Structures and possible functions of epoxypukalide and pukalide : Diterpenes associated with eggs of sinularian soft corals (Cnidaria, Anthozoa, Octocorallia, Alcyonacea, Alcyoniidae).

Chemical analysis of the eggs spawned by fiveSinularia soft corals (Octocorallia, Alcyoniidae) collected in the central region of the Great Barrier Reef, Australia, revealed the presence of the known cembranoid diterpenes epoxypukalide and/or pukalide in all cases. Examination of the colonies from which the eggs were released one month before spawning and also some time after spawning failed to detect either diterpene in the coral tissue. The three dimensional structures of pukalide and epoxypukalide, as determined by the single-crystal X-ray technique, are reported for the first time. The wide distribution of pukalide and epoxypukalide and of related compounds within the octocorallia is discussed.