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Five new cembrane-type diterpenes, lobocalines A–E (1–5), and four new steroids, lobocaloids A–D (9–12), along with six known related compounds (6–8 and 13–15) were isolated from the Yalong Bay soft coral Lobophytum catalai Tixier-Durivault. The structures of the new compounds were elucidated by extensive spectroscopic analysis, NMR calculation with DP4+ analysis, time-dependent density functional theory–electronic circular dichroism (TDDFT-ECD) calculations, X-ray diffraction analyses and comparison with the reported spectroscopic data of known compounds. Further, with the aid of X-ray diffraction analysis, the structure of lobocrasol B (15) was firmly revised as 15a. In in vitro bioassays, compound 2 showed moderate antibacterial activities against fish pathogenic bacteria Streptococcus parauberis KSP28 and Phoyobacterium damselae FP2244 with minimum inhibitory concentration (MIC) values of 8.7 and 17.3 µg/mL, respectively. All the steroids exhibited antibacterial activities against the S. parauberis KSP28 with MIC values ranging from 12.3 to 53.6 µg/mL. Compounds 2, 7 and 14 have remarkable inhibitory effects on the hemolysin production of Staphylococcus aureus, while compounds 8–12 have medium inhibitory effects on the pyocyanin production in Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

Marine soft corals are prolific sources of various natural products that have served as a wealthy reservoir of diverse chemical scaffolds with potential as new drug leads. The genus Litophyton contains almost 100 species but only a small proportion of them has been chemically investigated, which calls for more attentions from global researchers. In the current work, 175 secondary metabolites have been discussed, drawing from published data spanning almost five decades, up to July 2023. The studied species of the genus Litophyton resided in various tropical and temperate regions and encompassed a broad range of biologically active natural products including terpenes, steroids, nitrogen-containing metabolites, lipids, and other metabolites. A wide spectrum of pharmacological effects of these compounds had been evaluated, such as cytotoxic, antiviral, antibacterial, antifungal, anti-malarial, antifeedant, anti-inflammatory, molluscicidal, PTP1B inhibitory, insect growth inhibitory, and neuroprotective activities. This review aims to offer an up-to-date survey of the literature and provide a comprehensive understanding of the chemical structures, taxonomical distributions, and biological activities of the reported metabolites from the title genus whenever available. [ABSTRACT FROM AUTHOR]

To explore the steroidal constituents of the soft coral Lobophytum sp. at the coast of Xuwen County, Guangdong Province, China, a chemical investigation of the above-mentioned soft coral was carried out. After repeated column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC, six new steroids, namely lobosteroids A–F (1–6), along with four known compounds 7–10, were obtained. Their structures were determined by extensive spectroscopic analysis and comparison with the spectral data reported in the literature. Among them, the absolute configuration of 1 was determined by X-ray diffraction analysis using Cu Kα radiation. These steroids were characterized by either the presence of an α,β-α′,β′-unsaturated carbonyl, or an α,β-unsaturated carbonyl moiety in ring A, or the existence of a 5α,8α-epidioxy system in ring B, as well as diverse oxidation of side chains. The antibacterial bioassays showed that all isolated steroids exhibited significant inhibitory activities against the fish pathogenic bacteria Streptococcus parauberis FP KSP28, Phoyobacterium damselae FP2244, and Streptococcus parauberis SPOF3K, with IC90 values ranging from 0.1 to 11.0 µM. Meanwhile, compounds 2 and 6–10 displayed potent inhibitory effects against the vancomycin-resistant Enterococcus faecium bacterium G7 with IC90 values ranging from 4.4 to 18.3 µM. Therefore, ten highly oxidized steroids with strong antibacterial activities were isolated from the Chinese soft coral Lobophytum sp., which could be developed as new chemotypes of antibacterial drug leads. [ABSTRACT FROM AUTHOR]

Fifteen new diterpenoids, namely xishaklyanes A-O (1–15), along with three known related ones (16–18), were isolated from the soft coral Klyxum molle collected from Xisha Islands, South China Sea. The stereochemistry of the new compounds was elucidated by a combination of detailed spectroscopic analyses, chemical derivatization, quantum chemical calculations, and comparison with the reported data. The absolute configuration of compound 18 was established by the modified Mosher's method for the first time. In bioassay, some of these compounds exhibited considerable antibacterial activities on fish pathogenic bacteria, and compound 4 showed the most effective activity with MIC of 0.225 μg/mL against Lactococcus garvieae. [ABSTRACT FROM AUTHOR]

