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Kajal Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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First report of dual cyclooxygenase-2 and 5-lipoxygenase inhibitory halogen derivatives from the thallus of intertidal seaweed Kappaphycus alvarezii
Medicinal Chemistry Research, 2018Co-Authors: Fasina Makkar, Kajal ChakrabortyAbstract:Two halogen derivatives, characterized as 2-butyl-7-4-(chloromethyl) cyclooct-1-enyl) hept-5-en-1-ol (compound 1 ) and 4-(2-chloroethyl)-5-7-(methoxymethyl) undec-3-enyl) cyclooct-4-enone (compound 2 ) were isolated from the ethyl acetate-methanol extract of the intertidal red seaweed Kappaphycus alvarezii . The studied compounds were evaluated for their inhibitory effects towards pro-inflammatory 5-lipoxygenase along with cyclooxygenases, and also were determined the free radical scavenging potential. The halogenated cyclooctenone (compound 2 ) displayed greater 5-lipoxygenase (IC_50 0.90 mg mL^−1) inhibitory activity when compared to the non steroidal anti-inflammatory drug ibuprofen (IC_50 0.93 mg mL^−1). Similarly selectivity indices of the studied compounds were higher (anti-cyclooxygense-1 IC_50/anti-cyclooxygense-2 IC_50 ~1.06–1.07) when compared to those displayed by ibuprofen (0.44) and aspirin (0.02). The antioxidative activities of the halogen derivatives were found to be greater (IC_50 0.50 mg mL^−1). This is the first report on structural characterization of unusual halogen analogues from K. alvarezii with dual cyclooxygenase-2 and 5-lipoxygenase inhibitory activities.
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two rare antioxidative prenylated terpenoids from loop root asiatic mangrove rhizophora mucronata family rhizophoraceae and their activity against pro inflammatory cyclooxygenases and lipoxidase
Natural Product Research, 2017Co-Authors: Vamshi Krishna Raola, Kajal ChakrabortyAbstract:AbstractTwo new biogenic prenylated terpenoids were isolated from the methanol extract of Rhizophora mucronata. The extended C20 sesquiterpenoid with prenylated guaiane framework was characterised as (4E, 8Z)-3, 3a, 6, 7-tetrahydro-3, 9-dimethyl-5-(6-methylheptan-2-yl) cycloocta[b]furan-2-(9aH)-one (1). (35E)-1,2,3,5,6,6-icosahydro-4,4,8b,10,14,17,20,20-octamethylpicen-3-yl-34,35-dimethyloct-31-enoate (2) represents the first example of naturally occurring C40 prenylated oleanane-type triterpenoid, whereas one 4,5-dimethyloct-5-enoate side chain remains attached at C-3 position of the oleanane framework formed by the E-ring closure of C30 saccharide moiety. The structures of the compounds were elucidated using NMR and mass spectrometric analysis. Compound 1 was found to have significantly greater antioxidant activities (IC50 ~ 0.75 mg/mL) compared to 2 (IC50 > 0.80 mg/mL). No significant differences in anti-cyclooxygenase-2 of these compounds were discernable (IC50 0.8 – 0.9 mg/mL), whilst compound 1 show...
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Two rare antioxidative prenylated terpenoids from loop-root Asiatic mangrove Rhizophora mucronata (Family Rhizophoraceae) and their activity against pro-inflammatory cyclooxygenases and lipoxidase
2016Co-Authors: Vamshi Krishna Raola, Kajal ChakrabortyAbstract:Two new biogenic prenylated terpenoids were isolated from the methanol extract of Rhizophora mucronata. The extended C20 sesquiterpenoid with prenylated guaiane framework was characterised as (4E, 8Z)-3, 3a, 6, 7-tetrahydro-3, 9-dimethyl-5-(6-methylheptan-2-yl) cycloocta[b]furan-2-(9aH)-one (1). (35E)-1,2,3,5,6,6-icosahydro-4,4,8b,10,14,17,20,20-octamethylpicen-3-yl-34,35-dimethyloct-31-enoate (2) represents the first example of naturally occurring C40 prenylated oleanane-type triterpenoid, whereas one 4,5-dimethyloct-5-enoate side chain remains attached at C-3 position of the oleanane framework formed by the E-ring closure of C30 saccharide moiety. The structures of the compounds were elucidated using NMR and mass spectrometric analysis. Compound 1 was found to have significantly greater antioxidant activities (IC50 ~ 0.75 mg/mL) compared to 2 (IC50 > 0.80 mg/mL). No significant differences in anti-cyclooxygenase-2 of these compounds were discernable (IC50 0.8 – 0.9 mg/mL), whilst compound 1 showed greater anti-5-lipoxidase activities (IC50 ~ 0.8 mg/mL) those that of 2 (IC50 0.96 mg/mL). Bioactivities of the prenylated terpenoids were inversely proportional to lipophilic and bulk descriptors.
Hiroshi Suemune - One of the best experts on this subject based on the ideXlab platform.
