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Shi J, Peng D, Peng FF, Zhang QB, Duan YW, Huang Y. The Isolation and Structure Elucidation of Spirotetronate Lobophorins A, B, and H8 from Streptomyces sp. CB09030 and Their Biosynthetic Gene Cluster. Molecules 2023; 28:molecules28083597. [PMID: 37110828 PMCID: PMC10143065 DOI: 10.3390/molecules28083597] [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: 02/24/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Lobophorins (LOBs) are a growing family of spirotetronate natural products with significant cytotoxicity, anti-inflammatory, and antibacterial activities. Herein, we report the transwell-based discovery of Streptomyces sp. CB09030 from a panel of 16 in-house Streptomyces strains, which has significant anti-mycobacterial activity and produces LOB A (1), LOB B (2), and LOB H8 (3). Genome sequencing and bioinformatic analyses revealed the potential biosynthetic gene cluster (BGC) for 1-3, which is highly homologous with the reported BGCs for LOBs. However, the glycosyltransferase LobG1 in S. sp. CB09030 has certain point mutations compared to the reported LobG1. Finally, LOB analogue 4 (O-β-D-kijanosyl-(1→17)-kijanolide) was obtained through an acid-catalyzed hydrolysis of 2. Compounds 1-4 showed different antibacterial activities against Mycobacterium smegmatis and Bacillus subtilis, which revealed the varying roles of different sugars in their antibacterial activities.
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Affiliation(s)
- Jie Shi
- Xiangya International Academy of Translational Medicine, Central South University, Changsha 410013, China
| | - Dian Peng
- School of Pharmaceutical Sciences, Changsha Health Vocational College, Changsha 410100, China
| | - Fei-Fei Peng
- School of Pharmaceutical Sciences, Changsha Health Vocational College, Changsha 410100, China
| | - Qing-Bo Zhang
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Yan-Wen Duan
- Xiangya International Academy of Translational Medicine, Central South University, Changsha 410013, China
- Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha 410011, China
- National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha 410011, China
| | - Yong Huang
- Xiangya International Academy of Translational Medicine, Central South University, Changsha 410013, China
- National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha 410011, China
- Institute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei 230093, China
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2
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Stereoselective Synthesis and Anticancer Activity of 2,6-Disubstituted trans-3-Methylidenetetrahydropyran-4-ones. MATERIALS 2022; 15:ma15093030. [PMID: 35591364 PMCID: PMC9105583 DOI: 10.3390/ma15093030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 02/05/2023]
Abstract
In this report, we present efficient and stereoselective syntheses of 2,6-disubstituted trans-3-methylidenetetrahydropyran-4-ones and 2-(4-methoxyphenyl)-5-methylidenetetrahydropyran-4-one that significantly broaden the spectrum of the available methylidenetetrahydropyran-4-ones with various substitution patterns. Target compounds were obtained using Horner–Wadsworth–Emmons methodology for the introduction of methylidene group onto the pyranone ring. 3-Diethoxyphosphoryltetrahydropyran-4-ones, which were key intermediates in this synthesis, were prepared by fully or highly stereoselective addition of Gilman or Grignard reagents to 3-diethoxyphosphoryldihydropyran-4-ones. Addition occurred preferentially by axial attack of the Michael donors on the dihydropyranone ring. Relative configurations and conformations of the obtained adducts were assigned using a detailed analysis of the NMR spectra. The obtained methylidenepyran-4-ones were evaluated for cytotoxic activity against two cancer cell lines (HL-60 and MCF-7). 2,6-Disubstituted 3-methylidenetetrahydropyran-4-ones with isopropyl and phenyl substituents in position 2 were more cytotoxic than analogs with n-butyl substituent. Two of the most cytotoxic analogs were then selected for further investigation on the HL-60 cell line. Both analogs induced morphological changes characteristic of apoptosis in cancer cells, significantly inhibited proliferation and induced apoptotic cell death. Both compounds also generated DNA damage, and one of the analogs arrested the cell cycle of HL-60 cells in the G2/M phase. In addition, both analogs were able to inhibit the activity of topoisomerase IIα. Based on these findings, the investigated analogs may be further optimized for the development of new and effective topoisomerase II inhibitors.
