Horseradish (Armoracia rusticana), a neglected medical and condiment species with a relevant glucosinolate profile: a review

Armoracia rusticana (horseradish), a member of the Brassicaceae family, has been known since ancient times as a folk medicinal herb and as a plant of nutritional value and culinary interest. Currently horseradish is cultivated for its thick, fleshy and white roots which have a delicious intense pungency and for its tender leaves which are frequently used for salad mixed to other vegetables. The traditions to use horseradish plant for medicinal purpose are still applied in many countries. Horseradish is a rich source of a number of bioactive compounds such as glucosinolates (GLSs) and their breakdown products. Sinigrin is the dominant glucosinolate in both leaves and roots. Recent studies have shown that crude plant extracts have a complex profile of naturally occurring GLSs, with particular regard to sprouts. The increasing interest in these secondary metabolites, associated to the long and diffuse tradition of using horseradish in food preservation and as condiment in many parts of the world, is generating new applications of this plant in several agro-industrial and pharmaceutical sectors and is encouraging the use of its roots and leaves in functional food and medicine for human health. A bibliography review is discussed on ethnobotanical aspects and uses of this plant, as well as knowledge about its flavour compounds and GLS content and composition. This study summarizes also the updated information concerning the influence of the genotype and environment on GLS profile in horseradish.