Details of a Researcher - Suenaga, Kiyotake

Papers - Suenaga, Kiyotake

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A potent allelopathic substance in cucumber plants and allelopathy of cucumber

Kato-Noguchi Hisashi, Le Thi Ho, Sasaki Hiroaki, Suenaga Kiyotake

Acta Physiologiae Plantarum 34 ( 5 ) 2045 - 2049 2012.09

Accepted, ISSN 0137-5881

A potent growth inhibitory substance was isolated from an aqueous methanol extract of cucumber (Cucumis sativus L. cv. Phung Tuong) plants and determined as (2S)-2,3-dihydro-2α-(4-hydroxy-3-methoxyphenyl)-7-methoxy-5-(1,2,3-trihydroxypropyl)benzofuran-3β-methanol (sisymbrifolin) by spectral data. Sisymbrifolin inhibited the growth of cress (Lepidium sativum) and Echinochloa crus-galli seedlings at concentrations greater than 3 μM. Concentration of sisymbrifolin in the cucumber plants was the greatest among four growth inhibitory substances, (S)-2-benzoyloxy-3-phenyl-1-propanol, 9-hydroxy-4,7-megastigmadien-9-one, (6S,7E,9S)-6,9,10-trihydroxy-4,7-megastigmadien-3-one, and sisymbrifolin found in the cucumber, whereas growth inhibitory activity of 9-hydroxy-4,7-megastigmadien-9-one against cress and E. crus-galli was the greatest. Total activities of these substances (concentration of the substance/concentration required 50 % growth inhibition) were 14. 4, 13. 2, 8. 5 and 10. 7 for (S)-2-benzoyloxy-3-phenyl-1-propanol, 9-hydroxy-4,7-megastigmadien-9-one, (6S,7E,9S)-6,9,10-trihydroxy-4,7-megastigmadien-3-one and sisymbrifolin, respectively. These total activities were about 100-fold greater than those of phenolic acids, which are often mentioned as putative allelochemicals of plants. Thus, these substances may play important roles in the allelopathy of cucumber plants through the growth inhibition of neighboring plant species.

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Fluorescent Aplyronine A: Intracellular Accumulation and Disassembly of Actin Cytoskeleton in Tumor Cells.

Masaki Kita, Kozo Yoneda, Yuichiro Hirayama, Kota Yamagishi, Yuki Saito, Yuka Sugiyama, Yoshihiro Miwa, Osamu Ohno, Maho Morita, Kiyotake Suenaga, and Hideo Kigoshi:

ChemBioChem 13 1754-1758 2012.08

Research paper (scientific journal), Joint Work, Accepted

Isolation and structures of biselyngbyasides B, C, and D from the marine cyanobacterium Lyngbya sp., and the biological activities of biselyngbyasides

Morita Maho, Ohno Osamu, Teruya Toshiaki, Yamori Takao, Inuzuka Toshiyasu, Suenaga Kiyotake

Tetrahedron 68 ( 30 ) 5984 - 5990 2012.07

Accepted, ISSN 0040-4020

Bioassay-guided fractionation of the marine cyanobacterium Lyngbya sp. led to the isolation of biselyngbyasides B (3), C (4), and D (5), novel analogs of biselyngbyaside (1) and biselyngbyolide A (2). The gross structures of 3-5 were determined by NMR spectral analyses, and their stereochemistries were established based on NOESY spectra and CD data. Biselyngbyasides (1-3) showed growth-inhibitory activity and apoptosis-inducing activity against both HeLa S ₃ cells and HL60 cells. The fura-2 method revealed that biselyngbyasides (1-3) increased the cytosolic Ca ²⁺ concentration in HeLa S ₃ cells.

