The Chemical Entities of Biological Interest (ChEBI) ontology is downloaded weekly from EMBL-EBI at http://www.ebi.ac.uk/chebi/. The data is made available under the Creative Commons License (CC BY 3.0, http://creativecommons.org/licenses/by/3.0/). For more information see: Degtyarenko et al. (2008) ChEBI: a database and ontology for chemical entities of biological interest. Nucleic Acids Res. 36, D344–D350.
An organic heterotricyclic compound and guaianolide sesquiterpene lactone that is acrylic acid which is substituted at position 2 by a 4-hydroxy-3,8-bis(methylene)decahydoazulen-5-yl group and in which the hydroxy group and the carboxy group have undergone formal condensation to afford the corresponding gamma-lactone.