論文 - 末永　聖武

Kohamamides A, B, and C, Cyclic Depsipeptides from an Okeania sp. Marine Cyanobacterium

Iwasaki Arihiro, Shiota Ikuma, Sumimoto Shimpei, Matsubara Teruhiko, Sato Toshinori, Suenaga Kiyotake

Journal of Natural Products 80 （ 6 ） 1948 - 1952 2017年06月

査読有り,  ISSN  0163-3864

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<p>Kohamamides A, B, and C (1-3), new cyclic depsipeptides that belong to the kulolide superfamily, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions. Kohamamide B (2) exhibited moderate cytotoxicity against HL60 cells. Although many natural products in the kulolide superfamily have been isolated from cyanobacteria collected in various parts of the world, kohamamides 1-3 are the first members to be isolated from the East Asian marine environment. In addition, unlike other members of this superfamily, kohamamides 1-3 contain a Leu residue adjacent to the Pro residue, rather than another lipophilic amino acid.</p>

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Evaluation of phytotoxic potential and identification of phytotoxic compounds in Rumex maritimus

Islam M. S., Iwasaki A., Suenaga K., Kato-Noguchi H.

Plant Biosystems 152 （ 4 ） 804 - 809 2017年06月

査読有り,  ISSN  1126-3504

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<p>Rumex maritimus (Polygonaceae) is an annual herb and is well known for its use in medicinal treatments. Although the pharmacological properties of R. maritimus are well documented, no phytotoxic activity of R. maritimus has yet been found. Therefore, we investigated the phytotoxic potential of R. maritimus to identify phytotoxic compounds. Inhibitory activity was found in aqueous methanol extracts of R. maritimus on the seedling growth of cress, rapeseed, barnyard grass, and foxtail fescue, in which inhibition increased with increasing extract concentration. Two compounds were isolated using chromatography, and using spectroscopy their structure was determined as 5,7-dihydroxyphthalide and altechromone A. 5,7-Dihydroxyphthalide significantly inhibited cress seedling growth by 27.2–43.0% of control seedlings at 3 mM, whereas altechromone A inhibited seedling growth by 65.4–66.3% at 0.01 mM. The concentrations required for 50% inhibition of cress seedling growth were 1.73–2.48 mM for 5,7-dihydroxyphthalide and 0.66–1.41 mM for altechromone A. These results indicate that the compounds 5,7-dihydroxyphthalide and altechromone A may contribute, to a certain extent, to the phytotoxic activity of R. maritimus.</p>

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Phytotoxic property of the invasive plant Tithonia diversifolia and a phytotoxic substance

Suzuki Masahiko, Iwasaki Arihiro, Suenaga Kiyotake, Kato-Noguchi Hisashi

Acta Biologica Hungarica 68 （ 2 ） 187 - 195 2017年06月

査読有り,  ISSN  0236-5383

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<p>Tithonia diversifolia (Hermsl.) A. Gray is a perennial invasive plant and spreads quickly in the invasive areas. The extracts of T. diversifolia were found to be toxic to several crop plant species such as rice, maize, sorghum, lettuce and cowpea, and several putative allelopathic substances were identified. However, there is limited information available for the effects of T. diversifolia on wild plants including weed plant species. We investigated the allelopathic potential of T. diversifolia extracts on weed plants, and searched for phytotoxic substances with allelopathic activity. An aqueous methanol extract of T. diversifolia leaves inhibited the growth of weed plants, Lolium multiftorum Lam., Phleum pretense L., Echinochloa crus-galli (L.) Beauv. The extract was then purified by several chromatographic runs and a phytotoxic substance with allelopathic activity was isolated and identified by spectral analysis as tagitinin C. The substance inhibited the growth of Lolium multiftorum, Phleum pratense and Echinochloa crusgalli at concentrations greater than 0.1-0.3 mM. The present results suggest that T. diversifolia may possess allelopathic potential on weed plants and tagitinin C may be responsible for the allelopathic effects of T. diversifolia. The allelopathic potential of T. diversifolia may contribute to its invasive characteristics.</p>

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Asparagus decline: Autotoxicity and autotoxic compounds in asparagus rhizomes.

