Therapeutic prospects and biochemical matrix of Lactuca serriola L.: from physiological adaptation to sustainable pharmaceutical applications

Abstract

This comprehensive reference study reviews the taxonomic, morphological, phytochemical, and pharmacological activities of wild spiny lettuce (Lactuca serriola L.), a member of the Asteraceae family, which is the closest wild ancestor of commercially cultivated lettuce (Lactuca sativa). This herbaceous plant exhibits exceptional adaptability and global dispersal, growing in wastelands, high mountain regions, and environments affected by human activity. It possesses a unique physiological behavior known as "compass plant," where its leaves orient themselves vertically to avoid light and heat stress during the afternoon. Chemical analyses reveal a rich and unique matrix of secondary metabolites. Its organic content includes alkaloids, phenolic acids, flavonoids (such as quercetin, luteolin, and kaempferol), bitter sesquiterpenes, and a wide range of essential fatty acids, such as alpha-linolenic acid. The compound extracted from its milky sap (Lactucarium)—containing lactucin and lactocopicrin—is the cornerstone of the plant's therapeutic properties.

In vitro pharmacological studies have validated the plant's traditional uses. Its extracts have demonstrated dual activity on the smooth muscles of the digestive and respiratory systems, acting as an intestinal stimulant at low doses and as a bronchodilator and antispasmodic at high doses through calcium channel blockade and muscarinic receptor inhibition. Research has also documented the plant's potent antioxidant, antihypertensive, and analgesic activity (via lactocopicrin), as well as its promising cytotoxic properties against tumors and cancers, particularly in harsh, arid environments that stimulate the plant to secrete highly effective defensive compounds. This review concludes that the plant is a valuable genetic and chemical reservoir for the production and development of sustainable pharmaceuticals and cosmetics