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Coral reefs support rich levels of biodiversity, but are globally threatened by a multitude of factors, including land-sourced pollutants. Concentrations of organochlorine pesticides (OCPs) in three species of coral reef invertebrate at five sites along the Maputaland coast, South Africa were quantified. We aimed to assess spatial and interspecies variations in pesticide accumulation. Markedly high levels of a range of OCP residues were detected within tissues, with total concentrations (ng g−1 ww) ranging from 460 to 1200 (Sarcophyton glaucum), 1100–3000 (Sinularia gravis) and 450–1500 (Theonella swinhoei), respectively. A decreasing gradient in total pesticide concentrations was detected southward from Regal Reef, opposite Lake Sibaya, the hypothesised source of the pollutants. Observed gradients in pesticide concentrations and nitrogen isotope signatures indicated coastal groundwater to be the likely source of the pollutants. Further studies are required to assess the potential ecotoxicological impacts of these contaminants at the organismal and ecosystem level.

Two new steroids, ximaosteroid E (1) and ximaosteroid F (2), along with two known related compounds (3 and 4), were isolated from the Chinese soft coral Sinularia sp. Notably, 1 possesses an uncommon dihydrofuran group. Their structures were established from extensive spectroscopic analyses and comparisons of their spectral data with those reported in the literature. The absolute configuration of 2 was determined by applying the modified Mosher’s method. In bioassay, compounds 1, 2, and 4 showed significant cytotoxicity against the HL-60 tumor cell line with IC50 values of 1.79, 4.03 and 0.69 μM, respectively.

Chemical examination of a cultured octocoral, Sinularia sandensis, led to the isolation of a new constituent, (24S)-24-methylcholest-5-en-3β,4α-diol (1), together with two unusual sterols, 3β,4α-dihydroxyergosta-5,24(28)-diene (2) and gorgosterol (3). The structures of compounds 1−3 were established utilizing spectroscopic analysis and literature comparison. Additionally, the structure of 3 was identified by a single-crystal X-ray diffraction analysis directly, for the first time. Sterols 1 and 3 demonstrated slightly inhibition effects for the expression of inducible nitric oxide synthase (iNOS) protein in lipopolysaccharides (LPS)-induced RAW 264.7 mouse macrophage cells.

Climate change threatens coral reefs, with recent heatwaves causing widespread coral bleaching and mortality. Soft corals (order Alcyonacea) provide reef structure and habitat, but most reef research has instead focused on reef-building hard corals (order Scleractinia). Reviewing the primary literature documenting the effects of recent (2014–2020) marine heatwaves on corals, a period including the third global coral bleaching event, we found that only 20% (19/94) of studies presented any results of heat stress effects on soft corals, and even fewer (5%) presented taxonomic-specific results, highlighting the need for further study. Using images (n = 6265) collected on 16 expeditions to the world's largest atoll (Kiritimati; central equatorial Pacific) between 2007 and 2019, we quantified soft coral cover around the atoll's shallow (10-12 m depth) forereefs before and after a prolonged heatwave (the 2015/2016 El Nino). Prior to the heatwave, soft coral accounted for 3.0% of the benthic community, with greater cover at more sheltered sites with lower net primary productivity; Lobophytum and Sinularia were the most common genera. We documented a complete loss of soft coral after the heatwave within our sites. New soft corals were detected in 2019, three years after the heatwave. Photos of individual colonies tracked over time revealed that soft coral structures can persist for several years post-mortality, and hard corals can recruit onto these structures. Our study exposes the vulnerability of soft corals to heat stress, which has received scant previous documentation. Future studies examining the effects of heatwaves on coral bleaching and mortality should include soft corals.

This study aims to assess the soft corals community around Mauritius and Rodrigues Island due to the limited research on the abundance and diversity of soft corals in the area. Seven soft corals species are newly reported from Mauritian waters. Triplicates of 5-metreline transect were used to survey soft corals at twelve different monitoring sites. Of the sites monitored for soft coral occurrence, the highest Margalef richness index and Shannon index (H’) values were obtained at Port Mathurin for Rodrigues Island and at Les Salines for Mauritius. Identification was carried out using both morphological characters and a DNA-based marker. The morphological identification process was based on the external form and colouration, type of colony growth; the type of polyps and colonies and sclerites analysis. 41 different species showed dissimilar characteristics, and results grouped the colonies to three different families; 32 colonies of Alcyoniidae, 3 of Nephtheidae and 6 of Xeniidae were obtained. To ascertain morphological classification, the longest non-coding region of the mitochondrial COI-COII intergenic spacer (IGS) (consisting of 122 nucleotides) was used to construct a molecular phylogeny that included 21 species of octocorals. The COI-COII IGS phylogeny recovered 5 well supported clades, which did not tally with the cladogram based on morphological characters. Three dendrograms based on morphological characters were constructed where the first one involved mapping of all the morphological characters onto the tree, the second one was based mainly on the type of sclerites present and the third one based on the collection depth of the samples. The dendrogram based on morphological markers clustered all the soft corals from the Alcyoniidae family aside from the other families. The second dendrogram clustered all the soft corals from the genus Sinularia, Lobophytum, Sarcophyton as well as Cladiella kashmani together, away from the soft corals with distinct sclerite form. Furthermore, the third dendrogram clustered the soft corals into 2 major clades, one clade clustering the soft corals which are ubiquitous and a larger clade including all soft corals collected from a depth of 0 m to above 20 m. As documented by other studies on octocorals, construction of the phylogenetic tree has led to an appreciation of the importance of genetic work which has been overlooked while using traditional morphological characters.

