Changes of nutraceutical traits in baby leaves of sprouting broccoli (Brassica oleracea L. var. italica Plenck) induced by Moringa spp. extracts

Extracts of Moringa spp. are recognized for their healthy properties. The biostimulation of three Moringa extracts, Moringa hildebrandtii (M1), Moringa stenopetala (M2), and Moringa oleifera (M3) on baby leaves of a ‘Broccolo nero’ (Brassica oleracea L. var. italica) (BR) was studied. The trial compared plants treated with different Moringa extracts to a control group. Samples of Moringa and ‘Broccolo nero’ highlighted significant changes in treated plants. Significant increases in fresh weight were observed in BR treated with M3 (BR_M3) compared to the control (p < 0.001), while root angle was reduced in all treatments (p < 0.0001). BR_M1 enhanced the total phenolic content (459.29 ± 6.45 mg GAE/100 g DW) compared to control (358.00 ± 2.56 mg GAE/100 g DW). BR_M3 exhibited the highest antioxidant activity (126.35 ± 1.80 mg TE/100 g DW) showing an 11.9% increase compared to the control. The treatments with Moringa water extracts significantly decreased the content in indolic glucosinolates (i.e., neoglucobrassicin) and enhanced the aliphatic ones (i.e., glucoraphanin and glucoerucin), as along with their derived isothiocyanates. Notably, nitrile and isothiocyanate volatile derivatives varied among treatments, with BR_M2 showing a significant higher amount of phenyl propionitrile (404.48 ± 25.31 nmol/g DW) than the control (an increase of 57.6%). This increase was accompanied by a treatment-related decrease in the two main sulphides (dimethyl disulfide and dimethyl trisulfide). These findings indicate that treatments with leaf water extracts from different Moringa species induce significant changes in the phytochemical composition of baby leaves of Brassica oleracea var. italica.