Nanolobatone A, featuring an unprecedented tricyclo[10.3.0.01,2]pentadecane carbon skeleton, along with four new polyoxygenated and four unusual endoperoxide‐bridged casbane‐type diterpenoids were isolated from the Hainan soft coral Sinularia nanolobata. The structures of the new compounds were established by extensive spectroscopic analysis, X‐ray diffraction analysis, and time‐dependent density functional theory/electronic circular dichroism calculations. A plausible biosynthetic pathway of new isolates was proposed. Bioassays revealed that nanolobatone A showed weak antibacterial activity against the Gram‐positive bacteria Streptococcus pyogenes. [ABSTRACT FROM AUTHOR]

Documents on the chemical composition of the soft coral Sarcophyton mililatensis are sparse. The present investigation of the Hainan soft coral S. mililatensis resulted in the discovery of six new cembrane diterpenes, sarcoxacyclols A–F (1–6) and four known analogs (7–10). Their structures were elucidated by extensive spectroscopic analysis along with a comparison with the data in current literature. The nonaromatic oxacycles in their structures were the rarely found tetrahydrofuran ether across C-1 and C-12 and tetrahydropyran ether across C-1 and C-11, respectively. Moreover, the absolute configuration of compound 4 was established unambiguously by X-ray diffraction analysis using Ga Kα radiation (λ = 1.34139 Å). Based on the biogenetical consideration, the absolute configurations of other five new compounds were tentatively assumed. Assessment of the bioactivity for these secondary metabolites revealed that compound 1 exhibited significant tumor necrosis factor (TNF)-α inhibitory activity (IC50 = 9.5 μmol/L), similar to the positive control dexamethasone (IC50 = 8.7 μmol/L), but no obvious cytotoxicity towards RAW264.7 cells (CC50 > 50 μmol/L). The preliminary molecular docking suggested the crucial roles of the hydroxyl and acetoxyl groups in the computational prediction of the binding mode between the diterpene and the protein. [ABSTRACT FROM AUTHOR]

The present investigation of the South China Sea soft coral Sarcophyton trocheliophorum resulted in the discovery of six new polyoxygenated diterpenes, namely sartrocheliols A–E (1, 3, 5–8) along with four known ones, 2, 4, 9, and 10. Based on extensive spectroscopic data analysis, sartrocheliol A (1) was identified as an uncommon capnosane diterpene, while sartrocheliols B–E (3, 5–8) were established as cembrane diterpenes. They displayed diverse structural features not only at the distinctly different carbon frameworks but also at the various types of heterocycles, including the epoxide, γ-lactone, furan, and pyran rings. Moreover, their absolute configurations were determined by a combination of quantum mechanical-nuclear magnetic resonance (QM-NMR) approach, modified Mosher's method, and X-ray diffraction analysis. In the anti-tumor bioassay, compound 4 exhibited moderate cytotoxic activities against A549, H1975, MDA-MB-231, and H1299 cells with the IC50 values ranging from 26.3 to 47.9 μM. [ABSTRACT FROM AUTHOR]

The first investigation of the South China Sea soft coral Sarcophyton boettgeri afforded five new capnosane diterpenes, sarboettgerins A–E (1–5), together with one known related compound, pavidolide D (6). Their structures, including absolute configurations, were elucidated by the extensive spectroscopic analysis, 13C NMR calculations, and X-ray diffraction. Among them, new compounds 1–5 were featured by the rarely encountered Z-geometry double bond Δ1 within the 5/11-fused bicyclic capnosane carbon framework. Plausible biogenetic relationships of all isolates were proposed, and they might give an insight into future biomimetic synthesis of these novel compounds. In an in vitro bioassay, compound 5 displayed potent anti-neuroinflammatory activity against LPS-induced NO release in BV-2 microglial cells, which might be developed as a new type of potential neuroprotective agent in future. [ABSTRACT FROM AUTHOR]

Three unusual diterpenes with rare sarsolenane and capnosane skeletons, namely mililatensols A–C (1–3), were isolated from the South China Sea soft coral Sarcophyton mililatensis, leading to the first record of sarsolenane and capnosane diterpenes from the title animal. The structures of compounds 1–3 were established by extensive spectroscopic analysis and comparison with the literature data. Moreover, the absolute configuration of 2 was determined by TDDFT ECD calculations. In an in vitro bioassay, none of the isolated compounds showed obvious anti-inflammatory activity on LPS-induced TNF-α release in RAW264.7 macrophages. In the preliminary virtual screening of inhibitory potential against SARS-CoV-2 by molecular docking, the results showed these three diterpenes were potential SARS-CoV-2 Mpro inhibitors. [ABSTRACT FROM AUTHOR]

