1
|
Xiao JX, Li FX, Ren SJ, Qu J. Studies on the Biomimetic Synthesis of Marine Ladder Polyethers via Endo-Selective Epoxide-to-Epoxonium Ring-Opening Cascades. Angew Chem Int Ed Engl 2024; 63:e202403597. [PMID: 38752455 DOI: 10.1002/anie.202403597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Indexed: 07/16/2024]
Abstract
Marine ladder polyethers have attracted the attention of chemists and biologists because of their potent biological activities. Synthetic chemists have attempted to construct their polyether frameworks by epoxide ring-opening cascades, as Nakanishi hypothesis describes. However, Baldwin's rules of ring closure state that exo-selective intramolecular cyclization of epoxy alcohols is preferred over endo-selective cyclization. Herein, we investigated epoxide ring-opening cascades of polyepoxy alcohols in [EMIM]BF4/PFTB (1-ethyl-3-methylimidazolium tetrafluoroborate /perfluoro-tert-butyl alcohol) and found that all-endo products were formed via epoxide-to-epoxonium ring-opening cyclizations (not restricted by Baldwin's rules, which only apply to intramolecular hydroxyl-to-epoxide cyclizations). We determined that the key factor enabling polyepoxy alcohols to undergo a high proportion of all-endo-selective cyclization was inhibition of exo-selective hydroxyl-to-epoxide cyclization starting from the terminal hydroxyl group of a polyepoxy alcohol. By introducing a slow-release protecting group to the terminal hydroxyl group, we could markedly increase the cyclization yields of polyether fragments with hydrogen atoms at the ring junctions. For the first time, we constructed consecutively fused six-membered-ring and fused seven-, eight-, and nine-membered-ring polyether fragments by epoxide-to-epoxonium ring-opening cyclizations through the addition of a suitable Lewis acid. We also suggest that the biosynthesis of marine ladder polyethers may proceed via epoxide-to-epoxonium ring-opening cyclization of polyepoxide.
Collapse
Affiliation(s)
- Jia-Xi Xiao
- College of Chemistry, Nankai University, The State Key Laboratory and Institute of Elemento-Organic Chemistry, Tianjin, 300071, China
| | - Feng-Xing Li
- College of Chemistry, Nankai University, The State Key Laboratory and Institute of Elemento-Organic Chemistry, Tianjin, 300071, China
| | - Shu-Jian Ren
- College of Chemistry, Nankai University, The State Key Laboratory and Institute of Elemento-Organic Chemistry, Tianjin, 300071, China
| | - Jin Qu
- College of Chemistry, Nankai University, The State Key Laboratory and Institute of Elemento-Organic Chemistry, Tianjin, 300071, China
| |
Collapse
|
2
|
Chintalapudi V, Wilson C, Clark JS. Synthesis of the I-K Fused Polyether Array of CTX3C and Related Ciguatoxins by Use of a Gold-Catalyzed Cyclization Reaction. Org Lett 2024; 26:775-780. [PMID: 38238251 PMCID: PMC10845158 DOI: 10.1021/acs.orglett.3c03782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/04/2024] [Accepted: 01/15/2024] [Indexed: 02/03/2024]
Abstract
The I-K fragment (C31-C49) of the ciguatoxin CTX3C has been synthesized from a simple chiral pool derived tetrahydropyranyl alcohol. An efficient gold-catalyzed cyclization reaction of a γ'-hydroxy ynone has been used to accomplish efficient closure of ring K under mild conditions. The resulting vinylogous ester has been elaborated to give a complete tricyclic fragment bearing the dimethyl-substituted side chain required for assembly of the LM spirocyclic acetal portion of the target.
Collapse
Affiliation(s)
| | - Claire Wilson
- School of Chemistry, Joseph
Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, U.K.
| | - J. Stephen Clark
- School of Chemistry, Joseph
Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, U.K.
| |
Collapse
|
3
|
Triantafyllakis M, Alexander S, Woolford S, Wilson C, Clark JS. Synthesis of the A-F Fragment of the Pacific Ciguatoxin CTX3C by Iterative Ring-Closing Metathesis and Tsuji-Trost Allylation. Chemistry 2023; 29:e202303121. [PMID: 37830907 PMCID: PMC10946863 DOI: 10.1002/chem.202303121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/14/2023]
Abstract
The fully functionalized A-F fragment of the Pacific ciguatoxin CTX3C has been synthesized from a derivative of D-glucal, which serves as the B-ring. Rings A and C were introduced to either side of ring B by ring-closing diene and enyne metathesis (RCM). The seven-membered D-ring and eight-membered E-ring were assembled by iterative use of a six-step reaction sequence in which RCM was used for ring construction and Tsuji-Trost allylation was employed for subsequent stereoselective functionalization. The nine-membered F-ring was formed by use of an RCM reaction and bears the functionality required for attachment of the I-M fragment and subsequent closure of rings G and H.
Collapse
Affiliation(s)
- Myron Triantafyllakis
- School of ChemistryJoseph Black BuildingUniversity of GlasgowUniversity AvenueGlasgowG12 8QQUK
| | - Sam Alexander
- School of ChemistryJoseph Black BuildingUniversity of GlasgowUniversity AvenueGlasgowG12 8QQUK
| | - Sophie Woolford
- School of ChemistryJoseph Black BuildingUniversity of GlasgowUniversity AvenueGlasgowG12 8QQUK
| | - Claire Wilson
- School of ChemistryJoseph Black BuildingUniversity of GlasgowUniversity AvenueGlasgowG12 8QQUK
| | - J. Stephen Clark
- School of ChemistryJoseph Black BuildingUniversity of GlasgowUniversity AvenueGlasgowG12 8QQUK
| |
Collapse
|
4
|
Preparation of Ciguatoxin Reference Materials from Canary Islands (Spain) and Madeira Archipelago (Portugal) Fish. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10060835] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ciguatoxins (CTXs) are naturally occurring neurotoxins that can accumulate in fish and cause Ciguatera Poisoning (CP) in seafood consumers. Ciguatoxic fish have been detected in tropical and subtropical regions of the world including the Pacific and Indian Oceans, the Caribbean Sea, and more recently in the northeast Atlantic Ocean. The biogeographic distribution of ciguatoxic fish appears to be expanding; however, the paucity of CTX standards and reference materials limits the ability of public health authorities to monitor for these toxins in seafood supply chains. Recent reports establish that Caribbean Ciguatoxin-1 (C-CTX1) is the principal toxin responsible for CP cases and outbreaks in the northeast Atlantic Ocean and that C-CTX congener profiles in contaminated fish samples match those from the Caribbean Sea. Therefore, in this work, C-CTX reference materials were prepared from fish obtained from the northeast Atlantic Ocean. The collection of fish specimens (e.g., amberjack, grouper, or snapper) was screened for CTX-like toxicity using the in vitro sodium channel mouse neuroblastoma cytotoxicity assay (N2a cell assay). Muscle and liver tissues from toxic specimens were pooled for extraction and purified products were ultimately profiled and quantified by comparison with authentic C-CTX1 using LC-MS/MS. This work presents a detailed protocol for the preparation of purified C-CTX reference materials to enable continued research and monitoring of the ciguatera public health hazard. To carry out this work, C-CTX1 was isolated and purified from fish muscle and liver tissues obtained from the Canary Islands (Spain) and Madeira archipelago (Portugal).