Kato-Noguchi Hisashi, Nakamura Keisuke, Ohno Osamu, Suenaga Kiyotake, Okuda Nobuyuki

Journal of Plant Physiology 213   23 - 29 2017年06月

ISSN  0176-1617

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<p>Asparagus (Asparagus officinalis L.) is a perennial vegetable, but its crop productivity and quality decrease gradually. One possible reason for “asparagus decline” is thought to be the autotoxicity of asparagus. However, the autotoxic property of asparagus rhizomes remains unknown. The objective of this study was to determine the potential role of rhizomes in the autotoxicity of asparagus. An aqueous methanol extract of asparagus rhizomes inhibited the growth of asparagus seedlings and six other test plants in a concentration-dependent manners: garden cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.), ryegrass (Lolium multiflorum Lam.), timothy (Phleum pratense L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.). These results suggest that asparagus rhizomes contain autotoxic compounds. The extract was purified through several chromatographic steps with monitoring the autotoxic activity, and p-coumaric acid and iso-agatharesinol were isolated. These compounds inhibited the shoot and root growth of asparagus and two other test plants, garden cress and ryegrass, at concentrations higher than 0.1 mM. The concentrations required for 50% inhibition of the root and shoot growth of these test plants ranged from 0.36 to 0.85 mM and 0.41–1.22 mM for p-coumaric acid and iso-agatharesinol, respectively. Therefore, these compounds may contribute to the autotoxicity caused by asparagus rhizomes and may be involved in “asparagus decline”.</p>

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N-Octanoyl tyramine, a phytotoxic compound in the roots of Cymbopogon nardus

Suwitchayanon Prapaipit, Ohno Osamu, Suenaga Kiyotake, Kato-Noguchi Hisashi

Acta Physiologiae Plantarum 39 （ 6 ） 123 (8 pages) 2017年06月

査読有り,  ISSN  0137-5881

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<p>Citronella grass (Cymbopogon nardus) is a perennial herb. Many researchers have studied the exploitation of the active compounds in this plant for medicinal purposes, but there have been no studies on its phytotoxic compounds. Therefore, we investigated the phytotoxic active compounds in the roots of C. nardus. A significant inhibition was observed on the germination of cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), barnyard grass (Echinochloa crus-galli L.), and Italian ryegrass (Lolium multiflorum Lam.) by the aqueous methanol extract of C. nardus roots. The extract decreased the total germination percentage (GP) and germination index (GI, progressive total of daily cumulative germination), and extended the time required for 50% germination (T₅₀) of all test species. A phytotoxic compound of the extract was isolated and identified as N-octanoyl tyramine by spectral analysis. This compound showed the inhibition on the germination of cress and barnyard grass. The decline in GP, GI, and T₅₀ was observed at concentrations of 30–2000 μM of N-octanoyl tyramine. The compound also showed the significant inhibition on the growth of cress and barnyard grass seedlings at concentrations greater than 100 and 300 μM, respectively. This study suggests that C. nardus could produce phytotoxic compounds, and N-octanoyl tyramine may be responsible for its phytotoxic activity.</p>

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Apoptosis-inducing activity and antiproliferative effect of Paeoniflorigenone from moutan cortex

Huang Ying, Ohno Osamu, Suenaga Kiyotake, Miyamoto Kenji

Bioscience, Biotechnology and Biochemistry 81 （ 6 ） 1106 - 1113 2017年06月

査読有り,  ISSN  0916-8451

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<p>Ninety samples from the extracts of plants from traditional Chinese medicines were screened for antitumor activity. Paeoniflorigenone (PFG) was isolated as an active ingredient from the root of moutan cortex, which showed the strongest activity. In addition, our data indicated that PFG was cytotoxic and induced apoptosis selectively in the cancer cell lines. These effects were cancelled by the addition of caspase inhibitor Z-VAD-FMK, suggesting that it was mediated by caspase-3 activation.</p>

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Leptolyngbyolides, Cytotoxic Macrolides from the Marine Cyanobacterium Leptolyngbya sp.: Isolation, Biological Activity, and Catalytic Asymmetric Total Synthesis

