Fimbriatols A-J, Highly Oxidized ent-Kaurane Diterpenoids from Traditional Chinese Plant Flickingeria fimbriata (B1.) Hawkes.

Fimbriatols A-J (1-10), ten new ent-kaurane diterpenoids possessing differently highly oxidized sites, were isolated from Flickingeria fimbriata (B1.) Hawkes. The structures of these new compounds were determined by HRESI-MS, NMR, CD spectra and X-ray diffraction analysis. Compound 1 displayed moderately inhibitory ratio (48.5%) compared with the positive compound NSC-87877 (81.6%) at the concentration of 0.022 μg/mL. Compounds 7-10 possess 3, 4-seco-ent-kaurane skeleton containing a disaccharide moiety with an unusual linkage at C-2' to C-1'' instead of the common linkage at C-6' to C-1'', and this is the first report in 600 more ent-kauranes found in nature, which might be originated from ent-kaurane diterpenoids through post-modified reactions of Baeyer-Villiger oxygenation and glycosylation.