Details of a Researcher - Suenaga, Kiyotake

Papers - Suenaga, Kiyotake

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Isolation and identification of a plant growth inhibitor from Tinospora tuberculata Beumee

Kato-Noguchi Hisashi, Pukclai Piyatida, Ohno Osamu, Suenaga Kiyotake

Acta Physiologiae Plantarum 36 ( 7 ) 1621 - 1626 2014.07

Accepted, ISSN 0137-5881

Tinospora tuberculata Beumee has been used widely as a folk medicine and several bioactive compounds have been isolated. However, no herbicidal compound has been reported in this species. Therefore, we investigated the presence of phytotoxins in T. tuberculata. The aqueous methanol extracts of T. tuberculata inhibited the growth of roots and shoots of cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), timothy (Phleum pratense L.) and barnyard grass (Echinochloa crus-galli (L.) Beauv.). The extract was then purified by several chromatographic runs with monitoring the inhibitory activity and the main phytotoxic substance was isolated. The chemical structure of the compound was determined by spectral data as syringin (4-[(1E)-3-Hydroxyprop-1-en-1-yl]-2,6-dimethoxyphenyl β-d-glucopyranoside). It inhibited the root and shoot growth of all test plant species at concentrations >10 μM. The concentrations required for 50 % inhibition of root and shoot growth of cress and lettuce ranged from 78.2 to 412 μM, and that of timothy and barnyard grass renged from 9.8 to 73.2 μM. Effectiveness of syringin on monocotyledonous (timothy and barnyard grass) plants was greater than that on dicotyledonous (cress and lettuce) plants. These results suggest that syringin may contribute to the allelopathic effect caused by the T. tuberculata extract.

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Total synthesis of biselyngbyolide A

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

Organic Letters 16 ( 11 ) 2858 - 2861 2014.06

Accepted, ISSN 1523-7060

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Nimbolide B and Nimbic Acid B, Phytotoxic Substances in Neem Leaves with Allelopathic Activity

Kato-Noguchi, Hisashi, Salam, Md Abdus, Ohno, Osamu, Suenaga, Kiyotake

MOLECULES 19 ( 6 ) 6929 - 6940 2014.06

Research paper (scientific journal), Accepted, ISSN 1420-3049

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Kurahamide, a cyclic depsipeptide analog of dolastatin 13 from a marine cyanobacterial assemblage of Lyngbya sp.

Iwasaki Arihiro, Sumimoto Shinpei, Ohno Osamu, Suda Shoichiro, Suenaga Kiyotake

Bulletin of the Chemical Society of Japan 87 ( 5 ) 609 - 613 2014.05

Accepted, ISSN 0009-2673

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Phytotoxic substances with allelopathic activity may be central to the strong invasive potential of Brachiaria brizantha

Kato-Noguchi Hisashi, Kobayashi Ai, Ohno Osamu, Kimura Fukiko, Fujii Yoshiharu, Suenaga Kiyotake

Journal of Plant Physiology 171 ( 7 ) 525 - 530 2014.04

Accepted, ISSN 0176-1617

The grass Brachiaria brizantha, native to eastern Africa, becomes naturalized and dominant quickly in the non-native areas. It was hypothesized that phytotoxic chemical interaction between this plant and native plants may play an important role in the invasion of B. brizantha. However, no potent phytotoxic substance has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for phytotoxic substances with allelopathic activity in B. brizantha. An aqueous methanol extract of B. brizantha inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and three allelopathically active substances were isolated and identified by spectral analysis as (6R,. 9R)-3-oxo-α-ionol, (6R,. 9S)-3-oxo-α-ionol and 4-ketopinoresinol. (6R,. 9R)-3-Oxo-α-ionol and (6R,. 9S)-3-oxo-α-ionol inhibited root and shoot growth of garden cress at concentrations greater than 30 and 10. μM, respectively. The activity of (6R,. 9S)-3-oxo-α-ionol was 5.3- to 6.2-fold that of (6R,. 9R)-3-oxo-α-ionol. The stereochemistry of the hydroxyl group at position C-9 may be important for the inhibitory activities of those compounds. 4-Ketopinoresinol inhibited root and shoot growth of garden cress at concentrations greater than 30. μM. The growth inhibitory activity of (6R,. 9S)-3-oxo-α-ionol was the greatest and followed by 4-ketopinoresinol and (6R,. 9R)-3-oxo-α-ionol. These results suggest that those phytotoxic substances may contribute to the allelopathic effect caused by B. brizantha and may be involved in the invasion of B. brizantha.

