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A persistent study on soft coral

In an attempt to explore the bioactive metabolites of the soft coral

Pancreatic ductal adenocarcinoma is one of the most lethal malignancies: more than half of patients are diagnosed with a metastatic disease, which is associated with a five-year survival rate of only 3%. 5-epi-Sinuleptolide, a norditerpene isolated from Sinularia sp., has been demonstrated to possess cytotoxic activity against cancer cells. However, the cytotoxicity against pancreatic cancer cells and the related mechanisms are unknown. The aim of this study was to evaluate the anti-pancreatic cancer potential of 5-epi-sinuleptolide and to elucidate the underlying mechanisms. The inhibitory effects of 5-epi-sinuleptolide treatment on the proliferation of pancreatic cancer cells were determined and the results showed that 5-epi-sinuleptolide treatment inhibited cell proliferation, induced apoptosis and G2/M cell cycle arrest, and suppressed the invasion of pancreatic cancer cells. The results of western blotting further revealed that 5-epi-sinuleptolide could inhibit JAK2/STAT3, AKT, and ERK phosphorylation, which may account for the diverse cytotoxic effects of 5-epi-sinuleptolide. Taken together, our present investigation unveils a new therapeutic and anti-metastatic potential of 5-epi-sinuleptolide for pancreatic cancer treatment.

Two new isosarcophine derivatives, cherbonolides M (1) and N (2), were further isolated from a Formosan soft coral Sarcophyton cherbonnieri. The planar structure and relative configuration of both compounds were established by the detailed analysis of the IR, MS, and 1D and 2D NMR data. Further, the absolute configuration of both compounds was determined by the comparison of CD spectra with that of isosarcophine (3). Notably, cherbonolide N (2) possesses the unique cembranoidal scaffold of tetrahydrooxepane with the 12,17-ether linkage fusing with a γ-lactone. In addition, the assay for cytotoxicity of both new compounds revealed that they showed to be noncytotoxic toward the proliferation of A549, DLD-1, and HuCCT-1 cell lines. Moreover, the anti-inflammatory activities of both metabolites were carried out by measuring the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced generation of superoxide anion and elastase release in the primary human neutrophils. Cherbonolide N (2) was found to reduce the generation of superoxide anion (20.6 ± 6.8%) and the elastase release (30.1 ± 3.3%) in the fMLF/CB-induced human neutrophils at a concentration of 30 μM.

Chemical investigation of the marine soft coral Sarcophyton tenuispiculatum resulted in the isolation of a 1,4-dihydrobenzoquinone, sarcotenuhydroquinone (1), three new cembranoids, sarcotenusenes A‒C (2‒4), and ten previously reported metabolites 5–14. The chemical structures of all isolated metabolites were determined by detailed spectroscopic analyses. In biological assays, anti-inflammatory, cytotoxic, and peroxisome proliferator-activated receptor γ (PPAR-γ) transcription factor assays of all compounds were performed. None of the isolated compounds were found to exhibit activity in the PPAR-γ transcription factor assay. The anti-inflammatory assays showed that (+)-7α,8β-dihydroxydeepoxysarcophine (13) inhibited the production of IL-1β to 56 ± 1% at a concentration of 30 µM in lipopolysaccharide (LPS)-stimulated J774A.1 macrophage cells. In addition, 1 and 2 were found to exhibit cytotoxicity towards a panel of cancer cell lines.

The present investigation on chemical constituents of the soft coral Sarcophyton cherbonnieri resulted in the isolation of seven new cembranoids, cherbonolides F&ndash, L (1&ndash, 7). The chemical structures of 1&ndash, 7 were determined by spectroscopic methods, including infrared, one- and two-dimensional (1D and 2D) NMR (COSY, HSQC, HMBC, and NOESY), MS experiments, and a chemical reduction of hydroperoxide by triphenylphosphine. The anti-inflammatory activities of 1&ndash, 7 against neutrophil proinflammatory responses were evaluated by measuring their inhibitory ability toward N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced superoxide anion generation and elastase release in primary human neutrophils. The results showed that all isolates exhibited moderate activities, while cherbonolide G (2) and cherbonolide H (3) displayed a more active effect than others on the inhibition of elastase release (48.2% &plusmn, 6.2%) and superoxide anion generation (44.5% &plusmn, 4.6%) at 30 &micro, M, respectively.

