Zierane sesquiterpene lactone, cembrane and fusicoccane diterpenoids, from the Tahitian liverwort Chandonanthus hirtellus

Abstract

Cembrane-type diterpenoids, 13,18,20-epi-iso-chandonanthone (1) and (8E)-4alpha-acetoxy-12alpha,13alpha-epoxycembra-1(15),8-diene (2), two fusicoccane-type diterpenoids, fusicoauritone 6alpha-methyl ether (3) and 6beta,10beta-epoxy-5beta-hydroxyfusicocc-2-ene (4) and a zierane sesquiterpene gamma-lactone, chandolide (5) were isolated from the Tahitian liverwort Chandonanthus hirtellus (Web.) Mitt., together with eight known diterpenoids, chandonanthine (6), fusicogigantone A (7), fusicogigantone B (8), fusicogigantepoxide (9), anadensin (10), fusicoauritone (11), ent-verticillol (12) and ent-epi-verticillol (13). Their structures were established by a combination of extensive NMR spectroscopy and/or X-ray crystallographic analyses. Compounds 1, 5 and 10 showed weak cytotoxic activity against HL-60. Compound 3 also indicated weak cytotoxic activity against KB cell lines.