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Dive into the research topics where Yusuke Sakata is active.

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Featured researches published by Yusuke Sakata.


Bioscience, Biotechnology, and Biochemistry | 2003

Evaluation of the Anti-oxidative Effect (in vitro) of Tea Polyphenols

Fumio Hashimoto; Masateru Ono; Chikako Masuoka; Yasuyuki Ito; Yusuke Sakata; Keiichi Shimizu; Gen-ichiro Nonaka; Itsuo Nishioka; Toshihiro Nohara

Forty-three polyphenols from tea leaves were evaluated for their anti-oxidative effect against lipid peroxidation by the ferric thiocyanate method in vitro. Among these, 1,4,6-tri-O-galloyl-β-D-glucose (hydrolyzable tannin) showed the highest anti-oxidative activity against lipid peroxidation, even stronger than that of 3-tert.-butyl-4-hydroxyanisole (BHA). The assay demonstrates that tea polyphenols, except for desgalloylated dimeric proanthocyanidins that possess a catechin structure in the upper unit and desgalloylated flavan-3-ols, and excepting theaflavin 3,3′-di-O-gallate, had more anti-oxidative activity than that of α-tocopherol. The chemical structure-activity relationship shows that the anti-oxidative action advanced with the condensation of two molecules of flavan-3-ols as well as with 3-O-acylation in the flavan skeleton such as that by galloyl, (3′-O-methyl)-galloyl, and p-coumaroyl groups.


Journal of Plant Research | 2001

Analysis of Petal Anthocyanins to Investigate Flower Coloration of Zhongyuan (Chinese) and Daikon Island (Japanese) Tree Peony Cultivars

Liang-Sheng Wang; Aya Shiraishi; Fumio Hashimoto; Noriaki Aoki; Keiichi Shimizu; Yusuke Sakata

Pn, Pg; Pn, Pg > Cy; Pn, Cy and Pn, Cy > Pg groups. Each group consequently specified significant features among CIELAB color notation and petal pigmentation, being adequate to characterize tree peony flowers as similar between Zhongyuan and Daikon Island cultivars, thus the cultivars of the two areas are suggested to be related to one another.


Journal of Plant Research | 2001

Phenetics in Tree Peony Species from China by Flower Pigment Cluster Analysis

Liang-Sheng Wang; Fumio Hashimoto; Aya Shiraishi; Noriaki Aoki; Jia-Jue Li; Keiichi Shimizu; Yusuke Sakata

Paeonia section Moutan DC. (fifteen accessions) from China. As the pigment markers, five anthocyanins together with three flavone and three flavonol aglycones were used. Principal component analysis (PCA) provided five eigenvectors from nineteen pigment patterns, in which peonidin and cyanidin as well as the types of glycosides greatly influenced the first factor, Z1. The Euclidean distances of standardized values obtained by eigenvector matrices with five factors (Z1 to Z5) produced a dendrogram in Wards minimum variance cluster analysis, which showed good agreement with a classification based on the morphological characteristics of two subsections Vaginatae F.C. Stern and Delavayanae F.C. Stern. The results obtained by PCA and clustering qualify a chemical classification of section Moutan using secondary metabolites, specifically flower pigments, as taxonomic markers.


Bioscience, Biotechnology, and Biochemistry | 2002

Changes in Flower Coloration and Sepal Anthocyanins of Cyanic Delphinium Cultivars during Flowering

Fumio Hashimoto; Mika Tanaka; Hiroko Maeda; Shoko Fukuda; Keiichi Shimizu; Yusuke Sakata