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3
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Desouky SE, Abu-Elghait M, Fayed EA, Selim S, Yousuf B, Igarashi Y, Abdel-Wahab BA, Mohammed Alsuhaibani A, Sonomoto K, Nakayama J. Secondary Metabolites of Actinomycetales as Potent Quorum Sensing Inhibitors Targeting Gram-Positive Pathogens: In Vitro and In Silico Study. Metabolites 2022; 12:metabo12030246. [PMID: 35323689 PMCID: PMC8955454 DOI: 10.3390/metabo12030246] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023] Open
Abstract
Anti-virulence agents are non-bacteriostatic and non-bactericidal emerging therapeutic options which hamper the production of virulence factors in pathogenic flora. In Staphylococcus aureus and Enterococcus faecalis, regulation of virulence genes’ expression occurs through the cyclic peptide-mediated accessory gene regulator (agr) and its ortholog fsr quorum sensing systems, respectively. In the present study, we screened a set of 54 actinomycetales secondary metabolites as novel anti-virulence compounds targeting quorum sensing system of the Gram-positive bacteria. The results indicated that four compounds, Phenalinolactones A–D, BU–4664LMe, 4,5-dehydrogeldamycin, and Questinomycin A, potentially inhibit the agr quorum sensing system and hemolytic activity of S. aureus. On the other hand, Decatromicin A and B, Okilactomycin, Rishirilide A, Abyssomicin I, and Rebeccamycin selectively blocked the fsr quorum sensing system and the gelatinase production in E. faecalis at sub-lethal concentrations. Interestingly, Synerazol uniquely showed the capability to inhibit both fsr and agr quorum sensing systems. Further, in silico molecular docking studies were performed which provided closer insights into the mode of action of these compounds and proposed that the inhibitory activity of these compounds could be attributed to their potential ability to bind to the ATP-active site of S. aureus AgrA. Taken together, our study highlights the potential of actinomycetales secondary metabolites with diverse structures as anti-virulence quorum sensing inhibitors.
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Affiliation(s)
- Said E. Desouky
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
- Correspondence:
| | - Mohammed Abu-Elghait
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
| | - Eman A. Fayed
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754, Egypt;
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72341, Saudi Arabia;
| | - Basit Yousuf
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan;
| | - Basel A. Abdel-Wahab
- Department of Medical Pharmacology, College of Medicine, Assiut University, Assiut 7111, Egypt;
- Department of Pharmacology, College of Pharmacy, Najran University, Najran 1988, Saudi Arabia
| | - Amnah Mohammed Alsuhaibani
- Department of Physical Sport Science, College of Education, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia;
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Jiro Nakayama
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
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4
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Abstract
Over a long period of time, humans have explored many natural resources looking for remedies of various ailments. Traditional medicines have played an intrinsic role in human life for thousands of years, with people depending on medicinal plants and their products as dietary supplements as well as using them therapeutically for treatment of chronic disorders, such as cancer, malaria, diabetes, arthritis, inflammation, and liver and cardiac disorders. However, plant resources are not sufficient for treatment of recently emerging diseases. In addition, the seasonal availability and other political factors put constrains on some rare plant species. The actual breakthrough in drug discovery came concurrently with the discovery of penicillin from Penicillium notatum in 1929. This discovery dramatically changed the research of natural products and positioned microbial natural products as one of the most important clues in drug discovery due to availability, variability, great biodiversity, unique structures, and the bioactivities produced. The number of commercially available therapeutically active compounds from microbial sources to date exceeds those discovered from other sources. In this review, we introduce a short history of microbial drug discovery as well as certain features and recent research approaches, specifying the microbial origin, their featured molecules, and the diversity of the producing species. Moreover, we discuss some bioactivities as well as new approaches and trends in research in this field.
