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Ul Karim MR, Fukaya K, In Y, Sharma AR, Harunari E, Oku N, Urabe D, Trianto A, Igarashi Y. Marinoquinolones and Marinobactoic Acid: Antimicrobial and Cytotoxic ortho-Dialkylbenzene-Class Metabolites Produced by a Marine Obligate Gammaproteobacterium of the Genus Marinobacterium. J Nat Prod 2022; 85:1763-1770. [PMID: 35802519 DOI: 10.1021/acs.jnatprod.2c00281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Chemical investigation of the culture extract of a marine obligate proteobacterium, Marinobacterium sp. C17-8, isolated from scleractinian coral Euphyllia sp., led to the discovery of three new o-dialkylbenzene-class metabolites, designated marinoquinolones A (1) and B (2) and marinobactoic acid (3). Spectroscopic analysis using MS and NMR revealed the structures of 1 and 2 to be 4-quinolones with an o-dialkylbenzene-containing side chain at C3 and 3 to be a fatty acid bearing an o-dialkylbenzene substructure. The 4-quinolone form of 1 and 2 was unequivocally determined by comparison of the 1H, 13C, and 15N chemical shifts of 1 with those predicted for 2-methyl-4-quinolone A and its tautomer 2-methyl-4-quinolinol B by quantum chemical calculation. Compound 1 was proven to be racemic by X-ray crystallographic analysis and chiral-phase HPLC analysis of its chemical degradation product. Compounds 1-3 exhibited antimicrobial activity against bacteria and filamentous fungi at MIC of 6.3-50 μg/mL. In addition, all compounds showed cytotoxicity against P388 murine leukemia cells at micromolar ranges.
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Affiliation(s)
- Md Rokon Ul Karim
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Keisuke Fukaya
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Yasuko In
- Department of Physical Chemistry, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka 569-1041, Japan
| | - Amit Raj Sharma
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Enjuro Harunari
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Daisuke Urabe
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Agus Trianto
- Faculty of Fisheries and Marine Sciences, Diponegoro University, Tembalang Campus, St. Prof. Soedarto, SH Semarang 50275, Central Java, Indonesia
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
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2
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Igarashi Y, Matsuyuki Y, Yamada M, Fujihara N, Harunari E, Oku N, Karim MRU, Yang T, Yamada K, Imada C, Fukaya K, Urabe D. Structure Determination, Biosynthetic Origin, and Total Synthesis of Akazaoxime, an Enteromycin-Class Metabolite from a Marine-Derived Actinomycete of the Genus Micromonospora. J Org Chem 2021; 86:6528-6537. [PMID: 33885295 DOI: 10.1021/acs.joc.1c00358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new enteromycin-class antibiotic, akazaoxime (1), possessing an aldoxime functionality in place of O-methyl nitronic acid, was isolated from the cultured extract of a marine-derived actinomycete of the genus Micromonospora, along with known A-76356 (2). The structure of 1, including the absolute stereochemistry of three chiral centers, was established by comprehensive analysis of nuclear magnetic resonance (NMR) and mass spectrometry data coupled with magnetic anisotropy analysis of its phenylglycine methyl ester derivatives. The stereochemistry of 2, not determined previously, was proven to be the same as that of 1 on the basis of the similarity of their NMR and specific rotation data. Precursor feeding experiments using 13C-labeled compounds elucidated that the carbon skeletons of 1 and 2 are constructed from propionate (methylmalonate), leucine, and glycine. Establishment of the concise and flexible synthetic route to 1 enabled us to implement biological evaluation of 1 and its unnatural analogues, demonstrating weak to moderate antimicrobial activities of 1 against Gram-positive Kocuria rhizophila [minimum inhibitory concentration (MIC) of 50 μg/mL] and those of synthetic analogues against a plant pathogen Glomerella cingulata (MIC of 50 μg/mL) and a human pathogen Trichophyton rubrum (MIC of 25-50 μg/mL).
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Affiliation(s)
- Yasuhiro Igarashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Yoe Matsuyuki
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Masayuki Yamada
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Nodoka Fujihara
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Enjuro Harunari
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Md Rokon Ul Karim
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Taehui Yang
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo 108-8477, Japan
| | - Katsuhisa Yamada
- DHC Corporation, 2-7-1 minami-Azabu, Minato-ku, Tokyo 106-8571, Japan
| | - Chiaki Imada
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo 108-8477, Japan
| | - Keisuke Fukaya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Daisuke Urabe
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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Karim MRU, In Y, Zhou T, Harunari E, Oku N, Igarashi Y. Nyuzenamides A and B: Bicyclic Peptides with Antifungal and Cytotoxic Activity from a Marine-Derived Streptomyces sp. Org Lett 2021; 23:2109-2113. [PMID: 33661652 DOI: 10.1021/acs.orglett.1c00210] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two bicyclic peptides, nyuzenamides A (1) and B (2), were discovered from Streptomyces isolated from suspended matter in deep sea water collected in the Sea of Japan. Their structures were determined through nuclear magnetic resonance and mass spectrometry analyses in combination with X-ray crystallography and the chiral-phase gas chromatography-mass spectrometry method to comprise ten amino acid residues containing four unusual amino acids along with aromatic acyl units. Both compounds displayed antifungal activity against pathogenic fungi and cytotoxicity against P388 murine leukemia cells.