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Biselyngbyolide B, a Novel ER Stress-inducer Isolated from the Marine Cyanobacterium Lyngbya sp.

Osamu Ohno, Ayane Watanabe, Maho Morita, and Kiyotake Suenaga

Chemistry Letters 43 ( 3 ) 287-289 2014.03

Research paper (scientific journal), Accepted

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Kurahyne, an acetylene-containing lipopeptide from a marine cyanobacterial assemblage of Lyngbya sp.

Arihiro Iwasaki, Osamu Ohno, Shinpei Sumimoto, Shoichiro Suda, and Kiyotake Suenaga

RSC Advances 4 12840-12843 2014.02

Research paper (scientific journal), Joint Work, Accepted

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A novel substance with allelopathic activity in Ginkgo biloba

Kato-Noguchi Hisashi, Takeshita Sayaka, Kimura Fukiko, Ohno Osamu, Suenaga Kiyotake

Journal of Plant Physiology 170 ( 18 ) 1595 - 1599 2013.12

Accepted, ISSN 0176-1617

Ginkgo (Ginkgo biloba) is one of the oldest living tree species and has been widely used in traditional medicine. Leaf extracts of ginkgo, such as the standardized extract EGb761, have become one of the best-selling herbal products. However, no bioactive compound directed at plants has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for allelopathically active substances in ginkgo leaves. An aqueous methanol leaf extract inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and an allelopathically active substance was isolated and identified by spectral analysis to be the novel compound 2-hydroxy-6-(10-hydroxypentadec-11-enyl)benzoic acid. The compound inhibited root and shoot growth of garden cress and timothy at concentrations greater than 3. μM. The activity of the compound was 10- to 52-fold that of nonanoic acid. These results suggest that 2-hydroxy-6-(10-hydroxypentadec-11-enyl)benzoic acid may contribute to the allelopathic effect caused by ginkgo leaf extract. The compound may also have potential as a template for the development of new plant control substances.

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Isolation and identification of an allelopathic substance from duckweed (Lemna minor L.)

Tran Thi Ngoc Bich, Osamu Ohno, Kiyotake Suenaga, and Hisashi Kato-Noguchi

Allelopathy Journal 32 ( 2 ) 213 - 222 2013.10

Research paper (scientific journal), Joint Work, Accepted

Effects of the methoxy group in the side chain of debromoaplysiatoxin on its tumor-promoting and anti-proliferative activities

Yanagita Ryo C., Kamachi Hiroaki, Kikumori Masayuki, Tokuda Harukuni, Suzuki Nobutaka, Suenaga Kiyotake, Nagai Hiroshi, Irie Kazuhiro

Bioorganic and Medicinal Chemistry Letters 23 ( 15 ) 4319 - 4323 2013.08

Accepted, ISSN 0960-894X

Debromoaplysiatoxin (DAT) is a tumor promoter isolated from sea hare and exhibits anti-proliferative activity against several cancer cell lines. To clarify key residues that are responsible for its tumor-promoting activity, we focused on the chiral methoxy group in the side chain, whose role had not yet been discussed or examined before. Demethoxy-DAT (8) was derived from DAT and we evaluated its tumor-promoting activity, anti-proliferative activity, and ability to bind to protein kinase C (PKC) isozymes. Compound 8 showed somewhat weaker tumor-promoting activity than that of DAT both in vitro and in vivo, but showed higher anti-proliferative activity against several cancer cell lines. Although the affinity to novel PKC isozymes of 8 was comparable to that of DAT, the affinity to conventional PKC isozymes decreased slightly. These results suggest that the methoxy group of DAT is one of the key residues critical for tumor-promoting activity but not for anti-proliferative activity. Since the methoxy group has little influence on the molecular hydrophobicity, this is the first report showing that structural factors other than hydrophobicity in the side chain of DAT affected its biological activities.