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Isolation of allelopathic substance from Piper sarmentosum Roxb

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

Allelopathy Journal 30 ( 1 ) 93 - 102 2012.07

Accepted, ISSN 0971-4693

Allelopathic activity of Piper sarmentosum Roxb. was determined and a potent growth inhibitory substance was isolated. The aqueous methanol extracts of P. sarmentosum inhibited the growth of 6-test plant species [cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.), timothy (Phleum pretense L.), Italian ryegrass (Lolium multiflorum Lam.) and crabgrass (Digitaria sanguinalis L.)] to various degrees in a dose-dependent manner. The active substance 3-phenylpropionic acid was purified from the aqueous methanol extract of P. sarmentosum and identified by ¹H-, ¹³C-NMR and MS. The threshold of 3-phenylpropionic acid for growth inhibition was 1 μM. The concentrations required for 50% growth inhibition of cress and lettuce were 1.2-9.3 μM and the concentrations required for 50% growth inhibition of timothy and Italian ryegrass were 4.7-51.8 μM. The endogenous concentration of 3-phenylpropionic acid in P. sarmentosum was 121 μmol/kg. Considering the endogenous level and the inhibitory activity, 3-phenylpropionic acid may work as allelopathic substance in P. sarmentosum through growth inhibition of neighbouring plant species.

Structure-activity studies on the spiroketal moiety of a simplified analogue of debromoaplysiatoxin with antiproliferative activity

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

Journal of Medicinal Chemistry 55 ( 11 ) 5614 - 5626 2012.06

Accepted, ISSN 0022-2623

Aplog-1, a simplified analogue of tumor-promoting debromoaplysiatoxin, is antiproliferative but not tumor-promoting. Our recent study has suggested that local hydrophobicity around the spiroketal moiety is a crucial determinant for antiproliferative activity. To further clarify the structural features relevant to the activity, we synthesized two methyl derivatives of aplog-1, where a methyl group was installed at position 4 or 10 of the spiroketal moiety. 10-Methyl-aplog-1 (5) bound to the C1B domains of novel PKCs (δ, η, and θ) with subnanomolar K _i values, approximately 10-20 times stronger than aplog-1, and markedly inhibited the growth of many human cancer cell lines, while 4-methyl-aplog-1 (4) had levels of activity similar to those of aplog-1. Interestingly, 5 showed little tumor-promoting activity unlike the tumor promoter debromoaplysiatoxin. These results suggest that 5 is a potent PKC ligand without tumor-promoting activity and could be a therapeutic lead for the treatment of cancer, like bryostatins.

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Identification of two phytotoxins, blumenol A and grasshopper ketone, in the allelopathic Japanese rice variety Awaakamai

Kato-Noguchi Hisashi, Tamura Kazuya, Sasaki Hiroaki, Suenaga Kiyotake

Journal of Plant Physiology 169 ( 7 ) 682 - 685 2012.05

Accepted, ISSN 0176-1617

Aqueous methanol extracts of the traditional rice (Oryza sativa) variety Awaakamai, which is known to have the greatest allelopathic activity among Japanese traditional rice varieties, inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense), Digitaria sanguinalis, Lolium multiflorum and Echinochloa crus-galli. Increasing the extract concentration increased the inhibition, suggesting that the extract of Awaakamai contains growth inhibitory substances. The extract of Awaakamai was purified and two main growth inhibitory substances were isolated and determined by spectral data as blumenol A and grasshopper ketone. Blumenol A and grasshopper ketone, respectively, inhibited the growth of cress shoots and roots at concentrations greater than 10 and 30 μmol/L. The concentrations required for 50% growth inhibition on cress roots and shoots were 84 and 27 μmol/L, respectively, for blumenol A, and 185 and 76 μmol/L, respectively, for grasshopper ketone. These results suggest that blumenol A and grasshopper ketone may contribute to the growth inhibitory effect of Awaakamai and may play an important role in the allelopathy of Awaakamai.