Cui, Jin, Morita, Maho, Ohno, Osamu, Kimura, Tomoyuki, Teruya, Toshiaki, Watanabe, Takumi, Suenaga, Kiyotake, Shibasaki, Masakatsu

CHEMISTRY-A EUROPEAN JOURNAL 23 （ 35 ） 8500 - 8509 2017年06月

研究論文（学術雑誌）, 共著,  ISSN  0947-6539

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Biseokeaniamides A, B, and C, Sterol O-Acyltransferase Inhibitors from an Okeania sp. Marine Cyanobacterium

Iwasaki Arihiro, Tadenuma Takato, Sumimoto Shimpei, Ohshiro Taichi, Ozaki Kaori, Kobayashi Keisuke, Teruya Toshiaki, Tomoda Hiroshi, Suenaga Kiyotake

Journal of Natural Products 80 （ 4 ） 1161 - 1166 2017年04月

査読有り,  ISSN  0163-3864

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<p>Biseokeaniamides A, B, and C (1-3), structurally novel sterol O-acyltransferase (SOAT) inhibitors, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions. Biseokeaniamide B (2) exhibited moderate cytotoxicity against human HeLa cancer cells, and compounds 1-3 inhibited both SOAT1 and SOAT2, not only at an enzyme level but also at a cellular level. Biseokeaniamides (1-3) are the first linear lipopeptides that have been shown to exhibit SOAT-inhibitory activity.</p>

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Odobromoamide, a terminal alkynyl bromide-containing cyclodepsipeptide from the marine cyanobacterium okeania sp.

Sueyoshi Kosuke, Kudo Takafumi, Yamano Aki, Sumimoto Shimpei, Iwasaki Arihiro, Suenaga Kiyotake, Teruya Toshiaki

Bulletin of the Chemical Society of Japan 90 （ 4 ） 436 - 440 2017年04月

共著,  ISSN  0009-2673

　概要を見る

<p>The bioassay-guided fractionation of the Okinawan marine cyanobacterium Okeania sp. led to the isolation of the novel cyclodepsipeptide odobromoamide (1). The gross structure of 1 was determined by spectroscopic analyses, and its absolute stereochemistry was determined using a variety of different methods, including chemical derivatization and degradation followed by HPLC analysis. In addition, odobromoamide (1) exhibited broad-spectrum cytotoxicity against a human cancer cell line panel.</p>

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Isolation and Total Synthesis of Hoshinolactam, an Antitrypanosomal Lactam from a Marine Cyanobacterium

Ogawa Hidetoshi, Iwasaki Arihiro, Sumimoto Shimpei, Iwatsuki Masato, Ishiyama Aki, Hokari Rei, Otoguro Kazuhiko, Omura Satoshi, Suenaga Kiyotake

Organic Letters 19 （ 4 ） 890 - 893 2017年02月

査読有り,  ISSN  1523-7060

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<p>In the search for new antiprotozoal substances, hoshinolactam, an antitrypanosomal lactam, was isolated from a marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configuration was determined by the first total synthesis. Hoshinolactam showed potent antitrypanosomal activity with an IC₅₀ value of 3.9 nM without cytotoxicity against human fetal lung fibroblast MRC-5 cells (IC₅₀ &gt; 25 μM).</p>

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Isolation and identification of two potential phytotoxic substances from the aquatic fern Marsilea crenata

