All issues
Volume 45, Issue 10
Displaying 1-34 of 34 articles from this issue
- |<
- <
- 1
- >
- >|
-
Kuniharu UTSUNO, Masamichi TSUBOI1997 Volume 45 Issue 10 Pages 1551-1557
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe effect of drug binding on the geometry of DNA duplex (plasmid pBR322) has been examined using topoisomerase I relaxation followed by gel electrophoresis. The binding of one molecule of aclacinomycin A was found to cause an unwinding of the DNA double helix by an angle of 8±2°in aqueous solution at 37°C. The unwinding angle of daunomycin was 12±2°, and that of ethidium bromide 15±3°. To determine the unwinding angle, precise determination of the equilibrium constant of drug-DNA binding-dissociation reaction in the same buffer as that for the topoisomerase reaction (at 37°C) was indispensable. This determination was made by ultraviolet absorption measurement of the same plasmid-drug system, followed by a Scatchard plot and analysis using McGhee-von Hippel's excluded site model. For the aclacinomycin-pBR322 system, the binding constant (K) was 7.2×104M-1, and the number of base pairs in the single site of drug binding (n) was 4.0. For daunomycin-pBR322, K=7.1×104M-1 and n=3.4, and for ethidium-pBR322, K=4.0×104M-1 and n=3.3. On the basis of these experimental results, the possible role of the sugar moieties of these antitumour drugs, as well as that of intercalating chromophores, was discussed.View full abstractDownload PDF (1147K) -
Kiyoshi HORITA, Youji SAKURAI, Masaaki NAGASAWA, Osamu YONEMITSU1997 Volume 45 Issue 10 Pages 1558-1572
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo C27-C36 units of halichondrin B were synthesized starting from a C31-C34 alcohol, which was easily available from dimethyl L-tartrate, via construction of the F ring, methylation at the C31 position and C-glycosylation. These crucial reactions proceeded completely stereoselectively, and in particular the stereoselective C-glycosylation with allyltrimethylsilane took place only in the presence of both of two Lewis acids, boron trifluoride etherate and trimethylsilyl triflate.View full abstractDownload PDF (2365K) -
Tokunaru HORIE, Yoshizumi OHTSURU, Noriko MINAMIMOTO, Kazuyo YAMASHITA ...1997 Volume 45 Issue 10 Pages 1573-1578
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the demethylation of 6-hydroxy-3, 4', 7-trimethoxy-5-tosyloxyflavone (1) with anhydrous aluminum bromide (AlBr3) or anhydrous aluminum chloride-sodium iodide (AlCl3-NaI) in acetonitrile, the elimination of the 5-tosyloxy group proceeded after demethylation to give 8-bromo-3, 6, 7-trihydroxy-4'-methoxyflavone (6) or 3, 6, 7-trihydroxy-4'-methoxyflavone (5) as a main product. The demethylation of 6-hydroxy-4', 7-dimethoxy-5-tosyloxyflavone (2) with AlCl3-NaI also afforded 6, 7-dihydroxy-4'-methoxyflavone (12), but that with AlBr3 afforded 8-bromo-5, 6, 7-trihydroxy-4'-methoxyflavone (13) as a main product. The demethylation of 1 with anhydrous aluminum chloride (AlCl3) was accompanied by migration of the tosyl group to give a mixture of 3, 6-dihydroxy-7, 4'-dimethoxy-5-tosyloxyflavone (3) and 5-hydroxy-3, 4', 7-trimethoxy-6-tosyloxyflavone (9), but that of 2 proceeded after the cleavage of the 5-tosyloxy group to give a mixture of 5, 6-dihydroxy-7, 4'-dimethoxy- (14) and 5, 6, 7-trihydroxy-4'-methoxyflavones (15) other than the corresponding 6-tosyloxyflavone (16). In the demethylation of the acetates of 1 and 2 with AlCl3, the cleavage of the 5-tosyloxy group proceeded prior to the demethylation to afford the corresponding 5, 6, 7-trihydroxyflavones (8 and 15), although the demethylation of the former acetate was accompanied by formation of 3, 5, 7-trihydroxy-4'-methoxy-6-tosyloxyflavone (10). Mechanisms are proposed for these reactions.View full abstractDownload PDF (854K) -
Jyunichi KOYANAGI, Katsumi YAMAMOTO, Kouji NAKAYAMA, Akira TANAKA1997 Volume 45 Issue 10 Pages 1579-1581