Further chemical investigation of the EtOAc extract of the soft coral Lobophytum varium resulted in the discovery of eleven new diterpenoids lobovarols F&ndash, P (1&ndash, 11) of lobane&ndash, and prenyleudesmane&ndash, types, along with two known metabolites (12 and 13). The structures of the new metabolites were established by spectroscopic analyses, including 2D NMR experiments. The absolute configuration of 1 was determined using Mosher&rsquo, s method. The complete assignment of 1H and 13C NMR spectroscopic data of 12 and 13 and the identification of pyran-derived moieties in the prenyleudesmanes were reported for the first time. Anti-inflammatory activities of the isolated compounds in suppressing elastase release and superoxide anion generation in human neutrophils were disclosed for 1, 2, 4, 12, and 13. A stereospecific biosynthesis for lobanes and prenyleudesmanes from the related prenylgermacranes could explain the coexistence of lobanes and prenylgermacranes in L. varium.

Continuing study of the ethyl acetate (EtOAc) extract of the cultured soft coral Sinularia brassica afforded five new withanolides, sinubrasolides H-L (1-5). The structures of the new compounds were elucidated on the basis of spectroscopic analysis. The cytotoxicities of new compounds 1-5 and a known compound sinubrasolide A (6) against the proliferation of a limited panel of cancer cell lines were assayed. The anti-inflammatory activities of compounds 1-6 were evaluated by measuring their ability to suppress N-formyl-methionyl-leucyl-phenyl-alanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation and elastase release in human neutrophils.

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.

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.

Six new cembranoids, cherbonolides A&minus, E (1&ndash, 5) and bischerbolide peroxide (6), along with one known cembranoid, isosarcophine (7), were isolated from the Formosan soft coral Sarcophyton cherbonnieri. The structures of these compounds were elucidated by detailed spectroscopic analysis and chemical methods. Compound 6 was discovered to be the first example of a molecular skeleton formed from two cembranoids connected by a peroxide group. Compounds 1&ndash, 7 were shown to have the ability of inhibiting the production of superoxide anions and elastase release in N-formyl-methionyl-leucyl-phenyl-alanine/cytochalasin B (fMLF/CB)-induced human neutrophils.

The peroxisome proliferator-activated receptor &gamma, (PPAR&gamma, ) is a nuclear receptor that plays a key role in regulating cellular metabolism, and is a therapeutic target for cancer therapy. To search for potential PPAR&gamma, activators, a compound library comprising 11 marine compounds was examined. Among them, a sterol, 3&beta, 11-dihydroxy-9,11-secogorgost-5-en-9-one (compound 1), showed the highest PPAR&gamma, activity with an IC50 value of 8.3 &mu, M for inhibiting human breast adenocarcinoma cell (MCF-7) growth. Western blotting experiments showed that compound 1 induces caspase activation and PARP cleavage. In addition, compound 1 modulated the expression of various PPAR&gamma, regulated downstream biomarkers including cyclin D1, cyclin-dependent kinase (CDK)6, B-cell lymphoma 2 (Bcl-2), p38, and extracellular-signal-regulated kinase (ERK). Moreover, compound 1 increased reactive oxygen species (ROS) generation, upregulated the phosphorylation and expression of H2AX, and induced autophagy. Interestingly, pre-treatment with the autophagy inhibitor 3-methyladenine rescued cells from compound 1-induced growth inhibition, which indicates that the cytotoxic effect of compound 1 is, in part, attributable to its ability to induce autophagy. In conclusion, these findings suggest the translational potential of compound 1 in breast cancer therapy.

Five new cembranoid-related diterpenoids, namely, flexibilisins D and E (1 and 2), secoflexibilisolides A and B (3 and 4), and flexibilisolide H (5), along with nine known compounds (6–14), were isolated from the soft coral Sinularia flexibilis. Their structures were established by extensive spectral analysis. Compound 3 possesses an unusual skeleton that could be biogenetically derived from cembranoids. The cytotoxicity and anti-inflammatory activities of the isolates were investigated, and the results showed that dehydrosinulariolide (7) and 11-epi-sinulariolide acetate (8) exhibited cytotoxicity toward a limited panel of cancer cell lines and 14-deoxycrassin (9) displayed anti-inflammatory activity by inhibition of superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophils.

