Glaucolide B, A Molluscicidal Sesquiterpene Lactone, and Other Constituents of Vernonia eremophila.

The sesquiterpene lactone glaucolide B was isolated from the molluscicidal extract of VERNONIA EREMOPHILA Mart, and shown to be responsible for the molluscicidal activity. Hydrogenolysis of glaucolide B resulted in the disappearance of the activity. Other inactive constituents of the extract were 3,7-dimethoxy-5,3',4'-trihydroxyflavone and two transformation products, possibly artefacts, of glaucolide B. Glaucolide B exhibited strong antimicrobial activity against B, CEREUS and moderate activity against S. AURENS, but was inactive in several other systems.