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Kurt Hostettmann - One of the best experts on this subject based on the ideXlab platform.
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ent Labdane glycosides from the aquatic plant potamogeton lucens and analytical evaluation of the lipophilic extract constituents of various potamogeton species
Phytochemistry, 2004Co-Authors: Patrice Waridel, Jean-luc Wolfender, Jean-bernard Lachavanne, Kurt HostettmannAbstract:Abstract Two new ent -Labdane glycosides, one known furano- ent -Labdane and a new hydroxylated fatty acid were isolated from the dichloromethane extract of the freshwater aquatic plant Potamogeton lucens. The new compounds were assigned the structures of β- d -glucopyranosyl-8(17),13 -ent -labdadien-16,15-olid-18-oate, 18-β- d -glucopyranosyloxy-8(17),13 -ent -labdadien-16,15-olide and 13( R )-hydroxy-octadeca-(9 Z ,11 E ,15 Z )-trien-oic acid by spectroscopic means. The algicidal activity of these compounds was tested against Raphidocelis subcapitata . Based on our previous study of Potamogeton pectinatus , other constituents were identified in P. lucens by LC–UV–MS, LC–NMR and GC–MS. The lipophilic extract profiles of both species are presented. Two other species, Potamogeton perfoliatus and P. crispus, were also investigated by analytical comparison of their non-polar extracts. The distribution of ent -Labdanes characterized in Potamogeton is summarized.
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ent Labdane diterpenes from the aquatic plant potamogeton pectinatus
Phytochemistry, 2003Co-Authors: Patrice Waridel, Jean-luc Wolfender, Jean-bernard Lachavanne, Kurt HostettmannAbstract:Four new ent-Labdane diterpenes were isolated from the freshwater aquatic plant Potamogeton pectinatus, together with two known furano-ent-Labdanes. The new compounds were assigned the structures methyl-15,16-epoxy-12(R)-acetoxy- 8(17),13(16),14-ent-labdatrien-19-oate, 15,16-epoxy-12(R)-acetoxy-8(17),13(16),14-ent-labdatrien-19-oic acid, 8(17),13-ent-labdadien-15 --> 16-lactone-19-oic acid and 16-hydroxy-8(17),13-ent-labdadien-15,16-olid-19-oic acid by spectroscopic means. Some of these Labdanes showed a strong algicidal activity against Raphidocelis subcapitata. (C) 2003 Elsevier Ltd. All rights reserved.
Christina L. L. Chai - One of the best experts on this subject based on the ideXlab platform.
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the identification of naturally occurring Labdane diterpenoid calcaratarin d as a potential anti inflammatory agent
European Journal of Medicinal Chemistry, 2019Co-Authors: Quy T N Tran, W Fred S Wong, Christina L. L. ChaiAbstract:Abstract In this study we report, for the first time, the synthesis of the natural product calcaratarin D via a stereo- and regio-selective aldol condensation with (S)-β-hydroxy-γ-butyrolactone as key steps. A concise synthetic route (under 10 steps) to a series of structurally related normal-Labdane diterpenes was also developed and their anti-inflammatory activities were evaluated in an in vitro model of inflammation. The structure-activity relationships (SARs) pertaining to the Labdane scaffold were elucidated and results suggest that an α-alkylidene-β-hydroxy-γ-butyrolactone system is necessary for potent activity in the Labdanes. Our studies identified the natural product calcaratarin D (1) as a promising anti-inflammatory agent, which effectively modulates the production of pro-inflammatory mediators (e.g., TNF-α, IL-6, NO) at both transcriptional and translational levels. These inhibitory effects are likely to occur via the suppression of nuclear factor kappa B (NF-κB) activation by reducing the p65 nuclear translocation but not its phosphorylation or protein expression. Calcaratarin D exhibited significantly greater inhibition of NF-κB activation than andrographolide, a well-known NF-κB inhibitor from the Labdane family, suggesting that a normal-configuration Labdane ring or the absence of hydroxyl groups at C-3 and C-19 positions is favorable for potent NF-κB inhibition. We further investigated the effects of calcaratarin D on the upstream signalling pathways and found that the compound selectively suppressed the LPS-induced activation of PI3K/Akt pathway without affecting much of the MAPK (i.e., ERK, JNK, and p38) activation. These findings demonstrate that calcaratarin D exerts its anti-inflammatory effects via a selective Akt-NF-κB-mediated mechanism and potentially offers a new therapeutic strategy for the management of inflammatory diseases.
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Labdane diterpenoids as potential anti-inflammatory agents.
Pharmacological Research, 2017Co-Authors: Quy T N Tran, W.s. Fred Wong, Christina L. L. ChaiAbstract:Abstract The search for new anti-inflammatory agents is challenging due to the complexity of the inflammatory process and its role in host defense. Over the past few decades, a significant body of evidence has emerged, supporting the prominent role of Labdane diterpenoids in therapeutic interventions of various inflammatory diseases. The anti-inflammatory activity of Labdane diterpenoids has been attributed mainly to the inhibition of nuclear factor-κB (NF-κB) activity, the modulation of arachidonic acid (AA) metabolism and the reduction of nitric oxide (NO) production. This article provides extensive coverage of naturally occurring Labdane diterpenes, discovered between 1981 and 2016, which have been verified as NF-κB, NO, or AA modulators. Herein, we also discuss the role of Michael acceptor, a common structural feature present in most of the active Labdane diterpenes, and its association with NF-κB signaling inhibition. In the cases where a sufficient amount of data exists, structure-activity relationship (SAR) studies and clinical studies performed on the anti-inflammatory Labdane diterpenoids are also discussed.
