Watercress: A Salad Crop with Chemopreventive Potential

Nasturtium officinale, Rorippa nasturtiumaquaticum, Phen(yl)ethyl isothiocyanate, Cruciferae Classification, origin, and developmentWatercress [Nasturtium officinale (also known as Rorippa nasturtiumaquaticum)] belongs to the family Brassicaceae (Cruciferae).It is a native of southeast Europe (Habegger et al., 1989), probably Germany (Humphrey, 1984) or England (Howard and Lyon, 1952).Watercress is a perennial herbaceous plant reported widely in several parts of Europe, China, New Zealand, and in North America, both as a wild growing species and a cultivated crop.Although described as a medicinal plant since the first century A.D. (Howard, 1976), and valued as a gift fit for royalty (Howard and Lyon 1952), its large-scale cultivation did not start until 1750 in Germany, 1808 in England, and 1811 in France (Manton, 1935).Two species of watercress, green watercress (N.officinale) and brown watercress (N.microphyllum), and a sterile hybrid (N.officinale x N. microphyllum) were introduced in about 1850 to New Zealand from England and both species were reported to be growing in Europe and North America (Michaelis, 1976).The Germans and French only cultivated green watercress while the English grew both green watercress and brown watercress on a large scale during the 19 th century.However, brown watercress soon was replaced in commercial cultivation by green watercress because of ease of propagation by seeds, and lower susceptibility to the fungal crook root disease caused by Spongospora subterranea sp.nasturtii (Howard and Lyon, 1952).Green watercress appears to be the only species currently cultivated and consumed around the world.