Marine invertebrates have a great variety of defensive strategies, with taste deterrence and protective coloration among the most important. Species of the gastropod family Ovulidae are closely associated with chemically defended soft corals and can accumulate food-derived defensive substances. A painted mantle covers the shell, camouflaging some ovulid mollusks and making other conspicuous, which makes these mollusks a good model object for studying correlations between types of protective coloration and taste deterrence. We compared the palatability of two ovulids: Ovula ovum, whose coloration most researchers have interpreted as aposematic (although never tested directly), and Calpurnus verrucosus, whose coloration cannot be confidently assigned as either aposematic or cryptic. In feeding experiments, agar pellets flavored with water extracts of two mollusks and six soft coral species were offered to sympatric fishes, the Indo-Pacific sergeant (Abudefduf vaigiensis) and the juvenile barramundi ( Lates calcarifer ). Additionally, we studied fish feeding behavior. We found that both the foot and mantle of Ovula ovum have a strong aversive taste for fish, which proves aposematism in this species. On the contrary, Calpurnus verrucosus had an attractive taste for fish, which excludes aposematism in this mollusk. We contemplate possible crypticity over a long distance and in low visibility, as well as unlikeness of mimetic nature of such coloration. All soft corals tested, including host species for mollusks ( Sarcophyton and Sinularia) were strongly aversive. Because both mollusks feed on soft corals but differ dramatically in palatability, it is probable that Ovula ovum and Calpurnus verrucosus transform soft coral antifeedants in different ways; however, we cannot rule out the possibility of de novo synthesis of taste deterrents in Ovula ovum. Both fish species orosensorially tested flavored pellets several times before swallowing or rejecting them. For pellets that produce aversive taste, the number of repeated grasps is smaller and retention time is longer than for pellets that produce attractive taste.

One novel sesquiterpenoid containing an unprecedented eight-membered cyclic peroxide motif, sinulatumolin A (1), along with four new related terpenoids, namely sinulatumolins B–E (2–4 and 6), were isolated from South China Sea soft coral Sinularia tumulosa. The structures of all the isolates were elucidated by detailed spectroscopic analysis, chemical transformations, and single X-ray diffraction analysis. Compound 1 represents the first example of sesquiterpene bearing an eight-membered cyclic peroxide ring from soft coral. All the new compounds isolated were evaluated for their anti-inflammatory activity. Compounds 1, 3, 4 and 6 displayed significant TNF-α inhibitory activity being comparable with that of the positive control dexamethasone (IC50 = 8.7 μM), with IC50 values of 7.5, 2.6, 5.5, and 3.6 μM, respectively.

Coral reef organisms, including octocorals, are facing the consequences of anthropogenic activities, such as increasing oceanic pH and sea surface temperature, threatening their long-term survival and well-being. Gene expression studies based on quantitative PCR (qPCR) are important tools to provide insight into the molecular basis of octocoral stress responses and their potential resilience mechanisms. Nevertheless, a lack of experimentally validated, stably expressed reference genes for the normalization of gene expression using quantitative reverse transcriptase PCR (qPCR) method limit such investigations among octocorals. Here, assessment of the expression stability of seven candidate reference genes was performed using a palette of statistical tools for valid qPCR-based gene expression studies on the octocoral Sinularia cf. cruciata during thermal (34 degrees C) and low-pH (pH 7.5) stress and the most suitable set of reference genes was determined for such experiments. The reliability of the selected reference genes was confirmed in a qPCR assay that targeted the heat shock protein 70 (HSP70) gene. The HSP70 gene was found to be significantly upregulated during thermal stress, whereas during low-pH stress the expression level of this gene decreased. This study provides experimentally validated stress-specific sets of stably expressed reference genes during climate change-induced stresses, which will benefit future gene expression studies on Sinularia cf. cruciata as well as other octocorals. These results also highlight potentially different acclimation strategies of octocorals to different sources of abiotic stresses, contributing to our understanding of the potential for the adaptation of coral reef organisms to a changing world. (C) 2016 Elsevier B.V. All rights reserved.

Five new diterpenoids, pambanolides A–C (1, 2a, 2b and 3) and 4,5-secosinulochmodin C (4) were isolated from the soft coral Sinularia inelegans along with five known compounds (5–9). The structures of all metabolites were elucidated by comprehensive analysis of spectroscopic data. A biosynthetic pathway has been proposed for the formation of pambanolides A (1) and rameswaralide (6). Seven of the isolated compounds were evaluated for cytotoxic activity against a panel of four human cancer cell lines A549, DU145, HeLa and MCF-7 and were found to have weak cytotoxicity.

A complete or partial loss of symbiotic dinoflagellates (SD) by the corals in response to thermal stress has been described as coral bleaching. A stress damages the photosynthetic apparatus of SD and their thylakoid membranes, and symbiotic alga cells disappear via exocytosis and/or apoptosis resulting in a disturbance of host cell membranes. Lipids play an essential role in coral metabolism and constitute the basis of membranes. At present, studies of coral bleaching typically deal with long-term lipid indices, such as total lipids and fatty acids (FAs), while short-term dynamics of lipidome (full range of all lipid molecular species) has not been considered in the context of bleaching mechanism. To evaluate the lipidomic approach to characterizing coral bleaching, the soft coral Sinularia sp. was exposed to a short-term experimental thermal stress (33 °C). The dynamics of chlorophyll level, the composition of total FAs, the amounts of total lipids and major lipid classes (such as wax esters (WE), triacylglycerols (TAG), and monoalkyldiacylglycerols (MADAG), glycolipids, ethanolamine-, choline-, serine-, inositolglycerophospholipids (PE, PC, PS, PI), and ceramide aminoethylphosphonate (CAEP)) and the variations in the content of lipid molecular species were studied during a 36-h heat exposure. >160 molecular species were identified by tandem high-resolution mass spectrometry. Under the short-term stress, a considerable decline in the levels of chlorophylls, glycolipids, and FA markers of SD was detected, whereas the variations in the content of total lipids, total phospholipids, and major FAs were not significant. The heat exposure immediately disturbed the daily cycle of the composition of glycolipid molecular species. Among the storage lipids, the content of TAG and MADAG decreased, whereas the content of polyunsaturated WE molecular species increased under the stress. The following effects were recorded for the structural lipids: a depletion in the PE, PC, and PI amounts, a conversion of PE into their lyso and oxidized derivatives, an appearance of diacyl form of PE, and a disturbance of transfer of some polyunsaturated FAs from SD to the host. The content of PS was relatively stable. Probably, PE molecular species are a primary target of thermal stress in the Sinularia host. The most dramatical changes in the Sinularia lipidome were detected between 24 h and 36 h of the exposure. A lipidomic approach is important for studies of dynamics of the coral symbiotic association and a resistance of different coral taxa during short-term bleaching events.

