Bioactive Capnosanes and Cembranes from the Soft Coral Klyxum flaccidum.

Two new capnosane-based diterpenoids, flaccidenol A (1) and 7-epi-pavidolide D (2), two new cembranoids, flaccidodioxide (3) and flaccidodiol (4), and three known compounds 5 to 7 were characterized from the marine soft coral Klyxum flaccidum, collected off the coast of the island of Pratas. The structures of the new compounds were determined by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and spectroscopic data comparison with related structures. The rare capnosane diterpenoids were isolated herein from the genus Klyxum for the first time. The cytotoxicity of compounds 1 to 7 against the proliferation of a limited panel of cancer cell lines was assayed. The isolated diterpenoids also exhibited anti-inflammatory activity through suppression of superoxide anion generation and elastase release in the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-stimulated human neutrophils. Furthermore, 1 and 7 also exhibited cytotoxicity toward the tested cancer cells, and 7 could effectively inhibit elastase release. It is worth noting that the biological activities of 7 are reported for the first time in this paper.

Anti-Inflammatory Polyoxygenated Steroids from the Soft Coral Lobophytum michaelae.

Three new polyoxygenated steroids, michosterols A-C (1-3), and four known compounds (4-7) were isolated from the ethyl acetate (EtOAc) extract of the soft coral Lobophytum michaelae, collected off the coast of Taitung. The structures of the new compounds were elucidated on the basis of spectroscopic analyses and comparison of the nuclear magnetic resonance (NMR) data with related steroids. The cytotoxicity of compounds 1-3 against the proliferation of a limited panel of cancer cell lines was assayed. Compound 1 was found to display moderate cytotoxicity against adenocarcinomic human alveolar basal epithelial (A549) cancer cells. It also exhibited potent anti-inflammatory activity by suppressing superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-stimulated human neutrophils. Furthermore, 3 could effectively inhibit elastase release, as well.

Klyflaccisteroids K-M, bioactive steroidal derivatives from a soft coral Klyxum flaccidum.

New steroids, klyflaccisteroids K-M (1-3), were isolated from a soft coral Klyxum flaccidum. Their structures were elucidated on the basis of extensive spectroscopic analysis. Klyflaccisteroid K (1) is the unique 9,11-secosteroid with a 5,8-epidioxy-9-ene functional group. Klyflaccisteroid L (2) has an unusual 11-norsteroid skeleton and is the first example of 11-oxasteroid isolated from natural sources. Cytotoxicity assay showed that 1 and 3 possessed moderate to weak cytotoxicity against these cancer cells. Compound 1 was also found to display significant anti-inflammatory activity of suppressing superoxide anion generation (O2-) and elastase release, and compound 3 was found to show notable anti-inflammatory activity toward inhibition of elasstase release, too.

New cytotoxic and anti-inflammatory steroids from the soft coral Klyxum flaccidum.

Four new steroids, namely klyflaccisteroids G-J (1-4) were isolated from the Formosan soft coral Klyxum flaccidum. The structures of compounds 1-4 were established by spectral data analysis (IR, MS, 1D and 2D NMR) and comparison of spectral data with those of the related known compounds. Cytotoxicity assay revealed that 4 exhibited inhibition activity against the growth of HT-29, P388 and K562 cancer cell lines, whereas 2 showed selective cytotoxicity toward P388 cells. Compound 4 was also found to display significant anti-inflammatory activity for suppressing superoxide anion generation (O2(-)) and elastase release.