Halenaquinone and xestoquinone derivatives, inhibitors of Cdc25B phosphatase from a Xestospongia sp.

Nine quinones, including the new natural products 6 and 9, were isolated from a sponge of the genus Xestospongia. All the isolated compounds were inhibitory to the dual specificity phosphatase Cdc25B, and five were active at the nanomolar level.