Enhancement of in-vitro antioxidant properties and growth of amaranth seed sprouts treated with seaweed extracts

Abstract

Amaranth sprouts contain phytochemicals with antioxidant activity that can neutralize free radicals that damage cellular macromolecules and change the stability of cells. In some seeds, phytochemicals content can be enhanced when these are imbibed with an aqueous seaweed extract (ASE). This study evaluated the effect of different concentrations (0.5, 1.0, and 2.5 mg mL⁻¹) of Padina durvillei (TP) and Ulva lactuca (TU) extracts, with distilled water as a control treatment, on the growth of amaranth sprouts and content of total polyphenols (TPC), flavonoids (TFC), chlorophylls a and b (TCCa and TCCb), carotenoids (TCC), betacyanins (TBC) and, the antioxidant in-vitro activity of sprouts. There was a positive effect on hypocotyl and root growth of sprouts when treated with 2.5 mg mL⁻¹ and 0.5 mg mL⁻¹ TP and TU extracts, respectively. The highest antioxidant activity ocurred in sprouts grown in 0.5 mg mL⁻¹ TP. Sprouts treated with 0.5 mg mL⁻¹ ASE had a higher content of bioactive compounds compared to those treated with water, with the TP extract associated with the highest content of TPC (9.52 mg QE g⁻¹) and TFC (0.567 mg GAE g⁻¹), TCCa, and TCCb (0.09 and 0.12 mg g⁻¹, respectively), sprouts grown in 0.5 mg mL⁻¹ TU accumulated a higher TCC content (0.04 mg g⁻¹ dry sprout). Treatment with at 2.5 mg mL⁻¹ TP and TU extracts produced sprouts that accumulated a higher TBC content in the cotyledons. These results demonstrated the biostimulant effect of ASEs when applied to amaranth seeds, and can be a suitable option for sustainable agriculture.