Collapse
|
5
|
In vivo subchronic effects of ciguatoxin-related compounds, reevaluation of their toxicity. Arch Toxicol 2022; 96:2621-2638. [PMID: 35657391 PMCID: PMC9325831 DOI: 10.1007/s00204-022-03315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/11/2022] [Indexed: 11/22/2022]
Abstract
Ciguatoxins are marine compounds that share a ladder-shaped polyether structure produced by dinoflagellates of the genus Gambierdiscus and Fukuyoa, and include maitotoxins (MTX1 and MTX3), ciguatoxins (CTX3C) and analogues (gambierone), components of one of the most frequent human foodborne illness diseases known as ciguatera fish poisoning. This disease was previously found primarily in tropical and subtropical areas but nowadays, the dinoflagellates producers of ciguatoxins had spread to European coasts. One decade ago, the European Food Safety Authority has raised the need to complete the toxicological available data for the ciguatoxin group of compounds. Thus, in this work, the in vivo effects of ciguatoxin-related compounds have been investigated using internationally adopted guidelines for the testing of chemicals. Intraperitoneal acute toxicity was tested for maitotoxin 1 at doses between 200 and 3200 ng/kg and the acute oral toxicity of Pacific Ciguatoxin CTX3C at 330 and 1050 ng/kg and maitotoxin 1 at 800 ng/kg were also evaluated showing not effects on mice survival after a 96 h observation period. Therefore, for the following experiments the oral subchronic doses were between 172 and 1760 ng/kg for gambierone, 10 and 102 ng/kg for Pacific Ciguatoxin CTX3C, 550 and 1760 ng/kg for maitotoxin 3 and 800, 2560 and 5000 ng/kg for maitotoxin 1. The results presented here raise the need to reevaluate the in vivo activity of these agents. Although the intraperitoneal lethal dose of maitotoxin 1 is assumed to be 50 ng/kg, without chemical purity identifications and description of the bioassay procedures, in this work, an intraperitoneal lethal dose of 1107 ng/kg was obtained. Therefore, the data presented here highlight the need to use a common procedure and certified reference material to clearly establish the levels of these environmental contaminants in food.
Collapse
|
6
|
Ariga K. Biomimetic and Biological Nanoarchitectonics. Int J Mol Sci 2022; 23:3577. [PMID: 35408937 PMCID: PMC8998553 DOI: 10.3390/ijms23073577] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 12/13/2022] Open
Abstract
A post-nanotechnology concept has been assigned to an emerging concept, nanoarchitectonics. Nanoarchitectonics aims to establish a discipline in which functional materials are fabricated from nano-scale components such as atoms, molecules, and nanomaterials using various techniques. Nanoarchitectonics opens ways to form a more unified paradigm by integrating nanotechnology with organic chemistry, supramolecular chemistry, material chemistry, microfabrication technology, and biotechnology. On the other hand, biological systems consist of rational organization of constituent molecules. Their structures have highly asymmetric and hierarchical features that allow for chained functional coordination, signal amplification, and vector-like energy and signal flow. The process of nanoarchitectonics is based on the premise of combining several different processes, which makes it easier to obtain a hierarchical structure. Therefore, nanoarchitectonics is a more suitable methodology for creating highly functional systems based on structural asymmetry and hierarchy like biosystems. The creation of functional materials by nanoarchitectonics is somewhat similar to the creation of functional systems in biological systems. It can be said that the goal of nanoarchitectonics is to create highly functional systems similar to those found in biological systems. This review article summarizes the synthesis of biomimetic and biological molecules and their functional structure formation from various viewpoints, from the molecular level to the cellular level. Several recent examples are arranged and categorized to illustrate such a trend with sections of (i) synthetic nanoarchitectonics for bio-related units, (ii) self-assembly nanoarchitectonics with bio-related units, (iii) nanoarchitectonics with nucleic acids, (iv) nanoarchitectonics with peptides, (v) nanoarchitectonics with proteins, and (vi) bio-related nanoarchitectonics in conjugation with materials.
Collapse
Affiliation(s)
- Katsuhiko Ariga
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan;
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| |
Collapse
|
7
|
Ali R, Ahmed W, Jayant V, alvi S, Ahmed N, Ahmed A. Metathesis reactions in total‐ and natural product fragments syntheses. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202100753] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Rashid Ali
- Jamia Millia Islamia New Delhi India 110025 Department of Chemistry Jamia Nagar,New Delhi india110025 110025 New Delhi INDIA
| | - Waqar Ahmed
- Jamia Millia Islamia Central University: Jamia Millia Islamia Chemistry INDIA
| | - Vikrant Jayant
- Jamia Millia Islamia Central University: Jamia Millia Islamia Chemistry INDIA
| | - shakeel alvi
- Jamia Millia Islamia Central University: Jamia Millia Islamia Chemistry INDIA
| | - Nadeem Ahmed
- Jamia Millia Islamia Central University: Jamia Millia Islamia Chemistry INDIA
| | - Azeem Ahmed
- Jamia Millia Islamia Central University: Jamia Millia Islamia Chemistry INDIA
| |
Collapse
|
8
|
Campàs M, Leonardo S, Oshiro N, Kuniyoshi K, Tsumuraya T, Hirama M, Diogène J. A smartphone-controlled amperometric immunosensor for the detection of Pacific ciguatoxins in fish. Food Chem 2021; 374:131687. [PMID: 34891085 DOI: 10.1016/j.foodchem.2021.131687] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 12/11/2022]
Abstract
Ciguatoxins (CTXs) are marine neurotoxins produced by microalgae of the genera Gambierdiscus and Fukuyoa. CTXs may reach humans through food webs and cause ciguatera fish poisoning (CFP). An immunosensor for the detection of Pacific CTXs in fish was developed using multiwalled carbon nanotube (MWCNT)-modified carbon electrodes and a smartphone-controlled potentiostat. The biosensor attained a limit of detection (LOD) and a limit of quantification (LOQ) of 6 and 27 pg/mL of CTX1B, respectively, which were 0.001 and 0.005 μg/kg in fish flesh. In the analysis of fish samples from Japan and Fiji, excellent correlations were found with sandwich enzyme-linked immunosorbent assays (ELISAs), a cell-based assay (CBA) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Stability of at least 3 months at -20 °C was predicted. In just over 2 h, the biosensor provides reliable, accurate and precise Pacific CTX contents in fish extracts, being suitable for monitoring and research programs.
Collapse
Affiliation(s)
- Mònica Campàs
- IRTA, Ctra Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Spain.
