New Polyoxygenated Briarane Diterpenoids, Briaexcavatolides O−R, from the Gorgonian <i>Briareum excavatum</i>

Four new polyoxygenated briarane-type diterpenoids, briaexcavatolides O−R (1−4), have been isolated from a gorgonian octocoral Briareum excavatum. Their structures were determined using spectroscopic and chemical methods. Metabolites 1−3 were found to contain oxygenated substituents at C-2, C-3, and C-4, and the relative configurations were assigned as 2R*,3R*,4R* at these three positions. Briaranes containing this type of stereochemistry are reported for the first time. The structures of metabolites 1 and 2 were further confirmed by single-crystal X-ray analyses. Compound 2 has been shown to exhibit significant cytotoxicity toward P-388 and HT-29 cancer cells

Cytotoxic C₂₁ and C₂₂ Terpenoid-Derived Metabolites from the Sponge <i>Ircinia</i> sp.

One novel C21 terpenoidal natural product, ircinolin A (2), two new C22 furanoterpene metabolites, 15-acetylirciformonin B (3) and 10-acetylirciformonin B (4), and two known compounds, irciformonin B (1) and irciformonin F (5), were isolated from the sponge Ircinia sp. The structures of these compounds were elucidated on the basis of their spectroscopic data. Moreover, the absolute configuration of 1 was determined by Mosher’s method. Among these metabolites, 2 is the first C21 terpenoid-derived metabolite to be reported from this genus. Compounds 1 and 3–5 exhibited significant cytotoxic activity against K562, DLD-1, HepG2, and Hep3B cancer cell lines

N11 suppresses superoxide anion generation and ROS formation in FMLP-activated human neutrophils.

<p>Neutrophils were incubated with DMSO (control) or N11 (0.3, 1, and 3 µg/ml) and then stimulated with (A) FMLP (30 nM) or (B) PMA (5 nM). Superoxide anion generation was measured by spectrophotometry. (C) Neutrophils labeled with HE were incubated with DMSO (control) or N11 (0.3, 1, and 3 µg/ml) and monitored by flow cytometry under resting and stimulating conditions. The black line denotes the basal group comprising cells treated with DMSO without FMLP stimulation. The red line denotes the experimental groups. All data shown are means ± SEM. (n = 5 for A, n = 3 for B, n = 4 for C). <b>*</b><i>p</i><0.05, <b>**</b><i>p</i><0.01, <b>***</b><i>p</i><0.001 versus the control group.</p

Chromatography analysis of N11.

<p><i>Pseudomonas</i> sp. was aerobically cultivated in culture medium with 50% seawater at 25°C on a rotatory shaker at 150 rpm for 5 d. The metabolites were extracted using ethyl acetate and evaporated to dryness in a vacuum to obtain N11. The concentration of N11 for HPLC analysis was 4 mg/ml. The injection volume was 10 µl, and the UV detection wavelength was set at 220 nm.</p

N11 down-regulates calcium mobilization in FMLP-activated human neutrophils.

<p>(A) Fluo-3/AM loaded neutrophils were incubated with DMSO (control) or N11 and then activated with FMLP (30 nM). Mobilization of calcium was determined in real time in a spectrofluorometer. Representative traces from one of six experiments are shown. (B) Peak [Ca²⁺]_i induced by FMLP is expressed as means ± SEM. (n = 6). <b>*</b><i>p</i><0.05, <b>***</b><i>p</i><0.001 versus the control group.</p

N11 does not have superoxide anion-scavenging ability and antioxidant effect in cell-free systems.

<p>(A) Reduction of WST-1 by superoxide anion in xanthine/xanthine oxidase assay and (B) reduction of DPPH radical in the presence of N11, SOD, or α-tocopherol, were measured by spectrophotometry. All data shown are means ± SEM. (n = 3 for A, n = 4 for B). <b>***</b><i>p</i><0.001 versus the control group.</p

Junceellolides J−L, 11,20-Epoxybriaranes from the Gorgonian Coral <i>Junceella </i><i>f</i><i>ragilis</i>

Three new 11,20-epoxybriarane diterpenoids, junceellolides J−L (1−3), along with a known metabolite, 4, have been isolated from the gorgonian coral Junceella fragilis. The structures of these metabolites were elucidated using spectroscopic methods. The cyclohexane rings were found to exist in boat form in briaranes 1 and 4 and in chair form in 2 and 3. The structure of 1 was further confirmed by chemical conversion and single-crystal X-ray diffraction analysis. The relationship between 13C NMR chemical shifts and the conformation of the cyclohexane ring in briaranes possessing an 11,20-epoxy group are described. The briaranes 2 and 4 showed mild inhibitory effects on human neutrophil elastase release

N11 inhibits elastase release in FMLP-activated human neutrophils.

<p>(A) Neutrophils were incubated with DMSO (control) or N11 (0.3, 1, and 3 µg/ml) and then stimulated with FMLP (30 nM). Elastase release was measured by spectrophotometry. (B) Elastase supernatant was incubated with DMSO (control) or N11 before the addition of substrate. All data shown are means ± SEM. (n = 3 for A, n = 5 for B). <b>*</b><i>p</i><0.05, <b>**</b><i>p</i><0.01, <b>***</b><i>p</i><0.001 versus the control group.</p

Norterpenoids and Related Peroxides from the Formosan Marine Sponge <i>Negombata corticata</i>

Six norterpenes including negombatoperoxides A and B (4 and 5), the inseparable epimers negombatoperoxides C and D (6 and 7), negombatodiol (8), and negombatolactone (9), in combination with three known compounds, (+)-nuapapuin B (1), (+)-nuapapuin B methyl ester (2), and (+)-aikupikoxide C (3), were isolated from the Formosan marine sponge Negombata corticata. In addition, 6,6-dimethylundecane-2,5,10-trione (10) was isolated for the first time from a natural source. Their structures, including relative configurations, were elucidated on the basis of interpretation of spectroscopic data and by the application of the empirical rule established by Capon and MacLeod. The absolute configurations of 8 and 9 were established by the application of Mosher’s method and comparison of CD data with known lactones, respectively. Cytotoxicity of these isolates against human breast carcinoma, human liver carcinoma, and human lung carcinoma cell lines was evaluated

N11 inhibits phosphorylation of p38 and JNK, but not Erk and Akt, in FMLP-activated human neutrophils.

<p>Neutrophils were treated with N11 (1 and 3 µg/ml) and then activated with FMLP (30 nM). Phosphorylation of MAP kinases and Akt were analyzed by immunoblotting analysis. Densitometric analysis of all samples was normalized to the total protein. All data shown are means ± SEM. (n = 4). <b>*</b><i>p</i><0.05, <b>**</b><i>p</i><0.01, <b>***</b><i>p</i><0.001 versus the control group.</p