Six new polyoxygenated cembrane-based diterpenoids, stellatumolides A&ndash, C (1&ndash, 3), stellatumonins A and B (4 and 5), and stellatumonone (6), were isolated together with ten known related compounds (7&ndash, 16) from the ethyl acetate (EtOAc) extract of soft coral Sarcophyton stellatum. The structures of the new compounds were established by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and data comparison with related structures. Compounds 8 and 14 were isolated from a natural source for the first time. The isolated metabolites were shown to be not cytotoxic against a limited panel of cancer cells. Compound 9 showed anti-inflammatory activity by reducing the expression of proinflammatory cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proteins in lipopolysaccharide (LPS)-stimulated mouse leukaemic monocyte macrophage (RAW 264.7) cells.

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.

Hepatitis C virus (HCV) chronically infects 2–3% people of the global population, which leads to liver cirrhosis and hepatocellular carcinoma. Drug resistance remains a serious problem that limits the effectiveness of US Food and Drug Administration (FDA)-approved direct-acting antiviral (DAA) drugs against HCV proteins. The objective of our study was to discover new antivirals from natural products to supplement current therapeutics. We demonstrated that lobohedleolide, isolated from the Formosan soft coral Lobophytum crassum, significantly reduced HCV replication in replicon cells and JFH-1 infection system, with EC50 values of 10 ± 0.56 and 22 ± 0.75 μM, respectively, at non-toxic concentrations. We further observed that the inhibitory effect of lobohedleolide on HCV replication is due to suppression of HCV-induced cyclooxygenase-2 (COX-2) expression. Based on deletion-mutant analysis of the COX-2 promoter, we identified CCAAT/enhancer-binding protein (C/EBP) as a key transcription factor for the down-regulation of COX-2 by lobohedleolide, through which lobohedleolide decreased the phosphorylation of c-Jun NH2-terminal protein kinase and c-Jun to suppress HCV-induced C/EBP expression. The combination treatment of lobohedleolide with clinically used HCV drugs synergistically reduced HCV RNA replication, indicating that lobohedleolide exhibited a high biomedical potential to be used as a supplementary therapeutic agent to control HCV infection.

Two new tocopherol-derived metabolites, hirsutocospiro A (1) and hirsutocoquinone A (2), were isolated from the soft coral Cladiella hirsuta. The structures of 1 and 2 were determined by extensive spectroscopic analysis. The in vitro anti-inflammatory activity of compounds 1 and 2 was evaluated by measuring their ability in suppressing superoxide anion generation and elastase release in fMLP/CB-induced human neutrophils. Compound 1 was shown to exhibit significant anti-inflammatory activity.

A continuing chemical investigation of the ethyl acetate (EtOAc) extract of a reef soft coral Sinularia brassica, which was cultured in a tank, afforded four new steroids with methyl ester groups, sinubrasones A–D (1–4) for the first time. In particular, 1 possesses a β-D-xylopyranose. The structures of the new compounds were elucidated on the basis of spectroscopic analyses. The cytotoxicities of compounds 1–4 against the proliferation of a limited panel of cancer cell lines were assayed. The anti-inflammatory activities of these new compounds 1–4 were also evaluated by measuring their ability to suppress superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced human neutrophils. Compounds 2 and 3 were shown to exhibit significant cytotoxicity, and compounds 3 and 4 were also found to display attracting anti-inflammatory activities.

Five new isoprenoids, 3,4,8,16-tetra-epi-lobocrasol (1), 1,15β-epoxy-deoxysarcophine (2), 3,4-dihydro-4α,7β,8α-trihydroxy-Δ2-sarcophine (3), ent-sarcophyolide E (4), and 16-deacetyl- halicrasterol B (5) and ten known compounds 6‒15, were characterized from the marine soft coral Sarcophyton glaucum, collected off Taitung coastline. Their structures were defined by analyzing spectra data, especially 2D NMR and electronic circular dichroism (ECD). The structure of the known compound lobocrasol (7) was revised. Cytotoxicity potential of the isolated compounds was reported, too.

New cembranoids klyflaccicembranols A–I (1–9), along with gibberosene D (10), have been isolated from the organic extract of a Formosan soft coral Klyxum flaccidum. Their structures were established by extensive spectroscopic analyses, including 2D NMR spectroscopy, and spectral data comparison with related structures. The cytotoxicity of the isolated metabolites, as well as their nitric oxide (NO) inhibitory activity, were evaluated and reported. Metabolites 2, 4, 6, 8 and 9 were found to exhibit variable activities against a limited panel of cancer cell lines in a range of IC50 16.5–49.4 μM. Among the tested cembranoids, compounds 4, 5, 6, and 9 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages at a dose of 50 μg/mL.

