Briarenol L, a new chlorine-containing briarane from Briareum excavatum (Briareidae)

Abstract Chemical examination of Briareum excavatum, collected in the waters of Taiwan, led to the isolation of four briarane diterpenoids, including three known compounds, briarenol G (1), briaviolides Y (2), and Z (3), as well as a new metabolite, briarenol L (4). The absolute configuration of 1 was determined by a single-crystal X-ray diffraction analysis for the first time in this study and the structure of 4 was established on the basis of spectroscopic analysis. Briaranes 2 and 3 exerted inhibition effects on COX-2 and iNOS, respectively, release from RAW 264.7 macrophages.