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS2-Chloronaphtho[2, 3-b]furan-4, 9-dione (4) was allowed to react with sodium phenoxide to produce 2-phenoxynaphtho[2, 3-b]furan-4, 9-dione (8) in 55% yield. Also, in a similar manner, 8 was obtained from the reactions of 2-bromonaphtho[2, 3-b]furan-4, 9-dione (5), 2-iodonaphtho[2, 3-b]furan-4, 9-dione (6) and 2-nitronaphtho[2, 3-b]furan-4, 9-dione (7) with sodium phenoxide. The reaction of 4 with sodium methoxide gave methyl 3-hydroxy-1, 4-naphthoquinone-2-acetate (9) in which the furan ring was cleaved. 2-Phenylthionaphtho[2, 3-b]furan-4, 9-dione (11) and 2-methylthionaphtho[2, 3-b]furan-4, 9-dione (12) were obtained from the reactions of 4 with thiolates in 63% and 62% yields, respectively. Furthermore, 4 was treated with sodiomalonic ester ot give diethyl 2-(naphtho[2, 3-b]furan-4, 9-dione-2-yl)malonate (13) in 28% yield. Compound 13 was also obtained from the reactions of 5 and 7 with sodiomalonic ester. All these nucleophilic substitutions were carried out at room temperature. It was found that 4-7 had a high reactivity with various nucleophilic reagents.View full abstractDownload PDF (617K) -
Taisuke ITAYA, Yasutaka TAKADA, Tae KANAI, Miki KANEKO, Tozo FUJII1997 Volume 45 Issue 10 Pages 1582-1588
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS3-Alkyl-8-hydroxyadenines (5) have been shown to undergo regioselective methylation at the 7- or 9-position depending on the reaction conditions. Thus, treatment of 5a, c with dimetyl sulfate in aqueous NaOH provided 3-alkyl-7-methyl-8-oxoadenines (6b, h) in 48-60% yields, together with 3-alkyl-8-methoxyadenines 4d, h), whereas treatment of 5a-c with MeI in AcNMe2 at 40°C for 48h and subsequent anion exchange afforded 3-alkyl-9-methyl-8-oxoadenine hydrochlorides (7d, g, h·HCl) in 50-59% yieds. However, the reactions of 5a, c with EtI or PhCH2Br took place slowly, giving complex mixtures of products.Compounds 6d, h were alternatively prepared in 51% and 31% yields, respectively, together with 3-alkyl-7, 9-dimethyl-8-oxoadenine hydrochlorides (11d, h·HCl), by treatment of 3-alkyl-8-methoxyadenines (4d, h) with MeI in AcNMe2 at room temperature for 6 h, followed by hydrolysis with boiling aqueous HCl. This method was applicable to ethylation with EtI, and 7-ethyl-3-methyl-8-oxoadenine (6e) was obtained in 70% yield from 8-ethoxy-3-methyladenine (4e). Compound 11h was shown to be obtainable through futher methylation of 6h. Thus, 11d, h were prepared in good yields by treatment of 6d, h with MeI in AcNMe2.Compounds 7, to which zwitterionic structures were assigned, were stable in 0.1 N aqueous NaOH at room temperature, whereas 11d, h were no longer stable under such conditions.View full abstractDownload PDF (1233K) -
Koichi MACHIDA, Masao KIKUCHI1997 Volume 45 Issue 10 Pages 1589-1592
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFive new dammerane-type triterpenoids, viburnols A, B, C, D and E, were isolated from the leaves of Viburnum dilatatum THUNB. (Caprifoliaceae). The structures were determined by extensive spectroscopic studies. Viburnols A, B and C are the first examples of a new class of modified dammarane triterpene.View full abstractDownload PDF (656K) -
Toru IZUMI, Ayako NASU, Shigehiro KATAOKA, Shoichi TOKUTAKE, Akio OBAT ...1997 Volume 45 Issue 10 Pages 1593-1595
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSMinor components of isoflavones in soybeans, 7-(6-O-acetyl-β-D-glucopyranosyl)-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (6"-O-acetyldaidzin, 5) and 7-(6-O-acetyl-β-D-glucopyranosyl)-5-hydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (6"-O-acetylgenistin, 6), were efficiently prepared from 6"-O-malonyldaidzin (3) or 6"-O-malonylgenistin (4) by decarboxylation in N, N-dimethylformamide at 60°C in 46% or 57% yield, respectively. This reaction may explain the increase in the amount of the acetate during toasting of soybeans.View full abstractDownload PDF (526K) -
Takashi TANAKA, Akiko NISHIMURA, Isao KOUNO, Gen-ichiro NONAKA, Chong- ...1997 Volume 45 Issue 10 Pages 1596-1600