Islam Md Shafiqul, Iwasaki Arihiro, Suenaga Kiyotake, Kato-Noguchi Hisashi

Journal of Plant Biology 60 （ 1 ） 75 - 81 2017年02月

ISSN  1226-9239

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<p>Organic agriculture emphasized using of biologically originated herbicides and phytotoxic substances are being considered as a replacement to chemical herbicides. Marsilea crenata is an aquatic perennial fern distributed in the South-East Asian countries and is well known for various biological properties. However, to date, there has been no report that addresses the phytotoxicity of Marsilea crenata. Therefore, we explored phytotoxic properties and phytotoxic substances from Marsilea crenata. An aqueous methanol extracts of Marsilea crenata showed inhibition on the seedling growth of cress, lettuce, alfalfa, barnyard grass, Italian ryegrass, and foxtail fescue. Inhibition increased with increasing extract concentration. The extract was purified by several chromatographic steps and two phytotoxic substances were isolated and identified by spectroscopic analysis as loliolide and isololiolide. At the concentration of 30 μM, loliolide and isololiolide inhibited seedling growth of cress and barnyard grass by 41.3 to 51.1%, and 58.15 to 87.5% of control seedlings, respectively. The concentrations required for 50% inhibition of cress and barnyard grass seedlings ranged from 32.1 to 128.5 μM for loliolide, 37.0 to 176.2 μM for isololiolide. These results suggest these compounds may be responsible for phytotoxic effects of Marsilea crenata extract and could be an important part of organic agriculture.</p>

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Total synthesis and stereochemical determination of yoshinone A

Shinomiya Seiichi, Iwasaki Arihiro, Ohno Osamu, Suenaga Kiyotake

Phytochemistry 132   109 - 114 2016年12月

査読有り,  ISSN  0031-9422

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<p>In 2014, the γ-pyrone-containing polyketide, yoshinone A, was isolated from the marine cyanobacterium Leptolyngbya sp. and its structure was determined. Yoshinone A inhibited differentiation of 3T3-L1 cells into adipocytes, with an EC₅₀ value of 420 nM without any cytotoxicity, and therefore is expected to be a lead compound for obesity drugs. To establish its absolute configuration, and to provide sufficient amounts for further research, the total synthesis of yoshinone A was achieved through synthesis of its two possible diastereomers.</p>

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Total Synthesis of Miuraenamides A and D

Ojima Daisuke, Yasui Ayano, Tohyama Koh, Tokuzumi Keita, Toriihara Eisuke, Ito Kayoko, Iwasaki Arihiro, Tomura Tomohiko, Ojika Makoto, Suenaga Kiyotake

Journal of Organic Chemistry 81 （ 20 ） 9886 - 9894 2016年10月

査読有り,  ISSN  0022-3263

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<p>Miuraenamides A and D, cyclodepsipeptides with antimicrobial and antitumor activity, were synthesized. The synthesis of an unsaturated hydroxycarboxylic acid moiety, starting from a chiral epoxide, was achieved by Suzuki-Miyaura coupling as a key step. As a result, the overall yield for miuraenamide A over the longest linear sequence is 3.2%, while the yield of the previously reported procedure is 1.9%. In addition, the cell growth-inhibitory activity and anti-Phytophthora activity of the synthesized compounds were evaluated.</p>

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Kanamienamide, an Enamide with an Enol Ether from the Marine Cyanobacterium Moorea bouillonii

Sumimoto Shimpei, Iwasaki Arihiro, Ohno Osamu, Sueyoshi Kosuke, Teruya Toshiaki, Suenaga Kiyotake

Organic Letters 18 （ 19 ） 4884 - 4887 2016年10月

査読有り,  ISSN  1523-7060

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<p>Kanamienamide, an enamide with an enol ether, was isolated from the marine cyanobacterium Moorea bouillonii. The gross structure was established by spectroscopic analyses, and the relative stereochemistry was elucidated on the basis of the analyses of NOESY correlations and ¹H-¹H coupling constants. The absolute configuration was determined on the basis of the chiral HPLC analysis of the N-Me-Leu derived from kanamienamide. This is the first report of a natural product that possesses an N-Me-enamide adjacent to an enol ether. Kanamienamide showed growth-inhibitory activity toward HeLa cells with an IC₅₀ value of 2.5 μM and induced apoptosis-like cell death.</p>

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Urumamide, a novel chymotrypsin inhibitor with a β-amino acid from a marine cyanobacterium Okeania sp.