| | - Sandra Leonardo
- IRTA, Ctra Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Spain
| | - Naomasa Oshiro
- Division of Biomedical Food Research, National Institute of Health Sciences, Kanagawa 210-9501, Japan
| | - Kyoko Kuniyoshi
- Division of Biomedical Food Research, National Institute of Health Sciences, Kanagawa 210-9501, Japan
| | - Takeshi Tsumuraya
- Department of Biological Sciences, Graduate School of Science, Osaka Prefecture University, Osaka 599-8570, Japan
| | - Masahiro Hirama
- Department of Biological Sciences, Graduate School of Science, Osaka Prefecture University, Osaka 599-8570, Japan
| | - Jorge Diogène
- IRTA, Ctra Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Spain
| |
Collapse
|
9
|
Gwinn JK, Uhlig S, Ivanova L, Fæste CK, Kryuchkov F, Robertson A. In Vitro Glucuronidation of Caribbean Ciguatoxins in Fish: First Report of Conjugative Ciguatoxin Metabolites. Chem Res Toxicol 2021; 34:1910-1925. [PMID: 34319092 PMCID: PMC9215509 DOI: 10.1021/acs.chemrestox.1c00181] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ciguatoxins (CTX) are potent marine neurotoxins, which can bioaccumulate in seafood, causing a severe and prevalent human illness known as ciguatera poisoning (CP). Despite the worldwide impact of ciguatera, effective disease management is hindered by a lack of knowledge regarding the movement and biotransformation of CTX congeners in marine food webs, particularly in the Caribbean and Western Atlantic. In this study we investigated the hepatic biotransformation of C-CTX across several fish and mammalian species through a series of in vitro metabolism assays focused on phase I (CYP P450; functionalization) and phase II (UGT; conjugation) reactions. Using liquid chromatography high-resolution mass spectrometry to explore potential C-CTX metabolites, we observed two glucuronide products of C-CTX-1/-2 and provided additional evidence from high-resolution tandem mass spectrometry to support their identification. Chemical reduction experiments confirmed that the metabolites were comprised of four distinct glucuronide products with the sugar attached at two separate sites on C-CTX-1/-2 and excluded the C-56 hydroxyl group as the conjugation site. Glucuronidation is a novel biotransformation pathway not yet reported for CTX or other related polyether phycotoxins, yet its occurrence across all fish species tested suggests that it could be a prevalent and important detoxification mechanism in marine organisms. The absence of glucuronidation observed in this study for both rat and human microsomes suggests that alternate biotransformation pathways may be dominant in higher vertebrates.
Collapse
Affiliation(s)
- Jessica Kay Gwinn
- School of Marine and Environmental Sciences, University of South Alabama, Mobile, Alabama 36688, United States
- Dauphin Island Sea Lab, Dauphin Island, Alabama 36528, United States
| | - Silvio Uhlig
- Toxinology Research Group, Norwegian Veterinary Institute, Ås NO-1431, Norway
| | - Lada Ivanova
- Toxinology Research Group, Norwegian Veterinary Institute, Ås NO-1431, Norway
| | | | - Fedor Kryuchkov
- Toxinology Research Group, Norwegian Veterinary Institute, Ås NO-1431, Norway
| | - Alison Robertson
- School of Marine and Environmental Sciences, University of South Alabama, Mobile, Alabama 36688, United States
- Dauphin Island Sea Lab, Dauphin Island, Alabama 36528, United States
| |
Collapse
|
10
|
Sasaki M, Iwasaki K, Arai K. Synthesis and Structural Implication of the JKLMN-Ring Fragment of Caribbean Ciguatoxin C-CTX-1. J Org Chem 2021; 86:4580-4597. [PMID: 33667088 DOI: 10.1021/acs.joc.0c03031] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synthesis of the JKLMN-ring fragment of Caribbean ciguatoxin C-CTX-1, the causative toxin of ciguatera fish poisoning in the Caribbean Sea and the Northeast Atlantic areas, is described in detail. Key to the synthesis are a [2,3]-sigmatropic rearrangement to construct a seven-membered α-hydroxy exo-enol ether, stereoselective construction of an angular tetrasubstituted stereogenic center on the seven-membered M-ring by a hydrogen atom transfer-based reductive olefin coupling, Suzuki-Miyaura coupling of the KLMN-ring enol phosphate with a highly congested M-ring, and silica gel-mediated epoxide ring opening to form the J-ring. Comparison of the nuclear magnetic resonance spectroscopic data for the synthesized fragment with those for the natural product provided support for the formerly assigned structure of the N-ring in the right-hand terminal of C-CTX-1.
Collapse
Affiliation(s)
- Makoto Sasaki
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Japan
| | - Kotaro Iwasaki
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Japan
| | - Keisuke Arai
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Japan
| |
Collapse
|
11
|
Loeffler CR, Tartaglione L, Friedemann M, Spielmeyer A, Kappenstein O, Bodi D. Ciguatera Mini Review: 21st Century Environmental Challenges and the Interdisciplinary Research Efforts Rising to Meet Them. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:3027. [PMID: 33804281 PMCID: PMC7999458 DOI: 10.3390/ijerph18063027] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/19/2022]
Abstract
Globally, the livelihoods of over a billion people are affected by changes to marine ecosystems, both structurally and systematically. Resources and ecosystem services, provided by the marine environment, contribute nutrition, income, and health benefits for communities. One threat to these securities is ciguatera poisoning; worldwide, the most commonly reported non-bacterial seafood-related illness. Ciguatera is caused by the consumption of (primarily) finfish contaminated with ciguatoxins, potent neurotoxins produced by benthic single-cell microalgae. When consumed, ciguatoxins are biotransformed and can bioaccumulate throughout the food-web via complex pathways. Ciguatera-derived food insecurity is particularly extreme for small island-nations, where fear of intoxication can lead to fishing restrictions by region, species, or size. Exacerbating these complexities are anthropogenic or natural changes occurring in global marine habitats, e.g., climate change, greenhouse-gas induced physical oceanic changes, overfishing, invasive species, and even the international seafood trade. Here we provide an overview of the challenges and opportunities of the 21st century regarding the many facets of ciguatera, including the complex nature of this illness, the biological/environmental factors affecting the causative organisms, their toxins, vectors, detection methods, human-health oriented responses, and ultimately an outlook towards the future. Ciguatera research efforts face many social and environmental challenges this century. However, several future-oriented goals are within reach, including digital solutions for seafood supply chains, identifying novel compounds and methods with the potential for advanced diagnostics, treatments, and prediction capabilities. The advances described herein provide confidence that the tools are now available to answer many of the remaining questions surrounding ciguatera and therefore protection measures can become more accurate and routine.
Collapse
Affiliation(s)
- Christopher R. Loeffler
- National Reference Laboratory of Marine Biotoxins, Department Safety in the Food Chain, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (A.S.); (O.K.); (D.B.)
- Department of Pharmacy, School of Medicine and Surgery, University of Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
| | - Luciana Tartaglione
- Department of Pharmacy, School of Medicine and Surgery, University of Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
- CoNISMa—National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196 Rome, Italy
| | - Miriam Friedemann
- Department Exposure, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany;
| | - Astrid Spielmeyer
- National Reference Laboratory of Marine Biotoxins, Department Safety in the Food Chain, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (A.S.); (O.K.); (D.B.)
| | - Oliver Kappenstein
- National Reference Laboratory of Marine Biotoxins, Department Safety in the Food Chain, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (A.S.); (O.K.); (D.B.)
| | - Dorina Bodi
- National Reference Laboratory of Marine Biotoxins, Department Safety in the Food Chain, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (A.S.); (O.K.); (D.B.)
| |
Collapse
|
12
|
Stereoselective Synthesis of the I-L Fragment of the Pacific Ciguatoxins. Toxins (Basel) 2020; 12:toxins12120740. [PMID: 33255410 PMCID: PMC7760828 DOI: 10.3390/toxins12120740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 11/17/2022] Open
Abstract
The I-L ring system found in all the Pacific ciguatoxins has been prepared from a tricyclic precursor in a highly stereoselective manner. Subtle differences in the reactivity of the enones present in the seven- and eight-membered rings of the tricyclic ether starting material have been exploited to allow selective protection of the enone in the eight-membered ring. Subsequent distereoselective allylation of the seven-membered ring has been accomplished by a palladium-mediated Tsuji-Trost reaction. The K-ring methyl and hydroxyl groups have been installed in a highly stereoselective manner by sequential conjugate reduction and enolate oxidation reactions. Ring L has been constructed by a use of a novel relay ring-closing metathesis reaction to complete the tetracyclic framework, which possesses the functionality necessary for elaboration of rings I and L and the introduction of ring M.