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Biselyngbyaside, isolated from marine cyanobacteria, inhibits osteoclastogenesis and induces apoptosis in mature osteoclasts

Yonezawa Takayuki, Mase Naomi, Sasaki Hiroaki, Teruya Toshiaki, Hasegawa Shin Ichi, Cha Byung Yoon, Yagasaki Kazumi, Suenaga Kiyotake, Nagai Kazuo, Woo Je Tae

Journal of Cellular Biochemistry 113 ( 2 ) 440 - 448 2012.02

Accepted, ISSN 0730-2312

The mass and function of bones depend on the maintenance of a complicated balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. An inhibitor of osteoclast differentiation and/or function is expected to be useful for treatment of bone lytic diseases such as osteoporosis, rheumatoid arthritis, and tumor metastasis into bone. Biselyngbyaside is a recently isolated macrolide compound from marine cyanobacteria Lyngbya sp. that shows wide-spectrum cytotoxicity toward human tumor cell lines. In this study, we investigated the effects of biselyngbyaside on osteoclast differentiation and function. Biselyngbyaside inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in mouse monocytic RAW264 cells and primary bone marrow-derived macrophages at a low concentration. Similarly, biselyngbyaside suppressed osteoblastic cell-mediated osteoclast differentiation in cocultures. In the RANKL-induced signaling pathway, biselyngbyaside inhibited the expression of c-Fos and NFATc1, which are important transcription factors in osteoclast differentiation. In mature osteoclasts, biselyngbyaside decreased resorption-pit formation. Biselyngbyaside also induced apoptosis accompanied by the induction of caspase-3 activation and nuclear condensation, and these effects were negated by the pancaspase inhibitor z-VAD-FMK. Taken together, the present findings indicate that biselyngbyaside suppresses bone resorption via inhibition of osteoclastogenesis and induction of apoptosis. Thus, biselyngbyaside may be useful for the prevention of bone lytic diseases.

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Biselyngbyolide A, a Novel Cytotoxic Macrolide from the Marine Cyanobacterium Lyngbya sp.

Maho Morita, Osamu Ohno, and Kiyotake Suenaga

Chem. Lett. 41 ( 2 ) 165-167 2012.02

Research paper (scientific journal), Joint Work, Accepted

Aplyronines D-H from the sea hare Aplysia kurodai

Ojika Makoto, Kigoshi Hideo, Suenaga Kiyotake, Imamura Yoshifumi, Yoshikawa Kohji, Ishigaki Takeshi, Sakakura Akira, Mutou Tsuyoshi, Yamada Kiyoyuki

Tetrahedron 68 ( 4 ) 982 - 987 2012.01

Accepted, ISSN 0040-4020

Five cytotoxic macrolides, aplyronines D-H (4-8), were isolated from the Japanese sea hare Aplysia kurodai. They are new congeners of the antitumor compound aplyronine A (1), which was previously isolated from the same organism. Their structures were determined by spectroscopic analysis (NMR and MS). The cytotoxicity of these new compounds was evaluated in comparison with that of aplyronines A-C (1-3), suggesting the importance of the 7-O-seryl ester group for mediating the potent cytotoxicity of aplyronines.

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海洋シアノバクテリア由来の医薬品リード化合物

SUENAGA Kiyotake

月刊ファインケミカル 41 ( 1 ) 45-51 2012

Research paper (scientific journal), Single Work

Secondary Metabolites with New Medicinal Functions from Marine Organisms

Ohno Osamu, Suenaga Kiyotake, Uemura Daisuke

Advances in Food and Nutrition Research 65 185 - 193 2012

Accepted, ISSN 1043-4526

We have focused on the identification of natural key compounds that possess biologically and medicinally intriguing functions. Some of bioactive naturally occurring compounds isolated from marine organisms were found to possess unique biological activities. Halichlorine from the marine sponge Halichondria okadai was shown to inhibit the activity of nuclear factor-κB in endothelial cells and block L-type Ca ²⁺ channels. Thus, it may have therapeutic potentials for diseases such as atherosclerosis and hypertension.