Five new eunicellin-based diterpenoids, krempfielins E–I (1–5) and seven known compounds (6–12) were isolated from the organic extract of a Taiwanese soft coral Cladiella krempfi. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analysis. Metabolites 5, 6, 10 and 12 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 6 and 10 could potently inhibit the accumulation of the pro-inflammatory iNOS protein, and 6 and 12 could significantly reduce the expression of COX-2 protein in LPS-stimulated RAW264.7 macrophage cells.

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.

Three new steroids, petasitosterones A and B (1 and 2) and a spirosteroid petasitosterone C (3), along with eight known steroids (4–11), were isolated from a Formosan marine soft coral Umbellulifera petasites. The structures of these compounds were elucidated by extensive spectroscopic analysis and comparison of spectroscopic data with those reported. Compound 3 is a marine steroid with a rarely found A/B spiro[4,5]decane ring system. Compounds 1–3 and 5 displayed inhibitory activity against the proliferation of a limited panel of cancer cell lines, whereas 2 and 5 exhibited significant anti-inflammatory activity to inhibit nitric oxide (NO) production. The inhibitory activities for superoxide anion generation and elastase release of compounds 1–11 were also examined to evaluate the anti-inflammatory potential, and 2–4 were shown to exhibit significant activities.

Four new isoprenoids, including two norcembranoids sinulerectols A and B (1 and 2), a cembranoid sinulerectol C (3), and a degraded cembranoid sinulerectadione (4), along with three known isoprenoids, an unnamed norcembrene (5), sinularectin (6), and ineleganolide (7), and a known nitrogen-containing compound (Z)-N-[2-(4-hydroxyphenyl)ethyl]-3-methyldodec-2-enamide (8), were isolated from an extract of the marine soft coral Sinularia erecta. The structure of sinularectin (6) was revised, too. Compounds 3, 4, and 8 exhibited inhibitory activity against the proliferation of a limited panel of cancer cell lines, whereas 1, 2, and 8 displayed potent anti-inflammatory activity in fMLP/CB-stimulated human neutrophils.

Chemical investigations on the EtOAc-soluble fractions from the EtOH extract of Formosa soft coral afforded a new 9,11-secosteroid, 8αH-3β,11-dihydroxy-5α,6α-expoxy-24-methylene-9,11-secocholestan-9-one (1), along with one known steroid 3β,11-dihydroxy-5β,6β-expoxy-24-methylene-9,11-secocholestan-9-one (2) from Sinularia granosa. The structure of the new metabolite was elucidated on the basis of extensive spectroscopic analysis and by comparison of their NMR data with the known compounds, including 2. Both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory inducible nitric oxide synthase protein, and 1 also was found to effectively reduce the level of cyclooxygenase-2 protein, in lipopolysaccharide-stimulated RAW264.7 macrophage cells at 10 μM. Furthermore, cytotoxic activity of 1 and 2 toward a limited panel of cancer cell lines was also discovered.

Two new cadinane-type sesquiterpenoids, scabralins A (1) and B (2) were obtained from the soft coral Sinularia scabra. Metabolite 1 was shown to exhibit moderate to weak cytotoxicity against MCF-7, WiDr, Daoy, and HEp 2 cancer cell lines. Also, incubation with 10 µM compound 1 significantly inhibited the accumulation of the pro-inflammatory inducible nitric oxide synthase protein in lipopolysaccharide-stimulated RAW264.7 macrophage cells.

Three new cembranoids, sarcocrassocolides M–O (1–3), have been isolated from the soft coral Sarcophyton crassocaule. The structures of the metabolites were determined by extensive spectroscopic analysis. Compounds 1–3 were shown to exhibit moderate cytotoxicity toward a limited panel of cancer cell lines and display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein.

One new sterol, crassarosterol A (1), and four new steroidal glycosides, crassarosterosides A–D (2–5) were isolated from the Formosan soft coral Sinularia crassa. The absolute configuration of 1 was determined using the Mosher’s method. The absolute configurations for the sugar moieties of 2–5 were determined by HPLC analysis on the o-tolylthiocarbamates derived from the liberated sugar after acid hydrolysis. Compounds 2 and 4 could significantly inhibit the expression of pro-inflammatory iNOS protein at 10 µM. In contrast, 1–3 were found to stimulate the expression of COX-2 protein at this concentration. Steroids 1 and 4 also showed cytotoxicity toward the selected human liver cancer cells.

