Sun Domain ability -- only for undead?

[ajfonty]

As a DM, would you rule that the Sun Domain's ability can only affect undead, or could it also affect other turnable creatures?

I'm only worried about potentially wacky strategies, such as the one involving the Sun and Moon domain and cursing people with lycantropy and immediately turning them.

[Ernir]

Once per day, you can perform a greater turning against undead in place of a regular turning. The greater turning is like a normal turning except that the undead creatures that would be turned are destroyed instead.

Emphasis mine. Looks undead-specific to me.