P-29 ホヤの幼生の変態を誘起するJaspis属海綿由来の化合物 : Narainとその関連化合物について(ポスター発表の部)

抄録

In the course of our studies on inducers of larval settlement and metamorphosis we have isolated urochordamines A and B from two ascidians Ciona savignyi and Botrylloides sp., and phlorotannins and sulfoquinovosyl diacylglycerols from the brown alga Sargassum thunbergii, which promoted larval metamorphosis in two ascidians Halocynthia roretzi and C. savignyi. Subsequently, we found a similar activity in the MeOH extract of a marine sponge, Jaspis sp. collected off the Izu Peninsula. Bioassay-guided isolation afforded two active metabolites, (E)-and (Z)-narains (1, 2) along with several related compounds. The structures of 1 and 2 were elucidated by spectroscopic methods to be new N,N-dimethylguanidinium styryl sulfates. Compounds 3-5 were obtained as racemates. Since compound 8 was obtained when extracted with MeOH, whereas the acetone extract afforded 9, it is strongly suggested that 3-5, 8, and 9 were derived from a catechol derivative with C_2-unit during extraction. (Z)-Narain (2) as well as the anion alone induced larval metamorphosis in H. roretzi at a concentration of 5μM, while no larvae in the control group underwent metamorphosis. This suggested that 2 was ten times more active than urochordamine A. However, (E)-narain 1 and the related compounds were less active than 2. No abnormal effects on larvae was observed when exposed to 2, indicating that 2 will be a good tool to study the metamorphosis mechanism of ascidian larvae.