lactucin

Lactucin is a natural product classified as a sesquiterpene lactone in the guaianolide family. Structurally, it contains a lactone ring and a guaiane-type sesquiterpene skeleton. It is one of several bitter principles found in plants of the Lactuca genus (lettuce) and in Cichorium intybus (chicory). In these plants, lactucin often co-occurs with related lactones such as lactucopicrin, contributing to the distinctive bitterness of the latex or sap.

Natural occurrence and historical use: In lettuce and related species, lactucin is a major constituent of the milky latex that has been historically processed to produce lactucarium, commonly referred to as lettuce opium. The latex has been used in traditional practice as a mild sedative and analgesic. The concentration of lactucin varies with species, plant part, and growing conditions.

Pharmacology and research status: In laboratory studies, lactucin and related sesquiterpene lactones have shown analgesic, anti-inflammatory, and sedative effects in animal models, though evidence in humans is limited. As a component of plant extracts, its clinical relevance remains uncertain, and products containing lactucin are not approved as medicines in modern pharmacopoeias.