Little knowledge exists on the state of metal contamination in corals from the Western Indian Ocean (WIO). Fragments of four soft and five hard coral genera were collected from five sites in the WIO– Sodwana Bay and Aliwal Shoal from South Africa, and Agalega, Rodrigues, and St. Brandon's Rock from the Mascarene Basin. Fragments were analysed for 31 metallic elements using inductively coupled plasma mass spectrometry. Corals from the WIO contained lower concentrations of most metals than corals from the Red Sea. South African corals contained higher concentrations of most of the metallic elements than the Mascarene corals. Sinularia was the coral with the most elements at the highest mean concentrations. A very high concentration of Ni was found in Sinularia (1300 mg/kg dm) from Sodwana Bay. Corals from the Mascarene Islands, especially Agalega, had comparatively low concentrations and could serve as a benchmark for corals from other regions.

One new polycyclic furanobutenolide-derived norcembranoid, xiguscabrolide H (1), together with eleven known related norditerpenoids 2-12 were isolated from South China Sea soft corals Sinularia scabra and S. polydactyla, respectively. Among them, compounds 1, 6, 8, and 12 were discovered from the former species, while compounds 2-5, 7, and 9-11 were obtained from the latter species. The structure of new compound 1 was elucidated by extensive spectroscopic analysis and by the comparison with the reported data. With the assistance of time-dependent density functional theory electronic circular dichroism (TDDFT-ECD) calculations, its absolute configuration was determined. Moreover, the absolute stereostructures of the known compounds 3, 4, and 9-12, of which only relative configurations were assigned, were established for the first time by X-Ray diffraction analysis and TDDFT-ECD calculations, respectively. In bioassay, several isolates exhibited potent inhibitory effects on the ConA-induced T lymphocytes and/or LPS-induced B lymphocytes proliferation.

Natural coastlines around the world are increasingly being modified and replaced by breakwaters, revetments and seawalls. Although such infrastructure is primarily intended to protect existing and new shorelines from erosion, such coastal defence structures can also serve as viable habitats for biological communities. In this study, the feasibility of transplanting reef biota to the intertidal zone of seawalls was explored. Fragments of hard corals ( Porites lobata, Pocillopora damicornis, Hydnophora rigida, Diploastrea heliopora, Goniastrea minuta ), soft corals (Cladiella sp., Lobophytum sp., Sinularia sp.) and sponges ( Rhabdastrella globostellata, Spongia ceylonensis, Lendenfeldia chondrodes ) were collected and reared in an ex situ mariculture facility. They were then transferred and affixed to intertidal surfaces of a seawall located on a small island off Changi, Singapore. Survivorship was significantly different between G. minuta and D. heliopora fragments transplanted on the seawall for 13 months (90% vs 10%; χ 2 = 42.29, p χ 2 = 19.59), soft corals ( χ 2 = 41.94) and sponges ( χ 2 = 50.97) (all p Lobophytum , the sponge L. chondrodes and the hard coral P. lobata fared the best, registering high overall survivorship (87.5%, 68.1%, and 47.4%, respectively), long mean survival times (21.6 months, 17.8 months, and 12.3 months, respectively), and fast growth (50-fold, 23-fold and 10-fold increases in size, respectively) 24 months post-transplantation. In contrast, Pocillopora damicornis , H. rigida and R. globostellata were unable to establish on the seawall, with all transplants of the former two species perishing within two months, and those of the latter species succumbing 18 months after transplantation. Overall, species with massive and encrusting growth forms were most successful at establishing on the seawall, and were even observed to function as food and shelter for reef fish and gastropods. These results indicate that the transplantation of nursery-reared reef biota is a viable strategy that enhances the ecological value of seawalls.

Six common soft coral species ( Sarcophyton sp., Sinularia sp.1 and sp.2, Cladiella sp., Scleronephthya sp. and Dendronephthya sp.) from Bandar Al-Khayran (Sultanate of Oman) had significantly lower bacterial density in comparison with surfaces of empty shells. Methanol: chloroform (1:1) extracts of these species were tested against Gram positive ( Micrococcus luteus, Staphlococcus aureus, Bacillus subtilis, Bacillus sp.) and Gram negative ( Salmonella enterica, Pseudomonas aeruginosa, Escherichia coli, Cytophaga sp., Pseudomonas sp., Shewanella sp.) marine biofouling and pathogenic bacterial strains. All tested extracts had some activity against human pathogens and the highest antimicrobial activity was observed for extracts of Sinularia sp.1 and Cladiella sp. (inhibited 50% and 60% of the strains, respectively). Only ethyl acetate extracts of Cladiella sp. inhibited growth of biofouling bacteria. The active fraction was purified and identified as a mixture of hexadecyl palmitate and hexadecyl stearate. Pure hexadecyl palmitate inhibited growth ( Bacillus sp. and Psychrobacter sp.) and attachment ( Bacillus sp., Cytophaga sp., Pseudomonas sp., Psychrobacter sp., Shewanella sp.) of the marine biofouling bacteria. The results of this study suggest that soft corals have developed mechanisms to combat microbial infections and inhibit bacterial fouling.

