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12-epi-Briacavatolide B, a New Briarane Diterpenoid from the Octocoral Briareum stechei. HETEROCYCLES 2023. [DOI: 10.3987/com-22-14792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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2
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Briavioids A–C, discovery of new polyacetoxybriaranes from octocoral Briareum violaceum (Quoy & Gaimard, 1833). Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.133037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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3
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New 8,17-epoxybriaranes from octocoral Briareum stechei (Kükenthal, 1908). Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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4
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Discovery and Biosynthesis of a Structurally Dynamic Antibacterial Diterpenoid. Angew Chem Int Ed Engl 2021; 60:14163-14170. [PMID: 33780586 PMCID: PMC9247737 DOI: 10.1002/anie.202102453] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/07/2021] [Indexed: 01/07/2023]
Abstract
A new bicyclic diterpenoid, benditerpenoic acid, was isolated from soil-dwelling Streptomyces sp. (CL12-4). We sequenced the bacterial genome, identified the responsible biosynthetic gene cluster, verified the function of the terpene synthase, and heterologously produced the core diterpene. Comparative bioinformatics indicated this Streptomyces strain is phylogenetically unique and possesses nine terpene synthases. The absolute configurations of the new trans-fused bicyclo[8.4.0]tetradecanes were achieved by extensive spectroscopic analyses, including Mosher's analysis, J-based coupling analysis, and computations based on sparse NMR-derived experimental restraints. Interestingly, benditerpenoic acid exists in two distinct ring-flipped bicyclic conformations with a rotational barrier of ≈16 kcal mol-1 in solution. The diterpenes exhibit moderate antibacterial activity against Gram-positive bacteria including methicillin and multi-drug resistant Staphylococcus aureus. This is a rare example of an eunicellane-type diterpenoid from bacteria and the first identification of a diterpene synthase and biosynthetic gene cluster responsible for the construction of the eunicellane scaffold.
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5
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Entdeckung und Biosynthese eines strukturdynamischen antibakteriellen Diterpenoids. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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6
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Torsional steering as friend and foe: development of a synthetic route to the briarane diterpenoid stereotetrad. Org Biomol Chem 2017; 15:1876-1888. [PMID: 28169385 PMCID: PMC5330299 DOI: 10.1039/c7ob00124j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two synthetic routes to the briarane stereotetrad have been investigated. The first route employed a boron aldol reaction to establish the stereogenic all-carbon quaternary carbon (C1). In this case, it was found that torsional steering in the transition state led to the formation of the undesired configuration at this position. The second route makes use of a highly diastereoselective acetylide conjugate addition/β-ketoester alkylation sequence to construct the vicinal C1 and C10 stereocenters with the correct relative configuration. Originally, it was proposed that torsional steering in the transition state for the ketoester alkylation step was the primary factor responsible for generating the major product. DFT calculations reveal that while torsional steering does play a role, larger conformational factors must also be considered. These calculations also reveal that an unusual C-Hπ(alkyne) interaction may contribute to lowering the energy of one transition state that leads to the observed stereoisomer. Ultimately, this strategy leads to a concise synthesis (under 10 steps) of the stereotetrad core common to the briarane diterpenoids.
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Abstract
A new polyoxygenated briarane diterpenoid, briarenol B (1), was isolated from the octocoral Briareum excavatum and its structure determined from spectroscopic data. In RAW264.7 cells, a macrophage-like murine cell line, briarane B (1) was found to enhance the protein expression of pro-inflammatory cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) in cells stimulated by lipopolysaccharide (LPS).
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New 9-Hydroxybriarane Diterpenoids from a Gorgonian Coral Briareum sp. (Briareidae). Int J Mol Sci 2016; 17:ijms17010079. [PMID: 26761004 PMCID: PMC4730323 DOI: 10.3390/ijms17010079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 12/30/2015] [Accepted: 01/05/2016] [Indexed: 01/05/2023] Open
Abstract
Six new 9-hydroxybriarane diterpenoids, briarenolides ZI-ZVI (1-6), were isolated from a gorgonian coral Briareum sp. The structures of briaranes 1-6 were elucidated by spectroscopic methods and by comparison of their spectroscopic data with those of related analogues. Briarenolides ZII (2) and ZVI (6) were found to significantly inhibit the expression of the pro-inflammatory inducible nitric oxide synthase (iNOS) protein of lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells.
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Abstract
A concise synthesis (under 10 steps) of the stereotetrad core of the briarane diterpenoids is reported. This approach harnesses the unique reactivity of salicylate ester derived 2,5-cyclohexadienones to quickly build complexity. In particular, a highly diastereoselective acetylide conjugate addition/β-ketoester alkylation sequence was used to set the relative configuration of the C1 (quaternary) and C10 (tertiary) vicinal stereocenters. The sterochemical outcome of the β-ketoester alkylation appears to be governed by torsional steering in the transition state.