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new caffeic acid metabolites, named yunnaneic acids E-H were isolated from the root of Salvia yunnanensis. Their structures have been established on the basis of spectroscopic and chemical evidence. Yunnaneic acids E and F are biogenetically derived from yunnaneic acid C, which is a Diels-Alder adduct of rosmarinic acid and caffeic acid. On the other hand, yunnaneic acids G and H are arylnaphthalene-type lignan esters derived by oxidative coupling between two molecules of rosmarinic acid. The existence of these compounds indicates that caffeic acid metabolism in S. yunnanensis is more complex than that in S. miltiorrhiza.View full abstractDownload PDF (699K) -
Taisuke ITAYA, Tae KANAI, Mayumi SHIMADA, Toshiko NISHIKAWA, Yasutaka ...1997 Volume 45 Issue 10 Pages 1601-1607
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn alternative synthesis of 3, 9-dimethyl-8-oxoadenine (N6-demethylcaissarone) hydrochloride (5a·HCl) starting from 9-methyl-8-oxoadenine (17) is described. The synthesis proceeded through N(7)-benzylation, N(1)-oxidation, and O-benzylation to afford the 1-benzyloxy derivative 25, which afforded the ring-opened formamide derivative 26 on treatment with dilute aqueous NaOH. Methylation of the monocycle 26 with MeI in the presence of K2CO3, followed by acid-catalyzed cyclization and subsequent catalytic hydrogenolysis afforded 5a·HCl. The key intermediate 25 was alternatively prepared from 17 by N-oxidation and subsequent O, N(7)-dibenzylation with PhCH2Br in the presence of K2CO3.View full abstractDownload PDF (1208K) -
Kenji SHOJIMA, Yoko ARAI, Takahisa NAKANE, Hiroyuki AGETA, Shao-Qing C ...1997 Volume 45 Issue 10 Pages 1608-1610
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new triterpenoids, 4, 23-bisnor-3, 4-secofilic-5(24)-en-3-al(1), 4, 23-bisnor-3, 3-dimethoxy-3, 4-secofilic-5(24)-ene (2), 7β, 25-epoxyfern-9(11)-en-8α-ol (3) and 7α, 8α-epoxyfernan-25-ol (4) were isolated from the fresh leaves of Adiantum cuneatum, and their structures were elucidated by means of spectroscopic analysis.View full abstractDownload PDF (475K) -
Structural Elucidation of Glycosphingolipids by Collision-Induced Dissociation of Sodium Ion ComplexRyuichi ISOBE, Masanori INAGAKI, Yoichiro HARANO, Hiroshi SAKIYAMA, Ry ...1997 Volume 45 Issue 10 Pages 1611-1614
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSCollision-induced dissociation (CID) spectra of sodium ion complexed ([M+Na]+ ions) produced by FAB-MS of glycosphingolipids indicate the length of the fatty acyl chain of ceramide moieties without chemical degradation.View full abstractDownload PDF (491K) -
Motomasa KOBAYASHI, Taifo MAHMUD, Naoki YOSHIOKA, Hirotaka SHIBUYA, Is ...1997 Volume 45 Issue 10 Pages 1615-1619
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThrough bioassay-guided separation of the methanol extracts of Indonesian medicinal plants, three inhibitors of the Na+/H+ exchange system, erythrinin B (2), euchrenone b10 (3), and 1, 3, 5-trihydroxy-4-(3-methylbut-2-enyl)xanthen-9-one (4), were isolated from the bark of Erythrina variegata (Fabaceae)(for 2) and the roots of Maclura cochinchinensis (Moraceae)(for 2, 3, 4). Compounds 2, 3, and 4 significantly inhibited the Na+/H+ exchanges system of arterial smooth muscle cells, with minimum inhibitory concentrations of 1.25, 1.25, and 10μg/ml, respectively. Three new prenylated xanthones named isocudraniaxanthones B (5) and A (7) and isoalvaxanthone (9) were also isolated from M. cochinchinensis and the chemical structures were elucidated on the bases of their chemical and physicochemical properties.View full abstractDownload PDF (869K) -
Keizo MATSUO, Yusuke SAKAGUCHI1997 Volume 45 Issue 10 Pages 1620-1625
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS(-)-Vertinolide, a β-tetronic acid derivative isolated from Verticillium intertextum as one of the mycotoxins, was synthesized starting from (R)-lactic acid as the chiral source by using Seebach's chiral self-reproduction method. The β-tetronic acid moiety was constructed by reductive dehydroxylation of α, β-dihydroxybutanolide with samarium(II) iodide and subsequent oxdation.View full abstractDownload PDF (1012K) -