A new diterpenoid with an unusual capnosane skeleton, sinuhumilol A (1), alone with twelve known diverse compounds (2–13), were isolated from the South China Sea soft coral Sinularia humilis. Their structures and stereochemistry were elucidated by extensive spectroscopic analysis, quantum chemical calculations, and/or by the comparison of the spectroscopic data with those reported in the literature. In bioassay, compound 11 exhibited interesting specific cytotoxicity against the human colon adenocarcinoma cell line HT-29 with IC50 value of 12.5 µM. [ABSTRACT FROM AUTHOR]

A new cembrane-type diterpenoid, named iso-ximaonanolobatin G (1), and one known related one, namely ximaonanolobatin G (2), along with four known steroids, were isolated from the South China Sea soft coral Sinularia nanolobata. Their full structures were elucidated by extensive spectroscopic analysis, quantum mechanical (QM)-NMR methods, and by the comparison of the spectroscopic data with those reported in the literature. [ABSTRACT FROM AUTHOR]

Two new cladiellin-type diterpenoids (1 and 2) and four known related compounds 3–6, were isolated from the South China Sea soft coral Cladiella krempfi. Compound 2 is the third example of cladiellins of an unusual peroxy group in the C-6 position in C. krempfi. The structures and absolute configurations of the new compounds were established by extensive spectroscopic analysis, X-ray diffraction, and/or chemical correlation. In bioassay, all the compounds were evaluated for cytotoxicity and epidermal growth factor receptor (EGFR) inhibitory activity. A molecular docking experiment was conducted to study the structure–activity relationship of cladiellin-type diterpenoids on EGFR inhibitory activity. [ABSTRACT FROM AUTHOR]

Chemical investigation of the Hainan soft coral Sinularia hirta resulted in the isolation and identification of a library of sixteen structurally diverse terpenoids, including a dinorditerpenoid with an uncommon 17,19-dinorxeniaphyllane skeleton, namely sinuhirtone A (7), six new xeniaphyllane-type diterpenoids (1–6), one new norxeniaphyllanoid (8), two new norcaryophyllene-type sesquiterpenoids (9 and 10), together with six known related compounds (11–16). Compounds 1–3 are three new furanone-containing xeniaphyllane-type diterpenoids. The structures of the new compounds, including their absolute configurations, were determined by extensive spectroscopic analysis and a series of quantum chemical calculations, including quantum mechanical-nuclear magnetic resonance (QM–NMR), time-dependent density functional theory–electronic circular dichroism (TDDFT–ECD), and optical rotatory dispersion (ORD) methods. A plausible biosynthetic connection between new compounds 1–9 was also proposed. New compounds 2–4, 7, and 8 were evaluated for in vitro cytotoxicity against four cancer cell lines. [ABSTRACT FROM AUTHOR]

Three complex polyoxygenated diterpenoids possessing uncommon tetradecahydro-2,13:6,9-diepoxybenzo[10]annulene scaffold, namely ximaoornatins A–C (1–3), one new eunicellin-type diterpene, litophynin K (4), and a related known compound, litophynol B (5) were isolated from the South China Sea soft coral Sinularia ornata. The structures and absolute configurations of 1–4 were established by extensive spectroscopic analysis, X-ray diffraction analysis, and/or modified Mosher's method. A plausible biosynthetic relationship of 1 and its potential precursor 4 was proposed. In a bioassay, none of the isolated compounds showed obvious anti-inflammatory activity on LPS-induced TNF-α release in RAW264.7 macrophages and PTP1B inhibitory effects. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: A rare highly fused racemic merosesquiterpenoid, 9‐epi‐verrubenzospirolactone (1), six new asteriscane‐type sesquiterpenoids, sinuhumesins A—F (4—9), and two related known ones (10 and 11) were isolated from Hainan soft coral Sinularia humesi. Compound 1 was further separated by chiral HPLC resolution to one pair of enantiomers [(+)‐1 and (–)‐1], respectively. The full structures of the new compounds were unambiguously determined by extensive spectroscopic analysis, chemical computation approaches, modified Mosher's method and/or X‐ray diffraction analysis, as well as comparison with previously reported data of related model compounds. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Four new cembranoids, 6‐oxo‐cembrene‐A (1), lobocrassins G—H (2—3), and 14‐epi‐lobophytolide B (4), along with eight known related compounds (5—12), were isolated from the South China Sea soft coral Lobophytum crassum. Their structures were established by extensive spectroscopic analysis and by comparison of the spectral data with those reported in the literatures. The absolute stereochemistry of 14‐epi‐lobophytolide B (4) was established by time‐dependent density functional theory electronic circular dichroism (TDDFT‐ECD) calculations, whereas that of three known metabolites (6, 11 and 12) was also determined, for the first time, by using modified Mosher's method and/or X‐ray diffraction analyses. In bioassay, the cembranoids 6, 7 and 12 showed significant anti‐tumoral activity against A549, HT‐29, SNU‐398 and Capan‐1 tumor cell lines with IC50 values ranging from 1.5 to 7.4 μmol/L. A preliminary structure‐activity relationship was also discussed. [ABSTRACT FROM AUTHOR]

