Since the 1970s, more than 15,000 structurally diverse bioactive natural products with an astounding array of biological activities have been discovered from marine microbes, algae, and invertebrates. Although more than 70% of the Earth’s surface is covered by oceans, we use only less than 10% of the total ocean area (Schultes 1978). Notably, many marine organisms live in complex habitats exposed to extreme conditions and in adapting to a new environment, they produce a wide variety of secondary metabolites, which cannot be found in other organisms. Moreover, considering its great taxonomic diversity, investigations related to the search of new bioactive compounds from the marine environment can be seen as an almost unlimited eld. In addition, the biological productivity of terrestrial ecosystems has also simply reached what it can achieve; the marine biodiversity of the ocean can be expected to have new therapeutic agents (Bugni and Ireland 2004).