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Chen P, Wang J, Zhang S, Wang Y, Sun Y, Bai S, Wu Q, Cheng X, Cao P, Qi X. Total syntheses of Tetrodotoxin and 9-epiTetrodotoxin. Nat Commun 2024; 15:679. [PMID: 38263179 PMCID: PMC10806222 DOI: 10.1038/s41467-024-45037-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024] Open
Abstract
Tetrodotoxin and congeners are specific voltage-gated sodium channel blockers that exhibit remarkable anesthetic and analgesic effects. Here, we present a scalable asymmetric syntheses of Tetrodotoxin and 9-epiTetrodotoxin from the abundant chemical feedstock furfuryl alcohol. The optically pure cyclohexane skeleton is assembled via a stereoselective Diels-Alder reaction. The dense heteroatom substituents are established sequentially by a series of functional group interconversions on highly oxygenated cyclohexane frameworks, including a chemoselective cyclic anhydride opening, and a decarboxylative hydroxylation. An innovative SmI2-mediated concurrent fragmentation, an oxo-bridge ring opening and ester reduction followed by an Upjohn dihydroxylation deliver the highly oxidized skeleton. Ruthenium-catalyzed oxidative alkyne cleavage and formation of the hemiaminal and orthoester under acidic conditions enable the rapid assembly of Tetrodotoxin, anhydro-Tetrodotoxin, 9-epiTetrodotoxin, and 9-epi lactone-Tetrodotoxin.
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Affiliation(s)
- Peihao Chen
- School of Life Sciences, Peking University, Beijing, 100871, China
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Jing Wang
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Shuangfeng Zhang
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Yan Wang
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Yuze Sun
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Songlin Bai
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Qingcui Wu
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Xinyu Cheng
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- National Institute of Biological Sciences, Chinese Academy of Medical Sciences&Peking Union Medical College, Beijing, 100730, China
| | - Peng Cao
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Xiangbing Qi
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China.
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2
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Glasovac Z, Barešić L, Margetić D. A DFT Investigation of the Reactivity of Guanidinium Salts in Tandem aza-Michael Addition/Intramolecular Cyclization. Molecules 2023; 28:molecules28052218. [PMID: 36903463 PMCID: PMC10005421 DOI: 10.3390/molecules28052218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
A proposed mechanism of the reaction of guanidinium chlorides with dimethyl acetylenedicarboxylate in a tandem aza-Michael addition reaction/intramolecular cyclization was investigated by DFT M06-2X and B3LYP computational approaches. The energies of the products were compared against the G3, M08-HX, M11, and wB97xD data or experimentally obtained product ratios. The structural diversity of the products was interpreted by the concurrent formation of different tautomers formed in situ upon deprotonation with a 2-chlorofumarate anion. A comparison of relative energies of the characteristic stationary points along the examined reaction paths indicated that the initial nucleophilic addition is energetically the most demanding process. The overall reaction is strongly exergonic, as predicted by both methods, which is primarily due to methanol elimination during the intramolecular cyclization step producing cyclic amide structures. Formation of a five-membered ring upon intramolecular cyclization is highly favored for the acyclic guanidine, while optimal product structure for the cyclic guanidines is based on a 1,5,7-triaza [4.3.0]-bicyclononane skeleton. Relative stabilities of the possible products calculated by the employed DFT methods were compared against the experimental product ratio. The best agreement was obtained for the M08-HX approach while the B3LYP approach provided somewhat better results than the M06-2X and M11 methods.
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3
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Andres R, Sun F, Wang Q, Zhu J. Organocatalytic Enantioselective Pictet-Spengler Reaction of α-Ketoesters: Development and Application to the Total Synthesis of (+)-Alstratine A. Angew Chem Int Ed Engl 2023; 62:e202213831. [PMID: 36347809 DOI: 10.1002/anie.202213831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Indexed: 11/10/2022]
Abstract
We report herein an asymmetric Pictet-Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1-alkyl-1-methoxycarbonyl tetrahydro-β-carbolines (THBCs) in high yields and ee values. A primary kinetic isotope effect (KIE=4.5) using C2-deteurium-labelled tryptamine indicates that rearomatization through deprotonation of the pentahydro-β-carbolinium ion could be the rate- and enantioselectivity-determining step. A concise enantioselective total synthesis of (+)-alstratine A, a hexacyclic cagelike monoterpene indole alkaloid, featuring this reaction as a key step, was subsequently accomplished. Remeasurement of the [a]D value of the natural product indicates that natural alstratine A is dextrorotatory rather than levorotatory as it was initially reported in the isolation paper.