Lobane-type diterpenoids are not frequently discovered from marine soft corals. In this paper, three new lobane type diterpenes, 13-methoxyloba-8,10,15(16),17(18)-tetraene (1), 8,10,13(15) Z ,16 E -lobatetraene (2) and 19-hydroxy-lobatetraene (3), and a new natural compound, 17,18-epoxyloba-16-acetoxy-8,10,13(15)-trien (4), co-occurring with a known related diterpenoid, 18-methoxyloba-8,10,13(15),16(17)-tetraene (5), were isolated from the South China Sea soft coral Sinularia polydactyla. The structures of new compounds were determined by extensive spectroscopic analysis and by comparison with those reported in the literature. In bioassay, all the isolates were inactive on antibacterial, PTP1B inhibitory, and immunological activities. This study increased the chemical diversity of marine diterpenoids. [ABSTRACT FROM AUTHOR]

A new 5α,8α-epidioxysterol, namely yalongsterol A (1), along with two known related steroids 5α,8α-epidioxy-24-methyl-cholesta-6,24(28)-dien-3β-ol (2) and (22E,24S)-5α,8α-epidioxy-24-methyl-cholesta-6,22-dien-3β-ol (3), were isolated from the South China Sea soft coral Sinularia sp. Their structures were established by extensive spectroscopic analyses and comparisons of the spectral data with those reported in the literature. In bioassay, compounds 1–3 showed moderate immunosuppressive activities against T and/or B lymphocyte cells with IC50 values ranging from 19.30 to 59.49 μM, and low cytotoxicity on murine splenocytes with CC50 values ranging from 40.88 to 62.29 μM. [ABSTRACT FROM AUTHOR]

In the present study, two new trinor-guaiane sesquiterpenes, named clavuridins B ( 1 ), and A ( 2 ), along with three known sesquiterpenes ( 3 − 5 ), were isolated from the Xisha soft coral Clavularia viridis . Their structures and absolute configurations were determined on the basis of spectroscopic analysis, X-ray diffraction analysis with Cu Kα radiation and by comparison with related model compounds. Compounds 1 and 3 – 5 were evaluated for their cytotoxic activity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Methyl tortuoate D (1), together with five other known related bis-cembranoids, was isolated from Hainan soft coral Sarcophyton tortuosum. The structure of methyl tortuoate D (1a), firstly isolated and reported by Li et al. from the title organism, was corrected as 1 by an extensive analysis of its one-dimensional and two-dimensional nuclear magnetic resonance data and by comparison with those reported in the literature. In addition, lobophytone K (1b), recently isolated from Hainan soft coral Lobophytum pauciflorum by Lin et al., was proved to be the same compound as 1 and 1a. The absolute configuration of 1 was determined by comparing its electronic circular dichroism curve with that of co-occurring ximaolide A (2). [ABSTRACT FROM AUTHOR]

Two new metabolites, sarcophytonone (1) and sarcophytonamine (2), have been isolated from the Hainan soft coral Sarcophyton crassocaule. Their structures were elucidated on the basis of a detailed analysis of spectroscopic data, and by comparison of their NMR spectral data with those of the related model compounds. [ABSTRACT FROM AUTHOR]

A new cembrane-type diterpene, diepoxycembrene A (1), has been isolated from the Hainan soft coral Sinularia sp. Its structure was elucidated on the basis of detailed analysis of its spectroscopic data, and by comparison of its NMR spectral data with those of the related model compounds. [ABSTRACT FROM AUTHOR]

A new cembrane-type diterpene, 11,12-epoxy-sarcophytoxide (1), along with five related diterpenoids (2, and 4-7), has been isolated from the soft coral Lobophytum sp. The structure of the new compound 1 was elucidated on the basis of detailed analysis of its spectroscopic data, and by comparing its NMR spectral data with those of the model compounds. [ABSTRACT FROM AUTHOR]

A new dolabellane diterpenoid (1R\ast,3E,7E,9S\ast,11S\ast,12Z)-9-hydroxydolabella-3,7,12-triene (1), along with seven known compounds (2-8), has been isolated from the Hainan soft coral Spongodes sp. Their structures were elucidated on the basis of spectroscopic analysis and compared with those previously reported in literature. [ABSTRACT FROM AUTHOR]