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Synthesis and structure-activity studies of simplified analogues of aplysiatoxin with antiproliferative activity like bryostatin-1

Irie Kazuhiro, Kikumori Masayuki, Kamachi Hiroaki, Tanaka Keisuke, Murakami Akira, Yanagita Ryo C., Tokuda Harukuni, Suzuki Nobutaka, Nagai Hiroshi, Suenaga Kiyotake, Nakagawa Yu

Pure and Applied Chemistry 84 ( 6 ) 1341 - 1351 2012

Accepted, ISSN 0033-4545

Protein kinase C (PKC) isozymes are promising targets for anticancer therapy. Bryostatin-1 (bryo-1), a unique PKC activator with little tumor-promoting activity, is currently in clinical trials for the treatment of cancer. However, its limited availability from natural sources and its synthetic complexity have hampered studies of its mode of action and structural optimization as a therapeutic agent. The development of synthetically more accessible compounds with bryo-1-like activities is thus needed. Recently, we developed a simple and less lipophilic analogue of tumor-promoting aplysiatoxin (ATX) (aplog-1) as a promising lead for bryo-1-like anticancer drugs. Structure-activity studies suggested that local hydro -phobicity around the spiroketal moiety of aplog-1 is a crucial determinant of its antiproliferative activity. The hydrophobic analogue (12,12-dimethyl-aplog-1) displayed more potent antiproliferative activity. Moreover, it showed little tumor-promoting activity and even suppressed the tumor promotion by 12-O-tetradecanoylphorbol 13-acetate (TPA) in vivo and in vitro. Aplog-1 and bryo-1 bound selectively to novel PKC isozymes (δ, η, and θ) while tumor promoters bound to both conventional and novel PKC isozymes. These results suggest that the unique biological activities of aplog-1 and bryo-1 are ascribable in part to the ability to bind to PKCδ, but weak binding to conventional PKC isozymes might also be important.

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Halichonines A, B, and C, novel sesquiterpene alkaloids from the marine sponge Halichondria okadai Kadota

Ohno Osamu, Chiba Tatsuhiko, Todoroki Seiji, Yoshimura Hideaki, Maru Norihito, Maekawa Ken, Imagawa Hiroshi, Yamada Kaoru, Wakamiya Atsushi, Suenaga Kiyotake, Uemura Daisuke

Chemical Communications 47 ( 46 ) 12453 - 12455 2011.12

Accepted, ISSN 1359-7345

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Allelopathy of red pine: isolation and identification of an allelopathic substance in red pine needles.

Kato-Noguchi Hisashi, Fushimi Yoshiko, Tanaka Yukitoshi, Teruya Toshiaki, Suenaga Kiyotake

Plant Growth Regulation 65 ( 2 ) 299 - 304 2011.11

Accepted, ISSN 0167-6903

Since red pine (Pinus densiflora Sieb. et Zucc.) often forms sparse forest floors where herbaceous plants do not grow well, allelopathy of red pine was investigated. A growth inhibitory substance was isolated from an aqueous methanol extract of red pine needles and determined by spectral data as abscisic acid-β-d-glucopyranosyl ester (ABA-GE). This substance inhibited root and shoot growth of cress and E. crus-galli seedlings at concentrations greater than 0. 1 μM. The concentrations required for 50% growth inhibition on roots and shoots of cress were 0.23 and 0.61 μM, respectively, and those of E. crus-galli were 1. 1 and 2. 8 μM, respectively. The activity of ABA-β-d-glucosidase, which liberates free ABA from ABA-GE, in cress and E. crus-galli seedlings was 13-29 nmol mg^-1 protein min^-1. Endogenous concentration of ABA-GE in the pine needles was 4. 1-21. 5 μmol kg^-1 and the concentration in soil water of the pine forest was 2. 5 μM. The effectiveness of ABA-GE on growth inhibition and the occurrence of ABA-GE in pine needles and soil water suggest ABA-GE may play an important role in the allelopathy of red pine resulting in the formation of sparse forest floors.

