Publications by authors named "Toshio Ichiba"

14 Publications

  • Page 1 of 1

Castalagin and vescalagin purified from leaves of Syzygium samarangense (Blume) Merrill & L.M. Perry: Dual inhibitory activity against PARP1 and DNA topoisomerase II.

Fitoterapia 2018 Sep 19;129:94-101. Epub 2018 Jun 19.

Department of Biometabolic Chemistry, School of Health Science, Faculty of Medicine, University of the Ryukyus, Uehara 207, Nishihara-Cho, Okinawa 903-0215, Japan.. Electronic address:

Inhibition of poly(ADP-ribose) polymerase 1 (PARP1) is one of the most promising strategies for cancer chemotherapy, and a number of inhibitors possessing nicotinamide-like structures are being developed. To discover new types of PARP1 inhibitors, we screened a large number of substances of plant origin and isolated two inhibitory substances from the leaves of Syzygium samarangense (Blume) Merrill & L.M. Perry. The inhibitory substances were identified as vescalagin and its epimer castalagin by analyses using nuclear magnetic resonance and mass spectrometry. The IC of purified vescalagin and castalagin for PARP1 inhibition were 2.67 and 0.86 μM, respectively. Unlike most of synthetic PARP1 inhibitors, castalagin showed a mixed type inhibition, of which Ki was 1.64 μM. When SH-SY5Y cells were treated with these ellagitannins at concentrations of less than 5 μM, cellular poly(ADP-ribosyl)ation was obviously attenuated. Castalagin and vescalagin also possessed inhibitory activity against DNA topoisomerase II, implying that they function as dual inhibitors in cells.
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http://dx.doi.org/10.1016/j.fitote.2018.06.015DOI Listing
September 2018

Production of (R)-3-hydroxybutyric acid by fermentation and bioconversion processes with Azohydromonas lata.

Bioresour Technol 2011 Jun 27;102(12):6766-8. Epub 2011 Mar 27.

Okinawa Industrial Technology Center, Suzaki 12-2, Uruma, Okinawa 904-2234, Japan.

Feasibility of producing (R)-3-hydroxybutyric acid ((R)-3-HB) using wild type Azohydromonas lata and its mutants (derived by UV mutation) was investigated. A. lata mutant (M5) produced 780 m g/l in the culture broth when sucrose was used as the carbon source. M5 was further studied in terms of its specificity with various bioconversion substrates for production of (R)-3-HB. (R)-3-HB concentration produced in the culture broth by M5 mutant was 2.7-fold higher than that of the wild type strain when sucrose (3% w/v) and (R,S)-1,3-butanediol (3% v/v) were used as carbon source and bioconversion substrate, respectively. Bioconversion of resting cells (M5) with glucose (1% v/w), ethylacetoacetate (2% v/v), and (R,S)-1,3-butanediol (3% v/v), resulted in (R)-3-HB concentrations of 6.5 g/l, 7.3g/l and 8.7 g/l, respectively.
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http://dx.doi.org/10.1016/j.biortech.2011.03.073DOI Listing
June 2011

Antihypertensive effect of an extract of Passiflora edulis rind in spontaneously hypertensive rats.

Biosci Biotechnol Biochem 2006 Mar;70(3):718-21

Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan.

Orally administered methanol extract of Passiflora edulis rind (10 mg/kg or 50 mg/kg) or luteolin (50 mg/kg), which is one of consistent polyphenols of the extract, significantly lowered systolic blood pressure in spontaneously hypertensive rats (SHRs). Quantitative analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) showed that the extract contained 20 microg/g dry weight of luteolin and 41 microg/g dry weight of luteolin-6-C-glucoside. It also contained gamma-aminobutyric acid (GABA, 2.4 mg/g dry weight by LC-MS/MS or 4.4 mg/g dry weight by amino acid analysis) which has been reported to be an antihypertensive material. Since the extract contained a relatively high concentration of GABA, the antihypertensive effect of the extract in SHRs might be due mostly to the GABA-induced antihypertensive effect and partially to the vasodilatory effect of polyphenols including luteolin.
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http://dx.doi.org/10.1271/bbb.70.718DOI Listing
March 2006

Luteolin inhibits endothelin-1 secretion in cultured endothelial cells.

