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Kiefer A, Arnholdt M, Grimm V, Geske L, Groß J, Vierengel N, Opatz T, Erkel G. Structure elucidation and biological activities of perylenequinones from an Alternaria species. Mycotoxin Res 2023:10.1007/s12550-023-00495-1. [PMID: 37351768 PMCID: PMC10393905 DOI: 10.1007/s12550-023-00495-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 06/24/2023]
Abstract
The KEAP1-Nrf2/ARE pathway is a pivotal cytoprotective regulator against oxidative stress which plays an important role in the development of many inflammatory diseases and cancer. Activation of the Nrf2 transcription factor by oxidative stress or electrophiles regulates antioxidant response element (ARE)-dependent transcription of antioxidative, detoxifying, and anti-inflammatory proteins. Therefore, modulators of the KEAP1-Nrf2/ARE pathway have received considerable interest as therapeutics to protect against diseases where oxidative stress constitutes the underlying pathophysiology. In a search for fungal secondary metabolites affecting the Nrf2/ARE-dependent expression of a luciferase reporter gene in BEAS-2B cells, three new perylenequinones, compounds 1, 2, and 3, together with altertoxin-I (ATX-I), were isolated from fermentations of an Alternaria species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy and mass spectrometry. Compound 1 and ATX-I exhibited strong cytotoxic effects with LC50-values of 3.8 µM and 6.43 µM, respectively, whereas compound 3 showed no cytotoxic effects up to 100 µM on BEAS-2B cells. ATX-I induced ARE-dependent luciferase expression approximately fivefold and compound 1 approximately 2.6-fold at a concentration of 3 µM in transiently transfected BEAS-2B cells. In addition, compound 1 and ATX-I exhibited strong oxidative effects, whereas compound 3 did not show significant oxidative properties. For compound 1 and ATX-I, a strong upregulation of heme oxygenase-1 could be observed on mRNA and protein level in treated BEAS-2B cells. Moreover, compound 3 significantly decreased sod3 mRNA levels after induction of oxidative stress with benzoquinone.
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Affiliation(s)
- Anna Kiefer
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Marcel Arnholdt
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Viktoria Grimm
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Leander Geske
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Jonathan Groß
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Nina Vierengel
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Till Opatz
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany.
| | - Gerhard Erkel
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany.
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Geske L, Baier J, Boulos JC, Efferth T, Opatz T. Xylochemical Synthesis and Biological Evaluation of the Orchidaceous Natural Products Isoarundinin I, Bleochrin F, Blestanol K, and Pleionol. J Nat Prod 2023; 86:131-137. [PMID: 36538372 DOI: 10.1021/acs.jnatprod.2c00830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The first total syntheses of the orchid-derived natural products isoarundinin I (1), (±)-bleochrin F ((±)-2), (±)-blestanol K ((±)-3), and (±)-pleionol ((±)-4) from renewable starting materials are reported, along with the evaluation of their biological activities. The total syntheses were based on regioselective aromatic bromination reactions in combination with a key acid-promoted regioselective intramolecular cyclization. The biological results suggest that isoarundinin I (1), (±)-blestanol K ((±)-3), and (±)-pleionol ((±)-4) have the potential to inhibit the growth of both sensitive and multidrug-resistant cancer cells.
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Affiliation(s)
- Leander Geske
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Joris Baier
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Joelle C Boulos
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University, Staudingerweg 5, 55128 Mainz, Germany
| | - Thomas Efferth
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University, Staudingerweg 5, 55128 Mainz, Germany
| | - Till Opatz
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
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Abstract
Nitrogen heterocycles are essential parts of the chemical machinery of life and often reveal intriguing structures. They are not only widespread in terrestrial habitats but can also frequently be found as natural products in the marine environment. This review highlights the important class of marine pyrrole alkaloids, well-known for their diverse biological activities. A broad overview of the marine pyrrole alkaloids with a focus on their isolation, biological activities, chemical synthesis, and derivatization covering the decade from 2010 to 2020 is provided. With relevant structural subclasses categorized, this review shall provide a clear and timely synopsis of this area.
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Affiliation(s)
| | | | - Till Opatz
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10–14, 55128 Mainz, Germany; (K.S.); (L.G.)
