Vernonia amygdalina is a tropical African plant possibly used by wild chimpanzees for
medicinal purposes. 1) We have previously reported new bitter steroid glucosides,
vernonioside A 1-A3'and a related vernonioside B 1 from this plant. 2, 3) As another class of
bitter constituents, four known cytotoxic sesquiterpene lactones were also isolated. 4l The
most possible use of this plant by chimpanzees was suggested to be a medicine against
parasiterelated diseases; this idea is based on both the symptoms of the chimpanzee (loss …

From Vernonia amygdalina, a possible medicinal plant used by wild chimpanzees, three
bitter steroid glucosides, vernoniosides A1, A2, and A3 and a nonbitter vernonioside B1,
were isolated. The oxygenation patterns of the aglycone parts were new, especially the
pattern of the carboxyl group at C21. The oxygen functionalities at C16 were important for
the bitter taste.