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Bartosik T, Kędzia J, Drogosz-Stachowicz J, Janecka A, Krajewska U, Mirowski M, Janecki T. Synthesis of 2,2,6-Trisubstituted 5-Methylidene-tetrahydropyran-4-ones with Anticancer Activity. Molecules 2020; 25:molecules25030611. [PMID: 32019209 PMCID: PMC7038078 DOI: 10.3390/molecules25030611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 11/24/2022] Open
Abstract
In our continuous search for new, relatively simple 2-alkylidene-1-oxoheterocycles as promising anticancer drug candidates, herein we report an efficient synthesis of 2,2,6-trisubstituted 5-methylidenetetrahydropyran-4-ones. These compounds were obtained in a four step reaction sequence, in which starting diethyl 2-oxopropylphosphonate was transformed into 2,2-disubstituted 5-diethoxyphosphoryldihydropyran-4-ones, followed by Michael addition of various Grignard reagents and Horner-Wadsworth-Emmons reaction of the obtained adducts with formaldehyde. Stereochemistry of the intermediate Michael adducts is also discussed. Final 5-methylidenetetrahydropyran-4-ones were tested for their possible antiproliferative effect against three cancer cell lines and 6-isopropyl-2,2-dimethyl-5-methylidenetetrahydropyran-4-one (11c), which showed very high cytotoxic activity against HL-60 human leukemia cells and was three times more active than known anticancer drug carboplatin, was selected for further biological evaluation, in order to disclose its mechanism of action. The obtained results indicated that 11c induced apoptosis in HL-60 cells and caused the arrest of the cell cycle in the G2/M phase, which may suggest its cytotoxic and cytostatic activity.
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Affiliation(s)
- Tomasz Bartosik
- Institute of Organic Chemistry, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland; (T.B.); (J.K.)
| | - Jacek Kędzia
- Institute of Organic Chemistry, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland; (T.B.); (J.K.)
| | - Joanna Drogosz-Stachowicz
- Department of Biomolecular Chemistry, Medical University of Łódź, Mazowiecka 6/8, 92-215 Łódź, Poland; (J.D.-S.)
| | - Anna Janecka
- Department of Biomolecular Chemistry, Medical University of Łódź, Mazowiecka 6/8, 92-215 Łódź, Poland; (J.D.-S.)
| | - Urszula Krajewska
- Department of Pharmaceutical Biochemistry and Molecular Diagnostics, Faculty of Pharmacy, Medical University of Łódź, Muszyńskiego 1, 90-151, Łódź, Poland; (U.K.); (M.M.)
| | - Marek Mirowski
- Department of Pharmaceutical Biochemistry and Molecular Diagnostics, Faculty of Pharmacy, Medical University of Łódź, Muszyńskiego 1, 90-151, Łódź, Poland; (U.K.); (M.M.)
| | - Tomasz Janecki
- Institute of Organic Chemistry, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland; (T.B.); (J.K.)
- Correspondence: ; Tel.: +48-426313220
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6
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Abstract
Covering: 2006 to 2017Actinomycetes have been, for decades, one of the most important sources for the discovery of new antibiotics with an important number of drugs and analogs successfully introduced in the market and still used today in clinical practice. The intensive antibacterial discovery effort that generated the large number of highly potent broad-spectrum antibiotics, has seen a dramatic decline in the large pharma industry in the last two decades resulting in a lack of new classes of antibiotics with novel mechanisms of action reaching the clinic. Whereas the decline in the number of new chemical scaffolds and the rediscovery problem of old known molecules has become a hurdle for industrial natural products discovery programs, new actinomycetes compounds and leads have continued to be discovered and developed to the preclinical stages. Actinomycetes are still one of the most important sources of chemical diversity and a reservoir to mine for novel structures that is requiring the integration of diverse disciplines. These can range from novel strategies to isolate species previously not cultivated, innovative whole cell screening approaches and on-site analytical detection and dereplication tools for novel compounds, to in silico biosynthetic predictions from whole gene sequences and novel engineered heterologous expression, that have inspired the isolation of new NPs and shown their potential application in the discovery of novel antibiotics. This review will address the discovery of antibiotics from actinomycetes from two different perspectives including: (1) an update of the most important antibiotics that have only reached the clinical development in the recent years despite their early discovery, and (2) an overview of the most recent classes of antibiotics described from 2006 to 2017 in the framework of the different strategies employed to untap novel compounds previously overlooked with traditional approaches.
