Cytotoxic Activity of Capnellene-8β, 10α-Diol Derivatives from a Taiwanese Soft Coral Capnella sp.

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.