Papers - Suenaga, Kiyotake

Allelopathic potential and chemical composition of rhinacanthus nasutus extracts

Piyatida Pukclai, Suenaga Kiyotake, Kato-Noguchi Hisashi

Allelopathy Journal 26 ( 2 ) 207 - 216 2010.10

Accepted,  ISSN  0971-4693

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<p>Aqueous methanol extracts of Rhinacanthus nasutus (L.) Kurz inhibited the shoot and root growth of cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.), timothy (Phleum pratense L.), Italian ryegrass (Lolium multiflorum Lam) and crabgrass (Digitaria sanguinalis L.) at concentrations &gt; 0.1 g dry weight equivalent extract/mL and the inhibition increased with increasing extract concentration. These results suggest that the extract of R. nasutus may possess allelopathic activity. An active substance was then isolated and determined by ¹H-, ¹³C-NMR and MS as 4-hydroxy-3-methoxybenzoic acid (vanillic acid). This is the first report of finding the vanillic acid in R. nasutus. The concentrations required for 50% growth inhibition of cress and lettuce were about 470 - 800 μM and the concentrations required for 50% growth inhibition of timothy and Italian ryegrass were 0.17 - 8.2 μM, which suggest that effectiveness of vanillic acid on timothy and Italian ryegrass was much greater than on cress and lettuce. The inhibitory activity and the occurrence of vanillic acid in R. nasutus suggest that vanillic acid may play an important role in the allelopathic properties of R. nasutus. The information obtained could be utilized in the development of bioherbicide for future weed management.</p>

Total synthesis of auripyrones A and B and determination of the absolute configuration of auripyrone B

Hayakawa Ichiro, Takemura Takuma, Fukasawa Emi, Ebihara Yuta, Sato Natsuki, Nakamura Takayasu, Suenaga Kiyotake, Kigoshi Hideo

Angewandte Chemie - International Edition 49 ( 13 ) 2401 - 2405 2010.03

Accepted,  ISSN  1433-7851

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<p>(Figure Presented) The winner takes it aldol: The total synthesis of auripyrones A and B was achieved using a diastereoselective aldol-type reaction with 2, 6-diethyl-3, 5-dimethyl-4-pyrone as a key step. The stereostructure and absolute configura-tion of auripyrone B has also been determined.</p>

Isolation and identification of potent allelopathic substances in rattail fescue

Kato-Noguchi Hisashi, Yamamoto Madoka, Tamura Kazuya, Teruya Toshiaki, Suenaga Kiyotake, Fujii Yoshiharu

Plant Growth Regulation 60 ( 2 ) 127 - 131 2010.03

Accepted,  ISSN  0167-6903

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<p>Aqueous methanol extracts of rattail fescue (Vulpia myuros) inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), Digitaria sanguinalis and Lolium multiflorum. Increasing the extract concentration increased the inhibition, suggesting that rattail fescue may have growth inhibitory substances and possess allelopathic potential. The aqueous methanol extract of rattail fescue was purified and two main inhibitory substances were isolated and identified by spectral data as (-)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol. Both substances inhibited root and shoot growth of cress at concentrations greater than 0.3 μM. The concentrations required for 50% growth inhibition on root and shoot growth of cress, lettuce, alfalfa, timothy, D. sanguinalis and L. multiflorum were 2.7-19.7 μM for (-)-3-hydroxy-β-ionone, and 2.1-34.5 μM for (+)-3-oxo-α-ionol. The concentration of (-)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol, respectively, in rattail fescue was 7.8 and 3.7 μg g^-1 fresh weight. Considering the endogenous level and the inhibitory activity, (-)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol may work as allelopathic substances in rattail fescue through the growth inhibition of neighboring plant species.</p>

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Cytotoxic substances from two species of Japanese sea hares

Yamada Kiyoyuki, Ojika Makoto, Kigoshi Hideo, Suenaga Kiyotake

Proceedings of the Japan Academy Series B: Physical and Biological Sciences 86 ( 3 ) 176 - 189 2010.03

Accepted,  ISSN  0386-2208

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<p>From the sea hares belonging to two genera, Aplysia and Dolabella, a variety of new cytotoxic substances were isolated as minute constituents: their chemical structures were determined and their cytotoxicity was evaluated. Regarding the highly cytotoxic substances, further chemical and biological studies were performed that included their asymmetric chemical synthesis and elucidation of biological characteristics such as antitumor activity.</p>

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Isolation and structure of koshikalide, a 14-membered macrolide from the marine cyanobacterium Lyngbya sp.

