New sesquiterpene lactones with antibacterial activity from Vernonia fastigiata.

Sesquiterpene lactones 1-5 were isolated for the first time from the ethyl acetate of Vernonia fastigiata (Asteraceae). Compounds 3, 4 and 5 are new, compounds 1 and 2 have been found earlier in other Vernonia species but not in V. fastigiata.