Two new 19-oxygenated polyhydroxy steroids, 24-methylcholesta-5, 24(28)-diene-3β, 7β, 19-triol-19-monoacetate ( 1 ), 24-methylcholesta-5, 24(28)-diene-3β, 7β, 19-triol-7β, 19-diacetate ( 3 ), together with a known steroid, 24-methylcholesta-5, 24(28)-diene-3β, 7β, 19-triol-7β-monoacetate ( 4 ), have been isolated from the soft coral Sinularia sp. collected from the South China Sea and characterized through interpretation of spectral data. [ABSTRACT FROM AUTHOR]

• Eleven new marine natural products were isolated by column chromatography. • All the structures of new compounds were elucidated completely. • Four compounds displayed interesting anti-inflammatory activities. Eleven new macrocyclic casbane-type diterpenes, namely sinueracasbanones E–O (1 – 11), have been isolated from the South China Sea soft coral Sinularia erecta using combined column chromatography. The structures of new compounds were elucidated by extensive spectroscopic data analysis, the modified Mosher's method, X-ray diffraction analysis and quantum mechanical calculation methods. In bioassay, compounds 2, 5, 10 and 11 displayed interesting anti-inflammatory activities by the inhibition of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α protein release with half maximal inhibitory concentration (IC 50) values of 15.6, 7.1, 13.7 and 6.6 µM, respectively. [ABSTRACT FROM AUTHOR]

Molecular networking strategy-based prioritization of the isolation of the rarely studied soft coral Sinularia tumulosa yielded 14 sesquiterpenes. These isolated constituents consisted of nine different types of carbon frameworks, namely asteriscane, humulane, capillosane, seco-asteriscane, guaiane, dumortane, cadinane, farnesane, and benzofarnesane. Among them, situmulosaols A–C (1 , 3 and 4) were previously undescribed ones, whose structures with absolute configurations were established by the combination of extensive spectral data analyses, quantum mechanical-nuclear magnetic resonance and time-dependent density functional theory electronic circular dichroism calculations, the Snatzke's method, and the modified Mosher's method. Notably, situmulosaol C (4) was the second member of capillosane-type sesquiterpenes. The plausible biogenetic relationships of these skeletally different sesquiterpenes were proposed. All sesquiterpenoids were evaluated for their antibacterial, cytotoxic and anti-inflammatory effects. The bioassay results showed compound 14 exhibited significant antibacterial activities against a variety of fish and human pathogenic bacteria with MIC 90 values ranging from 3.6 to 33.8 μg/mL. Moreover, moderate cytotoxic effects against HEL cells for components 13 and 14 and moderate inhibitory effect on lipopolysaccharide-induced inflammatory responses in RAW264.7 cells for substance 13 were also observed. [Display omitted] • 14 sesquiterpenes were isolated from Sinularia tumulosa applying molecular networking. • These isolates possessed nine different carbon frameworks. • Situmulosaol C (4) was the second member of capillosane-type sesquiterpenes. • Absolute configurations were assigned by QM-NMR, TDDFT ECD, ICD, and Mosher's method. • Compound 14 showed significant antibacterial and moderate cytotoxic activities. [ABSTRACT FROM AUTHOR]

Abstract: One novel uncommon steroid, ximaosteroid A (1), possessing an unusual tetrahydrofuran moiety and three new pregnane steroids, ximaosteroids B–D (2–4), were isolated from the Hainan soft coral Scleronephthya sp. Their structures were elucidated on the basis of detailed spectroscopic (IR, MS, and 2D NMR) analysis and by comparison with those reported in the literature. [Copyright &y& Elsevier]

Main observation and conclusion: A rare highly fused racemic merosesquiterpenoid, 9‐epi‐verrubenzospirolactone (1), six new asteriscane‐type sesquiterpenoids, sinuhumesins A—F (4—9), and two related known ones (10 and 11) were isolated from Hainan soft coral Sinularia humesi. Compound 1 was further separated by chiral HPLC resolution to one pair of enantiomers [(+)‐1 and (–)‐1], respectively. The full structures of the new compounds were unambiguously determined by extensive spectroscopic analysis, chemical computation approaches, modified Mosher's method and/or X‐ray diffraction analysis, as well as comparison with previously reported data of related model compounds. [ABSTRACT FROM AUTHOR]