Yoshiyuki ONO, Hiroyoshi WATANABE, Ayako SHIRAISHI, Satoshi TAKEDA, Yo ...1997 Volume 45 Issue 10 Pages 1626-1630
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAnalogs related to 1α, 25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)(4), oxa-type and carba-type analogs of vitamin D3 bearing substituents at the 2β-position of 1α, 25-dihydroxyvitamin D3 (1), were synthesized from the α-epoxides (6 and 13). Three analogs, ED-71 (4) and two carba-type analogs (16 and 26), showed potent preventive effects on bone mineral loss in pre-osteoporosis model rats. ED-71 (4) was concluded to be an optimized analog and a promising candidate for the treatment of osteoporosis.View full abstractDownload PDF (841K) -
Yasuki YAMADA, Koji ANDO, Yukishige IKEMOTO, Hiroki TADA, Eiji SHIRAKA ...1997 Volume 45 Issue 10 Pages 1631-1641
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of renin inhibitors containing the (2S, 3S, 5S)-2-amino-1-cyclohexyl-6-methyl-3, 5-heptanediol (2-amino-3, 5-anti-diol) fragment as a novel transition-state mimic was synthesized, and their biological activities were evaluated. All of the synthesized compounds containing the 2-amino-3, 5-anti-diol fragment at the P1-P1' position showed high in vitro renin-inhibitory activity with IC50 values in the 10-8-10-10M range, and most of them caused a reduction of blood pressure when administered orally to salt-depleted, conscious marmosets. The inhibitor (29) with the 4-hydroxypiperidine residue at the P4 position showed the highest activity in terms of both potency and duration of the blood pressure-lowering effect.View full abstractDownload PDF (1533K) -
Yoshinori IKEURA, Toshimasa TANAKA, Yutaka KIYOTA, Shinji MORIMOTO, Ma ...1997 Volume 45 Issue 10 Pages 1642-1652
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSVarious N-[3, 5-bis(trifluoromethyl)benzyl]-N-methylcarbamoyl heterocycles (1, 2 and 3) modified at rings A and B in the isoquinolone (1a) and pyrido[3, 4-b]pyridine (2a) nuclei were prepared and evaluated for NK1 receptor antagonistic activities. The structure-activity relationship studies on this series, along with conformational analysis, showed that (i) for ring A, 6-membered heterocycles are preferable to 5-membered heterocycles (a ca. 300-fold difference in potency), (ii) the 6-membered ring seems to function as an anchor by fixing the pendant phenyl group in a desirable orientation for receptor binding, and (iii) since compounds with aromatic rings (2) and those with aliphatic rings (3) as ring B both show good potency, this ring does not seem to be essential for receptor recognition. Among the compounds synthesized, the tetrahydropyridine derivatives 3a, 3b and 3f exhibited excellent inhibitory effects both in vitro and in vivo, with potent activity upon oral administration (ED50=0.20-0.27 mg/kg)(capsaicin-induced plasma extravasation in guinea pig trachea).View full abstractDownload PDF (1590K) -
Chisako YAMAGAMI, Kaname IWASAKI, Ayako ISHIKAWA1997 Volume 45 Issue 10 Pages 1653-1658
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPartition coefficients (P) of pyrazine and its COOMe derivative (strong hydrogen bond acceptor), were measured for the octane/aqueous methanol partitioning system (PO/M-W) at different methanol (MeOH) concentrations and the dependence of log PO/M-W on the methanol concentration was compared to the corresponding change in log k' (k' : capacity factor) obtained by reversed-phase liquid chromatography with aqueous methanol. Next, in order to make the chromatographic system approximate more closely to the octanol/water partitioning system, a small quantity of octanol was added to the eluents and also to the octane/aqueous methanol partitioning system and further comparisons were made. It was found that the octanol effect was minimum at 50% MeOH, suggesting that the chromatographic system with eluents containing about 50% MeOH has properties more similar to the octanol/water partitioning system than with eluents of other compositions. This confirms our previous result that the log k' parameter obtained at 50% MeOH yields a better correlation with log Poct (Poct : octanol/water partition coefficient) than those obtained at other mobile phase compositions in the range from 5 to 70% MeOH.View full abstractDownload PDF (858K) -
