Abstract More than 100 species of the Lactuca genus (Compositae family) are distributed across the northern hemisphere and also in temperate and warm regions of the world, namely 17 species in Europe, 51 in Asia, 43 in Africa, 12 in North and South America. In the Mongolian flora, four species of Lactuca, Lactuca unduiata Ledeb. Lactuca tatarica C.A.M, Lactuca serriola L. and Lactuca sibirica L Benth ex Maxim., are found. Their chemical constituents and biological activities have not been thoroughly studied. Plants of Lactuca species are widely used in traditional medicine, to treat acute respiratory infection and they have antipyretic and analgesic activities.
Since the 1980's, chemical constituents of Lactuca species started to be studied. Currently, about 148 secondary metabolites from more than 20 species were isolated and their structures elucidated, including sesquiterpene lactones-65 (43.91%), flavonoids-20 (13.51%), phenolic compounds-26 (17.56%), coumarins-2 (1.35%), triterpenes and steroids-20 (13.51%), lignans-5(3.39%), and other class of compounds-10 (6.75%). Among the isolated secondary metabolites, 9 were registered as new natural compounds. Extracts and isolated pure compounds from Lactuca species showed hepaprotective, antidiabetic, anticancer and antioxidant activities.