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Briarenolides K and L, new anti-inflammatory briarane diterpenoids from an octocoral Briareum sp. (Briareidae). Mar Drugs 2015; 13:1037-50. [PMID: 25689566 PMCID: PMC4344617 DOI: 10.3390/md13021037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 01/03/2023] Open
Abstract
Two new briarane-type diterpenoids, briarenolides K (1) and L (2), were isolated from an octocoral identified as Briareum sp. The structures of new briaranes 1 and 2 were elucidated by spectroscopic methods. In the in vitro anti-inflammatory effects test, briaranes 1 and 2 were found to significantly inhibit the accumulation of the pro-inflammatory iNOS protein of the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells.
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New briarane diterpenoids from Taiwanese soft coral Briareum violacea. Mar Drugs 2014; 12:4677-92. [PMID: 25153765 PMCID: PMC4145337 DOI: 10.3390/md12084677] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/24/2014] [Accepted: 07/24/2014] [Indexed: 11/18/2022] Open
Abstract
Ten new briarane diterpenoids, briaviolides A-J (1-10), together with six known briaranes, solenolides A and D, excavatolide A, briaexcavatolide I, 4β-acetoxy-9-deacetystylatulide lactone and 9-deacetylstylatulide lactone, were isolated from the Taiwanese soft coral, Briareum violacea. Their structures were determined on the basis of spectroscopic data ((1)H- and (13)C-NMR, (1)H-(1)H COSY, HSQC, HMBC and NOESY), HR-MS and chemical methods. The absolute configuration of briaviolide A (1) was determined by X-ray crystallographic analysis. Compounds 5, 9 and derivative 11 showed moderate inhibitory activities on superoxide-anion generation and elastase release by human neutrophils in response to N-formyl-methionyl-leucyl-phenylalanine/ Cytochalasin B (fMLP/CB).
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Cytotoxic and cytolytic cnidarian venoms. A review on health implications and possible therapeutic applications. Toxins (Basel) 2013; 6:108-51. [PMID: 24379089 PMCID: PMC3920253 DOI: 10.3390/toxins6010108] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 01/20/2023] Open
Abstract
The toxicity of Cnidaria is a subject of concern for its influence on human activities and public health. During the last decades, the mechanisms of cell injury caused by cnidarian venoms have been studied utilizing extracts from several Cnidaria that have been tested in order to evaluate some fundamental parameters, such as the activity on cell survival, functioning and metabolism, and to improve the knowledge about the mechanisms of action of these compounds. In agreement with the modern tendency aimed to avoid the utilization of living animals in the experiments and to substitute them with in vitro systems, established cell lines or primary cultures have been employed to test cnidarian extracts or derivatives. Several cnidarian venoms have been found to have cytotoxic properties and have been also shown to cause hemolytic effects. Some studied substances have been shown to affect tumour cells and microorganisms, so making cnidarian extracts particularly interesting for their possible therapeutic employment. The review aims to emphasize the up-to-date knowledge about this subject taking in consideration the importance of such venoms in human pathology, the health implications and the possible therapeutic application of these natural compounds.
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Briarenolides H and I: New 8-Hydroxybriarane Diterpenoids from a Formosan Octocoral Briareum sp. (Briareidae). BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Briarenolides F and G, new briarane diterpenoids from a Briareum sp. octocoral. Mar Drugs 2012; 10:1156-1168. [PMID: 22822363 PMCID: PMC3397458 DOI: 10.3390/md10051156] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 05/15/2012] [Accepted: 05/22/2012] [Indexed: 11/16/2022] Open
Abstract
Two new briarane diterpenoids, briarenolides, F (1) and G (2), were isolated from an octocoral identified as Briareum sp. The structures of briaranes 1 and 2 were established by spectroscopic methods and by comparison of the spectroscopic data with those of known briarane analogues. Briarenolide F was proven to be the first 6-hydroperoxybriarane derivative and this compound displayed a significant inhibitory effect on the generation of superoxide anion by human neutrophils.