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Affiliation(s)
- Rémi Andres
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Fenggang Sun
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland.,School of Chemical Engineering, Shandong University of Technology, Zibo, 255049, P. R. China
| | - Qian Wang
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland
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4
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Munawar S, Zahoor AF, Ali S, Javed S, Irfan M, Irfan A, Kotwica-Mojzych K, Mojzych M. Mitsunobu Reaction: A Powerful Tool for the Synthesis of Natural Products: A Review. Molecules 2022; 27:6953. [PMID: 36296545 PMCID: PMC9609662 DOI: 10.3390/molecules27206953] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/06/2022] [Accepted: 10/08/2022] [Indexed: 08/13/2023] Open
Abstract
The Mitsunobu reaction plays a vital part in organic chemistry due to its wide synthetic applications. It is considered as a significant reaction for the interconversion of one functional group (alcohol) to another (ester) in the presence of oxidizing agents (azodicarboxylates) and reducing agents (phosphines). It is a renowned stereoselective reaction which inverts the stereochemical configuration of end products. One of the most important applications of the Mitsunobu reaction is its role in the synthesis of natural products. This review article will focus on the contribution of the Mitsunobu reaction towards the total synthesis of natural products, highlighting their biological potential during recent years.
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Affiliation(s)
- Saba Munawar
- Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Ameer Fawad Zahoor
- Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Shafaqat Ali
- College of Agriculture and Environmental Sciences, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Sadia Javed
- Department of Biochemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Muhammad Irfan
- Department of Pharmaceutics, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Ali Irfan
- Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Katarzyna Kotwica-Mojzych
- Laboratory of Experimental Cytology, Medical University of Lublin, Radziwiłłowska 11, 20-080 Lublin, Poland
| | - Mariusz Mojzych
- Department of Chemistry, Siedlce University of Natural Sciences and Humanities, 3-go Maja 54, 08-110 Siedlce, Poland
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5
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Yaegashi Y, Kudo Y, Ueyama N, Onodera KI, Cho Y, Konoki K, Yotsu-Yamashita M. Isolation and Biological Activity of 9- epiTetrodotoxin and Isolation of Tb-242B, Possible Biosynthetic Shunt Products of Tetrodotoxin from Pufferfish. JOURNAL OF NATURAL PRODUCTS 2022; 85:2199-2206. [PMID: 35994072 DOI: 10.1021/acs.jnatprod.2c00588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Tetrodotoxin (TTX, 1) is a potent voltage-gated sodium channel blocker detected in certain marine and terrestrial organisms. We report here a new TTX analogue, 9-epiTTX (2), and a TTX-related compound, Tb-242B (4), isolated from the pufferfish Takifugu flavipterus and Dichotomyctere ocellatus, respectively. NMR analysis suggested that 2 exists as a mixture of hemilactal and 10,8-lactone forms, whereas other reported TTX analogues are commonly present as an equilibrium mixture of hemilactal and 10,7-lactone forms. Compound 2 and TTX were confirmed not to convert to each other by incubation under neutral and acidic conditions at 37 °C for 24 h. Compound 4 was identified as the 9-epimer of Tb-242A (3), previously reported as a possible biosynthetic precursor of TTX. Compound 4 was partially converted to 3 by incubation in a neutral buffer at 37 °C for 7 days, whereas 3 was not converted to 4 under this condition. Compound 2 was detected in several TTX-containing marine animals and a newt. Mice injected with 600 ng of 2 by intraperitoneal injection did not show any adverse symptoms, suggesting that the C-9 configuration in TTX is critical for its biological activity. Based on the structures, 2 and 4 were predicted to be shunt products for TTX biosynthesis.
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Affiliation(s)
- Yuji Yaegashi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Nozomi Ueyama
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Ken-Ichi Onodera
- Faculty of Agriculture and Marine Sciences, Kochi University, 200 Otsu, Monobe, Nankoku, Kochi 783-8502, Japan
| | - Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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6
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Nishiumi M, Miyasaka T, Adachi M, Nishikawa T. Total Syntheses of the Proposed Biosynthetic Intermediates of Tetrodotoxin Tb-210B, Tb-226, Tb-242C, and Tb-258. J Org Chem 2022; 87:9023-9033. [PMID: 35765754 DOI: 10.1021/acs.joc.2c00704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The collective synthesis of the four spiro-cyclic guanidines Tb-210B, Tb-226, Tb-242C, and Tb-258, all of which have been isolated from puffer fish and are considered possible biosynthetic intermediates of tetrodotoxin, has been achieved. Our synthesis is based on the stepwise deoxygenation or hydroxylation of a common intermediate, prepared from a known oxazoline.
