Sinugrandisterols A-D, trihydroxysteroids from the soft coral Sinularia grandilobata

Bioactive Steroids Bearing Oxirane Ring

This review explores the biological activity and structural diversity of steroids and related isoprenoid lipids, with a particular focus on compounds containing an oxirane ring. These natural compounds are derived from fungi, fungal endophytes, as well as extracts of plants, algae, and marine invertebrates. To evaluate their biological activity, an extensive examination of refereed literature sources was conducted, including in vivo and in vitro studies and the utilization of the QSAR method. Notable properties observed among these compounds include strong anti-inflammatory, antineoplastic, antiproliferative, anti-hypercholesterolemic, antiparkinsonian, diuretic, anti-eczematic, anti-psoriatic, and various other activities. Throughout this review, 3D graphs illustrating the activity of individual steroids are presented, accompanied by images of selected terrestrial or marine organisms. Furthermore, this review provides explanations for specific types of biological activity associated with these compounds. The data presented in this review are of scientific interest to the academic community and carry practical implications in the fields of pharmacology and medicine. By analyzing the biological activity and structural diversity of steroids and related isoprenoid lipids, this review offers valuable insights that contribute to both theoretical understanding and applied research. This review draws upon data from various authors to compile information on the biological activity of natural steroids containing an oxirane ring.

Structural diversity of bioactive steroid compounds isolated from soft corals in the period 2015-2020

Marine soft corals are known as a good source of biologically active compounds, among which a large number of steroid compounds are identified. Structures and activities of these compounds have been used in drug discovery and development. From 2015 to 2020, 179 new steroid compounds were isolated from soft corals and structurally characterized. In this review, we report the structural classification and bioactivities of these compounds. The largest group of steroids from soft corals are hydroxysteroids, while the most common biological activity is anticancer. Besides, anticancer hydroxysteroids from soft corals exhibit anti-inflammatory and antibacterial activity. Unlike anticancer and antibacterial activity that can be observed in a number of steroid classes, antioxidant activity and antileishmanial effect were observed only in 19-oxygenated steroids, antiviral activity in pregnane-type steroids and spirosteroids, immunosuppressive activity in epoxy- and epidioxysteroids, and antibacterial activity in two steroid classes, hydroxysteroids and ketosteroids. This systematically analyzed link between the structure and activity of natural marine steroids is a good starting point for future drug design.

Cytotoxic Compounds from Alcyoniidae. An Overview of the Last 30 Years

The octocoral family Alcyoniidae represents a rich source of bioactive substances with intriguing and unique structural features. This review aims to provide an updated overview of the compounds isolated from Alcyoniidae and displaying potential cytotoxic activity. In order to allow a better comparison among the bioactive compounds, we focused on molecules evaluated in vitro by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, by far the most widely used method to analyze cell proliferation and viability. Specifically, we surveyed the last thirty years of research, finding 153 papers reporting on 344 compounds with proven cytotoxicity. The data were organized in tables to provide a ranking of the most active compounds, to be exploited for the selection of the most promising candidates for further screening and pre-clinical evaluation as anti-cancer agents. Specifically, we found that (22S,24S)-24-methyl-22,25-epoxyfurost-5-ene-3β,20β-diol (16), 3β,11-dihydroxy-24-methylene-9,11-secocholestan-5-en-9-one (23), (24S)-ergostane-3β,5α,6β,25 tetraol (146), sinulerectadione (227), sinulerectol C (229), and cladieunicellin I (277) exhibited stronger cytotoxicity than their respective positive control and that their mechanism of action has not yet been further investigated.

Novel 16,17-epoxy-23-methylergostane derivative from Sinularia variabilis, a soft coral from the Persian Gulf, with apoptotic activities against breast cancer cell lines

The steroidal and terpenoidal composition of Sinularia variabilis was investigated by chromatography methods. One new (1), and four known [gorgasta-5-en-3β-ol (2), ergosta-5-en-3β-ol (3), ergosta-5, 22(Z)-dien-3β-ol (4), 5,8-epidioxy-5α, 8α-ergosta-6, 22E-dien-3β-ol (5)] steroids, in addition to one known diterpenoidal alkaloid [sinulasulfone (6)] isolated for the first time from S. variabilis. If we named the 23-methylergostane core structure as sinustane, new compound (1) was elucidated as 16α,17α-epoxysinusta-5-en-3β-ol-20β-yl sulfate based on NMR and HR Mass data. It was submitted for cytotoxic activity evaluation against MCF-7 and MDA-MB-231 cell lines using MTT assay. Apoptosis induction was checked by flow cytometry (annexin V/propidium iodide) staining. To determine the production of reactive oxygen species, and the mitochondrial transmembrane potential (ΔΨm), the DCFDA, and JC-1 probes were used in this study.