Hitoshi NAGAOKA, Hiromu HARA, Takeshi SUZUKI, Takumi TAKAHASHI, Makoto ...1997 Volume 45 Issue 10 Pages 1659-1664
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn a search for novel platelet-activating factor (PAF) antagonists, we found that 1-(3-phenylpropyl)-4-[2-(3-pyridyl)thiazolidine-4-carboyl]piperazine (3%) showed in vitro and in vivo PAF-antagonistic activities. Introduction of functional groups at the benzylic methylene carbon of 3x afforded some compounds with more potent PAF-antagonistic activity than 3x. Among them 1-(3-methyl-3-phenylbutyl)-4-[2-(3-pyridyl)thiazolidine-4-carbonyl]-piperazine fumarate (3al, YM264) was found to be one of the most potent PAF antagonists.View full abstractDownload PDF (868K) -
Yasuhiro NODA, Toyo KAIYA, Kohfuku KOHDA, Yutaka KAWAZOE1997 Volume 45 Issue 10 Pages 1665-1670
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSeveral triterpenes were tested for cytotoxicity by our contrived primary screening method using resting or dormant leukemia L1210 cells after 3 d-preculture without medium change. Some triterpenes were found to be more cytotoxic toward the 3 d-precultured resting cells than toward the growing cells in a fresh medium. These triterpenes are distinguished by highly selective cytotoxicity toward the starved resting cells unlike common anticancer agents. The highest selectivity was shown by betulinic acid, the ratio of its IC50 values toward the growing versus resting cells amounting to 175. It is suggested that this selective cytotoxicity is attributable to low pH (≤6.8) of the medium. It is noteworthy that betulinic acid is not cytotoxic at all in media of ordinary pH (≥7.0) even after a 48-h exposure. Betulinic acid might be promising as an antitumor agent toward solid tumors because the interior pH of tumor tissues is generally lower than in normal tissues.View full abstractDownload PDF (804K) -
Masayuki YOSHIKAWA, Toshiyuki MURAKAMI, Masashi KADOYA, Yuhao LI, Nobu ...1997 Volume 45 Issue 10 Pages 1671-1676
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAlthough the glycosidic fraction from the dried leaves of Gymnema sylvestre R. BR., gymnemic acid, was reported to be effective for diabetes, it showed little inhibitory activity on the increase of serum glucose level in oral glucose-loaded rats. From the glycosidic fraction, six triterpene glycosides, gymnemosides a, b, c, d, e, and f, were isolated tohether with nine known triterpene glycosides. The structures of gymnemosides a and b were determined on the basis of chemical and physicochemical evidence as 21-O-tigloyl-22-O-acetylgymnemagenin 3-O-β-D-glucopyranosiduronic acid and 16-O-acetyl-21-O-tigloylgymnemagenin 3-O-β-D-glucopyranosiduronic acid, respectively. In addition, an acetyl group linked to the 16- or 22-hydroxyl group in gymnemosides a and b was found to migrate easily to the primary 28-hydroxyl group, while the acyl migration from the 28-position was rarely observed.The inhibitory activity of each trierpene glycoside from gymnemic acid was examined to determine its impact on the increase of serum glucose level in oral glucose-loaded rats. Gymnemoside b and gumnemic acids III, V, and VII were found to exhibit a little inhibitory activity against glucose absorption, but the principal constituents, gymnemic acid I and gymnemasaponin V, lacked this activity.View full abstractDownload PDF (911K) -
Koichi YAJIMA, Akira OKAHIRA, Masanori HOSHINO1997 Volume 45 Issue 10 Pages 1677-1682