AIM:To study the minor diterpenes from the soft coral Sinularia depressa.METHOD:The chemical constituents were isolated and purified by various chromatographic techniques,and the chemical structures,including absolute configuration,were established on the basis of detailed analysis of spectroscopic data and by literature comparison with the data of related known compounds.RESULTS:A new casbane-type diterpene,2-epi-10-hydroxydepressin(1),was isolated and identified.CONCLUSION:Compound 1 is a new casbane-type diterpene.

One novel nine-membered macrocyclic polysulfur cembranoid lactone, sinulariaoid A (1); three new multioxygenated cembranoids, sinulariaoid B (2), sinulariaoid C (3), sinulariaoid D (4); and four known cembranoids, capilloloid (5), dihydrosinularin (6), sinularin (7), and dihydrosinuflexolide (8) were isolated from the soft coral Sinularia sp. collected off of Sanya Bay in the South China Sea. Their stereochemical structures were determined on the basis of extensive spectroscopic methods, including single crystal X-ray diffraction analysis. Sinulariaoid A (1) is the first reported nine-membered macrocyclic polysulfur cembranoid from soft coral. The cytotoxic activities of compounds 1–8 were determined in four human cancer cell lines (HepG2, HepG2/ADM, MCF-7, and MCF-7/ADM). Of these, sinulariaoid A (1) exhibited the most potent anticancer activity in vitro, and its cytotoxicity in HepG2/ADM was more potent than in the other three cell lines. Furthermore, it was found that sinulariaoid A (1) induced apoptosis, and its selective toxicity toward HepG2/ADM cells was not related to P-glycoproteins.

Chemical examination of the soft coral Sinularia capillosa resulted in the isolation of eight new sesquiterpenoids named capillosananes S–Z (1–8) and six known sesquiterpenes. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including CD effects and Mosher method for the assignment of their absolute configurations. Capillosananes S–U (1–3) presented as the novel carbon skeletons with bicyclo[3,6,0] and bicyclo[4,5,0] systems, while capillosanane V (4) was characteristic of an unprecedented tricyclic skeleton. Capillosananes W–X (5–6) were assigned to the unusual dumortane-type sesquiterpenes. In addition, the absolute configurations of the stereoisomers of isodaucene-9,14-diol were assigned for the first time.

Two new highly oxygenated ergostane-type sterols (1, 2) together with one known related compound sinugrandisterol A (3) were isolated from the soft coral Sinularia sp. collected from the water area near the Xisha Islands, South China Sea. Their structures were elucidated on the basis of detailed spectroscopic analysis, chemical transformations, and by comparison with those reported in literature. In bioassays, compounds 1 and 2 showed in vitro antiproliferative activity against a panel of cancer cell lines, including MDA-MB-436, A549, Hep3B, HT-29 and H157. Morphological observation and Hoechst 33,258 staining assays showed that compound 1-treated H157 cells displayed apoptosis characteristics. Moreover, western blot assays suggested that 1 could increase the expression of Bax and down-regulate expression of Bcl-2.

The chemical investigation of soft coral Sinularia kavarattiensis is described. It yielded furano-sesquiterpene carboxylic acids 1 and 2 and their methyl esters 3 and 4. Semi-synthesis of furano-sesquiterpene carboxylic acid 1 gave amide derivatives 5-12. Structures of all the compounds were established by IR, NMR and mass spectral analysis. Interestingly all compounds are selectively potent on leukemia cell line. All these compounds were screened for cytotoxic activity against five human cancer cell lines (leukemia, prostate, lung, breast and cervix). Among these compounds 9 and 10 showed promising activity against leukemia and prostate cancer cell lines.

A chromatographic and NMR spectroscopy-based fractionation on the acetone extracts of the soft coral Sinularia sandensis led to the isolation of a novel sesquiterpenoid, sandensone A (1). The structure of 1 was elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as HRESIMS spectrometry. The absolute configuration at C-12 of 1 was determined as R using a modified Mosher’s method. The cytotoxicity against A549 (human lung carcinoma), HT-29 (human colon adenocarcinoma), and P-388 (mouse lymphocytic leukemia) cancer cell lines as well as antiviral activity against HCMV (human cytomegalovirus) were evaluated in vitro.

A novel norcembranoidal diterpene, sinulanorcembranolide A (1), which was found to possess a new carbon skeleton, was isolated from an octocoral identified as Sinularia gaweli. The structure of 1 was elucidated by spectroscopic methods. Sinulanorcembranolide A (1) was proven to be the first norcembranoidal diterpene with carbon–carbon linages between C-5/13 and C-7/12. A plausible biosynthetic pathway of 1 was proposed.

