- In vivo Structure-Activity Relationship of Dihydromethysticin in Reducing Nicotine-Derived Nitrosamine Ketone (NNK)-Induced Lung DNA Damage against Lung Carcinogenesis in A/J Mice
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Lung cancer is the leading cause of cancer-related deaths and chemoprevention should be developed. We recently identified dihydromethysticin (DHM) as a promising candidate to prevent NNK-induced lung tumorigenesis. To probe its mechanisms and facilitate its future translation, we investigated the structure-activity relationship of DHM on NNK-induced DNA damage in A/J mice. Twenty DHM analogs were designed and synthesized. Their activity in reducing NNK-induced DNA damage in the target lung tissues was evaluated. The unnatural enantiomer of DHM was identified to be more potent than the natural enantiomer. The methylenedioxy functional moiety did not tolerate modifications while the other functional groups (the lactone ring and the ethyl linker) accommodated various modifications. Importantly, analogs of high structural similarity to DHM with distinct efficacy in reducing NNK-induced DNA damage have been identified. They will serve as chemical probes to elucidate the mechanisms of DHM in blocking NNK-induced lung carcinogenesis.
- Hati, Santanu,Hu, Qi,Huo, Zhiguang,Lu, Junxuan,Xing, Chengguo
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- Soft template-based bismuth doped zinc oxide nanocomposites for photocatalytic depolymerization of lignin
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Lignin depolymerization is a growing research area for the synthesis of aromatic molecules. In current studies, photocatalytic lignin depolymerization has been investigated by designing a series of soft template-based Zn0.95Bi0.05O nano-materials (SK1-SK5). Synthesized nano-materials were characterized by PXRD, SEM/EDX, BET, FTIR and utilized for photocatalytic lignin depolymerization in the presence of direct sunlight. Lignin depolymerization was monitored by UV–Visible Spectroscopy and catalytic pathway analyzed by different kinetic models. Percent depolymerization was studied for the effect of catalyst dose, starting lignin concentration and different temperatures. Pseudo second order was found the best fitted kinetic model indicating chemically rate controlled mechanism. Activation energy (Ea) for the reaction was found to be 11 kJ/mol that is remarkably lower than conventional lignin depolymerization i.e. 59.75 kJ/mol depicting better catalytic efficiencies of tested materials. Lignin depolymerization products were characterized by HPLC and FTIR Spectroscopy and their analysis indicated the conversion of lignin into smaller subunits like syringaldehyde, sinapyl alcohol, phthalates, and 4-hydroxy-benzoic acid. Specifically, phenol (21%) and 2-methoxy-4-methylphenol (16%) were detected by GCMS analysis in the products of lignin depolymerization by SK2.
- Kausar, Samia,Ali Altaf, Ataf,Hamayun, Muhammad,Danish, Muhammad,Zubair, Muhammad,Naz, Sumbal,Muhammad, Shabbir,Zaheer, Muhammad,Ullah, Shafiq,Badshah, Amin
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- Rhodium catalyzed selective hydroaminomethylation of biorenewable eugenol under aqueous biphasic condition
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This work reports a highly regioselective hydroaminomethylation of eugenol, anethole and estragole with piperidine in aqueous medium. This catalytic system was composed of rhodium complexes stabilized by trisulfonated triphenylphosphine (TPPTS) and of a native or chemically modified cyclodextrins. Various cyclodextrins such as α-cyclodextrins (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), 2-hydroxy-propyl β-cyclodextrin (hp-β-CD) and RAndomly MEthylated β-cyclodextrin (RAME-β-CD) have been tested. The effect of different parameters such as syngas pressure, time, temperature, catalyst precursor/loading and the ratio of Metal/Ligand/Cyclodextrin were also investigated. The addition of cyclodextrins as a mass transfer agent remarkably increased the rate reaction and the selectivity of linear amines, specially in the case of RAME-β-CD. So, the Rh/TPPTS/RAME-β-CD as a catalyst exhibited high conversion (92%) and selectivity (79.2%) towards the linear amine as major product under mild conditions. Finally, the catalytic system was recycled up to five times without a significant loss in activity and selectivity.
- Jagtap, Samadhan A.,Gowalkar, Shilpa P.,Monflier, Eric,Ponchel, Anne,Bhanage, Bhalchandra M.
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p. 108 - 116
(2018/04/17)
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- Tobacco smoke chemistry. 2. Alkyl and alkenyl substituted guaiacols found in cigarette smoke condensate.
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A series of alkyl and alkenyl substituted guaiacols, which comprise a group of biologically and organoleptically active compounds, have been synthesized. Mass spectra and GC retention times for these have been recorded and compared with those obtained for constituents of a weakly acidic fraction of smoke condensate derived from American blend type cigarettes. On the basis of these results, 25 guaiacols have been identified, 18 of which have not been detected in tobacco smoke condensate previously.
- Arnarp,Bielawski,Dahlin,Dahlman,Enzell,Pettersson
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