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Allelopathy is involved in the formation of pure colonies of the fern Gleichenia japonica

Kato-Noguchi Hisashi, Saito Yoshihumi, Ohno Osamu, Suenaga Kiyotake

Journal of Plant Physiology 170 ( 6 ) 577 - 582 2013.04

Accepted, ISSN 0176-1617

The fern Gleichenia japonica is one of the most widely distributed fern and occurs throughout East to South Asia. The species often dominates plant communities by forming large monospecific colonies. However, the potential mechanism for this domination has not yet been described. The objective of this study was to test the hypothesis that allelochemicals are involved in the formation of G. japonica colonies. An aqueous methanol extract of G. japonica inhibited the growth of seedlings of garden cress (Lepidium sativum), lettuce (Lactuca sativa), ryegrass (Lolium multiflorum) and timothy (Phleum pratense). Increasing extract concentration increased the inhibition. These results suggest that G. japonica contain allelopathic substances. The extract was then purified by several chromatographies with monitoring the inhibitory activity and two growth inhibitory substances causing the allelopathic effect were isolated. The chemical structures of the two substances were determined by spectral data to be a novel compound 3- O-β-allopyranosyl-13- O-β-fucopyranosyl-3β-hydroxymanool (1) and 18- O-α- l-rhamnopyranosyl-(1→2)-β- d-glucopyranosyl-13-epitorreferol (2). These compounds inhibited the shoot and root growth of garden cress, lettuce, alfalfa (Medicago sativa), timothy, ryegrass and barnyardgrass (Echinochloa crus-galli) at concentrations greater than 0.1-1.0 mM. The concentrations required for 50% growth inhibition of root and shoot growth of these test plants ranged from 0.72 to 3.49 mM and 0.79 to 3.51 mM for compounds 1 and 2, respectively. Concentration of compounds 1 and 2 in soil under the pure colony of G. japonica was 4.9 and 5.7 mM, respectively, indicating concentrations over those required for 50% growth inhibition are potentially available under monocultural stands of these ferns. Therefore, these compounds may contribute to the allelopathic effects caused by presence of G. japonica and may thus contribute to the establishment of monocultural stands by this fern.

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Total synthesis, structural elucidation, and structure-cytotoxic activity relationship of (-)-gummiferol

Takamura Hiroyoshi, Wada Hiroko, Lu Nan, Ohno Osamu, Suenaga Kiyotake, Kadota Isao

Journal of Organic Chemistry 78 ( 6 ) 2443 - 2454 2013.03

Accepted, ISSN 0022-3263

A highly stereoselective and stereodivergent synthesis of two possible diastereomers of (-)-gummiferol was achieved, wherein the stepwise epoxidation and Cadiot-Chodkiewicz reaction were utilized for the construction of the diepoxide moiety and triacetylene part, respectively. Detailed comparison of their ¹H and ¹³C NMR data and specific rotation with those of the natural product unambiguously elucidated the absolute stereostructure of gummiferol. In addition, the cytotoxic activity of the synthesized gummiferol, its stereoisomers, and its truncated analogues was evaluated, which clearly indicates that (1) the absolute configuration of the diepoxide moiety has little influence on the cytotoxic activity against human cancer cells and (2) the triacetylene unit is the crucial structural element required for exerting the cytotoxic activity.

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Apoptosis-inducing activity of the actin-depolymerizing agent aplyronine A and its side-chain derivatives

Ohno Osamu, Morita Maho, Kitamura Kazuhiro, Teruya Toshiaki, Yoneda Kozo, Kita Masaki, Kigoshi Hideo, Suenaga Kiyotake

Bioorganic and Medicinal Chemistry Letters 23 ( 5 ) 1467 - 1471 2013.03

Accepted, ISSN 0960-894X

Aplyronine A (1) and mycalolide B (2), which are cytotoxic actin-depolymerizing marine macrolides, were revealed to induce apoptosis in human leukemia HL60 cells and human epithelial carcinoma HeLa S₃ cells. Based on these results, actin-depolymerizing compounds were expected to exhibit apoptosis-inducing activity in cancer cells. Compounds 3-6, which were synthesized based on the side-chain structure of aplyronine A, were evaluated for their actin-depolymerizing activities in vitro and cytotoxicities against HL60 cells. The growth-inhibitory activities of 3-6 were well correlated with their actin-depolymerizing activities, and derivative 6 was shown to induce the disruption of actin filaments and apoptosis in HL60 cells. These results suggested that actin-depolymerizing agents 1, 2, and 6-induced apoptosis in HL60 cells may have been due to their actin-depolymerizing activity.

