Tomatine (sometimes called tomatin or lycopersicin) is a glycoalkaloid, found in the stems and leaves of tomato plants, and in the fruits at much lower concentrations. Chemically pure tomatine is a white crystalline solid at standard temperature and pressure. Tomatine is sometimes confused with the glycoalkaloid solanine, which is found in potatoes. History Tomatoes were brought to Europe in the early 1500s. The English botanist John Gerard was one of the first cultivators of the tomato plant. In his publication Grete Herball, he considered tomatoes poisonous due to their levels of what would later be called tomatine, plus high acid content. Consequently, tomatoes were generally not eaten in Britain until the mid-18th century. In 1837, the first medicinal tomato pills were advertised in the United States because of their positive effects upon the biliary organs. The product “Phelp’s Compound Tomato Pills” was extracted from the tomato plant, and contained tomatine. The pills were made by the medic Guy R. Phelps, who stated that the alkaloid tomatine was one of the most useful discoveries ever made. Tomatine then was said to be an antidote to mercury. In the mid 20th century, scientists from the US Department of Agriculture were the first to isolate tomatine from the wild tomato species Lycopersicon pimpinelifolium and the cultured species Lycopersicon esculentum. Structure and biosynthesis () belongs to the compound group steroidal glycoalkaloids. These compounds consist of an aglycon, which is a cholesterol derivative, and a carbohydrate chain, which in the case of α-tomatine consists of two d-glucose units, a d-galactose unit, and a d-xylose unit. In α-tomatine, the tetrasaccharide called lycotetraose is attached to the O-3 of the steroidal aglycone. At first it was thought that the synthesis of steroidal alkaloids only involved multiple steps of hydroxylation, oxidation and amination of cholesterol with arginine as the source of the incorporated nitrogen. Later the glycoalkaloid metabolism genes were discovered. These genes produce the glycoalkaloid metabolism enzymes, which are responsible for the synthesis of steroidal alkaloid aglycones in potato and tomato plants. The reaction these enzymes perform are shown in the figure 1. Mechanism of action Tomatine may play a major role in resistance of the tomato plant against fungal, microbial, insect, and herbivoral attack. The effects of the glycoalkaloids (to which tomatine belongs), can be divided in two main parts: the disruption of cellular membranes and the inhibition of the enzyme acetylcholinesterase. Tomatine is responsible in