Lisianthus Flowers Emitted Volatile Components Including Iridoids and Actinidine Which Attract Cats

Lisianthus (Eustoma grandiflorum [Raf.] Shinners) is one of the world’s major cut flowers, characterized by its wide variety of flower colors, flower shapes, long stem, and long vase life. Lisianthus is said to be scentless, but there are cultivars that have a weak or faint scent. Cats exhibit a characteristic response to lisianthus flowers similar to their response to Actinidia polygama leaves, which have a very weak scent for humans. These observations suggested that the scent of lisianthus flowers may have a component that attracts cats. The volatile components of Eustoma ‘New Lination White’ flowers, which has a weakly sweet scent, and 12 lisianthus cultivars, which have a very faint scent, were analyzed. Thirty-six kinds of volatile components were detected in the flowers of ‘New Lination White’, including four iridoid compounds (nepetalactone, isodihydronepetalactone, iridomyrmecin, and isoiridomyrmecin) and actinidine, which have been recognized as attracting cats. The major volatile components are sesquiterpenes, and phenypropanoids such as eugenol were identified as components with a sweet scent. Iridoid compounds and actinidine were detected only in flowers, but not in leaves or stems. In addition, iridoid compounds were detected in all 12 cultivars analyzed. Lisianthus flowers were thought to be scentless but we identified many volatile components, including iridoid compounds and actinidine, that attracts cats. This research is the first report on the scent of lisianthus flowers.