lipid steroid 259.243 259.450 Any of naturally occurring compounds and synthetic analogues, based on the cyclopenta[a]phenanthrene carbon skeleton, partially or completely hydrogenated; there are usually methyl groups at C-10 and C-13, and often an alkyl group at C-17. By extension, one or more bond scissions, ring expansions and/or ring contractions of the skeleton may have occurred. Natural steroids are derived biogenetically from squalene, so may be considered as triterpenoids. C12C(C3C(C(CC3)*)(C)CC1)CCC4C2(CCCC4)C C19H31R CHEBI:13687 CHEBI:26768 CHEBI:35341 CHEBI:9263 KEGG:C00377 MetaCyc:Steroids Steroid a steroid chebi_ontology steroids organic polycyclic compound