Iwasaki Arihiro, Teruya Toshiaki, Suenaga Kiyotake

Tetrahedron Letters 51 ( 6 ) 959 - 960 2010.02

Accepted,  ISSN  0040-4039

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<p>A 14-membered macrolide, koshikalide (1), was isolated from the marine cyanobacterium Lyngbya sp., and its planar structure was elucidated by spectroscopic analysis. The relative stereochemistry of C-11 and C-13 was elucidated by NOESY experiments and by an analysis of ¹H-¹H coupling constants. Koshikalide (1) exhibited weak cytotoxicity against HeLa S₃ cells.</p>

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Synthesis of palau'amide and its diastereomers: Confirmation of its stereostructure

Sugiyama Hirokazu, Watanabe Atsushi, Teruya Toshiaki, Suenaga Kiyotake

Tetrahedron Letters 50 ( 52 ) 7343 - 7345 2009.12

Accepted,  ISSN  0040-4039

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<p>Four diastereomers of palau'amide (1-4), a cytotoxic cyclodepsipeptide, were synthesized. The ¹H NMR spectrum of 1 was identical to that of natural palau'amide. This established the complete stereostructure of palau'amide.</p>

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Isolation of C ₁₁ cyclopentenones from two didemnid species, Lissoclinum sp. and Diplosoma sp.

Ogi Takayuki, Margiastuti Palupi, Teruya Toshiaki, Taira Junsei, Suenaga Kiyotake, Ueda Katsuhiro

Marine Drugs 7 ( 4 ) 816 - 832 2009.12

Accepted,  ISSN  1660-3397

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<p>A series of new C ₁₁ cyclopentenones 1-7 was isolated, together with four known metabolites 9/10, 12 and 13, from the extract of the didemnid ascidian Lissoclinum sp. The other didemnid ascidian Diplosoma sp. contained didemnenones 1, 2 and 5, and five known metabolites 8-12. The structures of 1-7 were elucidated by spectroscopic analyses. Cytotoxicity of the isolated compounds was evaluated against three human cancer cell lines (HCT116, A431 and A549).</p>

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Bisebromoamide, a potent cytotoxic peptide from the marine cyanobacterium lyngbya sp.

Teruya Toshiaki, Sasaki Hiroaki, Fukazawa Hidesuke, Suenaga Kiyotake

Organic Letters 11 ( 21 ) 5062 - 5065 2009.11

Accepted,  ISSN  1523-7060

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<p>A novel cytotoxic peptide, termed bisebromoamide (1), has been Isolated from the marine cyanobacterium Lyngbya sp. Its planar structure was determined by 1D and 2D NMR spectroscopy. The absolute stereostructure of 1 was determined by chemical degradation followed by chiral HPLC analysis. Bisebromoamide (1) exhibited potent protein kinase Inhibition: the phosphorylation of ERK In NRK cells by PDGFstimulation was selectively Inhibited by treatment with 10-0.1 μM of 1.</p>

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Unusual intramolecular N→O acyl group migration occurring during conjugation of (-)-DHMEQ with cysteine

Kozawa Ikuko, Kato Kuniki, Teruya Toshiaki, Suenaga Kiyotake, Umezawa Kazuo

Bioorganic and Medicinal Chemistry Letters 19 ( 18 ) 5380 - 5382 2009.09

Accepted,  ISSN  0960-894X

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<p>Previously we found that (-)-DHMEQ, a specific NF-κB inhibitor, covalently bound to a specific cysteine of NF-κB component proteins. In the course of formation of the (-)-DHMEQ and protected cysteine conjugate, we observed an unusual intramolecular N→O acyl group migration.</p>

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Synthetic studies on reidispongiolide A, an actin-depolymerizing marine macrolide: Synthesis of C11-C22 and C23-C35 segments.