Collapse
|
13
|
Popadynec M, Gibbard H, Clark JS. Bidirectional Synthesis of the IJK Fragment of Ciguatoxin CTX3C by Sequential Double Ring-Closing Metathesis and Tsuji-Trost Allylation. Org Lett 2020; 22:3734-3738. [PMID: 32306737 PMCID: PMC7304930 DOI: 10.1021/acs.orglett.0c01238] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
A novel four-step bidirectional strategy
has been used to synthesize
the IJK fragment of the marine polyether natural product CTX3C from
a simple monocyclic precursor in a concise and efficient manner. The
four-step bidirectional sequence involves ring-closing metathesis,
alcohol oxidation, enol carbonate formation, and palladium-mediated
Tsuji–Trost allylation.
Collapse
Affiliation(s)
- Michael Popadynec
- School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, United Kingdom
| | - Helen Gibbard
- School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, United Kingdom
| | - J Stephen Clark
- School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, United Kingdom
| |
Collapse
|
14
|
Soliño L, Costa PR. Global impact of ciguatoxins and ciguatera fish poisoning on fish, fisheries and consumers. ENVIRONMENTAL RESEARCH 2020; 182:109111. [PMID: 31927300 DOI: 10.1016/j.envres.2020.109111] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/31/2019] [Accepted: 01/01/2020] [Indexed: 06/10/2023]
Abstract
Ciguatera fish poisoning (CFP) is one of the most devastating food-borne illnesses caused by fish consumption. Ciguatoxins (CTXs) are potent neurotoxins synthesized by the benthic microalgae Gambierdiscus spp. and Fukuyoa spp. that are transmitted to fish by grazing and predation. Despite the high incidence of CFP, affecting an estimated number of 50,000 persons per year in tropical and subtropical latitudes, the factors underlying CTXs occurrence are still not well understood. Toxin transfer and dynamics in fish and food-webs are complex. Feeding habits and metabolic pathways determine the toxin profile and toxicity of fish, and migratory species may transport and spread the hazard. Furthermore, CTX effect on fish may be a limiting factor for fish recruitment and toxin prevalence. Recently, new occurrences of Gambierdiscus spp. in temperate areas have been concomitant with the detection of toxic fish and CFP incidents in non-endemic areas. CFP cases in Europe have led to implementation of monitoring programs and fisheries restrictions with considerable impact on local economies. More than 400 species of fish can be vectors of CTXs, and most of them are high-valued commercial species. Thus, the risk uncertainty and the spread of Gambierdiscus have serious consequences for fisheries and food safety. Here, we present a critical review of CTXs impacts on fish, fisheries, and humans, based on the current knowledge on CFP incidence and CTXs prevalence in microalgae and fish.
Collapse
Affiliation(s)
- Lucía Soliño
- IPMA - Instituto Português do Mar da Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006, Lisbon, Portugal; CCMAR - Centre of Marine Sciences, University of Algarve, Campus of Gambelas, 8005-139, Faro, Portugal.
| | - Pedro Reis Costa
- IPMA - Instituto Português do Mar da Atmosfera, Rua Alfredo Magalhães Ramalho, 6, 1495-006, Lisbon, Portugal; CCMAR - Centre of Marine Sciences, University of Algarve, Campus of Gambelas, 8005-139, Faro, Portugal
| |
Collapse
|
15
|
Tsumuraya T, Hirama M. Rationally Designed Synthetic Haptens to Generate Anti-Ciguatoxin Monoclonal Antibodies, and Development of a Practical Sandwich ELISA to Detect Ciguatoxins. Toxins (Basel) 2019; 11:E533. [PMID: 31540301 PMCID: PMC6784113 DOI: 10.3390/toxins11090533] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/02/2019] [Accepted: 09/06/2019] [Indexed: 12/02/2022] Open
Abstract
"Ciguatera" fish poisoning (CFP) is one of the well-known food poisoning caused by the ingestion of fish that have accumulated trace amounts of ciguatoxins (CTXs). CFP affects more than 50,000 individuals annually. The difficulty in preventing CFP comes from the lack of reliable methods for analysis of CTXs in contaminated fish, together with the normal appearance, taste, and smell of CTX-contaminated fish. Thus, a sensitive, accurate, routine, and portable analytical method to detect CTXs is urgently required. Monoclonal antibodies (mAbs) specific against either wing of major CTX congeners (CTX1B, 54-deoxyCTX1B, CTX3C, and 51-hydroxyCTX3C) were generated by immunizing mice with rationally designed synthetic haptens-KLH conjugates instead of the CTXs. Haptenic groups with a surface area greater than 400 Å2 are required to produce mAbs that can strongly bind to CTXs. Furthermore, a highly sensitive fluorescence-based sandwich enzyme-linked immunosorbent assay (ELISA) was developed. This protocol can detect and quantify four major CTX congeners (CTX1B, 54-deoxyCTX1B, CTX3C, and 51-hydroxyCTX3C) with a limit of detection (LOD) of less than 1 pg/mL. The LOD determined for this sandwich ELISA is sufficient to detect CTX1B-contaminated fish at the FDA guidance level of 0.01 ppb.
Collapse
Affiliation(s)
- Takeshi Tsumuraya
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan.
| | - Masahiro Hirama
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan.
| |
Collapse
|
16
|
Konoki K, Baden DG, Scheuer T, Catterall WA. Molecular Determinants of Brevetoxin Binding to Voltage-Gated Sodium Channels. Toxins (Basel) 2019; 11:toxins11090513. [PMID: 31484365 PMCID: PMC6784055 DOI: 10.3390/toxins11090513] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/30/2019] [Accepted: 08/30/2019] [Indexed: 12/19/2022] Open
Abstract
Brevetoxins are produced by dinoflagellates such as Karenia brevis in warm-water red tides and cause neurotoxic shellfish poisoning. They bind to voltage-gated sodium channels at neurotoxin receptor 5, making the channels more active by shifting the voltage-dependence of activation to more negative potentials and by slowing the inactivation process. Previous work using photoaffinity labeling identified binding to the IS6 and IVS5 transmembrane segments of the channel α subunit. We used alanine-scanning mutagenesis to identify molecular determinants for brevetoxin binding in these regions as well as adjacent regions IVS5-SS1 and IVS6. Most of the mutant channels containing single alanine substitutions expressed functional protein in tsA-201 cells and bound to the radioligand [42-3H]-PbTx3. Binding affinity for the great majority of mutant channels was indistinguishable from wild type. However, transmembrane segments IS6, IVS5 and IVS6 each contained 2 to 4 amino acid positions where alanine substitution resulted in a 2–3-fold reduction in brevetoxin affinity, and additional mutations caused a similar increase in brevetoxin affinity. These findings are consistent with a model in which brevetoxin binds to a protein cleft comprising transmembrane segments IS6, IVS5 and IVS6 and makes multiple distributed interactions with these α helices. Determination of brevetoxin affinity for Nav1.2, Nav1.4 and Nav1.5 channels showed that Nav1.5 channels had a characteristic 5-fold reduction in affinity for brevetoxin relative to the other channel isoforms, suggesting the interaction with sodium channels is specific despite the distributed binding determinants.