Biosci Biotechnol Biochem 2005 Aug;69(8):1613-5

Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.

We discovered that luteolin, a typical flavonoid contained in various kinds of plants, inhibits the secretion and gene expression of endothelin-1 (ET-1), a potent vasoconstrictor regulating blood pressure, in porcine aortic endothelial cells. Its ED50 was about 10 microM. In addition, the inhibition of ET-1 by a glycoside compound of luteolin (luteolin-6-C-glucoside) was weak.
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http://dx.doi.org/10.1271/bbb.69.1613DOI Listing
August 2005

Free radical scavenging and hepatoprotective actions of the medicinal herb, Crassocephalum crepidioides from the Okinawa Islands.

Biol Pharm Bull 2005 Jan;28(1):19-23

Laboratory of Molecular Pharmacology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan.

Free radical scavenging and protective actions against chemically induced hepatotoxicity of Crassocephalum crepidioides were investigated. A water extract of C. crepidioides strongly scavenged superoxide anion, hydroxyl radical and also stable radical 1,1-diphenyl-2-picrylhydrazyl. Galactosamine (GalN, 400 mg/kg) and lipopolysaccharide (LPS, 0.5 microg/kg) induced hepatotoxicity of rats as seen by an elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and of lipid peroxidation in liver homogenates was significantly depressed when the herbal extract was given intraperitoneally 1 and 15 h before GalN and LPS treatment. Similarly, carbon tetrachloride (CCl4) induced liver injury as evidenced by an increase in AST and ALT activities in serum was also inhibited by the extract pretreatment. Isochlorogenic acids, quercetin and kaempferol glycosides were identified as active components of C. crepidioides with strong free radical scavenging action. These results demonstrate that C. crepidioides is a potent antioxidant and protective against GalN plus LPS- or CCl4-induced hepatotoxicity.
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http://dx.doi.org/10.1248/bpb.28.19DOI Listing
January 2005

Briarane diterpenes from two species of octocorals, Ellisella sp. and Pteroeides sp.

J Nat Prod 2004 Aug;67(8):1368-73

Department of Chemistry, Biology, and Marine Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.

Eight new briarane diterpenes (1-4, 7-10) have been isolated from two species of octocorals and the structures elucidated by spectroscopic analysis. Two diterpenes (2, 3) from the gorgonian Ellisella sp. inhibited cytokinesis, causing multinuclei formation on NBT-II cells, while a known briarane (12) from the sea pen Pteroeides sp. showed reversal of multidrug resistance.
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http://dx.doi.org/10.1021/np049923oDOI Listing
August 2004

The modifying effect of Peucedanum japonicum, a herb in the Ryukyu Islands, on azoxymethane-induced colon preneoplastic lesions in male F344 rats.

Cancer Lett 2004 Mar;205(2):133-41

Tumor Pathology, Faculty of Medicine, University of the Ryukyus, 207 Uehara Nishihara-cho, Okinawa 903-0215, Japan.

The modifying effect of dietary Peucedanum japonicum (PJ), which is a traditional herb in the Ryukyu Islands and is an anti-oxidant, on azoxymethane (AOM)-induced rat colon carcinogenesis was examined. Male F344 rats were divided into six groups: rats in groups 1-4 were given subcutaneous injection of AOM (20 mg/kg body weight) once a week for 2 weeks. Rats in groups 2, 3 and 4 were fed the diets containing 0.2 and 1% PJ and 0.025% chlorogenic acid, respectively. We observed modification of the preneoplastic lesions of both aberrant crypt foci (ACF) and beta-catenin accumulated crypts (BCAC) in colon carcinogenesis, microscopically and immunohistochemically. The numbers of ACF consisting of more than four aberrant crypts per rat in groups 2 (3.2+/-1.7) and 3 (3.0+/-3.2) were significantly lower than that of group 1 (10.8+/-4.9; P<0.05, respectively). The mean number of BCAC in both groups 2 (0.88+/-0.48/cm2/rat) and 3 (0.81+/-0.34/cm2/rat) was significantly lower than that in group 1 (2.13+/-0.54/cm2/rat; P < 0.0001, respectively). In addition, proliferating cell nuclear antigen labeling indices in group 2 (10.98+/-2.03) and group 3 (9.85+/-2.62) were significantly lower than that in group 1 (14.87+/-3.93; P < 0.001 and P < 0.0001, respectively). These findings indicate that PJ inhibits both ACF formation and accumulation of beta-catenin, and that PJ also reduces the cell proliferation activity, suggesting that PJ may have chemopreventive potential for colon carcinogenesis.
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http://dx.doi.org/10.1016/j.canlet.2003.10.002DOI Listing
March 2004

Enzymatic nitration of phytophenolics: evidence for peroxynitrite-independent nitration of plant secondary metabolites.

