Bioassay-guided fractionation of the EtOAc extract of Casearia membranacea leaves and twigs afforded three new clerodane diterpenes, caseamembrins M-O (1-3), and the known rel-(2S,5R,6R,8S,9S,10R,18S,19R)-2-(2-methylbutyryloxy)-6-hydroxy-18,19-di-O-acetyl-18,19-epoxycleroda-3,13(16),14-triene (4) and caseamembrin D (5). The structures of 1-3, including the relative configurations, were established by extensive NMR spectroscopic analyses. The cytotoxic activities of the isolated diterpenoids against human oral epidermoid (KB), medulla (Med), and colon (DLD-1) cancer cell lines were evaluated.

The sesquiterpene capnellene‐8β, 10α‐diol (1) was isolated from non‐polar extract of the soft coral Capnella sp. Ten acylation products of capnellene‐8β, 10α‐diol were prepared: 10α‐hydroxy‐8β‐O‐benzoylcapnellene (2), 10α‐hydroxy‐8β‐O‐p‐toluoylcapnellene (3), 10α‐hydroxy‐8β‐O‐4‐chlorobenzoyl‐capnellene (4), 10α‐hydroxy‐8β‐O‐2‐furoylcapnellene (5), 10α‐hydroxy‐8β‐O‐2‐thiophenoylcapnellene (6), 10α‐hydroxy‐8β‐O‐4‐fluorobenzoylcapnellene (7), 10α‐hydroxy‐8β‐O‐4‐propylbenzoylcapnellene (8), 10α‐hydroxy‐8β‐O‐cinnamoylcapnellene (9), 10α‐hydroxy‐8β‐O‐4‐nitrobenzoylcapnellene (10), and 10α‐hydroxy‐8β‐O‐4‐anisoylcapnellene (11). The structures of capnellene‐8β, 10α‐diol as well as its derivatives were established through standard spectroscopic analysis. The in vitro cytotoxic activities of the eleven compounds were evaluated against Hela, KB, Daoy, and WiDr human tumor cell lines.

Chromatographic investigation of an acetone extract of the octocoral Xenia puerto‐galerae afforded three new cadinene sesquiterpenes; 8‐epi‐xenitorin A (1), 10‐epi‐xenitorin C (2), and 7‐isopropenyl‐4,10‐dimethyl‐2,3,4,5‐tetrahydronaphthalene (3), in addition to four known cadinene analogs (4, 11–13) and six xenicanes (5–10). The structures were elucidated through spectroscopic analysis, especially 2D NMR. A biogenetic pathway of 1–3 and analogs was proposed.