mM SA-treated wheatgrass extract. The DPPH radical and nitrite-scavenging capacities were the highest in the 1.00 mM SA-treated wheatgrass extract. The 0.50 mM SA-treated wheatgrass extract showed the highest superoxide dismutase-like capacity, whereas the 2.00 mM SA-treated wheatgrass extract showed the highest anthocyanin content and ABTS radical-scavenging capacity. Therefore, it might be suggested that the appropriate levels of SA-treatment were between 0.5 and 1.0 mM to enhance the bioactive phytochemicals and antioxidant capacity of wheatgrass.