Bioprospecting of Maldivian soft corals: chemical ecology and anticancer activity of their secondary metabolites

Marine environments, especially coral reefs, are the source of a wide range of bioactive natural products with structurally unique features. Secondary metabolites extracted from soft corals have been extensively studied for their potential pharmacological properties of interest to human health, especially concerning their possible cytotoxic effect against different cancer cell lines. Our recently published review related to this topic focuses on Alcyoniidae, one of the largest octocoral families. From this research, 344 cytotoxic compounds were found, most of which have been discovered in the last 20 years proving that this particular research field only recently exploded. To prove and underline the potential of this research, 21 of these secondary metabolites displayed comparable and even higher cytotoxic activity than the chemotherapy drug used as a positive control in the various studies against specific cancer lines. However, the important comparison between the viability study on the cancer cells and on the normal one of the same tissues remains to be further investigated. In the initial part of our research project, we extracted the Maldivian soft coral Sarcophyton sp. by using ethyl acetate and dichloromethane solvents. Moreover, further purification by column chromatography of the ethyl acetate extract led to three fractions and the metabolites profile was determined by applying a multi- analytical approach based on mass spectrometry and by comparison with reference data from the current literature. By MTT assay was found that ethyl acetate and dichloromethane crude extracts caused a reduction in viability of human colorectal cancer (CRC) cell lines SW480 and E705, while were only weakly active against human healthy mucosa cell line CCD841. Furthermore, fraction 2 and 3 displayed cytotoxicity against CRC cell lines while showing a lower effect toward CCD841. This study provides a better understanding of the chemical nature of Sarcophyton sp. and indicates a promising ethyl acetate fraction which represents an excellent starting point for further work on the isolation, structural characterization, and biochemical investigation of new compounds with a potential anticancer effect. In addition, the future aim of this research project will be to extend the study to other cancer cell lines and other pharmacological properties and at the same time also to expand the investigation to other coral genera to identify the most promising ones as well as other marine organisms.