Chemical investigation of the octocoral Briareum stechei, collected in the Ie Island, Okinawa, Japan, resulted in the isolation of a new briarane-type diterpenoid, briastecholide A (1), as well as the previously reported metabolites, solenolide C (2) and briarenolide S (3). The structures of briaranes 1–3 were characterized through spectroscopic analysis, and the absolute configuration of 2 was corroborated by a single-crystal X-ray diffraction analysis. Briarane 3 exhibited bioactivity against the protein expression of inducible nitric oxide synthase (iNOS).