New cytotoxic ergostane-type sterols from the Chinese soft coral Sinularia sp

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.

A new 5α,8α-epidioxysterol with immunosuppressive activity from the South China Sea soft coral Sinularia sp

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.[Formula: see text].

MS-based metabolomics revealing Bornean Sinularia sp. extract dysregulated lipids triggering programmed cell death in Hepatocellular carcinoma

Soft coral, Sinularia sp. had been proven to inherit promising anti-cancer properties against variety of cancer. Current study, Sinularia sp. extract was introduced to Hepatocellular carcinoma (Hep 3B). Cell viability assay indicated the extract exhibit a dose and time dependent cytotoxicity. LC₅₀ exhibited the lowest at 72 h post treatment estimated as 45.3 µg/mL. Morphological alterations including nuclear condensation, cytoplasm shrinkage and deformed cellular shape in treated Hep 3B were observable. Chemometric analysis revealed hydrophobic metabolites were significantly altered. Elevated vitamin D and derivatives tend to up-regulation Ca²⁺ and ROS subsequently triggering apoptosis. Dysregulated glycerolipids may suggest that they were biotransformed to compensate the needs of phospholipids during cell damage. Perturbation of sphingolipids, ceramide and carbohydrate-conjugated ceramides species increased the release of pro-apoptotic components reside within mitochondria and promote programmed cell death in treated Hep 3B. To conclude, MS-based metabolomics enabled the characterization of Sinularia sp. extract-induced cell death.

Metabolites from the Paracel Islands Soft Coral Sinularia cf. molesta

Five new oxygenated sesquiterpenes, molestins A–D (1, 3–5) and epi-gibberodione (2), three new cyclopentenone derivatives, ent-sinulolides C, D, and F ((+)-9–(+)-11), one new butenolide derivative, ent-sinulolide H ((+)-13), and one new cembranolide, molestin E (14), together with 14 known related metabolites (6–8, (–)-9–(–)-11, (±)-12, (–)-13, 15–19) were isolated from the Paracel Islands soft coral Sinularia cf. molesta. The structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, quantum chemical calculations, and comparison with the literature data. Compound 5 is the first example of a norsesquiterpene with a de-isopropyl guaiane skeleton isolated from the genus Sinularia. Molestin E (14) exhibited cytotoxicities against HeLa and HCT-116 cell lines with IC₅₀ values of 5.26 and 8.37 μM, respectively. Compounds 4, 5, and 8 showed significant inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) with IC₅₀ values of 218, 344, and 1.24 μM, respectively.

Botrysphones A-C and Botrysphins A-F, Triketides and Diterpenoids from the Fungus Botrysphaeria laricina

Three new triketides, botrysphones A-C (1-3) and six new isopimarane-type diterpenoids, botrysphins A-F (4-9), together with the known triketides sphaeropsidone (10) and chlorosphaeropsidone (11) and diterpenoids sphaeropsidins A and B (12 and 13), were obtained from culture of the fungus Botrysphaeria laricina associated with the moss Rhodobryum umgiganteum. The structures of the new compounds were established on the basis of extensive spectroscopic techniques including HRMS and 1D and 2D NMR data. Compounds 7 and 12 showed significant quinone reductase inducing activity in Hepa 1c1c7 cells.

Isolation of a new cytotoxic polyhydroxysterol from the South China Sea soft coral Sinularia sp

A new polyhydroxysterol, (22E)-24-methylenecholestane-22-ene-3β,5α,6β-triol (1), together with four known analogues (2-5) were isolated from the South China Sea soft coral Sinularia sp. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All these compounds exhibited cytotoxic effect against both HepG2 and HeLa cell lines with IC₅₀ values ranging from 8.36 to 37.30 μM. Preliminary structure-activity relationship study identified that the presence of double bonds in the side chains of these polyhydroxysterols significantly reduced the biological effect obtained.

9,11-Secosteroids and polyhydroxylated steroids from two South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol (1), two new polyhydroxylated steroids, 7α-hydroxy-crassarosterol A (2) and 11-acetoxy-7α-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 IC50 value of 33.05μM. Compounds 1-3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60.