The chemical investigation on the soft coral Sinularia brassica collected off Xuwen Country, Guangdong Province, China, has resulted in the isolation and characterization of three uncommon cycloamphilectane-type diterpenoids, namely sinucycloamtin A–C (1 – 3), along with two known analogues (5 and 6). In addition, compounds 2 and 3 were hydrolyzed and their hydrolytic derivative sinucycloamtin D (4) was obtained. The structures of these previously undescribed compounds were established on the basis of extensive spectroscopic analysis, X-ray diffraction analysis, chemical conversion, as well as the comparison with the literature reported data. Compounds 1 – 3 represented the first examples of benzene-containing cycloamphilectane-type diterpenoids isolated from soft coral of genus Sinularia. In the in vitro bioassays, all the isolated and derived diterpenoids exhibited significant antibacterial activities against the fish pathogenic bacteria Phoyobacterium damselae FP2244 and Streptococcus parauberis SPOF3K with MIC 90 values ranging from 3.7 to 9.1 μM. [Display omitted] • Four uncommon diterpenoids were characterized from soft coral Sinularia brassica. • The structures of isolated compounds were unambiguously elucidated. • All isolates and derivative were evaluated for their antibacterial activities. [ABSTRACT FROM AUTHOR]

• New cembranoids were isolated and identified from the Hainan soft coral Sarcophyton crassocaule. • A pair of enantiomers were purified by chiral HPLC. • The absolute configurations were determined by TDDFT-ECD calculation, modified Mosher's method, and/or Snatzke's method. The determination of the stereochemistry of cembrane type diterpenoids is always a challenging task due to the flexibility of the 14-membered macrocycle. In this paper, three new cembranoids, ximaocembrols A–C (1 – 3), were isolated from the Hainan soft coral Sarcophyton crassocaule , and ximaocembrol C was further separated by chiral HPLC to its corresponding enantiomers (±)- 3 , respectively. The absolute configurations of these new compounds were successfully elucidated by using a series of reliable approaches, including extensive spectroscopic analysis, TDDFT-ECD calculation, modified Mosher's method, and Snatzke's method. [ABSTRACT FROM AUTHOR]

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 IC 50 value of 4.4 μ M 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. [ABSTRACT FROM AUTHOR]

Further chemical investigation of the South China Sea soft coral Lemnalia flava resulted in the isolation and characterization of two new cembranoids, namely, xishaflavalins G and H (1 and 2), along with three known related compounds (3 – 5). 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. The discovery of cembrane-type diterpenes from soft coral of the genus Lemnalia was reported for the first time. In addition, compound 5 exhibited moderate inhibitory effects on the ConA-induced T lymphocytes and/or lipopolysaccharide (LPS)-induced B lymphocytes proliferation. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Three new diterpenoids with an unusual capnosane skeleton named lobophytrols A–C (1 – 3) were isolated from the South China Sea soft coral Lobophytum sp. along with one known related diterpene, (11 S ,12 S ,1 E ,3 E ,7 E)-11,12-epoxycembra-1,3,7-triene (7). Their structures were elucidated on the basis of spectroscopic analysis and by comparison with those reported in the literature. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Four new polyhydroxylated steroids lobophysterols A–D (1 – 4), were isolated from the South Chinese Sea soft coral Lobophytum sp. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with those reported in the literature. In bioassay, compound 4 showed weak cytotoxicities against HT-29, SNU-398, and Capan-1 cells. Highlights • Four new polyhydroxylated steroids were isolated from a Chinese soft coral Lobophytum sp. • Lobophysterols A and B with a hydroperoxyl group have been rarely found in the genus Lobophytum. • Lobophysterol D showed weak cytotoxicities against HT-29, SNU-398, and Capan-1 cells. Abstract Four new polyhydroxylated steroids lobophysterols A–D (1 – 4), together with two known related compounds sarcophytosterol (5) and klyflaccisteroid B (6), were isolated from the South China Sea soft coral Lobophytum sp. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with those reported in the literature. In bioassay, compound 4 showed weak cytotoxicities against HT-29, SNU-398, and Capan-1 cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four new oxygenated steroids were isolated from Sinularia depressa. • New compounds sinulasterols D and E featured on uncommon C-18 oxygenated pattern. • Sinulasterols D-F exhibited interesting antibacterial activity. Four new steroids, namely sinulasterols D–G (1–4), along with seven known related ones 5–11 , were isolated from the Xisha soft coral Sinularia depressa. The structures of the new compounds were elucidated by a combination of extensive spectroscopic analyses, chemical conversion method, and comparison of the NMR data with those of known analogues. In in vitro bioassays, compounds 1–3 showed significant antibacterial activities against gram-positive bacteria Enterococcus faecium with minimum inhibitory concentration (MIC) values of 62.5, 125, and 125 µM, respectively, comparable with that of vancomycin (MIC: >44.2 µM). [ABSTRACT FROM AUTHOR]

