Volatile constituents from marine brown algae of japanese Dictyopteris

cis-3-Butyl-4-vinylcyclopentene, trans-1-[(1Z)-hexenyl]-2-vinylcyclopropane, 4-[(1E)-hexenyl]-cyclopentene, and 6-[(1E)-butenyl]-cyclohepta-1,4-diene were newly identified in the essential oils from fresh Dictyopteris prolifera and D. undulata. On the other hand, the oil of D. divaricata was found to consist mostly of a single sesquiterpene, cubenol (over 95%) instead of the C11-compounds. The growth-locality variation in the chemical compositions of the essential oils in the genus Dictyopteris was discussed.