FEBS Lett 2003 Oct;553(3):377-80

Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, 903-0213 Okinawa, Japan.

Peroxynitrite (ONOO(-)), a reactive nitrogen species, is capable of nitrating tyrosine residue of proteins. Here we show in vitro evidence that plant phenolic compounds can also be nitrated by an ONOO(-)-independent mechanism. In the presence of NaNO(2), H(2)O(2), and horseradish peroxidase (HRP), monophenolic p-coumaric acid (p-CA, 4-hydroxycinnamic acid) was nitrated to form 4-hydroxy-3-nitrocinnamic acid. The reaction was completely inhibited by KCN, an inhibitor for HRP. The antioxidant ascorbate suppressed p-CA nitration and its suppression time depended strongly on ascorbate concentration. We conclude that nitrogen dioxide radical (NO(2)(radical)), but not ONOO(-), produced by a guaiacol peroxidase is the intermediate for phytophenolic nitration.
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http://dx.doi.org/10.1016/s0014-5793(03)01059-7DOI Listing
October 2003

New phenolic compounds from Kokuto, non-centrifuged cane sugar.

Biosci Biotechnol Biochem 2003 Feb;67(2):376-9

Laboratory of Applied Biochemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Senbaru 1, Nishihara-cho, Okinawa 903-0213, Japan.

Five new phenolic compounds, 4-(beta-D-glucopyranosyloxy)-3,5-dimethoxyphenyl-propanone (8), 3-[5-[(threo) 2,3-dihydro-2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-7-methoxybenzofuranyl]-propanoic acid (12), 2-[4-(3-hydroxy-1-propenyl)-2,6-dimethoxyphenoxy]-3-hydroxy-3-(4-hydroxy-3,5-dimethoxyphenyl)propyl-beta-D-glucopyranoside (13), 4-[(erythro) 2,3-dihydro-3(hydroxymethyl)-5-(3-hydropropyl)-7-methoxy-2-benzofuranyl]-2,6-dimethoxyphenyl-beta-D-glucopyranoside (14), 9-O-beta-D-xylopyranoside of icariol A2 (15), and known phenolic compounds were isolated from Kokuto, non-centrifuged cane sugar (Saccharum officinarum L.). Their structures were determined by a spectral investigation.
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http://dx.doi.org/10.1271/bbb.67.376DOI Listing
February 2003

Thielavins as glucose-6-phosphatase (G6Pase) inhibitors: producing strain, fermentation, isolation, structural elucidation and biological activities.

J Antibiot (Tokyo) 2002 Nov;55(11):941-51

Exploratory Medicinal Sciences, Pfizer Global Research and Development (PGRD)-Nagoya Laboratories, Pfizer Inc., 5-2 Taketoyo, Aichi 470-2393, Japan.

High-throughput screening of microbial extracts using rat hepatic microsomal glucose-6-phosphatase (G6Pase) led us to find thielavin B as a G6Pase inhibitor with inhibition of glucose output from glucagon-stimulated hepatocytes. Further searching for more potent analogs identified 11 new thielavins F-P in addition to the known thielavins A and B from a fungus Chaetomium carinthiacum ATCC 46463. Thielavin G showed the strongest activity as a G6Pase inhibitor (IC50=0.33 microM), while the IC50 of thielavin B was 5.5 microM. According to the structure-activity relationship, including authentic thielavins C, D and 3 partial hydrolysates from thielavins A and B, 3 benzoic acid-units and carboxylic acid functions are essential for G6Pase inhibition.
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http://dx.doi.org/10.7164/antibiotics.55.941DOI Listing
November 2002

Bitungolides A-F, new polyketides from the Indonesian sponge Theonella cf. swinhoei.