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Affiliation(s)
- Masafumi Nishiumi
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Tadachika Miyasaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Masaatsu Adachi
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Toshio Nishikawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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7
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Abstract
This review deals with the synthesis of naturally occurring alkaloids containing partially or completely saturated pyrimidine nuclei. The interest in these compounds is associated with their structural diversity, high biological activity and toxicity. The review is divided into four parts, each of which describes a number of synthetic methodologies toward structurally different naturally occurring alkaloids containing saturated cyclic six-membered amidine, guanidine, aminal and urea (thiourea) moieties, respectively. The development of various synthetic strategies for the preparation of these compounds has remarkably increased during the past few decades. This is primarily due to the fact that some of these compounds are isolated only in limited quantities, which makes it practically impossible to study their full structural characteristics and biological activity.
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8
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Miyasaka T, Adachi M, Nishikawa T. Synthesis of the 8-Deoxy Analogue of 4,9-Anhydro-10-hemiketal-5-deoxy-tetrodotoxin, a Proposed Biosynthetic Precursor of Tetrodotoxin. Org Lett 2021; 23:9232-9236. [PMID: 34779634 DOI: 10.1021/acs.orglett.1c03565] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite decades of research, the biosynthesis of tetrodotoxin, also known as a puffer fish toxin, remains an unsolved mystery. We disclose a synthesis of the 8-deoxy analogue of 4,9-anhydro-10-hemiketal-5-deoxy-tetrodotoxin, a possible biosynthetic precursor of tetrodotoxin isolated from the Japanese toxic newt, by an intramolecular radical cyclization of a known starting material.
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Affiliation(s)
- Tadachika Miyasaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Masaatsu Adachi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Toshio Nishikawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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9
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Kudo Y, Hanifin CT, Yotsu-Yamashita M. Identification of Tricyclic Guanidino Compounds from the Tetrodotoxin-Bearing Newt Taricha granulosa. Org Lett 2021; 23:3513-3517. [PMID: 33830775 DOI: 10.1021/acs.orglett.1c00916] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The biosynthesis of the potent neurotoxin tetrodotoxin (TTX, 1) is still unresolved. We used MS-guided screening and nuclear magnetic resonance analyses including long-range HSQMBC to characterize two novel skeletal tricyclic guanidino compounds, Tgr-288 (2a and 2b) and Tgr-210 (3), from the TTX-bearing newt, Taricha granulosa. The presence of these compounds in toxic newts is congruent with a previously proposed pathway for TTX biosynthesis in terrestrial organisms that includes a monoterpene precursor and the production of structurally diversified guanidino compounds.
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Affiliation(s)
- Yuta Kudo
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.,Graduate School of Agricultural Science, Tohoku University 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Charles T Hanifin
- Department of Biology, Utah State University, Uintah Basin Campus, 320 North Aggie Boulevard (2000 W.), Vernal, Utah 84078, United States
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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10
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Nishikawa K, Noguchi T, Kikuchi S, Maruyama T, Araki Y, Yotsu-Yamashita M, Morimoto Y. Tetrodotoxin Framework Construction from Linear Substrates Utilizing a Hg(OTf)2-Catalyzed Cycloisomerization Reaction: Synthesis of the Unnatural Analogue 11-nor-6,7,8-Trideoxytetrodotoxin. Org Lett 2021; 23:1703-1708. [DOI: 10.1021/acs.orglett.1c00125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Keisuke Nishikawa
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
| | - Takayuki Noguchi
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
| | - Seiho Kikuchi
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
| | - Takahiro Maruyama
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
| | - Yusuke Araki
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi 980-8572, Japan
| | - Yoshiki Morimoto
- Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, Osaka 558-8585, Japan
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11
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Berlinck RGS, Bernardi DI, Fill T, Fernandes AAG, Jurberg ID. The chemistry and biology of guanidine secondary metabolites. Nat Prod Rep 2020; 38:586-667. [PMID: 33021301 DOI: 10.1039/d0np00051e] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.
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Affiliation(s)
- Roberto G S Berlinck
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil.
