has role independent continuant organic heterotricyclic compound sesquiterpene lactone plant hormone butenolide strigolactone A family of sesquiterpene lactones with a common structure consisting of two lactone moieties (one a butenolide, the other a tricyclic γ-lactone) connected by an enol-ether bridge. Originally used to describe phytohormones with diverse signaling activities, biosynthesised from carotenoids, the term also includes synthetic analogues. CHEBI:68487