A new 5α,8α-Epidioxysterol from the soft coral Sinularia gaweli

A new sterol, (22R,23R,24R)-5α,8α-epidioxy-22,23-methylene-24-methyl-cholest-6,9(11)-dien-3β-ol (1), and two known sterols, (22R,23R,24R)-5α,8α-epidioxy-22,23-methylene-24-methylcholest-6-en-3β-ol (2) and 24-methylenecholestane-1α,3β,5α, 6β,11α-pentol (3), were isolated from the soft coral Sinularia gaweli. The structure of sterol 1 was established by spectroscopic methods and by comparison of the spectral data with those of known analogues. The cytotoxicity of sterols 1–3 towards various tumor cells is reported.

Induction of apoptosis by 11-dehydrosinulariolide via mitochondrial dysregulation and ER stress pathways in human melanoma cells

In this study the isolated compound 11-dehydrosinulariolide from soft coral Sinularia leptoclados possessed anti-proliferative, anti-migratory and apoptosis-inducing activities against A2058 melanoma cells. Anti-tumor effects of 11-dehydrosinulariolide were determined by MTT assay, cell migration assay and flow cytometry. Growth and migration of melanoma cells were dose-dependently inhibited by 2–8 μg/mL 11-dehydrosinulariolide. Flow cytometric data indicated that 11-dehydrosinulariolide induces both early and late apoptosis in melanoma cells. It was found that the apoptosis induced by 11-dehydrosinulariolide is relevant to mitochondrial-mediated apoptosis via caspase-dependent pathways, elucidated by loss of mitochondrial membrane potential (∆Ψm), release of cytochrome C, activation of caspase-3/-9 and Bax as well as suppression of Bcl-2/Bcl-xL. The cleavage of PARP-1 suggested partial involvement of caspase-independent pathways. Immunoblotting data displayed up-regulations of PERK/eIF2α/ATF4/CHOP and ATF6/CHOP coupling with elevation of ER stress chaperones GRP78, GRP94, calnexin, calreticulin and PDI, implicating the involvement of these factors in ER stress-mediated apoptosis induced by 11-dehydrosinulariolide. The abolishment of apoptotic events after pre-treatment with salubrinal indicated that ER stress-mediated apoptosis is also induced by 11-dehydrosinulariolide against melanoma cells. The data in this study suggest that 11-dehydrosinulariolide potentially induces apoptosis against melanoma cells via mitochondrial dysregulation and ER stress pathways.

Proteomic profiling of the 11-dehydrosinulariolide-treated oral carcinoma cells Ca9-22: effects on the cell apoptosis through mitochondrial-related and ER stress pathway

An oral squamous cell carcinoma Ca9-22 cell line was treated with 11-dehydrosinulariolide, an active compound isolated from the soft coral Sinularia leptoclados, in order to evaluate the effect of this compound on cell growth and protein expression. Cell proliferation was strongly inhibited by 11-dehydrosinulariolide treatment. The 2-DE master maps of control and treated Ca9-22 cells were generated by analysis with the PDQuest software. The comparison between such maps showed up- and down-regulation of 23 proteins, of which 14 were upregulated and 9 were downregulated. The proteomic studies described here have identified some proteins, which are involved in the mitochondrial dysfunction and ER-stress pathway and imply that 11-dehydrosinulariolide induces cell apoptosis through either mitochondrial dysfunction-related or ER stress pathway. Based on this observation, several proteins related to apoptosis pathway were explored for the potential roles involved in this drug-induced cytotoxicity. Furthermore, Salubrinal, an ER stress inhibitor, is able to protect the cell from 11-dehydrosinulariolide-induced apoptosis in a physiological dosage. The significance of these studies illustrates the potential development of anticancer drugs from the natural derivatives of soft coral.

Proteomic analysis of anti-tumor effects of 11-dehydrosinulariolide on CAL-27 cells

The anti-tumor effects of 11-dehydrosinulariolide, an active ingredient isolated from soft coral Sinularia leptoclados, on CAL-27 cells were investigated in this study. In the MTT assay for cell proliferation, increasing concentrations of 11-dehydrosinulariolide decreased CAL-27 cell viability. When a concentration of 1.5 μg/mL of 11-dehydrosinulariolide was applied, the CAL-27 cells viability was reduced to a level of 70% of the control sample. The wound healing function decreased as the concentration of 11-dehydrosinulariolide increased. The results in this study indicated that treatment with 11-dehydrosinulariolide for 6 h significantly induced both early and late apoptosis of CAL-27 cells, observed by flow cytometric measurement and microscopic fluorescent observation. A comparative proteomic analysis was conducted to investigate the effects of 11-dehydrosinulariolide on CAL-27 cells at the molecular level by comparison between the protein profiling (revealed on a 2-DE map) of CAL-27 cells treated with 11-dehydrosinulariolide and that of CAL-27 cells without the treatment. A total of 28 differential proteins (12 up-regulated and 16 down-regulated) in CAL-27 cells treated with 11-dehydrosinulariolide have been identified by LC-MS/MS analysis. Some of the differential proteins are associated with cell proliferation, apoptosis, protein synthesis, protein folding, and energy metabolism. The results of this study provided clues for the investigation of biochemical mechanisms of the anti-tumor effects of 11-dehydrosinulariolide on CAL-27 cells and could be valuable information for drug development and progression monitoring of oral squamous cell carcinoma (OSCC).

