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Special Issue "Natural Products from Marine Actinomycetes"

A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (28 February 2019)

Special Issue Editors

Guest Editor
Prof. Dr. Dong-Chan Oh

Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
E-Mail
Interests: marine actinomycetes; natural products; NMR; structure elucidation; antibiotics; symbiosis; biosynthesis; genomics
Guest Editor
Prof. Dr. Sang-Jip Nam

Natural Product and Medicine Research Laboratory, Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
E-Mail
Interests: marine actinomycetes; natural products; NMR; structure elucidation; mixed-fermentation; marine-organisms associated microbes

Special Issue Information

Dear Colleagues, 

Actinobacteria had been recognized as an important chemical producer of bioactive secondary metabolites in the golden era of anticancer/antibiotic discovery. Unfortunately, the discovery of new bioactive natural products from this promising bacterial group has declined due to redundant studies on heavily investigated terrestrial actinomycetes. However, it has been increasingly highlighted that marine-derived actinomycetes are also very promising sources for discovering new secondary metabolites with pharmaceutical potential.

This Special Issue aims to integrate original research articles regarding studies of natural products from marine-derived actinomycetes including new natural products discovery, chemical biology, new methods for discovering secondary metabolites, structure elucidation, genomic and biosynthetic research of natural products, and new biological activities

Prof. Dr. Dong-Chan Oh
Prof. Dr. Sang-Jip Nam
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • marine actinomycete

  • natural products

  • secondary metabolite

  • biosynthesis

  • genomics

  • structure elucidation

  • drug discovery

Published Papers (17 papers)