Patrice Waridel - One of the best experts on this subject based on the ideXlab platform.
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ent Labdane glycosides from the aquatic plant potamogeton lucens and analytical evaluation of the lipophilic extract constituents of various potamogeton species
Phytochemistry, 2004Co-Authors: Patrice Waridel, Jean-luc Wolfender, Jean-bernard Lachavanne, Kurt HostettmannAbstract:Abstract Two new ent -Labdane glycosides, one known furano- ent -Labdane and a new hydroxylated fatty acid were isolated from the dichloromethane extract of the freshwater aquatic plant Potamogeton lucens. The new compounds were assigned the structures of β- d -glucopyranosyl-8(17),13 -ent -labdadien-16,15-olid-18-oate, 18-β- d -glucopyranosyloxy-8(17),13 -ent -labdadien-16,15-olide and 13( R )-hydroxy-octadeca-(9 Z ,11 E ,15 Z )-trien-oic acid by spectroscopic means. The algicidal activity of these compounds was tested against Raphidocelis subcapitata . Based on our previous study of Potamogeton pectinatus , other constituents were identified in P. lucens by LC–UV–MS, LC–NMR and GC–MS. The lipophilic extract profiles of both species are presented. Two other species, Potamogeton perfoliatus and P. crispus, were also investigated by analytical comparison of their non-polar extracts. The distribution of ent -Labdanes characterized in Potamogeton is summarized.
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ent Labdane diterpenes from the aquatic plant potamogeton pectinatus
Phytochemistry, 2003Co-Authors: Patrice Waridel, Jean-luc Wolfender, Jean-bernard Lachavanne, Kurt HostettmannAbstract:Four new ent-Labdane diterpenes were isolated from the freshwater aquatic plant Potamogeton pectinatus, together with two known furano-ent-Labdanes. The new compounds were assigned the structures methyl-15,16-epoxy-12(R)-acetoxy- 8(17),13(16),14-ent-labdatrien-19-oate, 15,16-epoxy-12(R)-acetoxy-8(17),13(16),14-ent-labdatrien-19-oic acid, 8(17),13-ent-labdadien-15 --> 16-lactone-19-oic acid and 16-hydroxy-8(17),13-ent-labdadien-15,16-olid-19-oic acid by spectroscopic means. Some of these Labdanes showed a strong algicidal activity against Raphidocelis subcapitata. (C) 2003 Elsevier Ltd. All rights reserved.
Hermann M. Niemeyer - One of the best experts on this subject based on the ideXlab platform.
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Seco-, nor-, normal and rearranged Labdanes fromHaplopappus parvifolius
Phytochemistry, 2001Co-Authors: Christa Zdero, Ferdinand Bohlmann, Hermann M. NiemeyerAbstract:Abstract The aerial parts of Haplopappus parvifolius afforded 30 new diterpenes including 21 Labdane derivatives, four nor -diterpenes, three rearranged ones, four seco -Labdanes and one with a new carbon skeleton whose structure was established by partial synthesis. All structures were elucidated by high field NMR spectroscopy and other spectroscopic techniques. Biogenetic relationships are discussed briefly.
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diterpenes and umbelliferone derivatives from haplopappus deserticola
Phytochemistry, 1990Co-Authors: Christa Zdero, Ferdinand Bohlmann, Hermann M. NiemeyerAbstract:Abstract The aerial parts of Haplopappus deserticola afforded three ent -Labdane and one Labdane derivative as well as a nor - ent -Labdane. Furthermore, in addition to three known umbelliferone derivatives, a dimeric coumarin was isolated. The structures were elucidated by high field 1 H NMR spectroscopy.
Lixia Chen - One of the best experts on this subject based on the ideXlab platform.
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unusual ent Labdane diterpenoid dimers and their selective activation of trpv channels
Journal of Organic Chemistry, 2019Co-Authors: Dun Wang, Xinxin Chen, Tianyu Li, Hao Chai, Jiamin Xu, Hua Li, Yang Li, Lixia ChenAbstract:Five unusual dimers of ent-Labdane diterpenoids (1–5) were isolated and identified from Andrographis paniculata, a famous medicinal plant. Bisandrographolide E (1) represents the first example of a...
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ent Labdane diterpenoid lactone stereoisomers from andrographis paniculata
Journal of Natural Products, 2008Co-Authors: Lixia Chen, Kailan Zhou, Rui Wang, Yongkui JingAbstract:Two pairs of ent-Labdane diterpenoid lactone stereoisomers (1−4) including three new compounds (1−3) were isolated from the 85% EtOH extract of the aerial parts of Andrographis paniculata. The structures of these compounds were identified as 7R-hydroxy-14-deoxyandrographolide (1), 7S-hydroxy-14-deoxyandrographolide (2), 12S,13S-hydroxyandrographolide (3), and 12R,13R-hydroxyandrographolide (4) by spectroscopic data analyses and calculated 13C NMR data at the B3LYP/6-311++G(2d,p)//B3LYP/6-31G* level using the GIAO method. The 12S-configuration of 4 was revised to 12R based on the spectroscopic data. The antiproliferative activities of the two pairs of stereoisomers and 14 other ent-Labdane diterpenoid derivatives were determined in human leukemia HL-60 cells. Andrographolide (7) and isoandrographolide (12) exhibited higher antiproliferative activities than other ent-Labdane diterpenoids with GI50ʼs of 9.33 and 6.30 µM, respectively.