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Affiliation(s)
- Olga Genilloud
- Fundación MEDINA, Avda Conocimiento 34, 18016 Granada, Spain.
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7
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McDonald BR, Scheidt KA. Pyranone natural products as inspirations for catalytic reaction discovery and development. Acc Chem Res 2015; 48:1172-83. [PMID: 25742935 DOI: 10.1021/ar5004576] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Natural products continue to provide a wealth of opportunities in the areas of chemical and therapeutic development. These structures are effective measuring sticks for the current state of chemical synthesis as a field and constantly inspire new approaches and strategies. Tetrahydropryans and tetrahydropyran-4-ones are found in numerous bioactive marine natural products and medicinal compounds. Our interest in exploring the therapeutic potential of natural products containing these motifs provided the impetus to explore new methods to access highly functionalized, chiral pyran molecules in the most direct and rapid fashion possible. This goal led to exploration and development of a Lewis acid-mediated Prins reaction between a chiral β-hydroxy-dioxinone and aldehyde to produce a pyran-dioxinone fused product that can be processed in a single pot operation to the desired tetrahydropyran-4-ones in excellent yield and stereoselectivity. Although the Prins reaction is a commonly employed approach toward pyrans, this method uniquely provides a 3-carboxy-trisubstituted pyran and utilizes dioxinones in a manner that was underexplored at the time. The 3-carboxy substituent served as a key synthetic handhold when this method was applied to the synthesis of highly functionalized pyrans within the macrocyclic natural products neopeltolide, okilactiomycin, and exiguolide. When employed in challenging macrocyclizations, this tetrahydropyranone forming reaction proved highly stereoselective and robust. Another major thrust in our lab has been the synthesis of benzopyranone natural products, specifically flavonoids, because this broad and diverse family of compounds possesses an equally broad range of biological and medicinal applications. With the goal of developing a broad platform toward the synthesis of enantioenriched flavonoid analogs and natural products, a biomimetic, asymmetric catalytic approach toward the synthesis of 2-aryl benzopyranones was developed. A bifunctional hydrogen bonding/Brønstead base catalyst was ultimately found to enable this transformation in analogous manner to the biosynthesis via the enzyme chalcone isomerase. Employing thiourea catalysts derived from the pseudoenantiomeric quinine and quinidine, alkylidene β-ketoesters can be isomerized to 3-carboxy flavanones and decarboxylated in a single pot operation to stereodivergently provide highly enantioenriched flavanones in excellent yield. This method was applied to the synthesis of the abyssinone family of natural products, as well as the rotenoid, deguelin. An analogous method to isomerize chalcones was developed and applied to the synthesis of isosilybin A. In both of these related endeavors, the need for novel enabling methodologies toward the efficient creation of targeted molecular complexity drove the discovery, development and deployment of these stereoselective catalytic transformations.