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Research

Open AccessArticle
Three New Isoflavonoid Glycosides from the Mangrove-Derived Actinomycete Micromonospora aurantiaca 110B
Mar. Drugs 2019, 17(5), 294; https://doi.org/10.3390/md17050294
Received: 4 May 2019 / Accepted: 13 May 2019 / Published: 17 May 2019
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Abstract
The mangrove ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science. Besides the genus Streptomyces, Micromonospora is also a source of new bioactive agents. We screened Micromonospora from the rhizosphere soil of mangrove plants in [...] Read more.
The mangrove ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science. Besides the genus Streptomyces, Micromonospora is also a source of new bioactive agents. We screened Micromonospora from the rhizosphere soil of mangrove plants in Fujian province, China, and 51 strains were obtained. Among them, the extracts of 12 isolates inhibited the growth of human lung carcinoma A549 cells. Strain 110B exhibited better cytotoxic activity, and its bioactive constituents were investigated. Consequently, three new isoflavonoid glycosides, daidzein-4′-(2-deoxy-α-l-fucopyranoside) (1), daidzein-7-(2-deoxy-α-l-fucopyranoside) (2), and daidzein-4′,7-di-(2-deoxy-α-l-fucopyranoside) (3) were isolated from the fermentation broth of strain 110B. The structures of the new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HR-ESIMS). The result of medium-changing experiments implicated that these new compounds were microbial biotransformation products of strain M. aurantiaca 110B. The three compounds displayed moderate cytotoxic activity to the human lung carcinoma cell line A549, hepatocellular liver carcinoma cell line HepG2, and the human colon tumor cell line HCT116, whereas none of them showed antifungal or antibacterial activities. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Cytotoxic, Anti-Migration, and Anti-Invasion Activities on Breast Cancer Cells of Angucycline Glycosides Isolated from a Marine-Derived Streptomyces sp.
Mar. Drugs 2019, 17(5), 277; https://doi.org/10.3390/md17050277
Received: 22 April 2019 / Revised: 3 May 2019 / Accepted: 7 May 2019 / Published: 9 May 2019
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Abstract
Four angucycline glycosides were previously characterized from marine-derived Streptomyces sp. OC1610.4. Further investigation of this strain cultured on different fermentation media from that used previously resulted in the isolation of two new angucycline glycosides, vineomycins E and F (12), [...] Read more.
Four angucycline glycosides were previously characterized from marine-derived Streptomyces sp. OC1610.4. Further investigation of this strain cultured on different fermentation media from that used previously resulted in the isolation of two new angucycline glycosides, vineomycins E and F (12), and five known homologues, grincamycin L (3), vineomycinone B2 (4), fridamycin D (5), moromycin B (7), and saquayamycin B1 (8). Vineomycin F (2) contains an unusual ring-cleavage deoxy sugar. All the angucycline glycosides isolated from Streptomyces sp. OC1610.4 were evaluated for their cytotoxic activity against breast cancer cells MCF-7, MDA-MB-231, and BT-474. Moromycin B (7), saquayamycin B1 (8), and saquayamycin B (9) displayed potent anti-proliferation against the tested cell lines, with IC50 values ranging from 0.16 to 0.67 μM. Saquayamycin B (9) inhibited the migration and invasion of MDA-MB-231 cells in a dose-dependent manner, as detected by Transwell and wound-healing assays. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Identification of the Actinomycin D Biosynthetic Pathway from Marine-Derived Streptomyces costaricanus SCSIO ZS0073
Mar. Drugs 2019, 17(4), 240; https://doi.org/10.3390/md17040240
Received: 13 March 2019 / Revised: 16 April 2019 / Accepted: 18 April 2019 / Published: 23 April 2019
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Abstract
Bioactive secondary metabolites from Streptomycetes are important sources of lead compounds in current drug development. Streptomyces costaricanus SCSIO ZS0073, a mangrove-derived actinomycete, produces actinomycin D, a clinically used therapeutic for Wilm’s tumor of the kidney, trophoblastic tumors and rhabdomyosarcoma. In this work, we [...] Read more.
Bioactive secondary metabolites from Streptomycetes are important sources of lead compounds in current drug development. Streptomyces costaricanus SCSIO ZS0073, a mangrove-derived actinomycete, produces actinomycin D, a clinically used therapeutic for Wilm’s tumor of the kidney, trophoblastic tumors and rhabdomyosarcoma. In this work, we identified the actinomycin biosynthetic gene cluster (BGC) acn by detailed analyses of the S. costaricanus SCSIO ZS0073 genome. This organism produces actinomycin D with a titer of ~69.8 μg mL−1 along with traces of actinomycin X. The acn cluster localized to a 39.8 kb length region consisting of 25 open reading frames (ORFs), including a set of four genes that drive the construction of the 4-methyl-3-hydroxy-anthranilic acid (4-MHA) precursor and three non-ribosomal peptide synthetases (NRPSs) that generate the 4-MHA pentapeptide semi-lactone, which, upon dimerization, affords final actinomycin D. Furthermore, the acn cluster contains four positive regulatory genes acnWU4RO, which were identified by in vivo gene inactivation studies. Our data provide insights into the genetic characteristics of this new mangrove-derived actinomycin D bioproducer, enabling future metabolic engineering campaigns to improve both titers and the structural diversities possible for actinomycin D and related analogues. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Characterization of Two Toxin-Antitoxin Systems in Deep-Sea Streptomyces sp. SCSIO 02999
