carotenoid chebi_ontology One of a class of tetraterpenoids (C<small>₄₀</small>), formally derived from the acyclic parent, ψ,ψ-carotene by hydrogenation, dehydrogenation, cyclization, oxidation, or combination of these processes. This class includes carotenes, xanthophylls and certain compounds that arise from rearrangement of the skeleton of ψ,ψ-carotene or by loss of part of this structure. Retinoids are excluded. carotenoids carotenoid carotenoid cas:36-88-4 carotenes and carotenoids CHEBI:23044 tetraterpenoid