Natural Products from Soft Corals in Taiwan: Insights into Chemical Taxonomy and Potential Interaction in Marine Environments

Natural products, specifically secondary metabolites, produced by marine organisms, play crucial roles in their survival and performance. Research on natural products derived from marine organisms, particularly soft corals, has been ongoing for over 30 years in Taiwan, resulting in the isolation and identification of over 2000 unique compounds from 100 species of soft corals. These studies have not only uncovered bioactive compounds with potential useful applications but have also provided insights into the chemical evidence for the taxonomy of soft corals as well as the biological functions of these products within soft corals. Following the central dogma of molecular biology, this review notes that, according to the biosynthesis pathways, the types of natural products identified for seven clades of soft corals align with the updated phylogenetic system of soft corals based on DNA sequencing analysis. Thus, these natural products can serve as chemical evidence to support our understanding of soft coral taxonomy. Furthermore, to understand the influences of geographic factors on the production of natural products in soft corals, we compiled data on natural products from species repeatedly collected at different locations around Taiwan. Interestingly, the oxidation levels of briaranes in Briareum stechei and Junceella fragilis, and cembranes in Sclerophytum flexibile and Lobophytum crassum, tended to increase with rising seawater temperatures, while other soft corals also exhibited different metabolite profiles across spatial and temporal scales. Finally, we highlight the challenges and future perspectives in studying natural products from soft corals and propose that recent advancements in techniques, which offer comprehensive tools, such as mass spectral molecular networking, can significantly improve the elucidation of secondary metabolite structures. By addressing these challenges and leveraging new technologies, future research can provide novel insights into the roles that natural products play in marine chemistry. Collectively, this will contribute to a better understanding of marine biodiversity, the chemical dynamics of marine chemical ecology, and potential biotechnological applications.