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synthesis of optically active 9 oxabicyclo 3 3 1 nona 2 6 diene as a cycloocta 1 5 diene equivalent and the corresponding tetrol
Tetrahedron, 2000Co-Authors: Akira Takahashi, Masakazu Tanaka, Hiroshi SuemuneAbstract:Abstract Highly enantio- and diastereo-selective synthesis of C2-symmetric 9-oxabicyclo[3.3.1]nona-2,6-diene and the corresponding C2-symmetric 2,3,6,7-tetrol has been achieved starting from optically active 5-cyclooctene-1,2-diol prepared by an enzymatic procedure.
Vamshi Krishna Raola - One of the best experts on this subject based on the ideXlab platform.
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two rare antioxidative prenylated terpenoids from loop root asiatic mangrove rhizophora mucronata family rhizophoraceae and their activity against pro inflammatory cyclooxygenases and lipoxidase
Natural Product Research, 2017Co-Authors: Vamshi Krishna Raola, Kajal ChakrabortyAbstract:AbstractTwo new biogenic prenylated terpenoids were isolated from the methanol extract of Rhizophora mucronata. The extended C20 sesquiterpenoid with prenylated guaiane framework was characterised as (4E, 8Z)-3, 3a, 6, 7-tetrahydro-3, 9-dimethyl-5-(6-methylheptan-2-yl) cycloocta[b]furan-2-(9aH)-one (1). (35E)-1,2,3,5,6,6-icosahydro-4,4,8b,10,14,17,20,20-octamethylpicen-3-yl-34,35-dimethyloct-31-enoate (2) represents the first example of naturally occurring C40 prenylated oleanane-type triterpenoid, whereas one 4,5-dimethyloct-5-enoate side chain remains attached at C-3 position of the oleanane framework formed by the E-ring closure of C30 saccharide moiety. The structures of the compounds were elucidated using NMR and mass spectrometric analysis. Compound 1 was found to have significantly greater antioxidant activities (IC50 ~ 0.75 mg/mL) compared to 2 (IC50 > 0.80 mg/mL). No significant differences in anti-cyclooxygenase-2 of these compounds were discernable (IC50 0.8 – 0.9 mg/mL), whilst compound 1 show...
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Two rare antioxidative prenylated terpenoids from loop-root Asiatic mangrove Rhizophora mucronata (Family Rhizophoraceae) and their activity against pro-inflammatory cyclooxygenases and lipoxidase
2016Co-Authors: Vamshi Krishna Raola, Kajal ChakrabortyAbstract:Two new biogenic prenylated terpenoids were isolated from the methanol extract of Rhizophora mucronata. The extended C20 sesquiterpenoid with prenylated guaiane framework was characterised as (4E, 8Z)-3, 3a, 6, 7-tetrahydro-3, 9-dimethyl-5-(6-methylheptan-2-yl) cycloocta[b]furan-2-(9aH)-one (1). (35E)-1,2,3,5,6,6-icosahydro-4,4,8b,10,14,17,20,20-octamethylpicen-3-yl-34,35-dimethyloct-31-enoate (2) represents the first example of naturally occurring C40 prenylated oleanane-type triterpenoid, whereas one 4,5-dimethyloct-5-enoate side chain remains attached at C-3 position of the oleanane framework formed by the E-ring closure of C30 saccharide moiety. The structures of the compounds were elucidated using NMR and mass spectrometric analysis. Compound 1 was found to have significantly greater antioxidant activities (IC50 ~ 0.75 mg/mL) compared to 2 (IC50 > 0.80 mg/mL). No significant differences in anti-cyclooxygenase-2 of these compounds were discernable (IC50 0.8 – 0.9 mg/mL), whilst compound 1 showed greater anti-5-lipoxidase activities (IC50 ~ 0.8 mg/mL) those that of 2 (IC50 0.96 mg/mL). Bioactivities of the prenylated terpenoids were inversely proportional to lipophilic and bulk descriptors.
Akira Takahashi - One of the best experts on this subject based on the ideXlab platform.
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synthesis of optically active 9 oxabicyclo 3 3 1 nona 2 6 diene as a cycloocta 1 5 diene equivalent and the corresponding tetrol
Tetrahedron, 2000Co-Authors: Akira Takahashi, Masakazu Tanaka, Hiroshi SuemuneAbstract:Abstract Highly enantio- and diastereo-selective synthesis of C2-symmetric 9-oxabicyclo[3.3.1]nona-2,6-diene and the corresponding C2-symmetric 2,3,6,7-tetrol has been achieved starting from optically active 5-cyclooctene-1,2-diol prepared by an enzymatic procedure.
Yves Gnanou - One of the best experts on this subject based on the ideXlab platform.
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Preparation of a polyethylene latex by catalytic hydrogenation of a polybuta-1,4-diene-based dispersion
Macromolecular Rapid Communications, 2005Co-Authors: Abraham Chemtob, Valérie Héroguez, Yves GnanouAbstract:Fully linear polyethylene-based latexes have been prepared by the hydrogenation of polybuta-1,4-diene dispersions. The latter were synthesized via dispersion ring-opening metathesis polymerization of cycloocta-1,5-diene, and hydrogenated using RuCl2(PPh3)(3) as catalyst, without any further treatment.. A high hydrogenation efficiency was achieved as demonstrated by different techniques including DSC, and H-1 NMR and FT-IR spectroscopy. The hydrogenation process Could be carried Out without detrimental effect oil particle size and colloidal stability as evidenced by optical microscopy and light scattering analysis.