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A novel allelopathic substance, 13-epi-orthosiphol N, in Orthosiphon stamineus

Kato-Noguchi Hisashi, Hamada Naoko, Morita Maho, Suenaga Kiyotake

Journal of Plant Physiology 170 ( 1 ) 1 - 5 2013.01

Accepted, ISSN 0176-1617

Orthosiphon stamineus (Java tea) has been widely used as traditional herb and several bioactive compounds against animal cells have been isolated. However, no bioactive compound against plants has been reported. Therefore, we investigated possible allelopathic properties and substances in O. stamineus. Aqueous methanol extracts of O. stamineus inhibited root and hypocotyl growth of cress (Lepidium sativum) and lettuce (Lactuca sativa) seedlings. Increasing the extract concentration increased the inhibition, which suggests that O. stamineus may have allelopathic properties. When the extract was divided into an ethyl acetate and an aqueous fraction, the ethyl acetate fraction showed the stronger inhibitory effect. Thus, the ethyl acetate phase was further purified, and the main allelopathic substance was isolated and identified as 13- epi-orthosiphol N, a novel compound, by spectral data. 13- epi-Orthosiphol N inhibited root and hypocotyl growth of cress and lettuce at concentrations greater than 10 μmol/L. The concentrations required for 50% inhibition ranged from 41 to 102 μmol/L. These results suggest that 13- epi-orthosiphol N may be an allelochemical and main contributor to the growth inhibitory effect of O. stamineus and may have potential as a template for the development of new plant control substances.

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Bisebromoamide, an extract from Lyngbya species, induces apoptosis through ERK and mTOR inhibitions in renal cancer cells.

Kenjiro Suzuki, Ryuichi Mizuno, Kiyotake Suenaga, Toshiaki Teruya, Nobuyuki Tanaka, Takeo Kosaka, Mototsugu Oya:

Cancer Medicine 2 ( 1 ) 32-39 2013

Research paper (scientific journal), Joint Work, Accepted

Apoptosis as a practical target for identifying anticancer agents of marine origin

Ohno Osamu, Teruya Toshiaki, Suenaga Kiyotake, Uemura Daisuke

Forum on Immunopathological Diseases and Therapeutics 4 ( 1 ) 33 - 41 2013

Accepted, ISSN 2151-8017

Natural products and their synthetic analogs are widely used as anticancer drugs. Many anticancer drugs originated from cytotoxic compounds, and most have been shown to induce apoptosis in cancer cells. Based on the variety of their modes of action, the identification of new cytotoxic compounds may lead to the discovery of new types of drugs. Recently, much attention has been given to the metabolites of marine organisms due to their strong cytotoxicity. For example, eribulin mesylate, a synthetic analog of halichondrin B isolated from H. okadai Kadota, has been developed as an anticancer drug. Novel cytotoxic substances, such as halichonines, bisebromoamides, and biselyngbyasides, have been isolated from marine organisms as apoptosis-inducing agents. All of these compounds may possess therapeutic potential, and thus, efforts to identify new apoptosis-inducing agents of marine origin may contribute to the discovery of new pharmaceuticals.

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Genetic diversity of filamentous cyanobacteria from shore regions of Okinawa

Suda Shoichiro, Moriya Rui, Sumimoto Shinpei, Ohno Osamu, Suenaga Kiyotake

Journal of Marine Science and Technology (Taiwan) 21 ( SUPPL ) 175 - 180 2013

Accepted, ISSN 1023-2796

Benthic marine cyanobacteria are ubiquitous oxygenic photosynthetic bacteria and they form major components of various communities, including epiphytic, epilithic and microbial mats, in coral reef environments. Filamentous groups may form almost monospecific macroscopic colonies, and sometimes make potentially harmful algal blooms (HABs). HABs bring serious problems for marine tourism but marine filamentous cyanobacteria are good resource for drug discovery. However, cultivation and identification of such filamentous cyanobacteria are difficult and there are taxonomic confusions. In this study, we investigate 17 samples from coral reef area of 10 localities in Okinawa. Macroscopic mats or cushions of filamentous cyanobacteria were collected. The samples were divided into three parts: (1) for morphological observation, (2) for molecular work, and (3) cultivation for further study. Dominant cyanobacteira of each sample identified morphologically as Anabaena, Hydrocoleum, Lyngbya, Oscillatoria, Phormidium, Schizothrix and Symploca. Molecular results of partial 16S rDNA sequences revealed six groups that composed of heterocystous group, Leptolyngbya group, Symploca group, Moorea group, Oscillatoria group and unknown group, respectively. Some samples corroborated between morphology and molecular results but some were not. In addition, four out of six groups closely related with natural product producers. These results suggest that there are high biodiversity of marine benthic filamentous cyanobacteria in Okinawa that may become seeds of HABs as well as providing promising resources for drug discovery.

