Brassicaceae are rich in flavonoids, glucosinolates and vitamins, and are therefore one of the most commonly consumed vegetables. The aim of this study was to compare the proportions of phenolic compounds of kohlrabi (Brassica oleracea var. acephala gongylodes), kale (B. oleracea sabauda), Brussels sprouts (B. oleracea gemmifera), cauliflower (B. oleracea botrytis), radish (Raphanus sativus) and cress (Lepidium sativum), and their antioxidant and hypoglycemic potential after in vitro simulated human digestion in order to single out a variety of seedlings of higher potential for each of the parameters. The richest in total flavonoids were cauliflower seedlings, and in hydroxycinnamic acids seedlings of kale and radish. After intestinal digestion the largest proportion of total phenolics had kale, and total flavonoids cauliflower seedlings. The richest in vitamin C before digestion were cress seedlings, and after gastric digestion radish seedlings. Brussels sprouts were the richest in ferulic acid, and kale seedlings were the richest in synapic acid before and after digestion. Cauliflower and cress seedlings had the highest concentration of quercetin before digestion, and cauliflower only after intestinal digestion. Radish seedlings had the highest concentration of kaempferol both before and after digestion. All pre-digestion seedlings` extracts showed antioxidant potential similar to or even higher than trolox standard. Extracts of all seedlings before digestion showed the same or higher degree of α-amylase inhibition than the standard antidiabetic drug acarbose. After intestinal digestion, the highest degree of inhibition of α- amylase activity was shown by kohlrabi. Before digestion, the highest degree of α-glucosidase inhibition was shown by radish seedlings, and after intestinal digestion by kohlrabi seedlings. Pre-digestion radish, kale, Brussels sprouts and kohlrabi seedlings` extracts inhibited α- glucosidase activity more strongly than acarbose. Therefore, Brassicaceae seedlings represent a biomaterial of great potential for human nutrition and health, and further analysis of their biopotential is very necessary and desirable.