Lithium biofortification of Brassicaceae baby leaves by soilless cultivation: nutritional value and implications on the Drosophila melanogaster

ABSTRACT: We accessed the impact of root application of Li carbonate (Li2CO3) on the productivity, nutritional, and bioactive properties of species of the Brassicaceae family. In addition, the species and Li concentrations that exhibited the highest content of bioactive compounds and agronomic characteristics were investigated regarding their impact climbing ability of the Drosophila melanogaster. The species of the Brassicaceae family (mustard (Brassica juncea), purple cabbage (Brassica oleracea var. capitata f. rubra), arugula (Eruca vesicaria ssp. sativa), and kale (Brassica oleracea L. var. acephala D.C.)) were cultivated in a nutrient solution enriched with Li2CO3 (0, 15, 30, 60, and 120 mg.L-1) for 15 days. Purple cabbage has the highest lithium absorption capacity (860.55 ppm), followed by arugula (722.43 ppm), kale (688.77 ppm), and mustard (485.48 ppm). Lithium accumulation demonstrated a dose-dependent effect, with Li2CO3 at 60 mg.L-1 showing the most significant growth effect on arugula compared to other tested doses. Arugula was the most promising species in the study, and at a concentration of 60 mg.L-1, it had the highest phenolic content (584.9 ± 8.08 µmol/g) and antioxidant activity (DPPH:11,063 ± 170.2 µmol/g; ABTS: 24,481 ± 1,950 µmol/g). It was also the second species with the best agronomic performance, after mustard. The arugula extracts were found to positively impact the survival rate and climbing ability of the Drosophila melanogaster. The results demonstrated that it is feasible to enhance the antioxidant activity of brassicas by supplementing them with lithium. Furthermore, extracts of brassicas exhibited favorable outcomes in tests with D. melanogaster, which might contribute to enhanced neuromuscular effects.