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Two potent allelopathic substances in cucumber plants

Kato-Noguchi Hisashi, Le Thi Ho, Teruya Toshiaki, Suenaga Kiyotake

Scientia Horticulturae 129 ( 4 ) 894 - 897 2011.07

Accepted, ISSN 0304-4238

Since cucumber plants are mostly discarded as large waste after crop harvesting, allelopathy of cucumber plants was investigated for possible weed management options and utilization of the waste. Two potent growth inhibitory substances were isolated from an aqueous methanol extract of cucumber (Cucumis sativus L. cv. Phung Tuong) plants. These substances were determined as 9-hydroxy-4,7-megastigmadien-9-one (HMO) and (6S,7E,9S)-6,9,10-trihydroxy-4,7-megastigmadien-3-one (THMO) by the analysis of MS, ¹H NMR spectra and optical rotation. HMO inhibited the growth of cress (Lepidium sativum L.) and Echinochloa crus-galli (L.) Beauv seedlings at concentrations greater than 0.3 and 1μM, respectively. THMO inhibited the growth of cress and E. crus-galli seedlings at concentrations greater than 1 and 3μM, respectively. The concentrations required for 50% growth inhibition on roots and shoots of cress and E. crus-galli were 2.4-29.3μM for HMO and 8.1-52.2μM for THMO. The endogenous levels of HMO and THMO in cucumber plants were 31.8 and 43.5μgg^-1 dry weight, respectively. These results suggest that HMO and THMO may be the causal factors for the growth inhibitory effect of cucumber plants. Therefore, cucumber plants may be potentially useful for weed management options in an agricultural setting, such as a cover crop and soil admixture, which should be investigated further in the field.

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Cell-morphology profiling of a natural product library identifies bisebromoamide and miuraenamide A as actin filament stabilizers

Sumiya Eriko, Shimogawa Hiroki, Sasaki Hiroaki, Tsutsumi Masato, Yoshita Keņichi, Ojika Makoto, Suenaga Kiyotake, Uesugi Motonari

ACS Chemical Biology 6 ( 5 ) 425 - 431 2011.05

Accepted, ISSN 1554-8929

Natural products provide a rich source of biological tools, but elucidating their molecular targets remains challenging. Here we report a cell morphological profiling of a natural product library, which permitted the identification of bisebromoamide and miuraenamide A as actin filament stabilizers. Automated high-content image analysis showed that these two structurally distinct marine natural products induce morphological changes in HeLa cells similar to those induced by known actin-stabilizing compounds. Bisebromoamide and miuraenamide A stabilized actin filaments in vitro, and fluorescein-conjugated bisebromoamide localized specifically to actin filaments in cells. Cell morphological profiling was also used to identify actinstabilizing or -destabilizing natural products from marine sponge extracts, leading to the isolation of pectenotoxin-2 and lyngbyabellin C. Overall, the results demonstrate that high-content imaging of nuclei and cell shapes offers a sensitive and convenient method for detecting and isolating molecules that target actin.

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N,N′-diphenethylurea isolated from Okinawan ascidian Didemnum molle enhances adipocyte differentiation in 3T3-L1 cells

Choi Sun Sil, Cha Byung Yoon, Kagami Iida, Lee Young Sil, Sasaki Hiroaki, Suenaga Kiyotake, Teruya Toshiaki, Yonezawa Takayuki, Nagai Kazuo, Woo Je Tae

Journal of Antibiotics 64 ( 3 ) 277 - 280 2011.03

Accepted, ISSN 0021-8820

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Revised structure and structure-activity relationship of bisebromoamide and structure of norbisebromoamide from the marine cyanobacterium Lyngbya sp.

