Corals are one of the common marine invertebrates in tropical coral reefecosystem. The surfaces of them are smooth without other substances attached, andthey are able to survive in the harsh marine environment. We deduce that they maydepend on the chemical defensive substances probably produced by themselves andtheir symbiotic microorganisms. These substances with the chemical ecologicalactivities usually have good pharmacological activities. Based on that, in presentstudy, the secondary metabolites from a ...