Crassocolides N-P, three cembranoids from the Formosan soft coral Sarcophyton crassocaule

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.     

Diterpenoids from the South China Sea soft coral Sarcophyton solidum

Chemical investigation of the South China Sea soft coral Sarcophyton solidum has led to the isolation of one new (1) and seven known (2–8) diterpenoids, including three sarsolenanes (1–3), two capnosanes (4 and 5), and three cembranes (6–8). Sarsolilide B (4) was firstly confirmed by single-crystal X-ray diffraction. Compounds 1, 3, 4, and 6–8 were isolated from S. solidum for the first time, and 1, 2, and 4–7 were considered as the chemotaxonomic markers for the species S. solidum.     

Chemical constituents of soft coral Sarcophyton infundibuliforme from the South China Sea

Chemical investigation on soft coral Sarcophyton infundibuliforme collected from the South China Sea led to the isolation and identification of 14 secondary metabolites, including ten cembrene diterpenoids (1–10), one α-tocopheryl quinone derivative (11), one prostaglandin (12), one lipid (13) and one carotinoid (14). Their structures were determined by extensive analysis of their spectroscopic data. All of these metabolites were isolated from this species for the first time. Diterpenoids 1, 2, 7 and 10 showed potent antifouling activity against the larval settlement of barnacle Balanus amphitrite.     

Distribution of sarcophytol A in soft coral of the Sarcophyton genus

The distribution of sarcophytol-A in the Sarcophyton genus was investigated in seven samples belonging to S. glaucum (3 samples), S. infundibulifurme (2 samples), S. crassocaule (1 sample) and S. trocheliophorum (1 sample) that were collected on Ishigaki Island in Okinawa Prefecture. Sarcophytol-A was present in one sample each of S. glaucum and S. infundibulifurme. This study indicates that the composition of cembranoids in the Sarcophyton genus is not related with the respective species, but with the individual samples collected.     

New anti-inflammatory steroids from the Formosan soft coral Clavularia viridis

Four new steroids, stoloniferones R-T (1-3), and (25S)-24-methylenecholestane-3 beta,5 alpha,6 beta-triol-26-acetate (4) were isolated from the methylene chloride solubles of the soft coral Clavularia viridis. The structures of the metabolites were elucidated by extensive spectral analysis and their anti-inflammatory activity was measured in vitro.     

Trochelioid A and B,new cembranoid diterpenes from the Red Sea soft coral Sarcophyton trocheliophorum

Chemical investigations of the soft coral Sarcophyton trocheliophorum, has led to the isolation of six cembranoids, two of which are new, Trochelioid A (1) and B (2), and one, 16-oxosarcophytonin E (3) isolated from nature for the first time. Additionally, two have been isolated from S. trocheliophorum for the first time (4 and 6). Structures were elucidated by employing extensive NMR and HR-FAB-MS experimentation.     

Bioactive polyoxygenated cembranoids from a novel Hainan chemotype of the soft coral Sinularia flexibilis

Different chemotypes of Sinularia flexibilis exist in the Hainan island. Thus, a collection of this soft coral from a location different from the one of our previous study afforded three novel cembranoid esters featuring a n-butyl alcohol moiety, a structural element rare in natural products of both terrestrial and marine origin. The structures of the new compounds were elucidated by detailed spectroscopic analysis and by the comparison of their spectroscopic data with those reported in the literature. In addition, the absolute stereochemistry of the previously reported diepoxycembrene (9) was first time determined by the X-ray diffraction analysis. In bioassays, compounds 6–8 exhibited strong anti-inflammatory effect with IC₅₀ values of 2.7, 4.7, and 4.2?μM, respectively, whereas compound 5 displayed cytotoxicity against several cancer cells with IC₅₀ values ranging from 8.9 to 27.4?μM. A preliminary structural-activity relationship (SAR) was also described.     

Crassocolides G–M,Cembranoids from the Formosan Soft Coral Sarcophyton crassocaule

Seven new polyoxygenated cembranoids possessing an α‐methylene‐γ‐lactone group, crassocolides G–M ( 1 – 7 , resp.), have been isolated from the AcOEt extract of the Formosan soft coral Sarcophyton crassocaule. The structures of compounds 1 – 7 were established by detailed spectroscopic analyses, including 2D‐NMR spectroscopy (¹H,¹H‐COSY, HMQC, HMBC, and NOESY), while the absolute configuration of 1 was determined using a modified reaction of Mosher's method. The cytotoxicity of compounds 1 – 7 against a limited panel of cancer cell lines was also determined.     

