Bioactive Compounds and Biological Activities of Kohlrabi (Brassica oleracea Convar. Acephala var. Gongylodes L.)

Kohlrabi can be easily distinguished from other brassica vegetables by its attractive and eye-catching shape. Nowadays, the plant is cultivated worldwide, and its green, white or purple, and red cultivars are popular vegetables in Europe, Asia, and North America. The young and even old swollen kohlrabi bulbs are the most often eaten part of the plant. Apart from the bulbs, young kohlrabi leaves and sprouts are also edible parts. Kohlrabi bulbs are an excellent example of low-calorie vegetables, which, when implemented into the daily diet, can be an important source of vitamin C and potassium. These bulbs contain phenolic compounds represented by flavonoids, phenolic acids, and anthocyanins, but also carotenoids and indolyl and aliphatic glucosinolates. Some studies described interesting anti-inflammatory, antioxidant, cytotoxic, antiproliferative, and antidiabetic potentials of kohlrabi bulbs. The new reliable evaluation of the possible biological potential of different kohlrabi cultivars is highly needed because a lack of criticism in a few of the published studies was recognized. Additionally, the investigation of regularly eaten kohlrabi on thyroid function is also necessary.