NMR spectral assignments of two sterols from a soft coral Sinularia brassica

Two new steroids, named 4α,22-dimethyl-Cholest-22-en-3β-ol (1) and 4α-methyl-Cholest-7,22-dien-3β-ol (2), along with two known steroids, were isolated from the soft coral Sinularia brassica. The structures of the new compounds were determined on the basis of extensive spectroscopic data (MS, (1)H and (13)C NMR, (1)H-(1)H COSY, (13)C-(1)H COSY, HMBC and NOESY) analysis.

Auroside, a Xylosyl-sterol, and Patusterol A and B, two Hydroxylated Sterols, from two Soft Corals Eleutherobia aurea and Lobophytum patulum

A new sterol glycoside, auroside (1) and two new hydroxylated sterols, patusterol A and B (2, 3) have been isolated from the South African soft coral Eleutherobia aurea and from the Kenyan soft coral Lobophytum patulum. The structure elucidation was achieved from extensive 1D- and 2D- NMR and MS data, and in the case of auroside also by chemical reactions. In addition, from Lobophytum patulum, was also isolated a known nitrogen containing compound (Z)-N-[2-(4-hydroxyphenyl)ethyl]-3-methyldodec-2-enamide, and from Eleutherobia aurea several, earlier reported, diterpenoids. Compound 2 was found to be toxic to brine shrimp embryos with an LC50 value of 2.30 μM.

Marine natural products

This review covers the literature published in 2007 for marine natural products, with 948 citations(627 for the period January to December 2007) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, cnidarians,bryozoans, molluscs, tunicates, echinoderms and true mangrove plants. The emphasis is on new compounds (961 for 2007), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.1 Introduction, 2 Reviews, 3 Marine microorganisms and phytoplankton, 4 Green algae, 5 Brown algae, 6 Red algae, 7 Sponges, 8 Cnidarians, 9 Bryozoans, 10 Molluscs, 11 Tunicates (ascidians),12 Echinoderms, 13 Miscellaneous, 14 Conclusion, 15 References.

Cytotoxic Effect of the Genus Sinularia Extracts on Human SCC25 and HaCaT Cells

Soft corals of the genus Sinularia are being increasingly adopted to treat a wide variety of disease processes. However, the mechanism underlying its activity against human oral cancer cells is poorly understood. This study evaluates the cyototoxicity effects of the genus Sinularia extracts (S. grandilobata, S. parva, S. triangula, S. scabra, S. nanolobata and S. gibberosa) by SCC25 and HaCaT cells. The cell adhesion assay indicates that extracts reduce the cell attachment. Extracts exhibit a dose-dependent cytotoxic effect using MTS assay.Treatment of extracts to observe the morphological alterations in cells, membrane blebbing, nuclear condensation, and apoptotic bodies is demonstrated. Flow cytometry shows that extracts sensitized the cells in the G₀/G₁ and G₂/M phases with a concomitant significantly increased sub-G₁ fraction, suggesting cell death by apoptosis. Extracts of the genus Sinularia thus apparently cause apoptosis of SCC25 and HaCaT cells, and warrant further research investigating the possible antioral cancer compounds in these soft corals.

Anti-inflammatory cembranoids from the soft corals Sinularia querciformis and Sinularia granosa

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

A C-3 methylated isocembranoid and 10-oxocembranoids from a formosan soft coral, Sinularia grandilobata

Five new cembranoids, designated grandilobatins A-E (1- 5), were isolated from the soft coral Sinularia grandilobata. Grandilobatin C (3) was found to have a novel skeleton with the C-4 methyl group of the normal cembranoid rearranged to C-3, while the other metabolites were identified as new 10-oxocembranoids. Metabolite 4 has weak cytotoxicity toward MDA-MB-23 human breast tumor cells. Also, 4 significantly inhibited the accumulation of the pro-inflammatory iNOS protein of LPS-stimulated RAW264.7 macrophage cells at 50 microM.