New anti-inflammatory 4-methylated steroids from the Formosan soft coral Nephthea chabroli

Eight new 4-methylated steroids, nebrosteroids A-H (1-8) were isolated from the acetone solubles of the Formosan soft coral Nephthea chabroli. The structures were elucidated by extensive NMR spectroscopic analysis and their anti-inflammatory activity was measured in vitro.     

Cytotoxic and antioxidant activities of diterpenes and sterols from the Vietnamese soft coral Lobophytum compactum

Two new diterpenes, lobocompactols A (1) and B (2), and five known compounds (3-7) were isolated from the methanol extract of the soft coral Lobophytum compactum using combined chromatographic methods and identified based on NMR and MS data. Each compound was evaluated for cytotoxic activity against A549 (lung) and HL-60 (acute promyelocytic leukemia) human cancer cell lines. Among them, compound 5 exhibited strong cytotoxic activity against the A549 cell line with an IC₅₀ of 4.97 ± 0.06 μM. Compounds 3, 4, and 7 showed moderate activity with IC₅₀ values of 23.03 ± 0.76, 31.13 ± 0.08, and 36.45 ± 0.01 μM, respectively. The cytotoxicity of 5 on the A549 cells was comparable to that of the positive control, mitoxantrone (MX). All compounds exhibited moderate cytotoxicity against the HL-60 cell line, with IC₅₀ values ranging from 17.80 ± 1.43 to 59.06 ± 2.31 μM. Their antioxidant activity was also measured using oxygen radical absorbance capacity method, compounds 1 and 2 exhibiting moderate peroxyl radical scavenging activity of 1.4 and 1.3 μM Trolox equivalents, respectively, at a concentration of 5 μM.     

Cembrane diterpenoids from the soft coral Sarcophyton trocheliophorum Marenzeller as a new class of PTP1B inhibitors

A detailed investigation of the South China Sea soft coral Sarcophyton trocheliophorum Marenzeller yielded, along with six known terpenes (6?11), the new sarcophytonolides N?R (1?5), whose structures have been elucidated by detailed spectroscopic analysis. Sarcophytonolides N–R are mono- or bicyclic cembranoids characterized by the presence of three/four double bonds and oxidized methyl groups. Some of the isolated compounds showed significant inhibitory activity against human protein tyrosine phosphatase 1B (PTP1B) enzyme, a key target for the treatment of type-II diabetes and obesity, and some preliminary structure–activity relationships have been drawn. This is the first report on the anti-PTP1B activity of cembrane diterpenoids.     

Marine sterols X. Minor constituents of the sterols of the soft coral Sarcophyton glaucum

The sterol mixture of the southern Japan soft coral $\text{Sarcophyton glaucum}$ was found to contain a variety of minor components overlooked in a previous study. Five 4α-methylsterols ($\text{1}$ to $\text{5}$) and three 4-demethyl-sterols ($\text{6}$ to $\text{8}$) were isolated and their structures were confirmed.     

Highly diverse cembranoids from the South China Sea soft coral Sinularia scabra as a new class of potential immunosuppressive agents

The first and in-depth chemical investigation of the South China Sea soft coral Sinularia scabra has resulted to the isolation of a library of diverse cembrane type diterpenoids, including six new compounds, namely xiguscabrates A and B (1 and 2), xiguscabral A (3), xiguscabrols A and B (4 and 5), and 8-epi-xiguscabrol B (6), and twenty-seven known analogs (7–33). Their structures were elucidated by extensive spectroscopic analysis and by the comparison with literature data. In bioassay, several isolates exhibited inhibitory effects on the ConA-induced T lymphocytes and/or LPS-induced B lymphocytes proliferation. Among them, compound 24 showed considerable specific inhibition on B cell proliferation, with IC₅₀ value of 4.4 μM and selectivity index (SI) of 10.9. The structure-activity relationship (SAR) of the tested metabolites was analyzed, and the further mechanism study of the specific B-cell targeted immunosuppressive compound 24 on purified CD19⁺ B cells was also performed to uncover the effects on the function and maturity of B cells, including cytokines production, abnormal activation, antigen presenting capacity and plasma cells formation.     