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe transformation of monohydrate, dihydrate, two polymorphic forms (A and B) of anhydrate and the amorphous form of lactitol [(+)-4-O-β-D-galactopyranosyl-D-glucitol] were investigated by infrared spectrum, differential scanning calorimetry and X-ray powder diffraction. Monohydrate and dihydrate were transformed to anhydrate A and anhydrate B after storage at 80°C for 24 h under reduced pressure, respectively, but both hydrates changed to anhydrate A after being at 105°C for 3d. Five solid forms were stored under the relative humidity (RH) range from 12 to 93% at 25°C for 14 d. Monohydrate was transformed into dihydrate at RH more than 90%, but no change was observed in the range from 12 to 84% RH. Dihydrate did not show any transformation in the experimental RH range, though weight increase and decrease were observed at 12 and 93% RH, respectively. Both anhydrate A and B, however, were changed to monohydrate but this transformation occurred under different RH conditions (anhydrate A : 22% RH, anhydrate B : 75% RH). The amorphous form was transformed into monohydrate and dihydrate in the RH range from 53 to 84% and at 90% RH, respectively. The effect of grinding on the thermal behavior of the two hydrates was investigated, dehydration temperatures of monohydrate, which was determined by controlled rate thermogravimetry, was about 15°C lower than the intact monohydrate. However, no change in dehydration temperature was observed for dihydrate. These results suggest that the influence of grinding on thermal behavior was different for the two hydrates.View full abstractDownload PDF (804K) -
Kunikazu MORIBE, Kazuo MARUYAMA, Motoharu IWATSURU1997 Volume 45 Issue 10 Pages 1683-1687
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPoly(ehylent glycol)-coated liposomes (PEG-liposomes) were prepared from distearoylphosphatidylcholine (DSPC)/cholesterol (Ch)(1 : 1, molar ratio) with various amounts of distearoyl-N-(monomethoxy poly(ethylene glycol)succinyl)phosphatidylethanolamine (DSPE-PEG). Surface potentials of PEG-liposomes showed negative values, however, the zeta potentials were almost neutral under physiological conditions (150 mM NaCl). Taking these electrical surface properties into consideration, a non-charge-sensitive phase system consisting of 5% PEG8000 and 5% dextran T-500, 0.01 M sodium phosphate, 0.15 M sodium chloride (pH 7.0) was used to estimate the alteration of surface state of PEG-liposomes after interaction with plasma in vitro and in vivo. PEG-liposomes showed increased partitioning to the PEG phase with increasing amount of DSPE-PEG. One hundred percent partitioning to the PEG phase was obtained when 2 or 1 mol% DSPE-PEG1K or 2K was incorporated into the liposomes, respectively. This PEG/lipid ratio (mol/mol) thus afforded complete protection of the liposomal surface by the PEG moiety. When these PEG-liposomes were incubated with plasma protein (in vitro) or were recovered from liposome-injected mice (in vivo), they showed decreased partitioning to the PEG phase. However, when the in vivo-treated PEG-liposomes were purified by column chromatography and ultracentrifugation, their partitioning to the PEG phase was restored to that of PEG-liposomes incubated in phosphate-buffered saline. Thus although PEG acts as a steric barrier against the attachment of plasma protein to the liposome surface and slows down liposome clearance from the circulation in vivo, a weak interaction remains between PEG-liposome and plasma protein when the incorporated amount of DSPE-PEG is low.View full abstractDownload PDF (864K) -
Hideshi SUZUKI, Hisakazu SUNADA1997 Volume 45 Issue 10 Pages 1688-1693