J Nat Prod 2002 Dec;65(12):1820-3

Department of Chemistry, Biology, and Marine Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.

Six new polyketides, bitungolides A-F (1-6), have been isolated from the Indonesian sponge Theonella cf. swinhoei and their structures elucidated by spectroscopic data and X-ray diffraction analysis. The bitungolides are a new class of Theonella metabolites that inhibit dual-specificity phosphatase VHR.
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http://dx.doi.org/10.1021/np0200865DOI Listing
December 2002

Pachastrissamine, a cytotoxic anhydrophytosphingosine from a marine sponge, Pachastrissa sp.

J Nat Prod 2002 Oct;65(10):1505-6

Department of Chemistry, Biology, and Marine Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.

An anhydrophytosphingosine named pachastrissamine (3) has been isolated as a cytotoxic principle of a sponge, Pachastrissa sp., and the structure including the absolute configuration determined by spectroscopic and chemical analysis.
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http://dx.doi.org/10.1021/np010659yDOI Listing
October 2002

Synergistic effect of deoxyanthocyanins from symbiotic fern Azolla spp. on hrmA gene induction in the cyanobacterium Nostoc punctiforme.

Mol Plant Microbe Interact 2002 Sep;15(9):875-82

Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, Japan.

The hrmA gene of the N2-fixing cyanobacterium Nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. Here, we report that anthocyanins can contribute to induction of hrmA expression. Aqueous extract from fronds of the fern Azolla pinnata, a host of symbiotic Nostoc spp., was found to be a potent inducer of hrmA-luxAB in N. punctiforme strain UCD 328. The hrmA-luxAB inducing activities of A. pinnata, as well as Azolla filiculoides, were positively correlated with levels of frond deoxyanthocyanins. Analyses of the deoxyanthocyanins in frond extracts revealed, in order of predominance, an acetylated glycoside derivative of luteolinidin (m/z 475) and of apigeninidin (m/z 459) and minor amounts of a second luteolinidin derivative. At up to 150 microM, a purified preparation of deoxyanthocyanins only weakly induced hrmA-luxAB on its own, but mixtures with hrmA-luxAB inducers (A. filiculoides extract or the flavonoid naringin) synergistically doubled to tripled their inducing activities. These results suggest that appropriately localized deoxyanthocyanins could function in plant-mediated mechanisms for repressing Nostoc spp. hormogonium formation.
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http://dx.doi.org/10.1094/MPMI.2002.15.9.875DOI Listing
September 2002

New antioxidative phenolic glycosides isolated from Kokuto non-centrifuged cane sugar.

Biosci Biotechnol Biochem 2002 Jan;66(1):29-35

Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan.

Nine compounds, 3-hydroxy-4,5-dimethoxyphenyl-beta-D-glucopyranoside (1), beta-D-fructfuranosyl-alpha-D-(6-vanilloyl)-glucopyranoside (2), beta-D-fructfuranosyl-alpha-D-(6-syringyl)-glucopyranoside (3), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2-methoxyphenoxy]propyl-beta-D-glucopyranoside (4), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2,6-dimethoxyphenoxy] propyl-beta-D-glucopyranoside (5), dehydrodiconiferyl alcohol-9'-beta-D-glucopyranoside (6), 4-[ethane-2-[3-(4-hydroxy-3-methoxyphenyl)-2-propen]oxy]-2,6-dimethoxyphenyl-beta-D-glucopyranoside (7), 4-[ethane-2-[3-(4-hydroxy-3-methoxyphenyl)-2-propen]oxy]-2-methoxyphenyl-beta-D-glucopyranoside (8), and 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-[4-(3-hydroxy-1-(E)-propenyl)-2,6-dimethoxyphenoxy]propyl-beta-D-glucopyranoside (9), were isolated from Kokuto non-centrifuged cane sugar. Their structures were elucidated by spectroscopic evidence, mainly based on the NMR technique. Among them, seven new glycosides were identified. The 2-deoxyribose oxidation method was used to measure their antioxidative activity. All of these compounds showed antioxidative activities.
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http://dx.doi.org/10.1271/bbb.66.29DOI Listing
January 2002
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