Akiyama Satoshi, Toriihara Eisuke, Suzuki Kazushi, Teruya Toshiaki, Suenaga Kiyotake

Tetrahedron Letters 50 ( 35 ) 5012 - 5014 2009.09

Accepted,  ISSN  0040-4039

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<p>The C11-C22 and C23-C35 segments 2 and 3 of reidispongiolide A (1), an actin-depolymerizing marine macrolide, were synthesized enantioselectively in 12 steps from (R)-glycidyl trityl ether and in 12 steps from chiral ketone 15, respectively.</p>

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Biselyngbyaside, a macrolide glycoside from the marine cyanobacterium lyngbya sp.

Teruya Toshiaki, Sasaki Hiroaki, Kitamura Kazuhiro, Nakayama Takeshi, Suenaga Kiyotake

Organic Letters 11 ( 11 ) 2421 - 2424 2009.06

Accepted,  ISSN  1523-7060

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<p>Bioassay-guided fractionation of the cytotoxic constituents of the marine cyanobacterium Lyngbya sp. led to the isolation of biselyngbyaside (1), a new 18-membered macrolide glycoside. The structure of 1 was established by spectroscopic analysis including 2D-NMR techniques and by synthetic studies. Biselyngbyaside (1) exhibits broad-spectrum cytotoxicity in a human tumor cell line panel.</p>

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Isolation and identification of a potent allelopathic substance in Bangladesh rice

Salam Md Abdus, Morokuma Masahiro, Teruya Toshiaki, Suenaga Kiyotake, Kato-Noguchi Hisashi

Plant Growth Regulation 58 ( 2 ) 137 - 140 2009.06

Accepted,  ISSN  0167-6903

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<p>Aqueous methanol extracts of Bangladesh rice (Oryza sativa L. cv. BR17) inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), Digitaria sanguinalis, Echinochloa crus-galli and Echinochloa colonum. Increasing the extract concentration increased the inhibition, suggesting that the BR17 may have growth inhibitory substances and possess allelopathic potential. The aqueous methanol extract of the BR17 was purified and a main inhibitory substance was isolated and determined by spectral data as 2,9-dihydroxy-4-megastigmen-3-one. This substance inhibited root and shoot growth of cress and E. crus-galli seedlings at concentrations greater than 0.03 and 3 μM, respectively. The concentrations required for 50% growth inhibition on cress roots and shoots were 0.22 and 0.47 μM, respectively, and on E. crus-galli roots and shoots were 36 and 133 μM, respectively. These results suggest that 2,9-dihydroxy-4-megastigmen-3-one may contribute to the growth inhibitory effect of BR17 and may play an important role in the allelopathy of BR17. Thus, Bangladesh rice BR17 may be potentially useful for weed management in a field setting.</p>

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Synthesis of actin-depolymerizing compounds

Kitamura Kazuhiro, Teruya Toshiaki, Kuroda Takeshi, Kigoshi Hideo, Suenaga Kiyotake

Bioorganic and Medicinal Chemistry Letters 19 ( 7 ) 1896 - 1898 2009.04

Accepted,  ISSN  0960-894X

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<p>The artificial actin-depolymerizing compounds 3-6, based on aplyronine A, an actin-depolymerizing antitumor marine macrolide, were synthesized, and their actin-depolymerizing activities and cytotoxicities were evaluated.</p>

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Synthetic studies of mangostin derivatives with an inhibitory activity on PDGF-induced human aortic smooth cells proliferation