Collapse
Affiliation(s)
- Keiichi Konoki
- Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195-7280, USA.
| | - Daniel G Baden
- Center for Marine Science, University of North Carolina, Wilmington, NC 28409, USA
| | - Todd Scheuer
- Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195-7280, USA
| | - William A Catterall
- Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195-7280, USA.
| |
Collapse
|
17
|
Elustondo F, Chintalapudi V, Clark JS. A Short Sequence for the Iterative Synthesis of Fused Polyethers. Helv Chim Acta 2019. [DOI: 10.1002/hlca.201900161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Frédéric Elustondo
- School of ChemistryUniversity of Nottingham, University Park Nottingham NG7 2RD United Kingdom
| | - Venkaiah Chintalapudi
- School of Chemistry, Joseph Black BuildingUniversity of Glasgow, University Avenue Glasgow G12 8QQ United Kingdom
| | - J. Stephen Clark
- School of Chemistry, Joseph Black BuildingUniversity of Glasgow, University Avenue Glasgow G12 8QQ United Kingdom
| |
Collapse
|
18
|
Saito F, Trapp N, Bode JW. Iterative Assembly of Polycyclic Saturated Heterocycles from Monomeric Building Blocks. J Am Chem Soc 2019; 141:5544-5554. [PMID: 30845799 DOI: 10.1021/jacs.9b01537] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Polycyclic saturated heterocycles with predictable shapes and structures are assembled by iterative couplings of bifunctional stannyl amine protocol (SnAP) reagents and a single morpholine-forming assembly reaction. Combinations of just a few monomers enable the programmable construction of rotationally restricted, nonplanar heterocyclic arrays with discrete sizes and molecular shapes. The three-dimensional structures of these constrained scaffolds can be quickly and reliably predicted by DFT calculations and the target structures immediately decompiled into the constituent building blocks and assembly sequences. As a demonstration, in silico combinations of the building blocks predict saturated heptacyclic structures with elementary shapes including helices, S-turns and U-turns, which are synthesized in 5-6 steps from the monomers using just three chemical reactions.
Collapse
Affiliation(s)
- Fumito Saito
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences , ETH-Zürich , 8093 Zürich , Switzerland
| | - Nils Trapp
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences , ETH-Zürich , 8093 Zürich , Switzerland
| | - Jeffrey W Bode
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences , ETH-Zürich , 8093 Zürich , Switzerland
| |
Collapse
|
19
|
Oishi T. Design and Synthesis of Artificial Ladder-Shaped Polyethers for Exploring Biological Functions. HETEROCYCLES 2019. [DOI: 10.3987/rev-18-sr(f)1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
20
|
Soliño L, Costa PR. Differential toxin profiles of ciguatoxins in marine organisms: Chemistry, fate and global distribution. Toxicon 2018; 150:124-143. [DOI: 10.1016/j.toxicon.2018.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/11/2018] [Accepted: 05/13/2018] [Indexed: 01/03/2023]
|
21
|
Tsumuraya T, Sato T, Hirama M, Fujii I. Highly Sensitive and Practical Fluorescent Sandwich ELISA for Ciguatoxins. Anal Chem 2018; 90:7318-7324. [PMID: 29770692 DOI: 10.1021/acs.analchem.8b00519] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ciguatera fish poisoning (CFP) caused by the consumption of fish that have accumulated ciguatoxins (CTXs) affects more than 50000 people annually. The spread of CFP causes enormous damage to public health, fishery resources, and the economies of tropical and subtropical endemic regions. The difficulty in avoiding CFP arises from the lack of sensitive and reliable analytical methods for the detection and quantification of CTXs in contaminated fish, along with the normal appearance, smell, and taste of fish contaminated with the causative toxins. Thus, an accurate, sensitive, routine, and portable detection method for CTXs is urgently required. We have successfully developed a highly sensitive fluorescent sandwich ELISA, which can detect, differentiate, and quantify four major CTX congeners (CTX1B, CTX3C, 51-hydroxyCTX3C, and 54-deoxyCTX1B) with a detection limit of less than 1 pg/mL. The ELISA protocol, using one microtiter plate coated with two mAbs (10C9 and 3G8), and ALP-linked 8H4, can detect any of the four CTX congeners in a single operation. CTX1B spiked into fish at the FDA guidance level of 0.01 ppb CTX1B equivalent toxicity in fish from Pacific regions was also proven to be reliably detected by this ELISA. Furthermore, the efficiency of extraction/purification procedures and the matrix effect of contaminants in fish were evaluated in detail, since pretreatment and matrix effects are critical for ELISA analysis.
Collapse
Affiliation(s)
- Takeshi Tsumuraya
- Department of Biological Science, Graduate School of Science , Osaka Prefecture University , Osaka 599-8570 , Japan
| | - Takeshi Sato
- Cell Science Inc. , Aoba-ku, Sendai , Miyagi 989-3212 , Japan
| | - Masahiro Hirama
- Department of Biological Science, Graduate School of Science , Osaka Prefecture University , Osaka 599-8570 , Japan
| | - Ikuo Fujii
- Department of Biological Science, Graduate School of Science , Osaka Prefecture University , Osaka 599-8570 , Japan
| |
Collapse
|
22
|
Shimono E, Inoue K, Kurita T, Ichiraku Y. Logistic Regression Analysis for the Material Design of Chiral Crystals. CHEM LETT 2018. [DOI: 10.1246/cl.171233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Eri Shimono
- Department of Chemistry, Faculty of Science and Chiral Research Center (CResCent), Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8526, Japan
| | - Katsuya Inoue
- Department of Chemistry, Faculty of Science and Chiral Research Center (CResCent), Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8526, Japan
| | - Takio Kurita
- Graduate School of Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8526, Japan
| | - Yoji Ichiraku
- Department of Chemistry, Faculty of Science and Chiral Research Center (CResCent), Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8526, Japan
| |
Collapse
|
23
|
Skardon-Duncan J, Sparenberg M, Bayle A, Alexander S, Clark JS. Stereoselective Synthesis of Medium-Sized Cyclic Ethers by Sequential Ring-Closing Metathesis and Tsuji–Trost Allylation. Org Lett 2018; 20:2782-2786. [DOI: 10.1021/acs.orglett.8b01082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- James Skardon-Duncan
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, United Kingdom
| | - Michael Sparenberg
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, United Kingdom
| | - Alexandre Bayle
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, United Kingdom
| | - Sam Alexander
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, United Kingdom
| | - J. Stephen Clark
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, United Kingdom
| |
Collapse
|
24
|
Tanaka T, Asakura H, Fujiwara R, Kumamoto K, Izuka H, Shiroma K, Takamura H, Kadota I. Improved Synthesis of the A–E Ring Segment of Ciguatoxin CTX3C by Using Intramolecular Allylations. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2018. [DOI: 10.1246/bcsj.20170390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tokihiro Tanaka
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Hiroki Asakura
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Rie Fujiwara
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Kentaro Kumamoto
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Hiroaki Izuka
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Kengo Shiroma
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Hiroyoshi Takamura
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| | - Isao Kadota
- Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kitaku, Okayama 700-8530, Japan
| |
Collapse
|
25
|
Saito T, Fujiwara K, Sano Y, Sato T, Kondo Y, Akiba U, Ishigaki Y, Katoono R, Suzuki T. An improved synthesis of the C42–C52 segment of ciguatoxin 3C. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.02.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
26
|
Farrell H, Murray SA, Zammit A, Edwards AW. Management of Ciguatoxin Risk in Eastern Australia. Toxins (Basel) 2017; 9:E367. [PMID: 29135913 PMCID: PMC5705982 DOI: 10.3390/toxins9110367] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/08/2017] [Accepted: 11/08/2017] [Indexed: 11/25/2022] Open
Abstract
Between 2014 and 2016, five cases of ciguatera fish poisoning (CFP), involving twenty four individuals, were linked to Spanish Mackerel (Scomberomorus commerson) caught in the coastal waters of the state of New South Wales (NSW) on the east coast of Australia. Previously, documented cases of CFP in NSW were few, and primarily linked to fish imported from other regions. Since 2015, thirteen individuals were affected across four additional CFP cases in NSW, linked to fish imported from tropical locations. The apparent increase in CFP in NSW from locally sourced catch, combined with the risk of CFP from imported fish, has highlighted several considerations that should be incorporated into risk management strategies to minimize CFP exposure for seafood consumers.