Phylogenetic relationships within the tropical soft coral genera Sarcophyton and Lobophytum (Anthozoa, Octocorallia)

Abstract. The alcyonacean soft coral genera Sarcophyton and Lobophytum are conspicuous, ecologically important members of shallow reef communities throughout the Indo-West Pacific. Study of their ecology is, however, hindered by incomplete knowledge of their taxonomy: most species cannot be identified in the field and the two genera cannot always be distinguished reliably. We used a 735-bp fragment of the octocoral-specific mitochondrial protein-coding gene msh1 to construct a phylogeny for 92 specimens identified to 19 species of Lobophytum and 16 species of Sarcophyton . All phylogenetic methods used recovered a tree with three strongly supported clades. One clade included only morphologically typical Sarcophyton species with a stalk distinct from the polypary, poorly formed club-shaped sclerites in the colony surface, and large spindles in the interior of the stalk. A second clade included only morphologically typical Lobophytum colonies with lobes and ridges on the colony surface, poorly formed clubs in the colony surface, and interior sclerites consisting of oval forms with regular girdles of ornamental warts. The third distinct clade included a mix of Sarcophyton and Lobophytum nominal species with intermediate morphologies. Most of the species in this mixed clade had a polypary that was not distinct from the stalk, and the sclerites in the colony surface were clubs with well-defined heads. Within the Sarcophyton clade, specimens identified as Sarcophyton glaucum belonged to six very distinct genetic sub-clades, suggesting that this morphologically heterogeneous species is actually a cryptic species complex. Our results highlight the need for a complete taxonomic revision of these genera, using molecular data to help confirm species boundaries as well as to guide higher taxonomic decisions.     

Steroids from the soft coral Dendronephthya sp

Fifteen steroids were isolated from the soft coral Dendronephthya sp., of which five are determined as new compounds, namely (22E)-3-O-beta-formylcholest-5,22-diene (1), (22E)-3-O-beta-formyl-24-methyl-cholest-5,22-diene (2), 2-ethoxycarbonyl-2-beta-hydroxy-A-nor-cholest-5-ene-4-one (3), (22E)-2-ethoxycarbonyl-2-beta-hydroxy-A-nor-cholest-5,22-diene-4-one (4), and (22E)-2-ethoxycarbonyl-2-beta-hydroxy-24-mthyl-A-nor-cholest-5,22-diene-4- one (5). 1 and 2 belonged to 3-O-formylated cholesterol analogues, and 3 to 5 are unique ring A-contracted steroids. Their structures were elucidated by extensive 2D NMR in association with IR, MS analysis.     

Spatial and temporal patterns of scleractinian coral, soft coral, and zoanthid disease on a remote, near-pristine coral reef (Palmyra Atoll, central Pacific)

There is an urgent need for accurate baselines of coral disease prevalence across our oceans in order for sudden or unnatural changes to be recognized. Palmyra Atoll allows us to study disease dynamics under near-pristine, functionally intact conditions. We examined disease prevalence among all known species of scleractinian coral, soft coral and zoanthid (Palythoa) at a variety of coral reef habitats at Palmyra over a 2 yr period. In 2008, overall disease prevalence across the atoll was low (0.33%), but higher on the shallower backreef (0.88%) and reef terrace (0.80%) than on the deeper forereef (0.09%). Scleractinian coral disease prevalence was higher (0.30%) than were soft coral and zoanthid disease (0.03% combined). Growth anomalies (GAs) were the most commonly encountered lesions, with scleractinian species in the genera Astreopora (2.12%), Acropora (1.30%), and Montipora (0.98%) showing the highest prevalence atoll-wide. Discoloration necrosis (DN) was most prevalent in the zoanthid Palythoa tuberculosa (1.18%), although the soft coral Sinulana and Montipora also had a prevalence of 0.44 and 0.01%, respectively. Overall disease prevalence within permanently marked transects increased from 0.65% in 2008 to 0.79% in 2009. Palythoa DN contributed most to this increased prevalence, which coincided with rising temperatures during the 2009 El Ni?o. GAs on the majority of susceptible genera at Palmyra increased in number over time, and led to tissue death. Host distribution and environmental factors (e.g., temperature) appear to be important for determining spatiotemporal patterns of disease at Palmyra. More sophisticated analyses are required to tease apart the likely inter-correlated proximate drivers of disease occurrence on remote, near-pristine reefs.