Mar. Drugs 2019, 17(4), 211; https://doi.org/10.3390/md17040211
Received: 22 February 2019 / Revised: 26 March 2019 / Accepted: 1 April 2019 / Published: 4 April 2019
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Abstract
Toxin-antitoxin (TA) systems are ubiquitous and abundant genetic elements in bacteria and archaea. Most previous TA studies have focused on commensal and pathogenic bacteria, but have rarely focused on marine bacteria, especially those isolated from the deep sea. Here, we identified and characterized [...] Read more.
Toxin-antitoxin (TA) systems are ubiquitous and abundant genetic elements in bacteria and archaea. Most previous TA studies have focused on commensal and pathogenic bacteria, but have rarely focused on marine bacteria, especially those isolated from the deep sea. Here, we identified and characterized three putative TA pairs in the deep-sea-derived Streptomyces sp. strain SCSIO 02999. Our results showed that Orf5461/Orf5462 and Orf2769/Orf2770 are bona fide TA pairs. We provide several lines of evidence to demonstrate that Orf5461 and Orf5462 constitute a type-II TA pair that are homologous to the YoeB/YefM TA pair from Escherichia coli. Although YoeB from SCSIO 02999 was toxic to an E. coli host, the homologous YefM antitoxin from SCSIO 02999 did not neutralize the toxic effect of YoeB from E. coli. For the Orf2769/Orf2770 TA pair, Orf2769 overexpression caused significant cell elongation and could lead to cell death in E. coli, and the neighboring Orf2770 could neutralize the toxic effect of Orf2769. However, no homologous toxin or antitoxin was found for this pair, and no direct interaction was found between Orf2769 and Orf2770. These results suggest that Orf2769 and Orf2770 may constitute a novel TA pair. Thus, deep-sea bacteria harbor typical and novel TA pairs. The biochemical and physiological functions of different TAs in deep-sea bacteria warrant further investigation. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Two New Piperazine-Triones from a Marine-Derived Streptomycetes sp. Strain SMS636
Mar. Drugs 2019, 17(3), 186; https://doi.org/10.3390/md17030186
Received: 28 February 2019 / Revised: 14 March 2019 / Accepted: 19 March 2019 / Published: 21 March 2019
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Abstract
Two new piperazine-triones lansai E and F (1, 2), together with four known secondary metabolites lansai D (3), 1-N-methyl-(E,Z)-albonoursin (4), imidazo[4,5-e]-1,2,4-triazine (5), and streptonigrin (6) were [...] Read more.
Two new piperazine-triones lansai E and F (1, 2), together with four known secondary metabolites lansai D (3), 1-N-methyl-(E,Z)-albonoursin (4), imidazo[4,5-e]-1,2,4-triazine (5), and streptonigrin (6) were isolated from a deep-sea-derived Streptomycetes sp. strain SMS636. The structures of the isolated compounds were confirmed by comprehensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR. Compound 4 exhibited moderate antibacterial activities against Staphylococcus aureus and methicillin resistant S. aureus (MRSA) with Minimum Inhibitory Concentration (MIC) values of 12.5 and 25 μg/mL, respectively. Compound 6 displayed significant antibacterial activities against S. aureus, MRSA and Bacillus Calmette-Guérin (BCG) with MIC values of 0.78, 0.78 and 1.25 μg/mL, respectively. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Acylated Aminooligosaccharides with Inhibitory Effects against α-Amylase from Streptomyces sp. HO1518
Mar. Drugs 2018, 16(11), 403; https://doi.org/10.3390/md16110403
Received: 4 August 2018 / Revised: 17 October 2018 / Accepted: 20 October 2018 / Published: 23 October 2018
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Abstract
Five new acylated aminooligosaccharides (15), together with one known related analogue (6), were isolated from Streptomyces sp. HO1518. Their structure was identified by extensive spectroscopic analysis, including 1D and 2D NMR data and high resolution electrospray ionization [...] Read more.
Five new acylated aminooligosaccharides (15), together with one known related analogue (6), were isolated from Streptomyces sp. HO1518. Their structure was identified by extensive spectroscopic analysis, including 1D and 2D NMR data and high resolution electrospray ionization mass spectrometry (HRESIMS), and by comparison with those reported in the literature. All of the new compounds showed more promising porcine pancreatic α-amylase (PPA) inhibitory activities than the clinical drug acarbose, indicating them as potential pharmaceutical drug leads toward type II diabetes. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Seco-Tetracenomycins from the Marine-Derived Actinomycete Saccharothrix sp. 10-10
Mar. Drugs 2018, 16(10), 345; https://doi.org/10.3390/md16100345
Received: 30 August 2018 / Revised: 17 September 2018 / Accepted: 18 September 2018 / Published: 20 September 2018