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Involvement of allelopathy in the establishment of pure colony of Dicranopteris linearis

Kato-Noguchi Hisashi, Saito Yoshihumi, Suenaga Kiyotake

Plant Ecology 213 ( 12 ) 1937 - 1944 2012.12

Accepted, ISSN 1385-0237

The fern Dicranopteris linearis Underw. (Old world forkedfern, Gleicheniaceae), the most widely distributed fern throughout tropical to temperature regions, dominates and often forms large pure colonies. Allelopathic chemical interaction of the fern was speculated to play an important role in the dominance. However, potential mechanisms, in particular, the allelopathic substance have not been reported. The objective of this study was the identification of its potential allelopathic substance and the evaluation of the ecological role of the substance. Extracts of D. linearis had an inhibitory effect on Echinochloa colonum and Avena fatua which are found near colonies of D. linearis in natural ecosystems. The extract was purified and a main inhibitory substance was isolated. The chemical structure of the substance was determined by high-resolution MS, and ¹H- and ¹³C-NMR spectral data and optical rotation as epicatechin-(2β → O → 7,4β → 8)-epicatechin-(4β → 8)-epicatechin (cinnamtannin B-1). Cinnamtannin B-1 inhibited the shoot and root growth of A. fatua and E. colonum at concentrations greater than 0. 2-0. 5 mM, and the concentrations required for 50 % growth inhibition on shoot and root growth of these plants were 0. 34-1. 31 mM. Cinnamtannin B-1 was found in soil under the colony, at concentrations of 4. 3 and 14. 5 mM in soil at the edge of and under the colony, respectively. These concentrations were over the concentration required for 50 % growth inhibition. Therefore, cinnamtannin B-1 may work as an allelopathic agent of D. linearis and may contribute to the establishment of pure colonies of D. linearis.

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Organ-specific-active allelopathic substance in red pine needles

Kato-Noguchi Hisashi, Fushimi Yoshiko, Kimura Fukiko, Morita Maho, Suenaga Kiyotake

Plant Growth Regulation 68 ( 2 ) 171 - 175 2012.11

Accepted, ISSN 0167-6903

An organ-specific-growth inhibitory substance was isolated from an aqueous methanol extract of red pine needles and determined by spectral data as 1-mono(16-hydroxyhexadecanoyl)glycerol. This substance inhibited root growth of cress (Lepidium sativum L.) and barnyard grass (Echinochloa crus-galli (L.) Beauv) seedlings at concentrations greater than 0.01 and 0.03 μM, respectively. The concentrations required for 50 % growth inhibition on roots of cress and barnyard grass were 0.16 and 3.4 μM, respectively. However, the inhibitory activity of the substance on shoots of cress and barnyard grass was very weak. The endogenous concentration of 1-mono(16-hydroxyhexadecanoyl)glycerol in the pine needles was 4.6 μmol kg ^-1. Two related compounds, 1-monohexadecanoylglycerol and 16-hydroxyhexadecanlic acid had no activity up to 1,000 μM on cress roots and shoots. The effectiveness of 1-mono(16-hydroxyhexadecanoyl)glycerol on root growth inhibition and the occurrence of 1-mono(16-hydroxyhexadecanoyl)glycerol in pine needles suggest the substance may play an important role in the allelopathy of red pine. Root-specific-growth-inhibition by the substance may be one of the strategies for red pine to compete with neighboring plants for nutrients and space because root growth of competitive plants may be very important for their whole plant development.

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Total synthesis and biological evaluation of auripyrones A and B

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

Bulletin of the Chemical Society of Japan 85 ( 10 ) 1077 - 1092 2012.10

Accepted, ISSN 0009-2673

The total synthesis of auripyrones was achieved by using a novel aldol-type reaction of γ-pyrone as a key step. From this synthetic work, we have established the stereostructure and absolute configuration of auripyrone B. Furthermore, the cytotoxicities of auripyrones against a panel of 39 human cancer cell lines (termed JFCR39) at the Japanese Foundation for Cancer Research were investigated. The patterns of the differential cytotoxicities of auripyrones were COMPARE negative, suggesting that they inhibit cancer cell proliferation through a novel mechanism.

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