Briarenolides H and I: New 8-Hydroxybriarane Diterpenoids from a Formosan Octocoral Briareum sp (Briareidae)

Chemical investigation on a Formosan octocoral identified as Briareum sp. has led to the isolation of two new 8-hydroxybriarane diterpenoids, briarenolides H (1) and 1 (2). The structures of briaranes 1 and 2 were established by spectroscopic methods and by comparison of the spectroscopic data with those of known briarane analogues. Briarenolide H (1) was proven to be the first 6-methoxybriarane derivative. Briarenolide 1 (2) displayed an inhibitory effect on the generation of superoxide anion by human neutrophils.