A detailed chemical investigation of the South China Sea soft coral Sarcophyton ehrenbergi has yield seven undescribed cembranoids, namely isoehrenbergol D and sarcoehrenolides F–K embodying a rare α , β -unsaturated-lactone moiety at C-6 to C-19, along with two known related compounds, ehrenbergol D and sarcoehrenolide A. Their structures and absolute configurations were unambiguously established in the light of extensive spectroscopic data analysis, modified Mosher's method, X-ray diffraction analysis, and quantum chemical computation method. In a bioassay for α -glucosidase inhibition, ehrenbergol D was evaluated as α -glucosidase inhibitor with an IC 50 value of 13.57 μM. Seven undescribed cembranoids and two known analogs were isolated and identified from the soft coral Sarcophyton ehrenbergi. The α -glucosidase inhibitory activity of these compounds was evaluated. [Display omitted] • Seven undescribed cembranoids were isolated from the soft coral Sarcophyton ehrenbergi. • Those cembranoids featured a rare α , β -unsaturated-lactone moiety at C-6 to C-19. • Ehrenbergol D was evaluated as α -glucosidase inhibitor with an IC 50 value of 13.57 μM. [ABSTRACT FROM AUTHOR]

Four new polyoxygenated cembranoids, namely sarcoboettgerol A (1), 12- epi -humilisin D (2), sarcoboettgerol B (3), and sarcoboettgerol C (4), together with one known related analogue, humilisin D (5), were isolated and characterized from the soft coral Sarcophyton boettgeri collected off Ximao island, Hainan Province, China. The structures and absolute configurations of the new compounds were determined by extensive spectroscopic data analyses, Cu k α single crystal X-ray diffraction analysis, and TDDFT-ECD calculations. A plausible biogenetic relationship of 3 and 4 was proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol ( 1 ), two new polyhydroxylated steroids, 7 α -hydroxy-crassarosterol A ( 2 ) and 11-acetoxy-7 α -hydroxy-crassarosterol A ( 3 ), together with three known related ones ( 4 – 6 ), were isolated from the South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis , respectively. The structures of the new steroids were elucidated on the basis of extensive spectroscopic analyses, comparison with the literature data and chemical correlation. Compound 2 exhibited a moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with an IC 50 value of 33.05 μ M. Compounds 1 – 3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is the first chemical study of Sinularia pedunculata from the South China Sea. • Three new diterpenoids (1 – 3) were isolated from Sinularia pedunculata. • The quantum mechanical (QM)-NMR methods and spectroscopic analyses were applied to determine relative configurations. • A plausible biosynthetic pathway of compounds 1 – 3 was proposed. Three new diterpenoids (1 – 3), along with four known related compounds (4 – 7), were isolated from the South China Sea soft coral Sinularia pedunculata. Their structures were established by extensive spectroscopic analysis and by comparison of the spectral data with those reported in the literature. The relative configuration of the new compounds was established by spectroscopic analyses and quantum mechanical (QM)-NMR methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • An uncommon eunicellin-based diterpenoid (clakrefielin A, 2) and a 9, 11-secosteroid (cladiellasterol A, 4) were isolated from soft coral Cladiella krempfi. • The absolute configurations of 2 and its butyrylated derivative 3 were unambiguously determined by combination of chemical transformation and X -ray diffraction analysis. • This is for the first time that the absolute configurations of eunicellin-based diterpenes containing C2−C6 THP ring are fully determined. • 9, 11-secosterols, like compound 4 , is the first such compound isolated from the soft corals of genus Cladiella. Two new compounds, namely an uncommon eunicellin-based diterpenoid (clakrefielin A, 2) and a 9, 11-secosteroid (cladiellasterol A, 4), along with a known carotenoid (all- trans -peridinin, 7), were isolated from the Ximao Island, Sanya Bay soft coral Cladiella krempfi. The structures of these compounds were established on the basis of extensive spectroscopic analysis, X -ray diffraction analysis, chemical transformations, as well as the comparison with the reported data in the literature. The biological activities of these compounds were investigated, and compound 7 was found to be a new protein tyrosine phosphatase 1B (PTP1B) inhibitor (IC 50 = 7.2 μM). [ABSTRACT FROM AUTHOR]

Abstract: Two new steroids, (2β,3β,4α,5α,8β)-4-methylergost-24(28)-ene-2,3,8-triol (1) and (3β,7α)-24-methyl-7-hydroperoxycholest-5,24(28)-diene-3-ol (2), together with 13 known analogues (3–15) were isolated from the soft coral Sinularia depressa Tixier-Durivault. The structures of the new compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. In the bioassay in vitro, compounds 3a, 4, and 14 exhibited potent PTP1B inhibitory activity, being similar as that of positive control oleanolic acid. Compound 14 also displayed a notable neuroprotective activity against both amyloid-β25–35- and serum deprivation-induced injuries in SH-SY5Y cells while compound 11 showed a considerable antibacterial activity against Staphylococcus aureus. Preliminary structure–activity relationships of these steroids were discussed. [Copyright &y& Elsevier]

