- Identification of key structural characteristics of schisandra chinensis lignans involved in P-glycoprotein inhibition
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The aim of the present study was to determine the structural requirements for dibenzocyclooctadiene lignans essential for P-glycoprotein inhibition. Altogether 15 structurally related lignans isolated from Schisandra chinensis or prepared by modification of their backbone were investigated, including three pairs of enantiomers. P-Glycoprotein inhibition was quantified using a doxorubicin accumulation assay in human promyelotic leukemia HL60/MDR cells overexpressing P-glycoprotein. A preliminary quantitative structure-activity relationship analysis revealed three main structural features involved in P-glycoprotein inhibition: a 1,2,3-trimethoxy moiety, a 6-acyloxy group, and the absence of a 7-hydroxy group. The most effective inhibitors, (-)-gomisin N (1) and (+)-deoxyschizandrin [(+)-2], were selected for further evaluation of their effects. Both these lignans restored the cytotoxic effect of doxorubicin in HL60/MDR cells and when combined with a subtoxic concentration of this compound increased the proportion of G2/M cells significantly, which is a usual response to treatment with this anticancer drug.
- Slanina, Jii,Pachnikova, Gabriela,arnecka, Martina,Porubova Koubikova, Ludmila,Adamkova, Lenka,Humpa, Otakar,mejkal, Karel,Slaninova, Iva
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- Biotransformation of isofraxetin-6-O-β-D-glucopyranoside by Angelica sinensis (Oliv.) Diels callus
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Isofraxetin-6-O-β-D-glucopyranoside, identified from traditional medicinal herbal Xanthoceras sorbifolia Bunge, has been demonstrated to be a natural neuroinflammatory inhibitor. In order to obtain more derivatives with potential anti-neuroinflammatory effects, biotransformation was carried out. According to the characteristics of coumarin skeleton, suspension cultures of Angelica sinensis (Oliv.) Diels callus (A. sinensis callus) were employed because of the presence of diverse phenylpropanoids biosynthetic enzymes. As a result, 15 products were yielded from the suspension cultures, including a new coumarin: 8′-dehydroxymethyl cleomiscosin A (1), together with 14 known compounds. Their structures were elucidated by extensive spectroscopic analysis. Furthermore, the biotransformed pathways were discussed. Among them, compound 13 was transformed from isofraxetin-6-O-β-D-glucopyranoside, while compounds 1–6, 10–12, 14–15 were derived from the culture medium stimulated by the substrate. The biotransformation processes include hydroxylation, oxidation and esterification. Furthermore, their inhibitory effects on lipopolysaccharide (LPS)-activated nitric oxide (NO) production were evaluated in BV2 microglial cells. It is worth noting that, 1, 1′-methanediylbis(4-methoxybenzene) (3), obtucarbamates A (5), 2-nonyl-4-hydroxyquinoline N-oxide (10) and 1H-indole-3-carbaldehyde (11) exhibited significant inhibitory effect against neuroinflammation with IC50values at 1.22, 10.57, 1.02 and 0.76?μM respectively, much stronger than that of the positive control minocycline (IC5035.82?μM).
- Zhou, Di,Zhang, Yuhua,Jiang, Zhe,Hou, Yue,Jiao, Kun,Yan, Chunyan,Li, Ning
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p. 248 - 253
(2016/12/27)
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- Structure-activity relationships of lignans from Schisandra chinensis as platelet activating factor antagonists
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We studied the structure-activity relationships of lignans from Schisandra chinensis and their derivatives as platelet activating factor (PAF) antagonists. Strong activity was shown in lignans without an ester group at C-6, a hydroxyl group at C-7 or a methylene dioxy moiety and with an R-biphenyl configuration. 6(7)-Dehydroschisandrol A, a derivative of schisandrol A, showed the highest activity (IC50, 2.1 x 10-6 M) in this study.
- Lee, Im Seon,Jung, Keun Young,Oh, Sei Ryang,Park, Si Hyung,Ahn, Kyung Seop,Lee, Hyeong-Kyu
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p. 265 - 267
(2007/10/03)
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- Total Syntheses of the Lignans Isolated from Schisandra Chinensis
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The total syntheses of wuweizisu C (4), gomisin J (6), gomisin N (7), and γ-schizandrin (8) having natural configuration were accomplished in a stereoselective manner.The catalytic hydrogenation or the metal mediated 1,4-reduction of the tetracyclic lactones (12, 17, 22, 30) played the significant role for the stereoselective introduction of C6, C7 dimethyl moiety.Furthermore, the neighboring carbonyl group assisted regioselective demethylation of 5 was essential for the synthesis of 6.
- Tanaka, Masahide,Ohshima, Toshihiro,Mitsuhashi, Hiroshi,Maruno, Masao,Wakamatsu, Takeshi
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p. 11693 - 11702
(2007/10/02)
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- THE FIRST TOTAL SYNTHESIS OF γ-SCHIZANDRIN AND GOMISIN N HAVING NATURAL CONFIGURATIONS
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The total syntheses of γ-schizandrin and gomisin N were achieved in a stereoselective manner.The success of these synthesis heavily depends on the stereoselective reduction of tetracyclic lactones with magnesium in methanol.
- Tanaka, Masahide,Ohshima, Toshihiro,Mitsuhashi, Hiroshi,Maruno, Masao,Wakamatsu, Takeshi
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p. 739 - 742
(2007/10/02)
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