Collapse
Affiliation(s)
- Hazel Farrell
- NSW Food Authority, 6 Avenue of the Americas, Newington, NSW 2127, Australia.
| | - Shauna A Murray
- Climate Change Cluster (C3), University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia.
| | - Anthony Zammit
- NSW Food Authority, 6 Avenue of the Americas, Newington, NSW 2127, Australia.
| | - Alan W Edwards
- NSW Food Authority, 6 Avenue of the Americas, Newington, NSW 2127, Australia.
| |
Collapse
|
27
|
Biooxidation of Ciguatoxins Leads to Species-Specific Toxin Profiles. Toxins (Basel) 2017; 9:toxins9070205. [PMID: 28661447 PMCID: PMC5535152 DOI: 10.3390/toxins9070205] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/17/2022] Open
Abstract
Ciguatoxins (CTXs) contaminate fish worldwide and cause the foodborne illness ciguatera. In the Pacific, these toxins are produced by the dinoflagellate Gambierdiscus toxicus, which accumulates in fish through the food chain and undergoes oxidative modification, giving rise to numerous analogs. In this study, we examined the oxidation of CTXs in vitro with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis using reference toxins, and found that CTX4A, CTX4B, and CTX3C, which are produced by the alga, are oxidized to the analogs found in fish, namely CTX1B, 52-epi-54-deoxyCTX1B, 54-deoxyCTX1B, 2-hydroxyCTX3C, and 2,3-dihydroxyCTX3C. This oxidation was catalyzed by human CYP3A4, fish liver S9 fractions, and microsomal fractions prepared from representative ciguateric fishes (Lutjanus bohar, L. monostigumus, and Oplegnathus punctatus). In addition, fish liver S9 fractions prepared from non-ciguateric fishes (L. gibbus and L. fulviflamma) in Okinawa also converted CTX4A and CTX4B to CTX1B, 54-deoxyCTX1B, and 52-epi-54-deoxyCTX1B in vitro. This is the first study to demonstrate the enzymatic oxidation of these toxins, and provides insight into the mechanism underlying the development of species-specific toxin profiles and the fate of these toxins in humans and fish.
Collapse
|
28
|
Kohli GS, Haslauer K, Sarowar C, Kretzschmar AL, Boulter M, Harwood DT, Laczka O, Murray SA. Qualitative and quantitative assessment of the presence of ciguatoxin, P-CTX-1B, in Spanish Mackerel ( Scomberomorus commerson) from waters in New South Wales (Australia). Toxicol Rep 2017; 4:328-334. [PMID: 28959656 PMCID: PMC5615149 DOI: 10.1016/j.toxrep.2017.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 11/25/2022] Open
Abstract
P-CTX-1B in 84 Spanish Mackerel from NSW and QLD were quantified using LC–MS/MS. Liver & flesh from 6 fish and liver from 4 other fish were positive for P-CTX-1B. Liver had significantly higher concentration (∼6 times) of P-CTX-1B than flesh. No relationship was observed between length/weight of fish & detection of P-CTX-1B.
Ciguatera Fish Poisoning (CFP) is a tropical disease caused by the consumption of fish contaminated with ciguatoxins (CTXs). Currently, the only feasible prevention methods for CFP are to avoid the consumption of fish of certain species from some regions, avoid larger fish of certain species, or avoid all fish caught from specific regions. Here, we quantified levels of P-CTX-1B in Spanish Mackerel (Scomberomorus commerson), which is the main fish species that causes CFP in New South Wales and Queensland, Australia, using LC–MS detection against a toxin standard. We found detectable P-CTX-1B in both flesh and liver tissues in fish from New South Wales (n = 71, 1.4% prevalence rate, with a confidence interval of 1%–4%, and 7% prevalence, 1%–12%, in flesh and liver, respectively). In the small sample of fish from Queensland, there was a 46% prevalence (19–73%, n = 13). Toxin levels found were 0.13 μg kg−1 to <0.1 μg kg−1 in flesh, and 1.39 μg kg−1 to <0.4 μg kg−1 in liver, indicating that liver tissue had a significantly higher concentration (∼5 fold) of P-CTX-1B. No apparent relationship was observed between the length or weight of S. commerson and the detection of P-CTX-1B in this study. Footnote
Collapse
Key Words
- CFP, Ciguatera Fish Poisoning
- CTX, Ciguatoxin
- Ciguatera fish poisoning
- Ciguatoxins
- Fish length
- LC–MS, Liquid chromatography mass spectrometry
- LC–MS/MS
- MTX, Maitotoxin
- NMR, Nuclear magnetic resonance
- NSW, New South Wales
- NT, Northern Territory
- P-CTX-1B, Pacific Ciguatoxin 1B
- QLD, Queensland
- RLB, Radio ligand binding
- SFM, Sydney Fish Market
- SIMS, The Sydney Institute for Marine Science
- Scomberomorus commerson
- Spanish Mackerel
- US-FDA, United States Food and Drug Administration
- WA, Western Australia
Collapse
Affiliation(s)
- Gurjeet S Kohli
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Kristina Haslauer
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Chowdhury Sarowar
- Sydney Institute of Marine Science, Chowder Bay Rd., Mosman, NSW 2088, Australia
| | - Anna Liza Kretzschmar
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Mark Boulter
- Sydney Fish Market, Pyrmont, NSW 2009, Australia
| | - D Tim Harwood
- Cawthron Institute, 98 Halifax Street East, Nelson 7010, New Zealand
| | - Olivier Laczka
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia.,Sydney Institute of Marine Science, Chowder Bay Rd., Mosman, NSW 2088, Australia
| |
Collapse
|
29
|
Coccini T, Caloni F, De Simone U. Human neuronal cell based assay: A new in vitro model for toxicity evaluation of ciguatoxin. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 52:200-213. [PMID: 28437641 DOI: 10.1016/j.etap.2017.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/31/2017] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
Ciguatoxins (CTXs) are emerging marine neurotoxins representing the main cause of ciguatera fish poisoning, an intoxication syndrome which configures a health emergency and constitutes an evolving issue constantly changing due to new vectors and derivatives of CTXs, as well as their presence in new non-endemic areas. The study applied the neuroblastoma cell model of human origin (SH-SY5Y) to evaluate species-specific mechanistic information on CTX toxicity. Metabolic functionality, cell morphology, cytosolic Ca2+i responses, neuronal cell growth and proliferation were assessed after short- (4-24h) and long-term exposure (10days) to P-CTX-3C. In SH-SY5Y, P-CTX-3C displayed a powerful cytotoxicity requiring the presence of both Veratridine and Ouabain. SH-SY5Y were very sensitive to Ouabain: 10 and 0.25nM appeared the optimal concentrations, for short- and long-term toxicity studies, respectively, to be used in co-incubation with Veratridine (25μM), simulating the physiological and pathological endogenous Ouabain levels in humans. P-CTX-3C cytotoxic effect, on human neurons co-incubated with OV (Ouabain+Veratridine) mix, was expressed starting from 100pM after short- and 25pM after long-term exposure. Notably, P-CTX-3C alone at 25nM induced cytotoxicity after 24h and prolonged exposure. This human brain-derived cell line appears a suitable cell-based-model to evaluate cytotoxicity of CTX present in marine food contaminated at low toxic levels and to characterize the toxicological profile of other/new congeners.