A novel polyhydroxylated sterol, 3β-25-dihydroxy-4-methyl-5α,8α-epidioxy-2-ketoergost-9-ene ( 1 ) along with three new ceramides, N -[(2 S ,3 R , E )-1,3-dihydroxyhexacos-4-en-2-yl]icosanamide ( 2 ), N -[(2 S ,3 S ,4 R )-1,3,4-trihydroxyhexacosan-2-yl]icosanamide ( 3 ), and ( R )-2′-hydroxy- N -[(2 S ,3 S ,4 R )-1,3,4-trihydroxypentacosan-2-yl] nonadecanamide ( 4 ) were isolated from the Red Sea soft coral, Sinularia candidula. Complete structure elucidation was achieved through extensive spectroscopic analysis including one- and two-dimensional nuclear magnetic resonance spectroscopy. Sinularia candidula extracts of different polarities as well as the isolated pure compounds were screened against the highly pathogenic H5N1 avian influenza strain using the plaque inhibition assay in MDCK. The results indicated that the extracts of the Red Sea soft coral Sinularia candidula possessed potent antiviral activity (100% inhibition at a concentration of 1 μg/mL). The isolates 1 , 2 , 3 , and 4 showed reduction of virus titer by 55.16%, 48.81%, 10.43%, and 15.76% at a concentration of 1 ng/mL, respectively.

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.

Soft corals of the genus Sinularia are one of the most widespread soft corals. They are a rich source of bioactive substances with intriguing and unique structural features. The present paper reviews the latest progress in the chemistry and pharmacological activities of terpenoids from Sinularia soft corals and provides a perspective on future areas of research interest.

Hard and soft coral community structures were studied in eight sites in the inshore zone of the Red Sea subdivided geo-morphologically into exposed and sheltered sites and geographically into northern and southern entities. Forty-one hard coral and 13 soft coral species were recorded in the exposed sites, while 42 hard coral and 19 soft coral species were observed in the sheltered sites. The southern entity showed 46 of hard coral and species and 14 soft coral species, while the northern entity showed 43 hard coral and 22 soft coral species. Abu Dabab recorded the highest number of species (35 hard and 9 soft) at the exposed sites, Ennadi recorded the highest number of species (48 hard and 17 soft) at the sheltered sites, while Rasel Behar was the poorest site in hard species (17 species) and Sharmel Bahari in the soft species (2 species). Acropora was the most dominant hard coral genus (25.16%, 23.22%), Sinularia and Sarcophyton were the most dominant soft genera (3.11%, 3.87%) at the exposed sites and the southern entity. Stylophora dominates the hard coral cover (16.15%, 15.63%), Sarcophyton and Heterxenia were dominating the soft coral cover (8.38%, 6.98%) at the sheltered sites and northern entity. Branching hard corals and dendrite soft corals were the main in all sites and interties. Hard and soft corals were controlled by; sedimentation rates, wide range of temperature changes, direct exposure to solar radiation, neap tide stresses, wave action and differential hydrodynamic exposure. The sheltered sites showed higher evenness index and richness than the exposed sites while the exposed sites showed higher diversity. Geographically, northern entity was significantly higher in diversity, evenness indexes and species richness than the southern ones.

Treatment of a solution of the macrocyclic norcembranoid 7 with lithium hexamethyldisilazide in THF at −78 °C to 0 °C, leads to the polycyclic norcembranoids ineleganolide 1 and sinulochmodin C ( 2 ) (65%), which are found in the corals Sinularia inelegans and Sinularia lochmodes , respectively. The conversions are believed to be biomimetic, and occur by successive transannular Michael reactions in 7 . Under different temperature conditions the novel polycycle 30 is the main product, alongside small quantities of 1 and 2 . The polycycle 30 is possibly produced from ineleganolide 1 , following a reverse oxy-Michael reaction and two successive aldol reactions. The significance of the synthesis of ineleganolide 1 , sinulochmodin C ( 2 ) and the structure 30 from 5-episinuleptolide 7 , to the likely biosynthesis of the related norcembranoids scabrolide A ( 3 ), scabrolide B ( 4 ) and horiolide 31 found in Sinularia sp. is discussed.

Chemical analysis of the secondary metabolite pattern of the aeolid nudibranch Phyllodesmium magnum collected from the South China sea resulted in the isolation of eight sesquiterpenes, exhibiting very different structural features, which included one asteriscane (1), two africanane (2, 3), one elemane (4), two selinane (5, 6), and two furano- (7,8) sesquiterpenes. Among them, compound 1, a new molecule, represents the fourth example of a rare asteriscane skeleton from a natural source, and the seven known sesquiterpenes (2-8) are new for P. magnum. The occurrence of the metabolites possessed by Phyllodesmium guamensis supports recent chemecological studies that it preys on the soft coral Sinularia sp., and uses these dietary chemicals as its defensive weapon. (C) 2011 Elsevier Ltd. All rights reserved.

Natural Product Antifoulants (NPAs) have been proposed as one of the best alternatives for the globally banned toxic biocide -TBT-in antifouling coatings. In search of NPAs from Indian waters twenty nine species of Octocorals, collected from Gulf of Mannar and Lakshadweep islands, were screened for their antifouling potential against the cyprids of the cosmopolitan biofouler, Balanus amphitrite . The crude extracts of 8 species of these corals ( Cladiella krempfi , Lobophytum irregulare , Lobophytum sarcophytoides , Sarcophyton ehrenbergi , Sarcophyton glaucum , Sinularia kavarattiensis , Melitodes sp. and Subergorgia reticulata ) exhibited relatively high settlement inhibition properties. The bioassay-guided purification of the crude extracts of 3 active and abundant species– Cladiella krempfi , Sinularia kavarattiensis and Subergorgia reticulata– yielded five NPAs, (l’E,5′E)-2-(2′,6′-dimethylocta-l’,5′,7′-trienyl)-4-furoic acid 1, (−)-6-α-hydroxy polyanthellin A 2, (+)-(7R,10S)-2-methoxy calamenene 3 , (+)-(7R,10S)-2,5-dimethoxy calamenene 4 and (+)-(7R,10S)-2-methoxy,5-acetoxy calamenene 5 ). Among these, 5 exhibited high future prospects on account of its low EC 50 value (0.0335 μg/ml) and high therapeutic ratio (799).