[Display omitted] One uncommon sesquiterpenoid dimer (1), a new nardosinane-type sesquiterpenoid (3), along with two known sesquiterpenoids (2 and 4) were isolated from soft coral Litophyton nigrum using a structure-oriented HR-MS/MS approach. The configurations of the isolates were determined by spectroscopic data analyses, including HR-ESI-MS, 1D/2D NMR, single crystal X-ray diffraction, and DP4+ statistical analyses. Compound 3 exhibited potent PTP1B inhibitory activity (IC 50 = 10.67 ± 1.81 μg/mL) compared to the positive control. [ABSTRACT FROM AUTHOR]

Abstract: A new cembranolide diterpene, isosarcophytonolide D (1), and two biscembranes with an unprecedented fused carbon skeleton, bislatumlides A (3) and B (4), were isolated from the Hainan soft coral Sarcophyton latum. Their structures and relative stereochemistry were established by 1D and 2D NMR spectroscopic techniques. Compounds 3 and 4 should be obtained by Diels–Alder addition of two cembranoid units. Compound 1 could be one of the biosynthetic precursors. Both 3 and 4 showed mild cytotoxicity toward A549, HT-29, and P388 cell lines. [Copyright &y& Elsevier]

[Display omitted] • Seven novel casbane diterpenoids were isolated from Sinularia erecta. • Sinuereperoxides B and C are two rare casbane diterpenoids with an uncommon 8,10-peroxide bridge. • The quantum chemical calculations and X-ray diffraction analysis were applied to determine absolute configurations. • Anti-inflammatory activity by the inhibition of TNF-α release was evaluated. A further systematically chemical investigation of the South China Sea soft coral Sinularia erecta led to the discovery of two rare casbane diterpenoids with an uncommon 8,10-peroxide bridge, sinuereperoxides B (1) and C (2), five new casbanes with other oxygenated patterns (3 – 7), and seven known casbanes (8 – 14). The structures and absolute configurations of 1 – 7 were established by extensive spectroscopic data analyses, X-ray diffraction analysis, and/or quantum chemical calculations. In bioassay, compounds 2 , 7 , 11 and 12 exhibited considerable anti-inflammatory activity by the inhibition of TNF-α release, with IC 50 values of 33.8 μM, 5 μM, 9.9 μM and 8 μM. [ABSTRACT FROM AUTHOR]

Five new uncommon cembranoids, named lobophycrasins A–D (1 and 3 – 5) and (−)-humilisin A (2), together with a known related one (6), have been isolated from Hainan soft coral Lobophytum crassum. Their structures were elucidated by extensive spectroscopic analysis, NMR calculation with DP4+ probability analysis, TDDFT-ECD (time-dependent density functional theory-electronic circular dichroism) calculations and comparison with the reported data. Further, with the aid of X-ray diffraction analysis, the structure of lobocrasol (6), which was announced possessing novel unprecedented skeleton, was firmly revised as 6a. In addition, a plausible biogenetic connection among these isolates was also proposed. [Display omitted] • Five new cembranoids have been isolated from Hainan soft coral Lobophytum crassum. • Their structures were elucidated by DP4+ calculation and/or TDDFT-ECD calculation. • With the aid of X-ray diffraction analysis, the structure of lobocrasol (6) was firmly revised as 6a. [ABSTRACT FROM AUTHOR]

Further chemical investigation of the Xisha soft coral Litophyton nigrum has resulted in the isolation of four new nardosinane-type sesquiterpenoids, namely linardosinenes D–G (1 – 4). The structures of new compounds were elucidated by extensive analyses of their spectroscopic data and by comparison with the reported data of known related ones. All compounds exhibited weak inhibitory effect against bromodomain-containing protein 4 (BRD4), a promising therapeutic target in various human diseases, at a concentration of 10 μM. [Display omitted] [ABSTRACT FROM AUTHOR]

Two new cembranoids, ximaosarcophytols A (1) and B (2), together with three related known ones (3 – 5), were isolated from the soft coral Sarcophyton trocheliophorum collected off the Ximao Island, Hainan Province, China. Their structures including the absolute configurations were elucidated by extensive spectroscopic analysis, TDDFT/ECD (time-dependent density functional theory/electronic circular dichroism) calculations and comparison with the reported data. [Display omitted] [ABSTRACT FROM AUTHOR]