Glaucumolides A (1) and B (2), novel biscembranes composed of an unprecedented α,β-unsaturated ε-lactone, along with the known metabolites ximaolide A (3) and isosarcophytonolide D (4), were isolated from the cultured soft coral Sarcophyton glaucum. The structures of the new metabolites were determined by extensive spectroscopic analyses. Compounds 1 and 2 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. In anti-inflammation assay, compounds 1 and 2 displayed strong inhibition of superoxide anion generation and elastase release in human neutrophils stimulated by fMLP/CB. Furthermore, both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory inducible nitric oxide synthase protein and compounds 1−3 were found to effectively reduce the expression of cyclooxygenase-2 protein, in lipopolysaccharide-stimulated RAW264.7 macrophage cells.

Eight new cembranoids, crassarines A–H (1–8) were isolated from the Formosan soft coral Sinularia crassa. Compounds 1–3 represent the rare cembranoids with a 1,12-oxa-bridged tetrahydrofuran ring, while 4 and 5 are the firstly discovered 1,11-oxa-bridged tetrahydropyranocembranoids. The absolute configuration of 6 was determined using the Mosher’s method. Compounds 6 and 8 were found to significantly inhibit the expression of both pro-inflammatory iNOS and COX-2 proteins at 10 µM, respectively, while compounds 4–8 were found to be non-cytotoxic toward the selected human liver cancer cells.

Five new nardosinane-type sesquiterpenoids, paralemnolins Q–U (1–5), along with three known compounds (6–8), were isolated from the Formosan soft coral Paralemnalia thyrsoides. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods, and the absolute configuration of 1 was determined by the application of Mosher’s method on 1. Among these metabolites, 1 and 3 are rarely found nardosinane-type sesquiterpenoids, possessing novel polycyclic structures. Compounds 1, 3, 6 and 7 were found to possess neuroprotective activity.

Four new cembranoids, querciformolides A-D (1-4), along with two known cembranoids, 7 and 8, have been isolated from the soft coral Sinularia querciformis. Furthermore, chemical investigation of Sinularia granosa has afforded three new cembranoids, querciformolide B (2) and granosolides A (5) and B (6). The structures of the new metabolites were elucidated on the basis of extensive spectroscopic methods, and that of 2 was further confirmed by X-ray diffraction analysis. The absolute configurations of 1 and 2 were determined by a modified Mosher's method. Among these metabolites, 2-6 are rarely found cembranoids possessing a tetrahydrofuran moiety with a 4,7-ether linkage; in addition, 1 is the first epsilon-lactone cembrane found that possesses a tetrahydropyran moiety with a 4,8-ether linkage. None of these compounds were found to be cytotoxic toward a limited panel of cancer cell lines. However, compounds 3, 7, and 8 significantly inhibited the accumulation of the pro-inflammatory iNOS and COX-2 proteins in LPS-stimulated RAW264.7 macrophage cells.

New lobane-based diterpenoids lobovarols A–D (1–4) and a prenyleudesmane-type diterpenoid lobovarol E (5) along with seven known related diterpenoids (6–12) were isolated from the ethyl acetate extract of a Taiwanese soft coral Lobophytum varium. Their structures were identified on the basis of multiple spectroscopic analyses and spectral comparison. The absolute configuration at C-16 of the known compound 11 is reported herein for the first time. The anti-inflammatory activities of compounds 1–12 were assessed by measuring their inhibitory effect on N-formyl-methionyl-leucyl-phenyl-alanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation and elastase release in human neutrophils. Metabolites 2, 5, and 11 were found to show moderate inhibitory activity on the generation of superoxide anion, while compounds 5, 8, 11, and 12 could effectively suppress elastase release in fMLP/CB-stimulated human neutrophil cells at 10 μM. All of the isolated diterpenoids did not exhibit cytotoxic activity (IC50 > 50 μM) towards a limited panel of cancer cell lines.