Chemical investigations of the soft coral Sinularia gyrosa resulted in the isolation of six new norcembranolides, gyrosanolides A-F (1-6), a new norcembrane, gyrosanin A (7), and 11 known norditerpenoids 8-18. The structures of the isolated compounds were elucidated through extensive spectroscopic data and by comparison with reported data in the literature. Compounds 1-3, 7-9, 12, and 13 at concentration of 10microM did not inhibit the COX-2 protein expression, but significantly reduced the levels of the iNOS protein (55.2+/-14.6%, 18.6+/-6.7%, 10.6+/-4.6%, 66.9+/-5.2%, 10.2+/-5.1%, 17.4+/-7.2%, 47.2+/-11.9%, and 56.3+/-5.1%, respectively) by LPS stimulation. Compound 8 showed significant antiviral activity against HCMV (human cytomegalovirus) cells with an IC(50) of 1.9microg/mL.

This work demonstrates the toxic effects of Sinularia leptoclados, Sinularia depressan and Sinularia inflate extracts on human oral squamous cell carcinoma (SCC4, SCC9 and SCC25) cells using cell adhesion and cell viability assays. The three extracts inhibited growth of human SCC25 (which exhibited effective differentiation) cells than they did SCC4 (moderate differentiation) and SCC9 (poor differentiation) cells. The morphological changes of the SCC25 cells upon treatment with the three extracts were caused by apoptosis, as determined from the morphological features (spheroid shape, chromatin condensation and formation of apoptotic bodies). Flow cytometry indicates that three extracts sensitized SCC25 cells in the G2/M phases with a concomitantly and significantly increased fraction of sub-G1. This investigation reveals that apoptosis that occurred when the SCC cells were treated with S. leptoclados, S. depressan and S. inflate extracts was accompanied by up-regulation of p53 and activation of caspase-3 expression.

Chemical investigation of the soft coral Sinularia flexibilis (Quoy and Gaimard), collected from the southern coast of Taiwan, led to the isolation of 10 new cembrenoid diterpenoids, the flexilarins A–J (1–10), along with 17 known compounds (11–27). The structures of these compounds were elucidated by spectroscopic techniques (NMR, MS, UV, IR). The structure of compound 1 was confirmed by X-ray crystallographic analysis. Compound 4 exhibited potent cytotoxicity against Hep2 tumor cells.

The deregulated activation of NF-kappaB is associated with cancer development and inflammatory diseases. With an aim to find new NF-kappaB inhibitors, we purified and characterized compounds from extracts of the Fijian sponge Rhabdastrella globostellata, the crinoid Comanthus parvicirrus, the soft corals Sarcophyton sp. nov. and Sinularia sp., and the gorgonian Subergorgia sp. after an initial screening of 266 extracts from different marine origins. Results obtained show that selected purified compounds had a cytotoxic effect on the human leukaemia cell line K562, inhibited both TNF-alpha-induced NF-kappaB-DNA binding as well as TNF-alpha-induced IkappaBalpha degradation and nuclear translocation of p50/p65. Furthermore, we observed the inhibition of NF-kappaB activation induced by an overexpression of IKKbeta. Interestingly, natural products inhibited IKKbeta kinase as well as the 26S proteasome proteolytic activity.

Four novel cyclic peroxide-containing sesquiterpenes ( 1–4 ), with a γ-alkylidene-α-methyl-α,β-unsaturated γ-lactone moiety, have been isolated from a Formosan soft coral of the genus Sinularia. Their structures were elucidated mainly by extensive 1D and 2D NMR experiments.

A repeated silica gel column chromatography followed by HPLC purification on the methanol extract of marine soft coral Sinularia dissecta , resulted in the isolation of fifteen polyhydroxylated steroids ( 1 – 15 ), involving six new C-18 functionalized steroids, 3β-acetoxy-1α,11α-dihydroxygorgost-5-en-18-oic acid ( 1 ), gorgost-5-en-1α,3β,11α,18-tetrol ( 2 ), 18-acetoxy-1α,3β,11α-trihydroxygorgost-5-ene ( 3 ), 24( S )-3β-acetoxy-1α, 11α-dihydroxyergost-5-en-18-oic acid ( 4 ), 24( S )-ergost-5-en-1α,3β,11α,18-tetrol ( 5 ), and dissectolide ( 6 ). The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, 1 H and 13 C NMR, HMQC, HMBC, and NOESY) analysis. Compound 6 was found as an unusual sterol bearing a lactone functionality.

The deleterious effects of temperature-induced coral bleaching, a process by which corals lose their endosymbiotic algae (zooxanthellae; genus Symbiodinium) primarily at temperatures above mean yearly maximums, has not been well described for alcyonacean soft corals (Coelenterata, Octocorallia). The study of Symbiodinium cells lost from Sarcophyton ehrenbergi, Sinularia sp., and Xenia sp., which have not been compared in bleaching studies, indicate that the soft coral S. ehrenbergi released the greatest number of symbiont cells, however, it was less susceptible to heat stress surviving temperatures of 34 degrees C for > 39 h. Sinularia sp. showed intermediate levels of bleaching tolerance to elevated temperatures, surviving prolonged exposures at 32 degrees C, but dying within 24 h at 34 degrees C. Xenia sp., however, was the most vulnerable to high heat stress maximally releasing Symbiodinium at temperatures