Kanamori Yuki, Iwasaki Arihiro, Sumimoto Shinpei, Suenaga Kiyotake

Tetrahedron Letters 57 （ 37 ） 4213 - 4216 2016年09月

査読有り,  ISSN  0040-4039

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<p>Urumamide, a novel cyclic depsipeptide that contains a β-amino acid, was isolated from a marine cyanobacterium Okeania sp. Its gross structure was determined by spectroscopic analyses, and the absolute configuration was established based on Marfey's analyses and chiral HPLC analyses of hydrolysis products. Biologically, urumamide inhibited the growth of human cancer cells. In addition, urumamide inhibited chymotrypsin.</p>

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Odoamide, a cytotoxic cyclodepsipeptide from the marine cyanobacterium Okeania sp.

Sueyoshi Kosuke, Kaneda Masato, Sumimoto Shinpei, Oishi Shinya, Fujii Nobutaka, Suenaga Kiyotake, Teruya Toshiaki

Tetrahedron 72 （ 35 ） 5472 - 5478 2016年09月

査読有り,  ISSN  0040-4020

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<p>The bioassay-guided fractionation of the Okinawan marine cyanobacterium Okeania sp. led to the isolation of the 26-membered cyclodepsipeptide odoamide (1). The gross structure of 1 was determined by 1D and 2D NMR analyses, whereas its absolute stereochemistry was determined using a variety of different methods, including synthesis and chemical degradation followed by chiral HPLC analysis. Notably, odoamide (1) showed potent cytotoxicity against HeLa S3 human cervical cancer cells with an IC₅₀ value of 26.3 nM.</p>

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Allelopathic potential and an allelopathic substance in mango leaves

Suzuki Masahiko, Khan Md Sirajul Islam, Iwasaki Arihiro, Suenaga Kiyotake, Kato-Noguchi Hisashi

Acta Agriculturae Scandinavica - Section B Soil and Plant Science 67 （ 1 ） 37 - 42 2016年08月

査読有り,  ISSN  0906-4710

　概要を見る

<p>The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I₅₀) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options.</p>

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Janadolide, a Cyclic Polyketide-Peptide Hybrid Possessing a tert-Butyl Group from an Okeania sp. Marine Cyanobacterium

Ogawa Hidetoshi, Iwasaki Arihiro, Sumimoto Shinpei, Kanamori Yuki, Ohno Osamu, Iwatsuki Masato, Ishiyama Aki, Hokari Rei, Otoguro Kazuhiko, Omura Satoshi, Suenaga Kiyotake

Journal of Natural Products 79 （ 7 ） 1862 - 1866 2016年07月

査読有り,  ISSN  0163-3864

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<p>Janadolide, a new cyclic polyketide-peptide hybrid possessing a tert-butyl group, was isolated from an Okeania sp. marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configurations of the amino acid moieties were determined by acid hydrolysis and chiral-phase HPLC analyses. The absolute configuration of the two stereogenic centers in the polyketide moiety was elucidated based on a combination of degradation reactions and spectroscopic analyses including the phenyl-glycine methyl ester method. Janadolide showed potent antitrypanosomal activity with an IC₅₀ value of 47 nM without cytotoxicity against human cells at 10 μM.</p>

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Total synthesis and absolute configuration of koshikalide

Kunifuda Kazuki, Iwasaki Arihiro, Nagamoto Masashi, Suenaga Kiyotake

Tetrahedron Letters 57 （ 29 ） 3121 - 3123 2016年07月

査読有り,  ISSN  0040-4039

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<p>The first total synthesis of koshikalide, a 14-membered macrolide that contains three olefins, was achieved. The skipped diene in the cyclic system was efficiently constructed by very mild Stille coupling at low temperature. The absolute stereochemistry was established by comparison of the specific optical rotations of natural and synthesized koshikalide.</p>

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Total Synthesis of Biselyngbyolide B

Sato Eisuke, Tanabe Yurika, Nakajima Naoya, Ohkubo Akifumi, Suenaga Kiyotake

Organic Letters 18 （ 9 ） 2047 - 2049 2016年05月

査読有り,  ISSN  1523-7060

　概要を見る

<p>The first total synthesis of biselyngbyolide B, an 18-membered macrolide, was achieved. The 18-membered ring structure was constructed by esterification using the Shiina reagent and an intramolecular Stille coupling reaction.</p>

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