New eunicellin-type hirsutalins N–R (1–5), along with two known eunicellins, (6 and 7) were isolated from the soft coral Cladiella hirsuta. The structures of the metabolites were determined by extensive spectroscopic analysis. Cytotoxic activity of compounds 1–7 against the proliferation of a limited panel of cancer cell lines was measured. The in vitro anti-inflammatory activity of compounds 1–7 was evaluated by measuring their ability in suppressing superoxide anion generation and elastase release in fMLP/CB-induced human neutrophils.

New cembranoids, sarcocrassocolides P–R (1–3) and four known compounds (4–7) were isolated from the soft coral Sarcophyton crassocaule. The structures of the metabolites were determined by extensive spectroscopic analysis. Compounds 3–5 and 7 were shown to exhibit cytotoxicity toward a limited panel of cancer cell lines and all compounds 1–7 displayed potent in vitro anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells by inhibiting the expression of inducible nitric oxide synthase (iNOS) protein. Compound 7 also showed significant activity in reducing the accumulation of cyclooxygenase-2 (COX-2) protein in the same macrophage cells.

Seven novel withanolides, sinubrasolides A-G (1-7), have been isolated from the cultured soft coral Sinularia brassica. The structures of the new metabolites were determined by extensive spectroscopic analyses, and the absolute configuration of 1 was established by X-ray crystallographic analysis. The cytotoxicities of compounds 1-7 against a limited panel of cancer cell lines also were determined.

Eleven new eunicellin-based diterpenoids possessing a cladiellane skeleton with a C-2, C-9 ether bridge, klymollins I-S (1-11), have been isolated from the EtOAc extract of the soft coral Klyxum molle from Taiwan waters. The structures of compounds 1-11 were elucidated by extensive spectroscopic analysis, including 2D NMR spectroscopy (COSY, HSQC, HMBC, and NOESY). Compound 5 exhibited cytotoxicity toward several cancer cell lines. Compound 5 is the first eunicellin-based metabolite bearing a phenyl group and displays significant inhibition of both superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced human neutrophils.

Epidermal growth factor receptor (EGFR) is overexpressed in many types of cancer cells. EGFR-mediated signaling involves inflammatory gene expression including cyclooxygenase (COX)-2 and interleukin (IL)-8, and is associated with cancer pathogenesis. In a search of phytochemicals with anti-inflammatory activity, the COX-2 and IL-8 inhibitory activities of some marine compounds were examined. After screening these compounds 11-episinulariolide acetate (1) from soft coral exhibited the most potent activity. Reverse-transcription PCR; western blotting; ELISA and luciferase assays were used to test the effect of compound 1 on EGF-stimulated expressions of COX-2 and IL-8 in A431 human epidermoid carcinoma cells. After exposure to 10 μM of compound 1, expression levels of COX-2 and IL-8 were reduced. In addition; intracellular Ca2+ increase and Ca2+-dependent transcription factor activation were blocked by compound 1. Thus, compound 1 can potentially serve as a lead compound for targeting Ca2+ signaling-dependent inflammatory diseases.

Nosocomial infections and increasing multi-drug resistance caused by Acinetobacter baumannii have been recognized as emerging problems worldwide. Moreover, A. baumannii is able to colonize various abiotic materials and medical devices, making it difficult to eradicate and leading to ventilator-associated pneumonia, and bacteremia. Development of novel molecules that inhibit bacterial biofilm formation may be an alternative prophylactic option for the treatment of biofilm-associated A. baumannii infections. Marine environments, which are unlike their terrestrial counterparts, harbor an abundant biodiversity of marine organisms that produce novel bioactive natural products with pharmaceutical potential. In this study, we identified 5-episinuleptolide, which was isolated from Sinularia leptoclados, as an inhibitor of biofilm formation in ATCC 19606 and three multi-drug resistant A. baumannii strains. In addition, the anti-biofilm activities of 5-episinuleptolide were observed for Gram-negative bacteria but not for Gram-positive bacteria, indicating that the inhibition mechanism of 5-episinuleptolide is effective against only Gram-negative bacteria. The mechanism of biofilm inhibition was demonstrated to correlate to decreased gene expression from the pgaABCD locus, which encodes the extracellular polysaccharide poly-β-(1,6)-N-acetylglucosamine (PNAG). Scanning electron microscopy (SEM) indicated that extracellular matrix of the biofilm was dramatically decreased by treatment with 5-episinuleptolide. Our study showed potentially synergistic activity of combination therapy with 5-episinuleptolide and levofloxacin against biofilm formation and biofilm cells. These data indicate that inhibition of biofilm formation via 5-episinuleptolide may represent another prophylactic option for solving the persistent problem of biofilm-associated A. baumannii infections.

