Acylated anthocyanins in broccoli sprouts

Broccoli is a nutritious vegetable and a good source of vitamins and minerals. It also contains important antioxidant phytochemicals like β-carotene and α-tocopherol, indoles and isothiocyanates. On the other hand, edible sprouts are novel nutritive plant-derived foods, good source of flavonoids and other polyphenols (Moreno, Pérez-Balibrea, et al., 2006).Anthocyanins have also been previously isolated from the Cruciferae (Brassicaceae) presenting unusually complex structures with one or more cinnamic acids but, as far as we are aware, never reported for broccoli sprouts. For this purpose, we studied the sprouts of commercial broccoli destined for head productions (‘Marathon’ and ‘Nubia’), a variety produced for edible sprouts (‘Intersemillas’ sprouts) and a purple broccoli sprouts (‘Viola’).Using HPLC–UV photo-diode array detection (PAD)–electrospray ionisation (ESI)-MS/MS (HPLC–PAD–ESI-MS/MS), acylated anthocyanins were characterised. The main peaks were cyanidin-3-O-diglucoside-5-O-glucoside acylated and double acylated with p-coumaric, sinapic, caffeic, ferulic or sinapic acids, with at least three predominant anthocyanins isomers of cyanidin 3-O-(acyl)diglucoside-5-O-glucoside, cyanidin 3-O-(acyl1)(acyl2)diglucoside-5-O-glucoside, and cyanidin 3-O-(acyl1)(acyl2)diglucoside-5-O-(malonyl)glucoside, within the 17 different anthocyanins characterised in broccoli sprouts for the first time. The qualitative and quantitative differences in the anthocyanin composition between the ‘green head’ broccoli cultivars (Marathon, Nubia), the green variety-for-sprouts (Intersemillas), and the richest variety in anthocyanins, the early purple sprouting broccoli sprouts (‘Viola’), showed the dependence on cultivar to drive the phytochemical load of vegetable foods.The broccoli sprouts could be potential naturally-healthy functional foods at the seedling stage for delivering significant levels of bioactive compounds besides other flavonoids, glucosinolate-derived isothiocyanates, together with vitamins and minerals.