The spiroketals containing a benzyloxymethyl moiety at C8 position showed the most potent apoptosis-inducing activity.

Mitsuhashi S, Shima H, Kawamura T, Kikuchi K, Oikawa M, Ichihara A, Oikawa H.Bioorg. Med. Chem. Lett. 1999 Jul 19;9(14):2007-12. doi: 10.1016/s0960-894x(99)00309-1