Collapse
Affiliation(s)
- Teresa Coccini
- Laboratory of Clinical and Experimental Toxicology, Poison Control Centre, Toxicology Unit, Maugeri Clinical Scientific Institutes S.p.A.-BS, IRCCS Pavia, Pavia Italy.
| | - Francesca Caloni
- Department of Veterinary Medicine (DIMEVET), Università degli Studi di Milano, Milano, Italy
| | - Uliana De Simone
- Laboratory of Clinical and Experimental Toxicology, Poison Control Centre, Toxicology Unit, Maugeri Clinical Scientific Institutes S.p.A.-BS, IRCCS Pavia, Pavia Italy
| |
Collapse
|
30
|
|
31
|
Onodera Y, Hirota K, Suga Y, Konoki K, Yotsu-Yamashita M, Sasaki M, Fuwa H. Diastereoselective Ring-Closing Metathesis as a Means to Construct Medium-Sized Cyclic Ethers: Application to the Synthesis of a Photoactivatable Gambierol Derivative. J Org Chem 2016; 81:8234-52. [DOI: 10.1021/acs.joc.6b01302] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Onodera
- Graduate
School of Life Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Kazuaki Hirota
- Graduate
School of Life Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Yuto Suga
- Graduate
School of Life Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Keiichi Konoki
- Graduate
School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Mari Yotsu-Yamashita
- Graduate
School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Makoto Sasaki
- Graduate
School of Life Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| | - Haruhiko Fuwa
- Graduate
School of Life Sciences, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai 980-8577, Japan
| |
Collapse
|
32
|
HIRAMA M. Total synthesis and related studies of large, strained, and bioactive natural products. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2016; 92:290-329. [PMID: 27725470 PMCID: PMC5243947 DOI: 10.2183/pjab.92.290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins.
Collapse
Affiliation(s)
- Masahiro HIRAMA
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, Japan
| |
Collapse
|
33
|
First Report of Ciguatoxins in Two Starfish Species: Ophidiaster ophidianus and Marthasterias glacialis. Toxins (Basel) 2015; 7:3740-57. [PMID: 26402702 PMCID: PMC4591666 DOI: 10.3390/toxins7093740] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 12/21/2022] Open
Abstract
Ciguatera fish poisoning (CFP) is a syndrome caused by the ingestion of fish contaminated with Ciguatoxins (CTXs). These phycotoxins are produced mainly by dinoflagellates that belong to the genus Gambierdiscus that are transformed in more toxic forms in predatory fish guts, and are more present in the Indo-Pacific and Caribbean areas. It is estimated that CFP causes per year more than 10,000 intoxications worldwide. With the rise of water temperature and anthropogenic intervention, it is important to study the prevalence of CFP in more temperate waters. Through inter- and subtidal sampling, 22 species of organisms were collected, in Madeira and Azores archipelagos and in the northwestern Moroccan coast, during September of 2012 and June and July of 2013. A total of 94 samples of 22 different species of bivalves, gastropods, echinoderms and crustaceans where analyzed by Ultra Performance Liquid Chromatography-Mass Spectometry-Ion Trap-Time of Flight (UPLC-MS-IT-TOF) and Ultra Performance Chromatography- Mass Spectrometry (UPLC-MS). Our main aim was to detect new vectors and ascertain if there were some geographical differences. We detected for the first time putative CTXs in echinoderms, in two starfish species-M. glacialis and O. ophidianus. We detected differences regarding uptake values by organisms and geographical location. Toxin amounts were significant, showing the importance and the need for continuity of these studies to gain more knowledge about the prevalence of these toxins, in order to better access human health risk. In addition, we suggest monitoring of these toxins should be extended to other vectors, starfish being a good alternative for protecting and accessing human health risk.
Collapse
|
34
|
Kadota I, Sato Y, Fujita N, Takamura H, Yamamoto Y. Convergent synthesis of the EFGH ring system of ciguatoxin CTX3C. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.04.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
35
|
Martín V, Vale C, Rubiolo JA, Roel M, Hirama M, Yamashita S, Vieytes MR, Botana LM. Chronic Ciguatoxin Treatment Induces Synaptic Scaling through Voltage Gated Sodium Channels in Cortical Neurons. Chem Res Toxicol 2015; 28:1109-19. [DOI: 10.1021/tx500506q] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Víctor Martín
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Carmen Vale
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Juan A. Rubiolo
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Maria Roel
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Masahiro Hirama
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shuji Yamashita
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Mercedes R. Vieytes
- Departamento
de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luís M. Botana
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| |
Collapse
|
36
|
Martín V, Vale C, Hirama M, Yamashita S, Rubiolo JA, Vieytes MR, Botana LM. Synthetic ciguatoxin CTX 3C induces a rapid imbalance in neuronal excitability. Chem Res Toxicol 2015; 28:1095-108. [PMID: 25945403 DOI: 10.1021/tx500503d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ciguatera is a human global disease caused by the consumption of contaminated fish that have accumulated ciguatoxins (CTXs), sodium channel activator toxins. Symptoms of ciguatera include neurological alterations such as paraesthesiae, dysaesthesiae, depression, and heightened nociperception, among others. An important issue to understand these long-term neurological alterations is to establish the role that changes in activity produced by CTX 3C represent to neurons. Here, the effects of synthetic ciguatoxin CTX 3C on membrane potential, spontaneous spiking, and properties of synaptic transmission in cultured cortical neurons of 11-18 days in vitro (DIV) were evaluated using electrophysiological approaches. CTX 3C induced a large depolarization that decreased neuronal firing and caused a rapid inward tonic current that was primarily GABAergic. Moreover, the toxin enhanced the amplitude of miniature postsynaptic inhibitory currents (mIPSCs), whereas it decreased the amplitude of miniature postsynaptic excitatory currents (mEPSCs). The frequency of mIPSCs increased, whereas the frequency of mEPSCs remained unaltered. We describe, for the first time, that a rapid membrane depolarization caused by CTX 3C in cortical neurons activates mechanisms that tend to suppress electrical activity by shifting the balance between excitatory and inhibitory synaptic transmission toward inhibition. Indeed, these results suggest that the acute effects of CTX on synaptic transmission could underlie some of the neurological symptoms caused by ciguatera in humans.
Collapse
Affiliation(s)
- Victor Martín
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Carmen Vale
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Masahiro Hirama
- ‡Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shuji Yamashita
- ‡Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Juan Andrés Rubiolo
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Mercedes R Vieytes
- §Departamento de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luis M Botana
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| |
Collapse
|
37
|
Yamashita S, Takeuchi K, Koyama T, Inoue M, Hayashi Y, Hirama M. Practical route to the left wing of CTX1B and total syntheses of CTX1B and 54-deoxyCTX1B. Chemistry 2014; 21:2621-8. [PMID: 25529606 DOI: 10.1002/chem.201405629] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Indexed: 11/07/2022]
Abstract
Ciguatoxins, the principal causative agents of ciguatera seafood poisoning, are extremely large polycyclic ethers. We report herein a reliable route for constructing the left wing of CTX1B, which possesses the acid/base/oxidant-sensitive bisallylic ether moiety, by a 6-exo radical cyclization/ring-closing metathesis strategy. This new route enabled us to achieve the second-generation total synthesis of CTX1B and the first synthesis of 54-deoxyCTX1B.