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe most prevalent means for producing solid dispersions of nifedipine, a poorly water-soluble drug, are the solvent based processes that bring problems of environmental and health. We have investigated the preparation of solid dispersions of nifedipine (mp 173°C) by the fusion method, using nicotinamide, ethylurea, polyethylene glycol (PEG) 6000 and hydroxypropylmethylcellulose (HPMC) as carriers. All these solid dispersions were obtained by cooling at room temperature after heating at 140°C for 15 min. As a single carrier, nicotinamide, ethylurea and PEG were used because nifedipine dissolved in their fused liquids. Compared with the physical mixtures, the solid dispersions with ethylurea or PEG led to a higher dissolution rate of the drug, whereas the difference in drug release between the physical mixtures and the solid dispersions with nicotinamide was not clear. This peculiarity might be due to the high solubilizing effect of nicotinamide for the drug. The fused mixtures of nicotinamide-, ethylurea- or PEG-HPMC were utilized as combined carriers. HPMC dissolved in the fused liquids of nicotinamide or ethylurea, which was effective in forming the amorphous nifedipine in solid dispersions. This resulted in not only the enhanced dissolution rate but also the supersaturation behavior of nifedipine. Further, for the nicotinamide-HPMC system, the supersaturation level of nifedipine increased with an increase in the HPMC content of solid dispersions. Nicotinamide was more applicable than ethylurea and PEG for preparation of the fused dispersions of nifedipine.View full abstractDownload PDF (964K) -
Mikiko OOIKE, Koohei NOZAWA, Shun-ichi UDAGAWA, Ken-ichi KAWAI1997 Volume 45 Issue 10 Pages 1694-1696
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new typw of indoloditerpene, petromindole (1), and a new asterriquinone derivative, PM-53 (2), were isolated from the ascostromata of Petromyces muricatus, along with bisindolylbenzenoids, petromurins A (3)-D (6). The structure of 1 was suggested by spectroscopic data and confirmed by an X-ray crystallographic analysis, while that of 2 was determined by analyses of the various NMR spectra.View full abstractDownload PDF (535K) -
Yoshiyasu KITAHARA, Masanori NAGATSU, Yoshikazu SHIBANO, Akinori KUBO1997 Volume 45 Issue 10 Pages 1697-1701
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS4-Phenyl-5, 8-quinolinediones (7, 8, 12, 13), 4-phenyl-5, 6-quinolinediones (9, 14), and 2-dialkylamino-4-phenyl-5, 8-quinolinediones (17, 18), were synthesized by oxidative demethylation of the corresponding 5, 8-dimethoxy- or 5, 6, 8-trimethoxy-4-phenylquinolines with cerium(IV) ammonium nitrate. Sulfur-containing quinolinequinones (21, 24) were prepared by oxidation of the corresponding 5, 8-dimethoxy- or 5, 6, 8-trimethoxy-2(1H)-quinolinethiones (20, 23).View full abstractDownload PDF (741K) -
Ryuichiro TANAKA, Hiroaki ISHIZAKI, Satoshi KAWANO, Hitohiro OKUDA, Ka ...1997 Volume 45 Issue 10 Pages 1702-1704
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFruiting-inducing activity and antifungal properties of lipid components in the phylum Annelida were examined. Some amphoteric cerebrosides carrying a phosphocholine group showed fruiting-inducing activity on Schizophyllum commune, and one of them possessed activity comparable to that of Sch II, the most potent substance known. Furthermore, alkyl lysophosphatidylcholines were found to have an inhibitory effect on the growth of phytopathogenic fungi, Alternaria kikuchiana and Phomopsis mali. The relationship between structure and biological activities is discussed.View full abstractDownload PDF (540K) -
Daisuke TANIYAMA, Motomu KANAI, Akira IIDA, Kiyoshi TOMIOKA1997 Volume 45 Issue 10 Pages 1705-1707
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reaction of N, N"-bis(4-methoxyphenyl)ethylenediimine with phenyllithium, with the mediation of a chiral ligand, provided the addition products, (1R, 2R)-N, N"-bis(4-methoxyphenyl)-1, 2-diphenylethanediamine of 67% ee and the meso-product, in a ratio of 41 : 59. The net reaction involves sequential double additions of phenyllithium. In the first addition a new chiral center is created, but with rather poor selectivity, and in the second addition kinetic discrimination takes place, giving the chiral double addition product.View full abstractDownload PDF (578K) -