Sasaki Hiroaki, Teruya Toshiaki, Fukazawa Hidesuke, Suenaga Kiyotake

Tetrahedron 67 ( 5 ) 990 - 994 2011.02

Accepted, ISSN 0040-4020

Novel potent cytotoxic peptides bisebromoamide (1) and norbisebromoamide (2) have been isolated from the marine cyanobacterium Lyngbya sp. The planar structure of these peptides was elucidated through the extensive application of 1D and 2D NMR techniques. The absolute stereostructure of 1 was determined by chemical degradation followed by chiral HPLC analysis. Recently, Tao and co-workers achieved synthesis of bisebromoamide, and the configuration of thiazoline moiety was revised. We re-investigated the stereochemistry of thiazoline moiety of 1. The structure-activity relationships of bisebromoamide (1) were investigated with the use of natural and synthetic analogs. Furthermore, bisebromoamide (1) potently inhibited protein kinase: the phosphorylation of ERK in NRK cells by PDGF-stimulation was selectively inhibited by treatment with 10-0.1 μM of 1.

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Marine natural product aurilide activates the opa1-mediated apoptosis by binding to prohibitin

Sato Shin Ichi, Murata Asako, Orihara Tsubasa, Shirakawa Takashi, Suenaga Kiyotake, Kigoshi Hideo, Uesugi Motonari

Chemistry and Biology 18 ( 1 ) 131 - 139 2011.01

Accepted, ISSN 1074-5521

Aurilide is a potent cytotoxic marine natural product that induces apoptosis in cultured human cells at the picomolar to nanomolar range; however, its mechanism of action has been unknown. Results of the present study showed that aurilide selectively binds to prohibitin 1 (PHB1) in the mitochondria, activating the proteolytic processing of optic atrophy 1 (OPA1) and resulting in mitochondria-induced apoptosis. The mechanism of aurilide cytotoxicity suggests that PHB1 is an apoptosis-regulating protein amenable to modulation by small molecules. Aurilide may serve as a small-molecule tool for studies of mitochondria-induced apoptosis.

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Isolation and identification of potent allelopathic substances in a traditional bangladeshi rice cultivar kartikshail

Kato-Noguchi Hisashi, Salam Md Abdus, Suenaga Kiyotake

Plant Production Science 14 ( 2 ) 128 - 134 2011

Accepted, ISSN 1343-943X

Aqueous methanol extracts of a traditional Bangladeshi rice cultivar (Oryza sativa L. cv. Kartikshail) inhibited root and shoot growth of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), crabgrass (Digitaria sanguinalis), Italian ryegrass (Lolium multiflorum), barnyardgrass (Echinochloa crus-galli) and jungle rice (Echinochloa colonum). The inhibition was increased with increasing the extract concentration, which suggests that cv. Kartikshail may have growth inhibitory substances and allelopathic potential. The aqueous methanol extract of cv. Kartikshail was purified and two main inhibitory substances were isolated and identified by spectral data as 3-hydroxy-β-ionone and 9-hydroxy-4-megastigmen-3-one. The concentrations required for 50% growth inhibition on cress roots and shoots, respectively, were 4.9 and 9.5 μM for 3-hydroxy-β-ionone, and 0.54 and 0.72 μM for 9-hydroxy-4-megastigmen-3-one. The concentrations required for 50% growth inhibition on barnyardgrass roots and shoots, respectively, were 160 and 310 μM for 3-hydroxy-β-ionone, and 53 and 140 μM for 9-hydroxy-4- megastigmen-3-one. The inhibitory activity of a mixture of the two compounds was much higher than that of the sum of the two compounds, suggesting that the two compounds may act synergistically to inhibit the growth of cress and barnyardgrass. The present research suggests that 3-hydroxy-β -ionone and 9-hydroxy-4-megastigmen-3-one may be responsible for the growth inhibitory effect of cv. Kartikshail and may play important roles in the allelopathy of cv. Kartikshail. The traditional Bangladeshi rice cultivar Kartikshail may be potentially useful for weed management as a weed suppressing agent when this rice cultivar is incorporated into the soil or included in rice-based cropping systems.

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