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12
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Kudo Y, Hanifin CT, Kotaki Y, Yotsu-Yamashita M. Structures of N-Hydroxy-Type Tetrodotoxin Analogues and Bicyclic Guanidinium Compounds Found in Toxic Newts. JOURNAL OF NATURAL PRODUCTS 2020; 83:2706-2717. [PMID: 32896120 DOI: 10.1021/acs.jnatprod.0c00623] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The biosynthesis of tetrodotoxin (TTX, 1), a potent neurotoxin widely distributed in marine and terrestrial metazoans, remains unresolved. A significant issue has been identifying intermediates and shunt products associated with the biosynthetic pathway of TTX. We investigated TTX biosynthesis by screening and identifying new TTX-related compounds from Cynops ensicauda popei and Taricha granulosa. Mass spectrometry (MS)-guided screening identified two new N-hydroxy TTX analogues in newts: 1-hydroxy-8-epiTTX (2) and 1-hydroxy-8-epi-5,11-dideoxyTTX (3, previously reported as 1-hydroxy-5,11-dideoxyTTX). We prepared a new analogue, 8-epi-5,11-dideoxyTTX (4), from 3 via N-OH reduction and confirmed the presence of 4 in T. granulosa using hydrophilic interaction liquid chromatography (HILIC)-LCMS. The presence of 8-epi-type TTX analogues in both Cynops and Taricha supports a branched biosynthetic pathway of terrestrial TTX, which produces 6- and 8-epimers. In addition, new bicyclic guanidinium compounds Tgr-238 (5) and Tgr-240 (6) were identified as putative shunt products of our proposed TTX biosynthesis pathway. A structural analysis of Cep-228A (7), another bicyclic compound, was performed using NMR. Based on the structures of 5-7 and their analogues, we propose a model of the shunt and metabolic pathways of the terrestrial TTX biosynthesis.
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Affiliation(s)
- Yuta Kudo
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
- Graduate School of Agricultural Science, Tohoku University 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Charles T Hanifin
- Department of Biology, Utah State University, Uintah Basin Campus, 320 N. Aggie Boulevard (2000 W.), Vernal, Utah 84078, United States
| | - Yuichi Kotaki
- Fukushima College, 1-1 Chigoike Miyashiro, Fukushima 960-0181, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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13
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Affiliation(s)
- Keigo Murakami
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Tatsuya Toma
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Tohru Fukuyama
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Satoshi Yokoshima
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
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14
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Murakami K, Toma T, Fukuyama T, Yokoshima S. Total Synthesis of Tetrodotoxin. Angew Chem Int Ed Engl 2020; 59:6253-6257. [DOI: 10.1002/anie.201916611] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Indexed: 01/03/2023]
Affiliation(s)
- Keigo Murakami
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Tatsuya Toma
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Tohru Fukuyama
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
| | - Satoshi Yokoshima
- Graduate School of Pharmaceutical SciencesNagoya University Furo-cho, Chikusa-ku Nagoya 464-8601 Japan
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15
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Kudo Y, Yotsu-Yamashita M. Isolation and Biological Activity of 8- Epitetrodotoxin and the Structure of a Possible Biosynthetic Shunt Product of Tetrodotoxin, Cep-226A, from the Newt Cynops ensicauda popei. JOURNAL OF NATURAL PRODUCTS 2019; 82:1656-1663. [PMID: 31117524 DOI: 10.1021/acs.jnatprod.9b00178] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tetrodotoxin (TTX, 1), a potent neurotoxin, has been found in various animal species in both marine and terrestrial environments. In this study, a new TTX analogue, 8- epiTTX (2), and a possible biosynthetic shunt compound of TTX, Cep-226A (3), were isolated from the newt Cynops ensicauda popei. The voltage-gated sodium ion channel (Nav) blocking activity of 2 and 6- epiTTX (4), a known analogue, were investigated by a colorimetric cell-based assay and compared with that of 1. The EC50 values for 2 and 4 were determined to be 110 ± 40 and 33 ± 11 nM, respectively, which were larger than that of 1 (1.9 ± 0.7 nM). The results indicated that the equatorial hydroxy group at C-8 in TTX significantly contributes to its Nav blocking activity, whereas the 6-epimer of TTX retains substantial activity, consistent with its previously reported toxicity in mice and binding affinity to rat brain membrane preparations. The presence of these epimers of TTX (2 and 4) and Cep-226A (3) in newts supports our hypothesis that TTX is derived from a monoterpene in terrestrial environments.
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Affiliation(s)
- Yuta Kudo
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba, Aoba-ku , Sendai , Miyagi 980-8572 , Japan
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba, Aoba-ku , Sendai , Miyagi 980-8578 , Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba, Aoba-ku , Sendai , Miyagi 980-8572 , Japan
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