Three new sesquiterpenoids from the aerial parts of Homalomena occulta

Three new eudesmane-type sesquiterpenoids, compounds 1-3, and eight known constituents, including mucrolidin (4), 1 beta,4 beta,7 alpha-trihydroxyeudcsmane (5), 1 beta,4 beta,6 beta,11-tetrahydroxyeudesmane (6), oplodiol (7), bullatantriol (8), acetylbullatantriol (9), homalomenol (10), and maristeminol (11), were isolated from the aerial parts of Homalomena occulta. Their structures were determined by interpretation of spectroscopic and mass-spectrometric data, and their antimicrobial activities toward six different bacterial strains were tested. Most of the compounds showed weak antibacterial activities in an agar-diffusion assay.