Isoapoptolidin, originally isolated from a Nocardiopsis sp., is a ring-expanded isomer of apoptolidin. In water, apoptolidin and isoapoptolidin equilibrate in a ratio of ~1.5:1 within hours. In a rapid F0F1-ATPase assay, isoapoptolidin was approximately half as potent as apoptolidin (IC50 17 μM vs. 0.7 μM ).
- Isoapoptolidin: structure and activity of the ring-expanded isomer of apoptolidin. Wender P.A. et al., Org. Lett. 2002, 4, 3819.
- Toward a stable apoptolidin derivative: identification of isoapoptolidin and selective deglycosylation of apoptolidin. Pennington J.D. et al., Org. Lett. 2002, 4, 3823.
- Apoptolidin analogs and derivatives for inducing apoptosis in transformed cells. Wender P.A. et al., US Patent Application, 20040180841.