Isolation and structure of lettucenin A, a novel guaianolide phytoalexin from Lactuca sativa var. capitata(Compositae)

Abstract

Inoculation of lettuce (Lactua sativa var. capitata) leaves with the pathogenic bacterium Pseudomonas cichorii induced the production of two antifungal sesquiterpenes, costunolide and anew compound named lettucenin A, whose structure has been elucidated on the basis of spectroscopic studies.