The changes in flower color related to sepal pigmentation of cyanic Delphinium cultivars were investigated during anthesis. The sepal hues of the purple and blue flowered varieties observed on the initial day of unfurling had changed with a decrease in hue angle three days after anthesis. In both the purple and blue cultivars, violdelphin (3) was the major component on day one of anthesis, and the chromaticity improved with increasing sepal concentrations of violdelphin (3) and cyanodelphin (4) after three days of unfurling. The flower hue was dominated by the constitution of acylated anthocyanins, and the chromaticity was ordered by the sepal concentration. The biosynthesis of cyanodelphin (4) from violdelphin (3) was postulated since an increase in the sepal concentration of cyanodelphin (4) was accompanied by a decrease in violdelphin (3). Acylation of the anthocyanins was initiated by an increase in the respective possible precursors, tulipanin (2) and violdelphin (3), to subsequently synthesize violdelphin (3) and cyanodelphin (4) during flowering.


Bioresource Technology | 2008

Bioconversion of squid pen by Lactobacillus paracasei subsp paracasei TKU010 for the production of proteases and lettuce growth enhancing biofertilizers

San-Lang Wang; Tsai-Yi Huang; Chun-Yuan Wang; Tzu-Wen Liang; Yue-Horng Yen; Yusuke Sakata

A protease-producing bacterium, strain TKU010, was isolated from infant vomited milk and identified as Lactobacillus paracasei subsp. paracasei. A surfactant-stable protease, purified 64-fold from the third day culture supernatant to homogeneity in an overall yield of 11%, has a molecular weight of about 49,000. The enzyme degraded casein and gelatin, but did not degrade albumin, fibrin, and elastin. The enzyme activity was increased about 1.5-fold by the addition of 5mM Ba(2+). However, Fe(2+) and Cu(2+) ions strongly inhibited the enzyme. The enzyme was maximally active at pH 10 and 60 degrees C and retained 94% and 71% activity in the presence of Tween 20 (2% w/v) and SDS (2mM), respectively. The result of identification of TKU010 protease showed that nine tryptic peptides were identical to Serratia protease (serralysin) (GenBank accession number gi999638) with 35% sequence coverage. In comparison with the tryptic peptides of L. paracasei subsp. paracasei TKU012 protease, TKU010 protease possessed two additional peptides with sequences of AATTGYDAVDDLLHYHER and QTFTHEIGHALGLSHPGDYNAGEGNPTYR. The fourth day culture supernatant of TKU010 showed maximal activity of about 5-fold growth enhancing effect on lettuce weight, which was not shown with L. paracasei subsp paracasei TKU012.


Journal of Natural Medicines | 2007

Chromone and flavonol glycosides from Delphinium hybridum cv. “Belladonna Casablanca”

Hitoshi Yoshimitsu; Makiko Nishida; Fumio Hashimoto; Mika Tanaka; Yusuke Sakata; Masafumi Okawa; Toshihiro Nohara

One new chromone and six known flavonol glycosides were isolated from the stems and leaves of Delphinium hybridum cv. “Belladonna Casablanca” (Ranunculaceae). The new chromone glycoside was elucidated as 2-methyl-chromone-5,7-diol 7-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (1). The six known flavonol glycosides were designated as compounds 2–5, being kaempferol-type glycosides, and compounds 6 and 7, being quercetin-type glycosides. The structures of these glycosides were determined by two-dimensional nuclear magnetic resonance (2D NMR) spectroscopic analysis and chemical evidence.


Journal of Integrative Plant Biology | 2009

A new acylated anthocyanin from the red flowers of Camellia hongkongensis and characterization of anthocyanins in the section Camellia species.