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Bioactive Compounds from Marine Gorgonian Corals. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/b978-0-444-59530-0.00012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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A new antifungal briarane diterpenoid from the gorgonian Junceella juncea Pallas. Bioorg Med Chem Lett 2011; 21:7522-5. [DOI: 10.1016/j.bmcl.2011.06.087] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 05/18/2011] [Accepted: 06/18/2011] [Indexed: 11/18/2022]
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18
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Bioactive (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids from the South China Sea gorgonian Dichotella gemmacea. Mar Drugs 2011; 9:1403-1418. [PMID: 21892354 PMCID: PMC3164382 DOI: 10.3390/md9081403] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 07/28/2011] [Accepted: 08/08/2011] [Indexed: 01/31/2023] Open
Abstract
Six new (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids, gemmacolides N-S (1-6), were isolated together with four known analogues, juncenolide D, and juncins R, S and U (7-10), from the South China Sea gorgonian Dichotella gemmacea. The structures of the new compounds were elucidated by the detailed analysis of spectroscopic data in combination with the comparison with reported data. The absolute configuration of 1 was determined by a TDDFT calculation of its solution ECD spectrum, affording the determination of absolute configuration of other analogues by simply comparing their ECD spectra with that of 1. The cytotoxic and antimicrobial activities of these compounds were evaluated. In preliminary in vitro bioassays, compounds 4, 5, 6, 8 and 9 showed cytotoxicity against A549 and MG63, while compounds 1, 2, 4, 7-10 showed antimicrobial activity against the fungus Septoria tritici and the bacterium Escherichia coli.
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Excavatoids E and F: discovery of two new briaranes from the cultured octocoral Briareum excavatum. Mar Drugs 2009; 7:472-82. [PMID: 19841727 PMCID: PMC2763113 DOI: 10.3390/md7030472] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 09/19/2009] [Accepted: 09/23/2009] [Indexed: 11/17/2022] Open
Abstract
Two new briarane-related diterpenoids, designated as excavatoids E (1) and F (2), were isolated from the cultured octocoral Briareum excavatum. The structures of compounds 1 and 2 were established on the basis of extensive spectral data analysis. Briaranes 1 and 2 were found to exhibit moderate inhibitory effects on elastase release by human neutrophils.
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Briaexcavatins V–Z, Discovery of New Briaranes from a Cultured OctocoralBriareum excavatum. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.987] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Covering: 1995 to April 2008. Gorgonian corals continue to provide a wealth of novel structures, many of which exhibit potentially useful biological activity. Notably, the families Briareidae, Gorgoniidae and Plexauridae have been demonstrated to contain a wide variety of natural products including steroids, acetogenins, sesquiterpenes and diterpenes. The most common of the gorgonian natural products are the diterpenes, and the intent of this review is to describe such compounds isolated from gorgonian corals, with a focus on the structures of new compounds as well as their biological activity. There have been developments improving our understanding of the biosynthetic origin of selected diterpenes, and these will also be discussed. This review describes 602 new compounds from 177 articles.
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Frajunolides E-K, briarane diterpenes from Junceella fragilis. JOURNAL OF NATURAL PRODUCTS 2008; 71:1551-1556. [PMID: 18774864 DOI: 10.1021/np800126f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, resulted in the isolation of seven new briarane-type diterpenes, frajunolides E-K (1-7), in addition to 14 known briaranes, praelolide, junceellin, junceellolides A-E, and K, 11a,20a-epoxy-4-deacetoxyjunceelolide D, umbraculolide A, junceellonoid A, and juncins Y, Z, and ZI, as well as ergosterol peroxide. The structures of 1-7 were determined by analysis of HRESIMS and 2D NMR spectroscopic data. Cytotoxicity and in vitro anti-inflammatory activities of compounds 1-7 were also evaluated.
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Briaexcavatins M-P, four new briarane-related diterpenoids from cultured octocoral Briareum excavatum (Briareidae). Chem Pharm Bull (Tokyo) 2008; 56:930-5. [PMID: 18591804 DOI: 10.1248/cpb.56.930] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four new briarane-related diterpenoids, designated as briaexcavatins M-P (1-4), were isolated from the cultured octocoral Briareum excavatum. The structures, including the relative configurations of natural products 1-4 were established on the basis of extensive spectral data analysis and by comparison with the spectral data from other known metabolites featuring a briarane carbon skeleton.
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Briaexcavatins G and H, Two New Briaranes from the OctocoralBriareum excavatum. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2006. [DOI: 10.1246/bcsj.79.1900] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Briaexcavatins C–F, four new briarane-related diterpenoids from the Formosan octocoral Briareum excavatum (Briareidae). Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.03.086] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Juncenolides F and G, Two New Briarane Diterpenoids from Taiwanese Gorgonian Junceella juncea. Chem Pharm Bull (Tokyo) 2005; 53:128-30. [PMID: 15635248 DOI: 10.1248/cpb.53.128] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chemical investigation of the gorgonian coral Junceella juncea collected in Taiwan has resulted in the isolation of the two novel briarane-type diterpenoid compounds, juncenolides F (1) and G (2). The structures were determined on the basis of spectral studies, especially 1D and 2D NMR.
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Briaexcavatolides X–Z, three new briarane-related derivatives from the gorgonian coral Briareum excavatum. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.132] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pachyclavulariolides G–L and secopachyclavulariaenone A, seven novel diterpenoids from the soft coral Pachyclavularia violacea. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00748-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Pachyclavulariaenones A–C, three novel diterpenoids from the soft coral Pachyclavularia violacea. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00180-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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