The review summarizes the scientific literature on the degree of knowledge of the chemical composition and biological activity of metabolites and plant extracts of the genus Equisetum L. of the world flora. Many types of horsetail are widely used in folk medicine as a diuretic, hemostatic, as well as for pulmonary tuberculosis and skin diseases, ulcers, dropsy, jaundice, as a heart remedy, for diseases of the kidneys, bladder, etc. Based on extracts of the horsetail canes (Equisetum arvense L.) a number of drugs and biologically active additives with a wide spectrum of pharmacological action have been created. The review presents data on the structural diversity and biological activity of metabolites of plants of the genus Equisetum L. Information is provided on the composition of the metabolites of 16 species of the genus Equisetum L., the structure and sources of more than 200 natural substances related to terpenoids, phytosterols, brassinosteroids, vitamins, alkaloids and other nitrogen-containing compounds , lignans, styryl pyrones, indanones, phenylpropanoids, organic acids, hydrocarbons, aldehydes and phenolic compounds. The main biologically active substances of plants of the genus Equisetum are flavonoids and other plant phenolic compounds. Extracts and individual compounds possess antioxidant, diuretic, antibacterial, antifungal, hepatoprotective, hypoglycemic, antimutagenic, sedative, anxiolytic, anti-tumor, anti-inflammatory properties. An analysis of literature data shows that plants of the genus Equisetum are promising for the creation of new effective drugs. The information presented in the review can be used as reference literature by phytochemists, biologists, and pharmacologists, as well as to solve the problems of chemosystematics of plants of the genus Equisetum L.