Jian-Bin Li; Fumio Hashimoto; Keiichi Shimizu; Yusuke Sakata

Twelve anthocyanins (1-12) were isolated from the red flowers of Camellia hongkongensis Seem. by chromatography using open columns. Their structures were elucidated on the basis of spectroscopic analyses, that is, proton-nuclear magnetic resonance, carbon 13-nuclear magnetic resonance, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, high resolution electrospray ionization mass and ultraviolet visible spectroscopies. Out of these anthocyanins, a novel acylated anthocyanin, cyanidin 3-O-(6-O-(Z)-p-coumaroyl)-beta-galactopyranoside (6), two known acylated anthocyanins, cyanidin 3-O-(6-O-(E)-p-coumaroyl)-beta-galactopyranoside (7) and cyanidin 3-O-(6-O-(E)-caffeoyl)-beta-galactopyranoside (8), and three known delphinidin glycosides (10-12) were for the first time isolated from the genus Camellia. Furthermore, pigment components in C. japonica L., C. chekiangoleosa Hu and C. semiserrata Chi were studied. The results indicated that the distribution of anthocyanins was differed among these species. Delphinidin glycoside was only detected in the flowers of C. hongkongensis, which is a special and important species in the section Camellia. Based on the characterization of anthocyanins in the section Camellia species, there is a close relationship among these species, and C. hongkongensis might be an important parent for creating new cultivars with bluish flower color.


Phytochemistry | 1992

Cyanidin 3-lathyroside from berries of Fatsia japonica

Norihiko Terahara; Norio Saito; Kenjiro Toki; Yusuke Sakata; Toshio Honda

Abstract The structure of the major anthocyanin in the ripe berries of Fatsia japonica has been identified as cyanidin 3-lathyroside by FABMS and 1 H NMR measurement using H-H COSY and difference NOE.


Phytochemistry | 2013

Chemical taxonomy of red - flowered wild Camellia species based on floral anthocyanins

Jian-Bin Li; Fumio Hashimoto; Keiichi Shimizu; Yusuke Sakata

This study uses anthocyanins in the red flowers of section Camellia as taxonomic markers to investigate the phenetic relationships among 33 wild species from China, Taiwan, and Japan. The 25 anthocyanins from section Camellia produced 38 pigment patterns that serve as phenetic markers. Principal Component Analysis (PCA) indicated that the attachment of one or two glucoses to the cyanidin-core structure at the 3- or the 3- and 5-positions, respectively, was the most influential pattern against the first factor, Z₁. In addition, two alternative pigment patterns, acylated or non-acylated, and the structural isomerism (cis- or trans-) of the p-coumaroyl group were relatively significant patterns. Wards minimum-variance cluster analysis (WMVCA) produced a dendrogram that consisted of two sub-clusters. One sub-cluster (A) was constructed by species that have mainly two types of anthocyanins: 3,5-di-O-β-glucosides (Camellia saluenensis) and sambubioside of cyanidin (Camellia reticulata). The other sub-cluster (B) was made up of the 3-O-β-glucosides of cyanidin (Camellia japonica) and delphinidin (Camellia hongkongensis), with a higher proportion of the 3-O-β-galactosides (Camellia mairei and Camellia boreali-yunnanica). The former group showed a higher proportion of acylation, over 63%, but with the exception of Camellia azalea. The latter group showed less than 52% acylation, but with the exception of C. hongkongensis and C. boreali-yunnanica. PCA and WMVCA indicated that the greater the amount of di-O-glycosides and acylation, the more primitive anthocyanin traits the species possess. Based on these results, in conjunction with geographical and literary information, the data suggest that the Xinan district is the site/center of origin for the red-flowered Camellia species of which both C. saluenensis and C. reticulata have the most primitive anthocyanin traits.


Bioscience, Biotechnology, and Biochemistry | 2007

Anthocyanins from Red Flowers of Camellia reticulata LINDL.

Jian-Bin Li; Fumio Hashimoto; Keiichi Shimizu; Yusuke Sakata

Ten anthocyanins, cyanidin 3-sambubioside, 3-glucoside and their acylated derivatives, cyanidin 3-lathyroside and cyanidin 3-galactoside, were isolated from red flowers of Camellia reticulata. Their structures were determined on the basis of spectroscopic analyses, and the chemotaxonomic distribution of the accumulated anthocyanins in the petals of wild Camellia reticulata and C. pitardii var. yunnanica is discussed.

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