Using activity-directed fractionation, the chromatography of the bioactive methanol extract of Annona senegalensis seeds led to isolation of a new mono-tetrahydrofuranic γ-lactone acetogenin characterized by the presence of a double bond on the alkyl chain, senegalene 1. Its structure was elucidated on the basis of spectroscopic (2D-NMR and MS) and chemical methods. Four known acetogenins have been also isolated: molvizarin 2, asimicin 3, rolliniastatin-2 4, and squamocin 5. Comparative structure–activity relationships were studied using senegalene 1 and its derivatives in KB and VERO cell lines in in vitro tests.