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Geske L, Kauhl U, Saeed MEM, Schüffler A, Thines E, Efferth T, Opatz T. Xylochemical Synthesis and Biological Evaluation of Shancigusin C and Bletistrin G. Molecules 2021; 26:3224. [PMID: 34072126 PMCID: PMC8198954 DOI: 10.3390/molecules26113224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 11/16/2022] Open
Abstract
The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regioselective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.
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Affiliation(s)
- Leander Geske
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany; (L.G.); (U.K.)
| | - Ulrich Kauhl
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany; (L.G.); (U.K.)
| | - Mohamed E. M. Saeed
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University, Staudingerweg 5, 55128 Mainz, Germany;
| | - Anja Schüffler
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; (A.S.); (E.T.)
- Institute for Microbiology, Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Eckhard Thines
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; (A.S.); (E.T.)
- Institute for Microbiology, Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Thomas Efferth
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University, Staudingerweg 5, 55128 Mainz, Germany;
| | - Till Opatz
- Department of Chemistry, Organic Chemistry Section, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany; (L.G.); (U.K.)
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Vierengel N, Geske L, Sato E, Opatz T. Synthesis of Morphinans through Anodic Aryl-Aryl Coupling. CHEM REC 2021; 21:2344-2353. [PMID: 33955153 DOI: 10.1002/tcr.202100078] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/07/2021] [Indexed: 11/08/2022]
Abstract
The morphinans are an important class of structurally fascinating and physiologically important natural products as exemplified by the famous opium alkaloids of the morphine family. Although this class of secondary metabolites from the juice of the opium poppy capsule was already used for medicinal purposes thousands of years ago, chemical modifications are still being applied to the core structure today in order to achieve the most specific effect on the various receptor subtypes possible with the fewest possible side effects. The unusual architecture of the morphinan core has also proven to be a highly challenging target for total synthesis. This review highlights electrosynthetic approaches towards natural and semisynthetic morphinan alkaloids. The historical progress in applying anodic aryl-aryl couplings to the construction of the morphinan framework is described in chronological order while particular benefits and challenges concerning the electrochemical transformations are grouped together, including the influence of substitution patterns, protecting groups, and reaction conditions.
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Affiliation(s)
- Nina Vierengel
- Department Chemie, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Leander Geske
- Department Chemie, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Eisuke Sato
- Department Chemie, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Till Opatz
- Department Chemie, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
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Orejarena Pacheco JC, Pusch S, Geske L, Opatz T. One-Pot Oxidative C-H Activation/Aza-Prins-Type Reaction of Tertiary Alkynylamines: A Counter Ion-Induced Iminium Ion-Alkyne Cyclization. J Org Chem 2021; 86:2760-2771. [PMID: 33496587 DOI: 10.1021/acs.joc.0c02737] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herein, the design and development of a new one-pot and metal-free oxidative C-H activation/aza-Prins type cyclization of alkynylamines is reported. The scope of this method was demonstrated by the preparation of ten new pyrido[2,1-a]isoquinolines in moderate to high yields (38-92%). Furthermore, a mechanistic proposal for the alkyne aza-Prins cyclization is described based on DFT calculations.
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Affiliation(s)
| | - Stefan Pusch
- Institute of Organic Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Leander Geske
- Institute of Organic Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Till Opatz
- Institute of Organic Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
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Abstract
Electrochemistry provides a valuable toolbox for organic synthesis and offers an appealing, environmentally benign alternative to the use of stoichiometric quantities of chemical oxidants or reductants. Its potential to control current efficiency along with providing alternative reaction conditions in a classical sense makes electrochemistry a suitable method for large-scale industrial transformations as well as for laboratory applications in the synthesis of complex molecular architectures. Even though research in this field has intensified over the recent decades, many synthetic chemists still hesitate to add electroorganic reactions to their standard repertoire, and hence, the full potential of preparative organic electrochemistry has not yet been unleashed. This short review highlights the versatility of anodic transformations by summarizing their application in natural product synthesis.1 Introduction2 Shono-Type Oxidation3 C–N/N–N Bond Formation4 Aryl–Alkene/Aryl–Aryl Coupling5 Cycloadditions Triggered by Oxidation of Electron-Rich Arenes6 Spirocycles7 Miscellaneous Transformations8 Future Prospects
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Affiliation(s)
- Till Opatz
- Department Chemie, Johannes Gutenberg-Universität
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