Nishihama Yuko, Ogamino Takahisa, Shi Wen Lei, Cha Byung Yoon, Yonezawa Takayuki, Teruya Toshiaki, Nagai Kazuo, Suenaga Kiyotake, Woo Je Tae, Nishiyama Shigeru

Heterocycles 77 ( 2 ) 759 - 765 2009.02

Accepted,  ISSN  0385-5414

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<p>The mangostin derivatives 310, were synthesized by halogenation, electrochemical oxidation, and mCPBA oxidation of α- and γ-mangostins (1, 2). Among them, the hydroxyl 9 and the benzopyran 10 derivatives produced by mCPBA, showed remarkable antiproliferative activities against human aortic smooth muscle cells (HASMC) induced by platelet-derived growth factor (PDGF).</p>

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Erratum to Isolation and identification of a potent allelopathic substance in Bangladesh rice (Plant Growth Regul, (2009), 58, (137-140), 10.1007/s10725-009-9360-5)

Salam Md Abdus, Morokuma Masahiro, Teruya Toshiaki, Suenaga Kiyotake, Kato-Noguchi Hisashi

Plant Growth Regulation 59 ( 2 ) 189 2009

Accepted,  ISSN  0167-6903

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Aplyronine A, a potent antitumour macrolide of marine origin, and the congeners aplyronines B-H

Yamada Kiyoyuki, Ojika Makoto, Kigoshi Hideo, Suenaga Kiyotake

Natural Product Reports 26 ( 1 ) 27 - 43 2009

Accepted,  ISSN  0265-0568

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<p>Aplyronines A-H are cytotoxic macrolides isolated from the sea hare Aplysia kurodai. Aplyronine A is the major constituent among the aplyronines, and this review concentrates on the results of chemical and biological research into this natural product. The isolation, determination of stereostructure and enantioselective total synthesis of the aplyronines are covered, together with discussion of their antitumour activity and structure-activity relationships, and the three-dimensional X-ray structure of the actin-aplyronine A complex.</p>

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Hexamollamide, a hexapeptide from an Okinawan ascidian Didemnum molle

Teruya Toshiaki, Sasaki Hiroaki, Suenaga Kiyotake

Tetrahedron Letters 49 ( 36 ) 5297 - 5299 2008.09

Accepted,  ISSN  0040-4039

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<p>The bioassay-guided fractionation of the cytotoxic constituents of the Okinawan ascidian Didemnum molle led to the isolation of hexamollamide (1), a hexapeptide. The gross structure and relative stereostructure of 1 were established by spectroscopic analysis including 2D NMR techniques and single-crystal X-ray diffraction analysis. The absolute stereostructure was determined by chiral HPLC analysis of acid hydrolysates of 1. Hexamollamide (1) exhibits moderate cytotoxicity against HeLa S₃ cells.</p>

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20-N-methylpurpuramine E

Teruya Toshiaki, Iwasaki Arihiro, Suenaga Kiyotake

Bulletin of the Chemical Society of Japan 81 ( 8 ) 1026 - 1027 2008.08

Accepted,  ISSN  0009-2673

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Synthesis and cytotoxicity of aurilide analogs

Suenaga Kiyotake, Kajiwara Shuri, Kuribayashi Satomi, Handa Tomohisa, Kigoshi Hideo

Bioorganic and Medicinal Chemistry Letters 18 ( 14 ) 3902 - 3905 2008.07

Accepted,  ISSN  0960-894X

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<p>The artificial analogs of aurilide (1), a potent cytotoxic cyclodepsipeptide of marine origin, were synthesized, and the structure-activity relationships were investigated.</p>

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An unusual iodinated 5′-deoxyxyrofuranosyl nucleoside from an okinawan ascidian, diplosoma sp. (Chemistry Letters (2008) (448-449))

Margiastuti Palupi, Ogi Takayuki, Teruya Toshiaki, Taira Junsei, Suenaga Kiyotake, Ueda Katsuhiro

Chemistry Letters 37 ( 6 ) 670 2008.06

Accepted,  ISSN  0366-7022

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