A new isobicyclogermacrene-type sesquiterpenoid, lochmolin H (1), along with one known sesquiterpenoid 2, were isolated from the soft coral Sinularia lochmodes. The structure and relative configuration of the new compound was assigned by a combination of one- and two-dimensional NMR spectroscopic analysis and comparison of the NMR data with those of known analogues.

Seven new sesquiterpenoids, lochmolins A–G (1–7), were isolated from a Taiwanese soft coral Sinularia lochmodes. The structures of these metabolites were elucidated by extensive spectroscopic study. Compounds 1–4 were found to inhibit the accumulation of the LPS-induced pro-inflammatory COX-2 protein in RAW264.7 macrophage cells.

Four new eunicellin-based diterpenes, simplexins P–S (1–4), and the known compound simplexin A (5), have been isolated from the soft coral Klyxum simplex. The structures of the new metabolites were determined on the basis of extensive spectroscopic analysis, particularly 1D and 2D NMR experiments. Compounds 1 and 3–5 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines, 3 being the most cytotoxic.

Eight new eunicellin-based diterpenoids, klymollins A–H (1–8), were isolated during the chemical investigation of the soft coral Klyxum molle from Taiwan waters. Their structures were elucidated by extensive spectroscopic analysis. The absolute configuration of 4 was determined by Mosher’s method. Bioassays of the new metabolites showed that compounds 3–8 displayed significant in vitro anti-inflammatory activity by inhibiting the expression of the iNOS protein, and compounds 3, 4, and 6–8 also could effectively reduce the accumulation of COX-2 protein in LPS-stimulated RAW264.7 macrophage cells.

Three new cembranoids crassocolides N–P (1–3), was isolated from the organic extract of a Formosan soft coral Sarcophyton crassocaule. These structures were elucidated on the basis of spectroscopic analyses and by comparison with those previously reported in literature. The cytotoxicity of these compounds toward various cancer cell lines has also been determined.

Four new nardosinane-type sesquiterpenoids, flavalins E—H (1—4) and two new nornardosinane-type norsesquiterpenoids, flavalins I (5) and J (6), along with five known compounds (7—11) have been isolated from a Formosan soft coral Lemnalia flava. The structures of these compounds were elucidated on the basis of their spectroscopic data. Moreover, the absolute configuration of 10 was further determined by Mosher's method.

New eunicellin-base diterpenoids, klysimplexins I–T (1–12), were isolated from a cultured soft coral Klyxum simplex. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute stereochemistry of 4 was determined by Mosher's method. Compounds 9 and 12 have been shown to exhibit cytotoxicity toward a limited panel of cancer cell lines. Compounds 2–6, 10 and 11 were found to display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein. Compounds 10 and 11 also could effectively reduce the level of COX-2 protein.

Eight new eunicellin-base diterpenoids, hirsutalins A-H (1-8), were isolated from the soft coral Cladiella hirsuta. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute configuration of 1 was determined by Mosher's method. Compounds 1, 5, and 6 have been shown to exhibit cytotoxicity toward several cancer cell lines. Compounds 2-4 and 8 were found to display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein, with compound 2 also effectively reducing the level of COX-2 protein.

Two new cembranoids, namely granosolides C (1) and D (2), along with one known cembranoid 4, were isolated from the soft coral Sinularia granosa. Chemical investigation of Sinularia querciformis also afforded one new cembranoid, querciformolide E (3), along with four known cembranoids 4—7. The structures of these compounds were elucidated on the basis of their spectroscopic data. Both 4 and 5 were shown to significantly inhibit the accumulation of the pro-inflammatory inducible nitric oxide synthase protein in lipopolysaccharide-stimulated RAW264.7 macrophage cells.

Seven new polyoxygenated steroids, hirsutosterols A-G (1-7), were isolated from the Formosan soft coral Cladiella hirsuta. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute configurations of 1 and 5 were determined by Mosher's method. Sterols 4-6 possess hydroxy groups at C-9 and C-11 and might be oxidatively cleaved to the corresponding 9,11-secosterols. Hirsutosterol A (1) was found to exhibit a stronger cytotoxicity against a limited panel of cancer cell lines.