Cited by 2 | PDF Full-text (1707 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Six new tetracenomycin congeners, saccharothrixones E–I (15) and 13-de-O-methyltetracenomycin X (6), were isolated from the rare marine-derived actinomycete Saccharothrix sp. 10-10. Their structures were elucidated by spectroscopic analysis and time-dependent density functional theory (TDDFT)-electronic circular [...] Read more.
Six new tetracenomycin congeners, saccharothrixones E–I (15) and 13-de-O-methyltetracenomycin X (6), were isolated from the rare marine-derived actinomycete Saccharothrix sp. 10-10. Their structures were elucidated by spectroscopic analysis and time-dependent density functional theory (TDDFT)-electronic circular dichroism (ECD) calculations. Saccharothrixones G (3) and H (4) are the first examples of tetracenomycins featuring a novel ring-A-cleaved chromophore. Saccharothrixone I (5) was determined to be a seco-tetracenomycin derivative with ring-B cleavage. The new structural characteristics, highlighted by different oxidations at C-5 and cleavages in rings A and B, enrich the structural diversity of tetracenomycins and provide evidence for tetracenomycin biosynthesis. Analysis of the structure–activity relationship of these compounds confirmed the importance of the planarity of the naphthacenequinone chromophore and the methylation of the polar carboxy groups for tetracenomycin cytotoxicity. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessCommunication
New Antibacterial Bagremycins F and G from the Marine-Derived Streptomyces sp. ZZ745
Mar. Drugs 2018, 16(9), 330; https://doi.org/10.3390/md16090330
Received: 11 August 2018 / Revised: 30 August 2018 / Accepted: 10 September 2018 / Published: 12 September 2018
Cited by 1 | PDF Full-text (710 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
As part of our research to discover novel bioactive natural products from marine microorganisms, five bagremycin analogues, including the previously unreported bagremycins F (1) and G (2), were isolated from a marine actinomycete Streptomyces sp. ZZ745. The structures of [...] Read more.
As part of our research to discover novel bioactive natural products from marine microorganisms, five bagremycin analogues, including the previously unreported bagremycins F (1) and G (2), were isolated from a marine actinomycete Streptomyces sp. ZZ745. The structures of these compounds were determined by means of NMR spectroscopic analysis, HRESIMS data, and optical rotation. Both bagremycins F (1) and G (2) showed antibacterial activity against Escherichia coli, with MIC values of 41.8 and 61.7 μM, respectively. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Albisporachelin, a New Hydroxamate Type Siderophore from the Deep Ocean Sediment-Derived Actinomycete Amycolatopsis albispora WP1T
Mar. Drugs 2018, 16(6), 199; https://doi.org/10.3390/md16060199
Received: 16 May 2018 / Revised: 4 June 2018 / Accepted: 5 June 2018 / Published: 7 June 2018
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Abstract
Marine actinobacteria continue to be a rich source for the discovery of structurally diverse secondary metabolites. Here we present a new hydroxymate siderophore produced by Amycolatopsis albispora, a recently described species of this less explored actinomycete genus. Strain WP1T was isolated [...] Read more.
Marine actinobacteria continue to be a rich source for the discovery of structurally diverse secondary metabolites. Here we present a new hydroxymate siderophore produced by Amycolatopsis albispora, a recently described species of this less explored actinomycete genus. Strain WP1T was isolated from sediments collected at −2945 m in the Indian Ocean. The new siderophore, designated albisporachelin, was isolated from iron depleted culture broths and the structure was established by 1D and 2D NMR and MS/MS experiments, and application of a modified Marfey’s method. Albisporachelin is composed of one N-methylated-formylated/hydroxylated l-ornithine (N-Me-fh-l-Orn), one l-serine (l-Ser), one formylated/hydroxylated l-ornithine (fh-l-Orn) and a cyclo-N-methylated-hydroxylated l-ornithine (cyclo-N-Me-h-l-Orn). Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Antartin, a Cytotoxic Zizaane-Type Sesquiterpenoid from a Streptomyces sp. Isolated from an Antarctic Marine Sediment
Mar. Drugs 2018, 16(4), 130; https://doi.org/10.3390/md16040130
Received: 27 March 2018 / Revised: 10 April 2018 / Accepted: 11 April 2018 / Published: 16 April 2018
Cited by 1 | PDF Full-text (4264 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Antartin (1), a new zizaane-type sesquiterpene, was isolated from Streptomyces sp. SCO736. The chemical structure of 1 was assigned from the interpretation of 1D and 2D NMR in addition to mass spectrometric data. The relative stereochemistry of 1 was determined by [...] Read more.
Antartin (1), a new zizaane-type sesquiterpene, was isolated from Streptomyces sp. SCO736. The chemical structure of 1 was assigned from the interpretation of 1D and 2D NMR in addition to mass spectrometric data. The relative stereochemistry of 1 was determined by analysis of NOE data, while the absolute stereochemistry was decided based on a comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Antartin (1) showed cytotoxicity against A549, H1299, and U87 cancer cell lines by causing cell cycle arrest at the G1 phase. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessCommunication
New Naphthoquinone Terpenoids from Marine Actinobacterium, Streptomyces sp. CNQ-509
Mar. Drugs 2018, 16(3), 90; https://doi.org/10.3390/md16030090
Received: 30 January 2018 / Revised: 8 March 2018 / Accepted: 9 March 2018 / Published: 12 March 2018
Cited by 3 | PDF Full-text (1112 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A member of the marine streptomycete clade MAR4, Streptomyces sp. CNQ-509, has genetic potential for the biosynthesis of hybrid isoprenoids and produces several meroterpenoids such as naphterpin, nitropyrrolin and marinophenazine. Our research on the strain CNQ-509 led to the isolation of two new [...] Read more.
A member of the marine streptomycete clade MAR4, Streptomyces sp. CNQ-509, has genetic potential for the biosynthesis of hybrid isoprenoids and produces several meroterpenoids such as naphterpin, nitropyrrolin and marinophenazine. Our research on the strain CNQ-509 led to the isolation of two new naphterpin derivatives (1 and 2) comprised of naphthoquinone and geranyl moieties along with the known terpenoid, debromomarinone. The two-dimensional structure of these compounds was determined through spectral data analysis using data from NMR, MS and UV spectroscopy. Furthermore, the full structures of 1 and 2 including absolute configurations were unequivocally established by a combination of NMR experiments and chemical modifications. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Fluostatins M–Q Featuring a 6-5-6-6 Ring Skeleton and High Oxidized A-Rings from Marine Streptomyces sp. PKU-MA00045
Mar. Drugs 2018, 16(3), 87; https://doi.org/10.3390/md16030087
Received: 6 February 2018 / Revised: 1 March 2018 / Accepted: 5 March 2018 / Published: 9 March 2018
Cited by 9 | PDF Full-text (1717 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Aromatic polyketides from marine actinomycetes have received increasing attention due to their unusual structures and potent bioactivities. Compared to their terrestrial counterparts, marine aromatic polyketides have been less discovered and their structural and biological diversities are far from being fully investigated. In this [...] Read more.
Aromatic polyketides from marine actinomycetes have received increasing attention due to their unusual structures and potent bioactivities. Compared to their terrestrial counterparts, marine aromatic polyketides have been less discovered and their structural and biological diversities are far from being fully investigated. In this study, we employed a PCR-based genome mining method to discover aromatic polyketides in our marine bacteria collection. Five new atypical angucyclinones, fluostatins M–Q (15) featuring a unique 6-5-6-6 ring skeleton, were discovered from one “positive” Streptomyces sp. PKU-MA00045. The structures of fluostatins M–Q (15) were elucidated based on comprehensive spectroscopic analyses and the crystallographic structure of fluostatin P (4), which contains the most oxidized A-ring, was solved by X-ray diffraction analysis with Cu Kα radiation. Compared to the published 16 fluostatin analogues, fluostatins M–Q (15) contained a different methoxy group attached at C-7 and hydroxy group attached at C-4, enriching the structural diversity of aromatic polyketides from marine actinomycetes. Genome sequencing of Streptomyces sp. PKU-MA00045 revealed the biosynthetic gene cluster of fluostatins M–Q (15), which contained different genes and gene organizations compared to known fluostatin gene clusters, facilitating the investigation of the biosynthesis of the unique 6-5-6-6 ring skeleton in all fluostatins. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Lactomycins A–C, Dephosphorylated Phoslactomycin Derivatives that Inhibit Cathepsin B, from the Marine-derived Streptomyces sp. ACT232
Mar. Drugs 2018, 16(2), 70; https://doi.org/10.3390/md16020070
Received: 12 December 2017 / Revised: 12 February 2018 / Accepted: 12 February 2018 / Published: 21 February 2018
PDF Full-text (596 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Three new polyketides, lactomycins A (1)–C (3), were isolated from the culture broth of a marine-derived Streptomyces sp. ACT232 as cathepsin B inhibitors. Their structures were determined by a combination of NMR and MS data analyses to be the dephosphorylated derivatives of a [...] Read more.
Three new polyketides, lactomycins A (1)–C (3), were isolated from the culture broth of a marine-derived Streptomyces sp. ACT232 as cathepsin B inhibitors. Their structures were determined by a combination of NMR and MS data analyses to be the dephosphorylated derivatives of a phoslactomycin class of metabolites. Lactomycins exhibited cathepsin B inhibitory activity (IC50 0.8 to 4.5 μg/mL). Even though the biosynthetic gene clusters found in the genome of the current strain have high similarity to those of phoslactomycin, neither phoslactomycins nor leustroducsins were detected by LC-MS analyses of the crude extract. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessFeature PaperArticle
Saccharomonopyrones A–C, New α-Pyrones from a Marine Sediment-Derived Bacterium Saccharomonospora sp. CNQ-490
Mar. Drugs 2017, 15(8), 239; https://doi.org/10.3390/md15080239
Received: 2 June 2017 / Revised: 13 July 2017 / Accepted: 25 July 2017 / Published: 3 August 2017