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Affiliation(s)
- Benjamin R. McDonald
- Department
of Chemistry,
Department of Pharmacology, and Center for Molecular Innovation and
Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Karl A. Scheidt
- Department
of Chemistry,
Department of Pharmacology, and Center for Molecular Innovation and
Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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8
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Lacoske M, Theodorakis EA. Spirotetronate polyketides as leads in drug discovery. JOURNAL OF NATURAL PRODUCTS 2015; 78:562-75. [PMID: 25434976 PMCID: PMC4380204 DOI: 10.1021/np500757w] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Indexed: 05/05/2023]
Abstract
The discovery of chlorothricin (1) defined a new family of microbial metabolites with potent antitumor antibiotic properties collectively referred to as spirotetronate polyketides. These microbial metabolites are structurally distinguished by the presence of a spirotetronate motif embedded within a macrocyclic core. Glycosylation at the periphery of this core contributes to the structural complexity and bioactivity of this motif. The spirotetronate family displays impressive chemical structures, potent bioactivities, and significant pharmacological potential. This review groups the family members based on structural and biosynthetic considerations and summarizes synthetic and biological studies that aim to elucidate their mode of action and explore their pharmacological potential.
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Affiliation(s)
- Michelle
H. Lacoske
- Department of Chemistry and
Biochemistry, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093-0358, United States
| | - Emmanuel A. Theodorakis
- Department of Chemistry and
Biochemistry, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093-0358, United States
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9
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Gianino JB, Campos CA, Lepore AJ, Pinkerton DM, Ashfeld BL. Redox and Lewis Acid Relay Catalysis: A Titanocene/Zinc Catalytic Platform in the Development of Multicomponent Coupling Reactions. J Org Chem 2014; 79:12083-95. [DOI: 10.1021/jo501890z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph B. Gianino
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Catherine A. Campos
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Antonio J. Lepore
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - David M. Pinkerton
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Brandon L. Ashfeld
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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10
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Expeditious synthesis of bicyclic pyrrolidine/pyrrolizidine/thiazolidine grafted macrocycles through intramolecular 1,3-dipolar cycloaddition of azomethine ylides. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.09.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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RETRACTED: Marine actinobacterial metabolites: current status and future perspectives. Microbiol Res 2013; 168:311-332. [PMID: 23480961 DOI: 10.1016/j.micres.2013.02.002] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 01/25/2013] [Accepted: 02/06/2013] [Indexed: 11/24/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).
This article has been retracted at the request of the Editor. Authors and Editor agreed to retract this article because substantial parts of the text were copied from the following sources without proper attribution: Lam, K.S. (2006), Discovery of novel metabolites from marine actinomycetes. Current Opinion in Microbiology 9(3), pp. 245–251; Subramani, R., Aalbersberg, W. (2012), Marine actinomycetes: An ongoing source of novel bioactive metabolites. Microbiological Research 167(10), pp. 571–580; Dharmaraj, S. (2010), Marine Streptomyces as a novel source of bioactive substances. World Journal of Microbiology and Biotechnology 26(12), pp. 2123–2139. The authors apologize for this oversight and any inconvenience caused.
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12
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Subramani R, Aalbersberg W. Marine actinomycetes: an ongoing source of novel bioactive metabolites. Microbiol Res 2012; 167:571-80. [PMID: 22796410 DOI: 10.1016/j.micres.2012.06.005] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 05/15/2012] [Accepted: 06/23/2012] [Indexed: 11/16/2022]
Abstract
Actinomycetes are virtually unlimited sources of novel compounds with many therapeutic applications and hold a prominent position due to their diversity and proven ability to produce novel bioactive compounds. There are more than 22,000 known microbial secondary metabolites, 70% of which are produced by actinomycetes, 20% from fungi, 7% from Bacillus spp. and 1-2% by other bacteria. Among the actinomycetes, streptomycetes group are considered economically important because out of the approximately more than 10,000 known antibiotics, 50-55% are produced by this genus. The ecological role of actinomycetes in the marine ecosystem is largely neglected and various assumptions meant there was little incentive to isolate marine strains for search and discovery of new drugs. The search for and discovery of rare and new actinomycetes is of significant interest to drug discovery due to a growing need for the development of new and potent therapeutic agents. Modern molecular technologies are adding strength to the target-directed search for detection and isolation of bioactive actinomycetes, and continued development of improved cultivation methods and molecular technologies for accessing the marine environment promises to provide access to this significant new source of chemical diversity with novel/rare actinomycetes including new species of previously reported actinomycetes.
