- Characterization of caffeoylglucoside derivatives and hypouricemic activity of the ethyl acetate fraction from Aster glehni
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In the search for xanthine oxidase (XOD) inhibitors as anti-gout agents from natural products, various chromatographic separations of the ethyl acetate-soluble fraction of Aster glehni (AGEF) led to the isolation of five new caffeoylglucoside derivatives, namely 6′-O-caffeoyl-(6S,9R)-roseoside (1), 6′-O-caffeoylampelopsisionoside (2), 6′-O-caffeoylsonchuinoside C (3), 6′-O-caffeoyldihydrosyringin (4), and (2E)-2-methyl-but-2-ene-1,4-diol-6′-O-caffeoyl-1-O-β-glucopyranoside (glehnoside, 5), together with 13 known compounds. The absolute stereochemistry of the 6′-O-caffeoylsonchuinoside C (3) was established with the help of spectroscopic analyses, enzymatic hydrolysis, and Mosher's method, as well as in comparison with literature data. All isolated substances were determined for their inhibitory activities on uric acid production by the xanthine/XOD system. Among them, 4,5-O-dicaffeoylquinic acid methyl ester (12) showed the most potent inhibitory activity with an IC50 value of 2.6 ± 0.1 μM, which was comparable to that of allopurinol used as a positive control. Furthermore, hypouricemic effects of AGEF were assessed by measuring serum uric acid levels 3 h after potassium oxonate treatment (250 mg/kg, i.p.) to induce hyperuricemia in rats. When preadministered orally once a day at doses of 50, 100, and 300 mg/kg for 7 days, AGEF reduced the potassium oxonate-induced elevated serum uric acid level by 15.4, 39.8, and 32.3%, respectively. The results suggest that AGEF has the potential to be a new source of agents for the prevention and/or treatment of hyperuricemia and gout.
- Son, Min Jeoung,Jin, Changbae,Lee, Yong Sup,Lee, Jae Yeol,Kim, Hyoung Ja
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- Synthesis of optically active vomifoliol and roseoside stereoisomers
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A synthesis of optically active vomifoliol stereoisomers 1-4 and their glucosides, roseoside stereoisomers 5-8, was accomplished via α-acetylenic alcohol 11a or 11b effectively prepared by an asymmetric transfer hydrogenation of α,β-acetylenic ketone 10. Simultaneous separation of these stereoisomers by HPLC was also perfomed.
- Yamano, Yumiko,Ito, Masayoshi
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p. 541 - 546
(2007/10/03)
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- Megastigmane glycosides from seeds of Trifolium alexandrinum
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Five megastigmane glycosides have been isolated from the seeds of Trifolium alexandrinum L., of which two are known compounds, while three are new compounds showing the presence of apiofuranosyl-(1→2)-glucopyranosyl residue as a sugar moiety. The structures of the isolated compounds were established on the basis of NMR and mass spectral data.
- Mohamed, Khaled M.,Mohamed, Mahmoud H.,Ohtani, Kazuhiro,Kasai, Ryoji,Yamasaki, Kazuo
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p. 859 - 862
(2007/10/03)
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- Novel synthesis of degradation products of carotenoids, megastigmatrienone analogues and blumenol-A
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Synthesis of 4-alkylidene-3,5,5-trimethylcyclohex-2-enones 7 has been achieved utilising 1,4-conjugate dehydrobromination of allylic bromides 5 as a key step. This chemical transformation is applied to the synthesis of degradation products of carotenoids: megastigmatrienones 7e/1-4,4-methylene-3,5,5-trimethylcyclohex-2-enone 7a, 4-(3-hydroxybutylidene)-3,5,5-trimethylcyclohex-2-enone 9,1,3,7,7-tetramethyl-2-oxabicyclo[4.4.0]dec-5-en-9-one 10a-b and 3,4,7,8-tetrahydro-4,4,7-trimethylnaphthalen-2(6H)-one 15. A novel photoisomerisation of 4-[(Z)-3-acetoxybut-2-enyl]-4-hydroxy-3,5,5-trimethylcyclohex-2-enone 19 to 4-[(E)-3-acetoxybut-2-enyl]-4-hydroxy-3,5,5-trimethylcyclohex-2-enone 20 enables us to synthesise blumenol-A 21.
- Ito, Nobuhiko,Etoh, Takeaki,Hagiwara, Hisahiro,Kato, Michiharu
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p. 1571 - 1579
(2007/10/03)
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- Medicinal foodstuffs. V. Moroheiya. (1): Absolute stereostructures of corchoionosides A, B, and C, histamine release inhibitors from the leaves of Vietnamese Corchorus olitorius L. (Tiliaceae)
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Three new ionone glucosides named corchoionosides A, B, and C were isolated from the leaves of Corchorus olitorius, commonly called 'moroheiya' in Japanese, together with seven known compounds, an ionone glucoside (6S,9R)-roseoside, a monoterpene glucosid
- Yoshikawa, Masayuki,Shimada, Hiromi,Saka, Masami,Yoshizumi, Satoshi,Yamahara, Johji,Matsuda, Hisashi
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p. 464 - 469
(2007/10/03)
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- Norisoprenoids in Vitis vinifera White Wine Grapes and the Identification of a Precursor of Damascenone in These Fruits
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Twenty-four norisoprenoids, which are either free volatile components of juices of Vitis vinifera cvv.Chardonnay, Semillon and Sauvignon Blanc, or are liberated by glycosidase enzyme, or acid hydrolysis of extracts of these juices, have been identified.Eleven of these norisoprenoids are reported as grape products for the first time.The hypothetical 7-oxomegastigmane precursors, grasshopper ketone (5) and megastigm-5-en-7-yne-3,9-diol (10), as well as the related allene, 9-hydroxymegastigma-4,6,7-trien-3-one (6), have been observed for the first time, cooccurring with damascenone (1), 3-hydroxy-β-damascone (2), 3-oxo-β-damascone (3) and 3-oxo-α-damascone (4).Hydrolytic studies have shown that megastigm-5-en-7-yne-3,9-diol (10) is a precursor of damascenone (1) and 3-hydroxy-β-damascone (2) during wine conservation.
- Sefton, Mark A.,Skouroumounis, George K.,Massy-Westropp, Ralph A.,Williams, Patrick J.
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p. 2071 - 2084
(2007/10/02)
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- METABOLISM OF ABSCISIC ACID: BACTERIAL CONVERSION TO DEHYDROVOMIFOLIOL AND VOMIFOLIOL DEHYDROGENASE ACTIVITY
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A species of Corynebacterium, capable of metabolizing abscisic acid (ABA), was isolated from soil.The organism converted ABA to dehydrovomifoliol as the major metabolite.A cell-free extract exhibited vomifoliol dehydrog
- Hasegawa, Shin,Poling, Stephen M.,Maier, V. P.,Bennett, Raymond D.
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p. 2769 - 2772
(2007/10/02)
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