Natural products have played a key role in cancer drug discovery, as well in
other therapeutic fields. In the past decades, marine organisms have proven to be a
primary source of new potentially bioactive natural products for drug discovery. By
reviewing the literature describing marine organisms and isolated metabolites, we can
notice a large increase in the number of studies today compared to the end of the 20th
century. The number of structures isolated each year has almost doubled over the past
20 years. Because of their topicality, we have focused on natural bioactive steroids
isolated from marine organisms. In the chapter ‘Bioactive Steroids from Marine
Organisms’, an overview of the new steroid compounds isolated from marine sponges,
macroalgae and cucumbers, described in the relevant literature in the period from 2011
to 2020, is given. To provide a comprehensive introduction in the field of marine
bioactive steroids, we highlighted typical molecules grouped according to their
structural characteristics with additional reference to their biological activity. The
structures of the new compounds, their natural origin (species of the organism) and
their rich biological activities are presented and described in detail. In addition,
biological tests performed on known compounds during this time period are also
described. Some of the compounds possess multiple activities and have been tested
only in a limited number of biological assays, which means that the full potential and
significance of these compounds may only be discovered in the future.
Keywords: Bioactivity, Biosynthetic origin, Marine cucumber, Marine
macroalgae, Marine sponges, Natural steroids, Structural characterization.