Keiichi SUTO, Shinichi KAKINUMA, Yuji ITO, Kazuhiko SAGARA, Hideki IWA ...1997 Volume 45 Issue 10 Pages 1708-1710
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIon-pair reagents and reversed micelles in supercritical carbon dioxide (SF-CO2) were tested as polar mobile phases for supercritical fluid chromatography (SFC). Dioctylsulphosuccinate sodium salt (DSS) was used as the counter-ion in ion-pair supercritical fluid chromatography (IP-SFC) with a packed silica-gel column. DSS/pentane reversed micelles were used in reversed micelle supercritical fluid chromatography (RM-SFC) with a packed fluoroalkyl silica-gel column. IP-SFC and RM-SFC using DSS was demonstrated for analytical separation of ephedrine alkaloids.View full abstractDownload PDF (481K) -
Yoshihiro SAITO, Kazunobu YOSHIHARA, Izumi TANEMURA, Haruhisa UEDA, Ta ...1997 Volume 45 Issue 10 Pages 1711-1713
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe stability constants for the inclusion of benzene and alkylbenzenes with α-cyclodextrin (α-CyD) in aqueous solution have been determined using static head-space gas chromatography (SHSGC). The 1 : 1 and 2 : 1 (host : guest) stability constants obtained by this method were in reasonable agreement with the corresponding values in the literature. Therefore, it was concluded that the SHSGC method is useful for determining the stability constant of the volatile compound/CyD complex.View full abstractDownload PDF (451K) -
Hidemitsu HARA, Naoki MARUYAMA, Shinsuke YAMASHITA, Yasuhisa HAYASHI, ...1997 Volume 45 Issue 10 Pages 1714-1716
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel new naphthoquinone called elecanacin (9) and a new naphthalene called isoeleutherol (10) were isolated from the bulb of Eleutherine americana MERR. et HEYNE (Iridaceae), together with two known naphthoquinones (2 and 3). The structures were determined by spectroscopic methods including the 2D-NMR techniques. Eleutherin (2) showed interesting inhibitory activity against human topoisomerase II, and isoeleutherin (3) and isoeleutherol (10) showed inhibitory activity against HIV.View full abstractDownload PDF (462K) -
Nobuo KAWAHARA, Masato NOZAWA, Diana FLORES, Pablo BONILLA, Setsuko SE ...1997 Volume 45 Issue 10 Pages 1717-1719
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe structure of a novel sesterterpenoid designated as nitidasin (1), isolated from the whole plant of Gentianella nitida, has been determined by extensive spectroscopic investigation and X-ray analysis.View full abstractDownload PDF (434K) -
Hideyuki ITO, Takashi MURANAKA, Kazuko MORI, Zhe Xiong JIN, Takashi YO ...1997 Volume 45 Issue 10 Pages 1720-1722
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe structures of dryofragin (5), a novel sesquiterpenoid connecting acylated filicinic acid, and a new aspidin analogue isolated as piscicidal components from the whole plant of Dryopteris fragrans have been elucidated by extensive spectroscopic analysis.View full abstractDownload PDF (459K) -
Takashi HARAYAMA, Toshihiko AKIYAMA, Yuichiro NAKANO1997 Volume 45 Issue 10 Pages 1723-1725
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel Pd reagent prepared from equimolar Pd(OAc)2, DPPP, and Bu3P (method B) was useful for the internal biaryl coupling reaction of not only triflate-amide but also halo-amide.View full abstractDownload PDF (480K) -
Takao IKAMI, Noboru TOMIYA, Takashi MORIMOTO, Noriyuki IWATA, Takahito ...1997 Volume 45 Issue 10 Pages 1726-1728
Published: October 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNovel sulfated and phosphorylated β-D-galactopyranoside dimers containing fatty-alkyl residues in place of ceramide have been synthesized. The synthetic glycolipids showed an interesting inhibition of the binding of HL-60 cells to immobilized P-, L-, and E-selectins in in vitro experiments. These glycolipids may be useful as effective therapeutic agents against selectin-dependent inflammation.View full abstractDownload PDF (446K)
- |<
- <
- 1
- >
- >|