The study of symbiont cells lost from bleached scleractinian corals Acropora hyacinthus, Favites complanata, and Porites solida and octocorals Sarcophyton ehrenbergi, Sinularia sp., and Xenia sp. using flow cytometry shows that Symbiodinium die from either apoptosis or necrosis. Despite the majority of lost Symbiodinium cells being viable at 28 °C, the predominance of apoptotic and necrotic symbiont cells at higher temperatures indicates that the proportion of live cells decreases with increasing temperature. This implies that reinfection of corals at high temperatures by Symbiodinium lost from scleractinian corals may be less frequent than previously described, since many of the symbiont cells exhibit nonreversible symptoms of approaching cell death. The fraction of viable Symbiodinium cells lost from S. ehrenbergi, Xenia sp., and Sinularia at 32 °C was greater than that at 28 °C. At 34 °C, the fraction of viable cells lost from S. ehrenbergi and Xenia sp. fell but not from Sinularia sp., which suggests that their symbionts have higher temperature tolerances. Thus, Symbiodinium from octocorals may represent “pools” of genetically resistant symbionts available for reinfection of other reef organisms. This has been proposed previously for Symbiodinium in some scleractinian corals, but this is the first evidence for such, particularly for an octocoral. Many of the viable cells, determined using Trypan blue staining techniques, are in fact actually undergoing apoptosis or necrosis, when examined using Annexin V-fluor and propidium iodide staining profiles. The characterization of more apoptotic and necrotic cells than viable cells is critical, as this indicates that the loss of Symbiodinium cells cannot be beneficial to other bleached corals for symbiotic reassociation.

One of the earliest quantitative surveys of soft corals, on a reef flat in Pago Pago Harbour, American Samoa, was repeated 85 years later. The alcyoniid communities there, which were the dominant benthic organisms during the initial survey, have suffered a drastic decline of 99% cover in the interim. The most likely causes of the decline are anthropogenic disturbance associated with reclamation along the harbour from the 1940s to early 1960s, compounded by chronic pollution from industrial wastewater discharge from the mid-1950s to late 1980s. The decline in one dominant species, Sinularia polydactyla, is likely to have serious consequences for the reef as unusually for a soft coral, this had been the major reef building species. Life-history traits of certain Sinularia and Sarcophyton, such as slow growth and low rates of sexual reproduction, mean they will be slower to recover from severe disturbance than many scleractinian corals.

Chemical analysis of the Indonesian soft coral Sinularia sp. (order Alcyonacea, family Alcyoniidae) afforded two new alkaloids, named sinulasulfoxide (1) and sinulasulfone (2), characterized by an amide linkage between a phytanic acid moiety and an uncommon sulfur-containing unit. Their complete stereostructures were elucidated by interpretation of MS and NMR data along with CD analysis and chemical modifications. Sinulasulfoxide (1) proved to moderately inhibit LPS-induced NO release.

A novel compound, named sinutriangulin A (1), was isolated from the soft coral Sinularia triangula. The compound possesses a new carbon skeleton that is derived from the cubitane skeleton. The structure was determined by extensive spectroscopic analyses. In addition, compound 1 exhibited weak cytotoxicity toward human tumor cell lines CCRF-CEM and DLD-1.

Chemical examination of the soft coral Sinularia dissecta furnished five steroids ( 1–5 ), which include four new polyhydroxy steroids ( 2–5 ). The structures of new compounds have been established by the study of their spectral data. Steroid 5 was a novel polyoxygenated epoxy steroid.

Sinulamide (1), a new tetraprenylated spermine derivative, has been isolated from a soft coral Sinularia sp. as an H,K-ATPase inhibitor. The structure was assigned on the basis of spectroscopic data and confirmed by a total synthesis.

Rameswaralide ( 4 ), a novel diterpene having a 5-7-6 tricyclic skeleton has been isolated along with known terpenes, africanene, 4,5- seco -african-4,5-dione, β-elemene and isomandapamate ( 3 ) from the soft coral Sinularia dissecta from the Mandapam coast, South India. The structure and stereochemistry of rameswaralide ( 4 ) were determined using spectroscopic methods and confirmed by selective reduction of the unusually stable enol group of 4 to form dihydrorameswaralide ( 5 ).

The isolation of a novel seco and spiro lactone diterpenoid, havellockate ( 1 ) from the Indian ocean soft coral Sinularia granosa and its structure elucidation using all spectral data including X-ray analysis is presented. © 1997 Elsevier Science Ltd. All rights reserved.

Chemical examination of a new soft coral species of Sinularia genus of the Indian Ocean resulted in the isolation of 4 new and rare aromadendrane type of diterpenoids, in addition to the known Δ 9(15) - africanene , batyl alcohol and three polyhydroxy steroids. The structures of new diterpenoids have been established by a study of their spectral data. The diterpenoids of this class have now been reported for the first time from a marine organism, while they were reported only once from a terrestrial source. The crude extract of the organism has showed moderate larvicidal activitiy.

The sesquiterpene (1′ E ,5′ E )-2-(2′,6′-dimethylocta-1′,5′,7′-trienyl)-4-furoic acid ( 2 ), which is an anti-inflammatory metabolite of the soft coral Sinularia spp. has been synthesized by two routes, both of which employ a Claisen rearrangement.

A novel terpenoid, polymaxenolide, has been isolated from the hybrid soft coral Sinularia maxima × Sinularia polydactyla. The structure and stereochemistry were determined using spectroscopic methods and X-ray diffraction analysis. This terpenoid with a biosynthetically mixed skeleton is characterized by a C,C-linkage between a cembrane-type diterpene and an africanane-type sesquiterpene. A possible biogenesis is proposed.

