Comparative assessment of iodine biofortification in two kale cultivars (Brassica oleracea L. var. sabellica): Effects on glucosinolates, water-soluble vitamins, antioxidants, and preliminary in vitro cytotoxicity screening.

This study investigated the effects of iodine form, kale cultivar, and their interaction on iodine accumulation, glucosinolate composition, water-soluble vitamins, antioxidant compounds, antioxidant capacity, and preliminary in vitro cytotoxicity of kale extracts. Two hydroponically grown kale cultivars ('Oldenbor F1' and 'Redbor F1') were biofortified with 10 μM potassium iodate (KIO3), 8-hydroxy-7-iodo-5-quinolinesulfonic acid (8-OH-7-I-5QSA), or 5-chloro-7-iodo-8-quinolinol (5-Cl-7-I-8-Q). Thirteen glucosinolates were identified, and their profiles differed according to cultivar and treatment. Biofortification with 8-OH-7-I-5QSA produced the greatest increase in total glucosinolates content, whereas 5-Cl-7-I-8-Q reduced it in 'Redbor F1'. Iodine biofortification increased vitamins B1, B3, B5, and B6, l-ascorbic acid, total polyphenols, and antioxidant capacity. Preliminary in vitro cytotoxicity screening demonstrated dose-dependent cellular responses. Overall, iodine biofortification modified kale composition in an iodine form- and cultivar-dependent manner.