Cytotoxic bistetrahydrofuran annonaceous acetogenins from the seeds of Annona squamosa

Three new bistetrahydrofuran annonaceous acetogenins (1-3) were isolated from a 95% EtOH extract of Annona squamosa seeds. Four known annonaceous acetogenins, uvarigrandin A (4), bullatacin (5), squamostatin-A (6), and squamostatin-D (7), were also isolated. Their structures were elucidated by spectroscopic analyses, and the absolute configurations of the carbinol centers of 1-3 were defined by application of the Mosher method. These compounds all exhibited significant cytotoxic activity in vitro against five human tumor cell lines.