The genus Lepidium L. (Brassicaceae), A comprehensive review of botany, traditional uses, pharmacology, phytochemistry and the possible toxicities

Lepidium L. an important weedy plant of Brassicaceae family, comprises approximately 265species which are endemic to all continents. Since ancient time, the therapeutic potential of Lepidium species were fully recognized and traditionally used in different parts of the world such as Asian, African and American countries. This review aimed to provide comprehensive information about the botanical characteristics, traditional uses, pharmacology, phytochemistry and toxicology of Lepidium, to discover therapeutic potentials of different Lepidium species for further research. The information available on Lepidium species were collected from scientific databases such as Science Direct, Google Scholar, Scopus, Web of Science, PubMed and some traditional texts. There are several promising bioactivities for this genus that some of them have long been recognized in traditional medicine such as coagulant, biofumigant, hepato-renal protective activities and fertility enhancement. To date, several types of phytochemicals isolated and identified from Lepidium species including glucosinolate, alkaloid, alkamide, macamide, mucilage, phytosterol, flavonoid and essential oil. A significant number of glucosinolates and their hydrolysis products (isothiocyanates), have been isolated from Lepidium species with potential pharmacological activities including anti-carcinogenic and chemoprotective activities with different mechanism of actions. Some studies on the safety assessment of L. sativum L., a common used Lepidium species, indicated some degree of toxicities in animal fetus which supposed to be related to its hydrolysis product constituents, named benzyl isothiocyanates (BITC). Moreover, exposure to goitrin, a glucosinolate degradation product from certain Lepidium species, may exert some adverse effects on thyroid glands, through the competitive inhibition of iodine uptake. It should be notice that despite the beneficial effects of Brassicaceae plants for reducing risk of different types of disease especially cancer, limit of the consumption of some Lepidium species as a routine meal should be considered.