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Affiliation(s)
- Ramesh Subramani
- Centre for Drug Discovery and Conservation, Institute of Applied Sciences, The University of the South Pacific, Laucala Campus, Suva, Fiji.
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13
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Abstract
The spirotetronate okilactomycin D (7) has been efficiently synthesized by a route featuring a substrate-controlled, diastereoselective (8:1) intramolecular Diels-Alder (IMDA) reaction of 11. The assigned absolute configuration of (-)-7 was confirmed.
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Affiliation(s)
- Dawen Niu
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455
| | - Thomas R. Hoye
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455
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14
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Tenenbaum JM, Morris WJ, Custar DW, Scheidt KA. Synthesis of (-)-okilactomycin by a Prins-type fragment-assembly strategy. Angew Chem Int Ed Engl 2011; 50:5892-5. [PMID: 21560215 DOI: 10.1002/anie.201102037] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Indexed: 11/09/2022]
Affiliation(s)
- Jason M Tenenbaum
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Silverman Hall, Northwestern University, Evanston, IL 60208, USA
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15
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Tenenbaum JM, Morris WJ, Custar DW, Scheidt KA. Synthesis of (−)-Okilactomycin by a Prins-Type Fragment-Assembly Strategy. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201102037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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In vitro antitrypanosomal activity of 12 low-molecular-weight antibiotics and observations of structure/activity relationships. J Antibiot (Tokyo) 2010; 63:619-22. [DOI: 10.1038/ja.2010.99] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Smith AB, Bosanac T, Basu K. Evolution of the total synthesis of (-)-okilactomycin exploiting a tandem oxy-cope rearrangement/oxidation, a Petasis-Ferrier union/rearrangement, and ring-closing metathesis. J Am Chem Soc 2009; 131:2348-58. [PMID: 19170499 PMCID: PMC2697663 DOI: 10.1021/ja8084669] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An effective, asymmetric total synthesis of the antitumor antibiotic (-)-okilactomycin (1), as well as assignment of the absolute configuration, has been achieved exploiting a convergent strategy. Highlights of the synthesis include a diastereoselective oxy-Cope rearrangement/oxidation sequence to install the C(1) and C(13) stereogenic centers, a Petasis-Ferrier union/rearrangement to construct the highly functionalized tetrahydropyranone inscribed within the 13-membered macrocycle ring, employing for the first time a sterically demanding acetal, an intramolecular chemoselective acylation to access an embedded bicyclic lactone, and an efficient ring-closing metathesis (RCM) reaction to generate the macrocyclic ring.
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Affiliation(s)
- Amos B Smith
- Department of Chemistry, Penn Center for Molecular Discovery, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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18
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Discovery of okilactomycin and congeners from Streptomyces scabrisporus by antisense differential sensitivity assay targeting ribosomal protein S4. J Antibiot (Tokyo) 2009; 62:55-61. [PMID: 19132063 DOI: 10.1038/ja.2008.8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Protein synthesis inhibition is a highly successful target for developing clinically effective and safe antibiotics. There are several targets within the ribosomal machinery, and small ribosomal protein S4 (RPSD) is one of the newer targets. Screening of microbial extracts using antisense-sensitized rpsD Staphylococcus aureus strain led to isolation of okilactomycin and four new congeners from Streptomyces scabrisporus. The major compound, okilactomycin, was the most active, with a minimum detection concentration of 3-12 microg ml(-1) against antisense assay, and showed an MIC of 4-16 microg ml(-1) against Gram-positive bacteria, including S. aureus. The congeners were significantly less active in all assays, and all compounds showed a slight preferential inhibition of RNA synthesis over DNA and protein synthesis. Antisense technology, due to increased sensitivity, continues to yield new, even though weakly active, antibiotics.