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Affiliation(s)
- Md Rokon Ul Karim
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Yasuko In
- Department of Physical Chemistry, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka 569-1041, Japan
| | - Tao Zhou
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Enjuro Harunari
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Yasuhiro Igarashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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Karim MRU, Harunari E, Sharma AR, Oku N, Akasaka K, Urabe D, Sibero MT, Igarashi Y. Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of 1 J C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites. Beilstein J Org Chem 2020; 16:2719-2727. [PMID: 33214797 PMCID: PMC7653330 DOI: 10.3762/bjoc.16.222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/20/2020] [Indexed: 11/23/2022] Open
Abstract
Chemical investigation of secondary metabolites from a marine-derived actinomycete strain of the genus Kocuria, isolated from a stony coral Mycedium sp., led to the identification of two new alkanoylimidazoles, nocarimidazoles C (1) and D (2) as well as three known congeners, nocarimidazoles A (3) and B (4) and bulbimidazole A (5). Structure analysis of 1 and 2 by NMR and MS revealed that both are 4-alkanoyl-5-aminoimidazoles with a 6-methyloctanoyl or decanoyl chain, respectively. Two possible positions of the amino group on the imidazole rings (C-2 and C-5) posed a challenge in the structure study, which was settled by the measurement of 1JC,H coupling constants for comparison with those of synthetically prepared model imidazoles. The absolute configurations of the anteisoalkanoyl group present in 1, 4, and 5 were determined by low-temperature HPLC analysis of the degradation products labeled with a chiral anthracene reagent, which revealed that 1 is a mixture of the R- and S-enantiomers with a ratio of 73:27, 4 is the pure (S)-enantiomer, and 5 is the (S)-enantiomer with 98% ee. The present study illustrates the diversity in the stereochemistry of anteiso branching in bacterial metabolites. Compounds 1−4 were moderately antimicrobial against Gram-positive bacteria and fungi, with MIC ranges of 6.25–25 μg/mL.
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Affiliation(s)
- Md Rokon Ul Karim
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Enjuro Harunari
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Amit Raj Sharma
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Kazuaki Akasaka
- Shokei Gakuin University, 4-10-1 Yurigaoka, Natori, Miyagi 981-1295, Japan
| | - Daisuke Urabe
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Mada Triandala Sibero
- Department of Marine Science, Faculty of Fisheries and Marine Science, Diponegoro University, Semarang, Central Java 50275, Indonesia
| | - Yasuhiro Igarashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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5
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Saito S, Atsumi K, Zhou T, Fukaya K, Urabe D, Oku N, Karim MRU, Komaki H, Igarashi Y. A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium. Beilstein J Org Chem 2020; 16:1100-1110. [PMID: 32550925 PMCID: PMC7277628 DOI: 10.3762/bjoc.16.97] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/05/2020] [Indexed: 12/14/2022] Open
Abstract
Aside from the well-studied conventional actinomycetes such as Streptomyces, the less investigated genera of actinomycetes also represent a promising source of natural products. Genome mining indicated that members of the underexplored genus Pseudosporangium, from which no secondary metabolites have been reported to date, may harbor the biosynthetic machinery for the formation of novel natural products. The strain RD062863, that is available at a public culture collection, was obtained and subjected to metabolite analysis, which resulted in the discovery of a novel cyclopeptide, pseudosporamide (1), along with three new oligomycin-class polyketides, pseudosporamicins A–C (2–4). The unusual structure of compound 1, featured by a biaryl-bond bridging across a tripeptide scaffold, N-acetyl-ʟ-Tyr-ʟ-Pro-ʟ-Trp, was determined by a combination of spectroscopic analyses, chemical derivatization, ECD calculation, and DFT-based theoretical chemical shift calculation, revealing the presence of an (Sa)-axial chirality around the biaryl bond. Compounds 2–4 lacked hydroxylation on the side chain of the spiroacetal rings, which showed clear contrast to other oligomycin congeners and related polyketides with ring-truncation or expansion. The new macrolides 2–4 displayed potent antimicrobial activity against the Gram-positive bacterium Kocuria rhizohpila and the plant pathogenic fungus Glomerella cingulata. All compounds showed moderate cytotoxicity against P388 murine leukemia cells with IC50 values in the micromolar to submicromolar ranges. These results exemplified the validity of phylogeny-focused strain selection combined with biosynthetic gene-directed genome mining for the efficient discovery of new natural products.
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Affiliation(s)
- Shun Saito
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Kota Atsumi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Tao Zhou
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Keisuke Fukaya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Daisuke Urabe
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Md Rokon Ul Karim
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Hisayuki Komaki
- Biological Resource Center, National Institute of Technology and Evaluation (NBRC), Kisarazu, Chiba 292-0818, Japan
| | - Yasuhiro Igarashi
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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6
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Karim MRU, Harunari E, Oku N, Akasaka K, Igarashi Y. Bulbimidazoles A-C, Antimicrobial and Cytotoxic Alkanoyl Imidazoles from a Marine Gammaproteobacterium Microbulbifer Species. J Nat Prod 2020; 83:1295-1299. [PMID: 32191468 DOI: 10.1021/acs.jnatprod.0c00082] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Three new alkanoyl imidazoles, designated bulbimidazoles A-C (1-3), were found from the culture extract of the gammaproteobacterium Microbulbifer sp. DC3-6 isolated from a stony coral of the genus Tubastraea. The absolute configuration of the anteiso-methyl substitution in 1 was established to be a mixture of (R)- and (S)-configurations in a ratio of 9:91 by applying the Ohrui-Akasaka method. Compounds 1-3 displayed unique broad-spectrum antimicrobial activity against Gram-positive and -negative bacteria and fungi with MICs ranging from 0.78 to 12.5 μg/mL. They also exhibited cytotoxicity toward P388 murine leukemia cells with IC50 in the micromolar range.
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Affiliation(s)
- Md Rokon Ul Karim
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Enjuro Harunari
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Naoya Oku
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Kazuaki Akasaka
- Shokei Gakuin University, 4-10-1 Yurigaoka, Natori, Miyagi 981-1295, Japan
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
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