has role independent continuant organic heterotricyclic compound antineoplastic agent secondary alcohol gamma-lactone sesquiterpene lactone cyclic ketone helenalin CHEBI:5635 A sesquiterpene lactone that is 3,3a,4,4a,7a,8,9,9a-octahydroazuleno[6,5-<em>b</em>]furan-2,5-dione substituted by a hydroxy group at position 4, methyl groups at positions 4a and 8 and a methylidene group at position 3 (the 3a<i>S</i>,4<i>S</i>,4a<i>R</i>,7a<i>R</i>,8<i>R</i>,9a<i>R</i> stereoisomer). anti-inflammatory agent plant metabolite