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Smith AB, Fox RJ, Razler TM. Evolution of the Petasis-Ferrier union/rearrangement tactic: construction of architecturally complex natural products possessing the ubiquitous cis-2,6-substituted tetrahydropyran structural element. Acc Chem Res 2008; 41:675-87. [PMID: 18489082 DOI: 10.1021/ar700234r] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The frequent low abundance of architecturally complex natural products possessing significant bioregulatory properties mandates the development of rapid, efficient, and stereocontrolled synthetic tactics, not only to provide access to the biologically rare target but also to enable elaboration of analogues for the development of new therapeutic agents with improved activities and/or pharmacokinetic properties. In this Account, the genesis and evolution of the Petasis-Ferrier union/rearrangement tactic, in the context of natural product total syntheses, is described. The reaction sequence comprises a powerful tactic for the construction of the 2,6- cis-substituted tetrahydropyran ring system, a ubiquitous structural element often found in complex natural products possessing significant bioactivities. The three-step sequence, developed in our laboratory, extends two independent methods introduced by Ferrier and Petasis and now comprises: condensation between a chiral, nonracemic beta-hydroxy acid and an aldehyde to furnish a dioxanone; carbonyl olefination; and Lewis-acid-induced rearrangement of the resultant enol acetal to generate the 2,6- cis-substituted tetrahydropyranone system in a highly stereocontrolled fashion. To demonstrate the envisioned versatility and robustness of the Petasis-Ferrier union/rearrangement tactic in complex molecule synthesis, we exploited the method as the cornerstone in our now successful total syntheses of (+)-phorboxazole A, (+)-zampanolide, (+)-dactylolide, (+)-spongistatins 1 and 2, (-)-kendomycin, (-)-clavosolide A, and most recently, (-)-okilactomycin. Although each target comprises a number of synthetic challenges, this Account focuses on the motivation, excitement, and frustrations associated with the evolution and implementation of the Petasis-Ferrier union/rearrangement tactic. For example, during our (+)-phorboxazole A endeavor, we recognized and exploited the inherent pseudo symmetry of the 2,6- cis-substituted tetrahydropyranone product to overcome the inherent chelation bias of an adjacent oxazolidine ring during the Lewis-acid-promoted rearrangement. In addition, we discovered that a more concentrated solution of Cp2TiMe2 (0.7 versus 0.5 M in THF) with the addition of ethyl pivalate dramatically improves the yield in the Petasis-Tebbe olefination. During the (+)-zampanolide and (+)-dactylolide programs, we observed that the addition of trifluoromethanesulfonic acid (TfOH), especially on a preparative scale, was crucial to the efficiency of the initial condensation/union reaction, while our efforts toward (-)-kendomycin led to the improved implementation of a modified Kurihara condensation of the beta-hydroxy acid and aldehyde involving i-PrOTMS and TMSOTf. Finally, the successful deployment of the Petasis-Ferrier tactic in our synthesis of (-)-clavosolide A validated the viability of this tactic with a system possessing the highly acid-labile cyclopropylcarbinyl moiety, while the challenges en route to (-)-okilactomycin demonstrated that a neighboring alkene functionality can participate in an intramolecular Prins cyclization during the TMSOTf-promoted union process, unless suitably protected.
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Affiliation(s)
- Amos B. Smith
- Department of Chemistry, Monell Chemical Senses Center, and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Richard J. Fox
- Department of Chemistry, Monell Chemical Senses Center, and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Thomas M. Razler
- Department of Chemistry, Monell Chemical Senses Center, and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Mandal SK, Paira M, Roy SC. Titanocene(III) Chloride Mediated Radical-Induced Addition to Baylis−Hillman Adducts: Synthesis of (E)- and (Z)-Trisubstituted Alkenes and α-Methylene/Arylidene δ-Lactones. J Org Chem 2008; 73:3823-7. [DOI: 10.1021/jo800049p] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samir K. Mandal
- Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Moumita Paira
- Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Subhas C. Roy
- Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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Affiliation(s)
- Amos B. Smith
- Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kallol Basu
- Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Todd Bosanac
- Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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