Cited by 7 | PDF Full-text (939 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Intensive study of the organic extract of the marine-derived bacterium Saccharomonospora sp. CNQ-490 has yielded three new α-pyrones, saccharomonopyrones A–C (13). The chemical structures of these compounds were assigned from the interpretation of 1D, 2D NMR and mass spectrometry [...] Read more.
Intensive study of the organic extract of the marine-derived bacterium Saccharomonospora sp. CNQ-490 has yielded three new α-pyrones, saccharomonopyrones A–C (13). The chemical structures of these compounds were assigned from the interpretation of 1D, 2D NMR and mass spectrometry data. Saccharomonopyrone A (1) is the first α-pyrone microbial natural product bearing the ethyl-butyl ether chain in the molecule, while saccharomonopyrones B and C possess unusual 3-methyl and a 6-alkyl side-chain within a 3,4,5,6-tetrasubstituted α-pyrone moiety. Saccharomonopyrone A exhibited weak antioxidant activity using a cation radical scavenging activity assay with an IC50 value of 140 μM. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessFeature PaperArticle
Strepchazolins A and B: Two New Alkaloids from a Marine Streptomyces chartreusis NA02069
Mar. Drugs 2017, 15(8), 244; https://doi.org/10.3390/md15080244
Received: 11 July 2017 / Revised: 11 July 2017 / Accepted: 27 July 2017 / Published: 2 August 2017
Cited by 10 | PDF Full-text (1773 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Two new alkaloids, strepchazolins A (1) and B (2), together with a previously reported compound, streptazolin (3), were isolated from a marine actinomycete, Streptomyces chartreusis NA02069, collected in the Coast of Hainan Island, China. The structures of [...] Read more.
Two new alkaloids, strepchazolins A (1) and B (2), together with a previously reported compound, streptazolin (3), were isolated from a marine actinomycete, Streptomyces chartreusis NA02069, collected in the Coast of Hainan Island, China. The structures of new compounds were determined by extensive NMR, mass spectroscopic and X-ray crystallographic analysis, as well as modified Mosher’s method. Compound 1 showed weak anti-Bacillus subtilis activity with the MIC value of 64.0 μM, and weak inhibitory activity against acetylcholinesterase (AChE) in vitro with IC50 value of 50.6 μM, while its diastereoisomer, Compound 2, is almost inactive. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessCommunication
Microindolinone A, a Novel 4,5,6,7-Tetrahydroindole, from the Deep-Sea-Derived Actinomycete Microbacterium sp. MCCC 1A11207
Mar. Drugs 2017, 15(7), 230; https://doi.org/10.3390/md15070230
Received: 25 May 2017 / Revised: 30 June 2017 / Accepted: 14 July 2017 / Published: 19 July 2017
Cited by 10 | PDF Full-text (881 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A novel indole, microindolinone A (1), was isolated from a deep-sea-derived actinomycete Microbacterium sp. MCCC 1A11207, together with 18 known compounds (219). By detailed analysis of the 1H, 13C, HSQC, COSY, HMBC, high resolution electron [...] Read more.
A novel indole, microindolinone A (1), was isolated from a deep-sea-derived actinomycete Microbacterium sp. MCCC 1A11207, together with 18 known compounds (219). By detailed analysis of the 1H, 13C, HSQC, COSY, HMBC, high resolution electron spray ionization mass spectrum (HRESIMS), and circular dichroism (CD) data, the absolute configuration of 1 was elucidated as 5R-hydroxy-4,5,6,7-tetrahydroindole-4-one. It is noteworthy that 1 is the second example of a saturated indole isolated from nature. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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Open AccessArticle
Lobophorin K, a New Natural Product with Cytotoxic Activity Produced by Streptomyces sp. M-207 Associated with the Deep-Sea Coral Lophelia pertusa
Mar. Drugs 2017, 15(5), 144; https://doi.org/10.3390/md15050144
Received: 24 February 2017 / Revised: 11 May 2017 / Accepted: 15 May 2017 / Published: 19 May 2017
Cited by 11 | PDF Full-text (716 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The present article describes the isolation of a new natural product of the lobophorin family, designated as lobophorin K (1), from cultures of the marine actinobacteria Streptomyces sp. M-207, previously isolated from the cold-water coral Lophelia pertusa collected at 1800 m [...] Read more.
The present article describes the isolation of a new natural product of the lobophorin family, designated as lobophorin K (1), from cultures of the marine actinobacteria Streptomyces sp. M-207, previously isolated from the cold-water coral Lophelia pertusa collected at 1800 m depth during an expedition to the submarine Avilés Canyon. Its structure was determined using a combination of spectroscopic techniques, mainly ESI-TOF MS and 1D and 2D NMR. This new natural product displayed cytotoxic activity against two human tumor cell lines, such as pancreatic carcinoma (MiaPaca-2) and breast adenocarcinoma (MCF-7). Lobophorin K also displayed moderate and selective antibiotic activity against pathogenic Gram-positive bacteria such as Staphylococcus aureus. Full article
(This article belongs to the Special Issue Natural Products from Marine Actinomycetes)
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