Naturally occurring compounds and synthetic analogues, based on the cyclopenta[a]phenanthrene carbon skeleton, partially or completely hydrogenated; there are usually methyl groups at
\(\ce{C-10}\) and
\(\ce{C-13}\), and often an alkyl group at
\(\ce{C-17}\). By extension, one or more bond scissions, ring expansions, and/or ring contractions of the skeleton may have occurred.
Note: Natural steroids are derived in biogenesis from triterpenoids; they play important roles as
hormones (sex
hormones),
membrane components (cholesterol) and emulsifying agents (bile acids).
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 808 (https://doi.org/10.1515/pac-2015-1202)