Brassica

Brassica (/ˈbræsɪkə/) is a genus of plants in the mustard family (Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called cole crops—derived from the Latin caulis, denoting the stem or stalk of a plant. The genus Brassica is known for its important agricultural and horticultural crops and includes a number of weeds, both of wild taxa and escapees from cultivation. Brassica species and varieties commonly used for food include broccoli, cauliflower, cabbage, choy sum, rutabaga, turnip and some seeds used in the production of canola oil and the condiment mustard. Over 30 wild species and hybrids are in cultivation, plus numerous cultivars and hybrids of cultivated origin. Most are seasonal plants (annuals or biennials), but some are small shrubs. Brassica plants have been the subject of much scientific interest for their agricultural importance. Six particular species (B. carinata, B. juncea, B. oleracea, B. napus, B. nigra, and B. rapa) evolved by the combining of chromosomes from three earlier species, as described by the Triangle of U theory. Although of no agricultural importance of itself, the brassica Arabidopsis thaliana is of great scientific importance as a model plant species. The genus is native to Western Europe, the Mediterranean and temperate regions of Asia. Many wild species grow as weeds, especially in North America, South America, and Australia. A dislike for cabbage or broccoli can result from the fact that these plants contain a compound similar to phenylthiocarbamide (PTC), which is either bitter or tasteless to people depending on their taste buds. Almost all parts of some species or other have been developed for food, including the root (rutabaga, turnip), stems (kohlrabi), leaves (cabbage, collard greens, kale), flowers (cauliflower, broccoli), buds (Brussels sprouts, cabbage), and seeds (many, including mustard seed, and oil-producing rapeseed). Some forms with white or purple foliage or flowerheads are also sometimes grown for ornament. Brassica species are sometimes used as food plants by the larvae of a number of Lepidoptera species—see List of Lepidoptera that feed on Brassica. Brassica vegetables provide high amounts of vitamin C, vitamin K, manganese, and soluble fiber, and contain glucosinolates which are under preliminary research for their potential biological properties when consumed. Epidemiological studies suggest that brassica vegetables are protective against cancers of the lungs and alimentary tract. Cruciferous vegetables are the dietary source of glucosinolates, a large group of sulfur-containing glucosides. These compounds remain intact unless brought into contact with the enzyme myrosinase by pests, food processing, or chewing. Myrosinase releases glucose and breakdown products, including isothiocyanates. These highly reactive compounds are potent inducers of Phase II enzymes in vitro. Isothiocyanates also inhibit mitosis and stimulate apoptosis in human tumor cells, in vitro and in vivo. Boiling substantially reduces the levels of broccoli glucosinolates, while other cooking methods, such as steaming, microwaving, and stir frying, have no significant effect on glucosinolate levels.