Collapse
Affiliation(s)
- Shuji Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan).
| | | | | | | | | | | |
Collapse
|
38
|
Segade Y, Montaos MA, Rodríguez J, Jiménez C. A Short Stereoselective Synthesis of Prepiscibactin Using a SmI2-Mediated Reformatsky Reaction and Zn2+-Induced Asymmetric Thiazolidine Formation. Org Lett 2014; 16:5820-3. [DOI: 10.1021/ol502958u] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Yuri Segade
- Departamento de
Química
Fundamental, Facultade de Ciencias e Centro de Investigacións
de Ciencias Avanzadas (CICA), Universidade da Coruña, A Coruña E-15071, Spain
| | - Marcos A. Montaos
- Departamento de
Química
Fundamental, Facultade de Ciencias e Centro de Investigacións
de Ciencias Avanzadas (CICA), Universidade da Coruña, A Coruña E-15071, Spain
| | - Jaime Rodríguez
- Departamento de
Química
Fundamental, Facultade de Ciencias e Centro de Investigacións
de Ciencias Avanzadas (CICA), Universidade da Coruña, A Coruña E-15071, Spain
| | - Carlos Jiménez
- Departamento de
Química
Fundamental, Facultade de Ciencias e Centro de Investigacións
de Ciencias Avanzadas (CICA), Universidade da Coruña, A Coruña E-15071, Spain
| |
Collapse
|
39
|
Sasaki M, Fuwa H. Total synthesis and complete structural assignment of gambieric acid A, a large polycyclic ether marine natural product. CHEM REC 2014; 14:678-703. [PMID: 25092231 DOI: 10.1002/tcr.201402052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Indexed: 12/30/2022]
Abstract
More than thirty years after the discovery of polycyclic ether marine natural products, they continue to receive intense attention from the chemical, biological, and pharmacological communities because of their potent biological activities and highly complex molecular architectures. Gambieric acids are intriguing polycyclic ethers that exhibit potent antifungal activity with minimal toxicity against mammals. Despite the recent advances in the synthesis of this class of natural products, gambieric acids remain unconquered due to their daunting structural complexity, which poses a formidable synthetic challenge to organic chemists. This paper reviews our long-term studies on the total synthesis, complete configurational reassignment, and structure-activity relationships of gambieric acid A over the last decade.
Collapse
Affiliation(s)
- Makoto Sasaki
- Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | | |
Collapse
|
40
|
Pazos G, Pérez M, Gándara Z, Gómez G, Fall Y. Synthesis of a chiral building block for highly functionalized polycyclic ethers. Org Biomol Chem 2014; 12:7750-7. [DOI: 10.1039/c4ob01439a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
41
|
Martin V, Vale C, Antelo A, Hirama M, Yamashita S, Vieytes MR, Botana LM. Differential Effects of Ciguatoxin and Maitotoxin in Primary Cultures of Cortical Neurons. Chem Res Toxicol 2014; 27:1387-400. [DOI: 10.1021/tx5000969] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
| | | | | | - Masahiro Hirama
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shuji Yamashita
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | | | | |
Collapse
|
42
|
Rueping M, Dufour J, Bui L. Convergent Catalysis: Asymmetric Synthesis of Dihydroquinolines Using a Combined Metal Catalysis and Organocatalysis Approach. ACS Catal 2014. [DOI: 10.1021/cs401176s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Magnus Rueping
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Jeremy Dufour
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Lan Bui
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| |
Collapse
|
43
|
Abstract
Voltage-gated sodium (Nav) channels are essential contributors to neuronal excitability, making them the most commonly targeted ion channel family by toxins found in animal venoms. These molecules can be used to probe the functional aspects of Nav channels on a molecular level and to explore their physiological role in normal and diseased tissues. This chapter summarizes our existing knowledge of the mechanisms by which animal toxins influence Nav channels as well as their potential application in designing therapeutic drugs.
Collapse
|
44
|
Kadota I, Shiroma K, Asakura H, Tanaka T, Takamura H. Improved Synthesis of the A-E Ring Segment of Ciguatoxin CTX3C. HETEROCYCLES 2014. [DOI: 10.3987/com-13-s(s)106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
45
|
|
46
|
Domon D, Fujiwara K, Kawamura N, Katoono R, Kawai H, Suzuki T. A New Variant of Fused Cyclic Ether Synthesis Based on Ireland-Claisen Rearrangement and RCM. Nat Prod Commun 2013. [DOI: 10.1177/1934578x1300800718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A new variant of fused cyclic ether synthesis based on Ireland-Claisen rearrangement and ring-closing olefin metathesis (RCM) was developed. The Ireland-Claisen rearrangement and ring-closing olefin metathesis (RCM) was developed. The Ireland-Claisen rearrangement of a ( Z)-3-alkoxyprop-2-en-1-yl glycolate ester having a cyclic ether on the oxygen at C3 of the ( Z)-prop-2-en-1-yl group stereoselectively produced an anti-α,β-dialkoxyester which was successfully transformed to a fused bicyclic ether via a reaction sequence including RCM.
Collapse
Affiliation(s)
- Daisuke Domon
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| | - Kenshu Fujiwara
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| | - Natsumi Kawamura
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| | - Ryo Katoono
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| | - Hidetoshi Kawai
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| | - Takanori Suzuki
- Department of Chemistry Faculty of Science Hokkaido University Sapporo 606-0810 Japan
| |
Collapse
|
47
|
Nogoshi K, Domon D, Fujiwara K, Kawamura N, Katoono R, Kawai H, Suzuki T. An Ireland–Claisen rearrangement/RCM based approach for the construction of the EF-ring of ciguatoxin 3C. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2012.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
48
|
Sakai T, Sugimoto A, Tatematsu H, Mori Y. Divergent synthesis of trans-fused polycyclic ethers by a convergent oxiranyl anion strategy. J Org Chem 2012; 77:11177-91. [PMID: 23214941 DOI: 10.1021/jo302267f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Octacyclic polyethers that correspond to the CDEFGHIJ-ring system of yessotoxin as well as G- and/or I-ring-modified analogues were synthesized in a divergent manner, starting from a common intermediate, using an [X + 2 + Y]-type convergent method. Reaction of a triflate with the oxiranyl anion generated from an epoxy sulfone, followed by ring expansion, allowed for the incorporation of medium-sized ring ethers into the key intermediate. Subsequent acetal formation and reductive etherification afforded various octacycles containing seven- and eight-membered ether rings.
Collapse
Affiliation(s)
- Takeo Sakai
- Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | | | | | | |
Collapse
|
49
|
Tsumuraya T, Takeuchi K, Yamashita S, Fujii I, Hirama M. Development of a monoclonal antibody against the left wing of ciguatoxin CTX1B: Thiol strategy and detection using a sandwich ELISA. Toxicon 2012; 60:348-57. [DOI: 10.1016/j.toxicon.2012.04.347] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 02/20/2012] [Accepted: 04/18/2012] [Indexed: 11/30/2022]
|
50
|
|