An associationsl refuge occurs when an organism escapes predation by being closely associated with another organism. We describe a refuge provided by the soft coral Sinularia sp. for algae of the genus Halimeda growing at its bases. Total algal biomass was significantly greater in the 0–10 cm zone than in zones 10–20 and 20–30 cm around individual soft coral colonies. Total algal biomass was also significantly greater within clusters of colonies than in zones 0–10, 10–20, and 20–30 cm around the perimeter of the clusters. Halimeda incrassata (Ellis) and Halimeda opuntia (Linnaeus) Lamouroux comprised the bulk of the total algal biomass and were the only species that showed a pattern of growth similar to the total biomass. Fishes consistently grazed less algae ( Halimeda incrassata and Acanthophora spicifera (Vahl) Boergesen and seagrass ( Halodule uninervis Ascherson) strands placed next to soft corals than farther away. Fishes grazed indiscriminately around objects (rocks or outcrops of dead hard coral), whereas differential grazing occurred around soft corals. This suggested that the presence of an object alone is not responsible for reduced grazing next to the soft coral. When soft corals were removed, the pattern of grazing was disrupted, whereas around intact colonies the pattern persisted. Subsequently, funnel-shaped carrageenan models, that resembled the arborescent shape of Sinularia sp., produced a similar grazing pattern. Removing soft corals did not appear to encourage grazing of exposed Halimeda spp. by fishes. This may be explained by the chemically deterrent or heavily calcified nature of Halimeda spp. (the dominant algae around soft corals) which would prohibit vigorous consumption by herbivorous fishes. Algal species richness did not appear to be enhanced by the presence of Sinularia sp. We found no evidence for chemical defense in experiments with soft coral extracts, carrageenan models, and rehydrated Sinularia sp. colonies. Just as much seagrass was grazed around models and colonies with added extracts as around controls, suggesting that terpenes and other metabolites present in the extracts were not responsible for the protective refuge provided by the soft coral. However, a significant effect of distance was consistently obtained in experiments with funnel-shaped models and rehydrated soft corals, whereas, no effect of distance occurred with beaker-shaped models. These results suggest that the arborescent shape of Sinularia sp. provides a refuge for young recruits of Halimeda spp., and allows the algae to mature until they are not preferred by herbivorous fishes. This study is the first to directly test whether morphological features or chemical properties of a benthic marine organism are responsible for protecting closely associated algae.

Concentrations and types of antipredator defenses vary among tissues within colonies of many colonial marine invertebrates. However, experimental tests have rarely been conducted to assess the consequences of differences in defenses among tissues. We used field bioassays at Guam with generalist carnivorous fishes to compare feeding rates on artificial diets that contained physical and chemical defenses from three species of tropical soft corals, Sinularia maxima, S. polydactyla , and an undescribed species of Sinularia . Crude extracts and sclerite concentrations were added to the diets in concentrations similar to those found in two areas of the colonies, the polypcontaining tips and the sterile bases. By manipulating extract and sclerite concentrations in the diets, we determined that extracts were the major form of protection in the tips of the colonies of all three species. Sclerites from the tips had little impact on predator deterrence. In the bases of two species, S. polydactyla and Sinularia sp., both extracts and sclerites contributed to the deterrence of predators. However, in S. maxima , only base sclerites affected the foraging rates of fishes, the addition of base extracts had no effect. We also manipulated crude extract concentrations without sclerites present to determine whether differences in crude extracts concentrations between the bases and the tips of the colonies were responsible for the differences in the effectiveness of the extracts as predator deterrents. When tested at the same concentrations, tip and base extracts were equally effective deterrents. Field bioassays with flash coloumn fractions demonstrated that in all three species of soft corals, predator deterrence is due to the combined effect of several different compounds. Our results show that differences in the types and concentrations of antipredator defenses present in different locations within the colonies of benthic invertebrates affect the susceptibility of those tissues to predation.

The specialized predator Chaetodon melannotus (Bloch et Schneider) (Vertebrata, Pisces), which feeds on highly toxic and sometimes allelopathic octocorals, initially locates its prey using visual rather than chemical cues. A novel controlled experiment was carried out to further understand the basis of food preference and selection. Organic extracts were interchanged between colonies of three species of octocoral: Alcyonium molle (Dean), Clavularia inflata (Schenck) and Sinularia flexibilis (Quoy et Gaimard0 (Coelenterata, Octocorallia). Extracts were prepared by stepwise solvent extraction of the octocoral; first with ethanol, then with mixtures containing dichloromethane in ethanol, and finally with dichloromethane. All extractable organic material was removed. Concentrated extracts (in ether) were then reintroduced into the extracted colonies in the six possible permutations. In three smorgasbord-type experiments using two octocoral species at a time, C. melannotus were offered the six types of modified colonies, including controls without any extract, yielding a balanced matrix of visual and chemical cue combinations. Responses of the fish to prey choices were nonrandom in all cases. Alcyonium colonies with original extracts reintroduced were strongly preferred over Clavularia. Clavularia colonies and any colony containing their extracts received low preference. When offered with Sinularia, Clavularia colonies devoid of organic components received high preference. Chemical cues were determined to be important in this selection process. The Sinularia colonies in this situation received moderate acceptance. Sinularia colonies with their own extract reintroduced, received high preference when offered with Alcyonium. This indicated that there might be a subtle change in appearance or texture of Alcyonium (the preferred choice in an earlier study) as a result of the extraction. Responses were significantly different from that expected if the fish were cueing solely on the basis of either visual or chemical cues. A combination of visual and chemical cueing, possibly in sequence, appears to have produced the observed results. These results suggest that C. melannotus use visual cues to locate their prey and probably further select on the basis of chemical cues. We believe that the technique used here is valuable for use in the separation of visual and chemical cues for feeding.