- Anibamine and Its Analogues: Potent Antiplasmodial Agents from Aniba citrifolia
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In our continuing search for novel natural products with antiplasmodial activity, an extract of Aniba citrifolia was found to have good activity, with an IC50 value less than 1.25 μg/mL. After bioassay-directed fractionation, the known indolizinium alkaloid anibamine (1) and the new indolizinium alkaloid anibamine B (2) were isolated as the major bioactive constituents, with antiplasmodial IC50 values of 0.170 and 0.244 μM against the drug-resistant Dd2 strain of Plasmodium falciparum. The new coumarin anibomarin A (3), the new norneolignan anibignan A (5), and six known neolignans (7-12) were also obtained. The structures of all the isolated compounds were determined based on analyses of 1D and 2D NMR spectroscopic and mass spectrometric data, and the absolute configuration of anibignan A (5) was assigned from its ECD spectrum. Evaluation of a library of 28 anibamine analogues (13-40) indicated that quaternary charged analogues had IC50 values as low as 58 nM, while uncharged analogues were inactive or significantly less active. Assessment of the potential effects of anibamine and its analogues on the intraerythrocytic stages and morphological development of P. falciparum revealed substantial activity against ring stages for compounds with two C-10 side chains, while those with only one C-10 side chain exhibited substantial activity against trophozoite stages, suggesting different mechanisms of action.
- Du, Yongle,Valenciano, Ana Lisa,Dai, Yumin,Zheng, Yi,Zhang, Feng,Zhang, Yan,Clement, Jason,Goetz, Michael,Kingston, David G. I.,Cassera, Maria B.
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- Catalytic chain-breaking pyridinol antioxidants
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(Chemical Equation Presented) When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-pyridinols were readily regenerable by N-acetylcysteine contained in the aqueous phase. The best inhibitors quenched peroxyl radicals more efficiently than α-tocopherol, and the duration of inhibition was limited only by the availability of the thiol reducing agent. The compounds were also found to catalyze reduction of hydrogen peroxide in the presence of thiol reducing agent.
- Kumar, Sangit,Johansson, Henrik,Kanda, Takahiro,Engman, Lars,Mueller, Thomas,Jonsson, Mats,Pedulli, Gian Franco,Petrucci, Silvia,Valgimigli, Luca
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- The potential role of anibamine, a natural product CCR5 antagonist, and its analogues as leads toward development of anti-ovarian cancer agents
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Chemokines and their receptors play important roles in the development of primary tumors and their metastases. Particularly CC chemokine receptor 5 (CCR5) and its ligand CC chemokine ligand 5 (CCL5/RANTES) seem to be critical in proliferation and invasion of ovarian cancer, the leading cause of death from gynecological malignancies in the United States. Anibamine, the first natural product CCR5 antagonist, and its analogues were examined for their effects on proliferation of the OVCAR-3 ovarian cancer cells in order to validate their candidacy as leads to develop novel anti-ovarian cancer agents. Acting as CCR5 antagonists, anibamine and its analogues significantly suppressed CCL5-induced intracellular Ca2+ flux. The compounds also inhibited the proliferation of OVCAR-3 at micromolar to submicromolar range. Moreover, anibamine and several analogues did not show significant cytotoxicity in NIH 3T3 cells at concentrations up to 20 μM. Based on these results, anibamine and one of its synthetic analogues were defined as potential leads to develop novel agents against ovarian cancer.
- Zhang, Yan,Arnatt, Christopher K.,Zhang, Feng,Wang, Jiannan,Haney, Kendra M.,Fang, Xianjun
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p. 5093 - 5097
(2012/09/07)
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- Structure activity relationship studies of natural product chemokine receptor CCR5 antagonist anibamine toward the development of novel anti prostate cancer agents
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Recent studies have indicated that the CCR5 chemokine receptor may be a potential target for treating prostate cancer. Thus, development of CCR5 antagonists may provide novel prostate cancer therapy. Anibamine, a novel pyridine quaternary alkaloid isolated from Aniba sp., was found to effectively compete with 125I-gp120 in binding to the chemokine receptor CCR5, with an IC50 = 1 μM. Anibamine is the first natural product reported as a CCR5 antagonist, and thus provides a novel structural skeleton unique from other lead compounds that have generally been identified from high-throughput screening efforts. In order to refine the lead compound's structure and improve the therapeutic index of anibamine derivatives as potential anti prostate cancer agents, the approach of "deconstruction- reconstruction-elaboration" was applied in the structure-activity relationship studies of this work. Here, we report the design, syntheses and anti prostate cancer activities of anibamine and 17 analogues. The results from the in vitro and in vivo studies described here show that this class of compounds has potential to provide novel leads as anti prostate cancer agents.
- Zhang, Feng,Arnatt, Christopher K.,Haney, Kendra M.,Fang, Harrison C.,Bajacan, John E.,Zhang, Yan,Richardson, Amanda C.,Ware, Joy L.
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p. 395 - 408,14
(2020/07/30)
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- Catalytic chain-breaking pyridinol antioxidants
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(Chemical Equation Presented) The synthesis of 3-pyridinols carrying alkyltelluro, alkylseleno, and alkylthio groups is described together with a detailed kinetic, thermodynamic, and mechanistic study of their antioxidant activity. When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-pyridinols were readily regenerable by N-acetylcysteine contained in the aqueous phase. The best inhibitors quenched peroxyl radicals more efficiently than α-tocopherol, and the duration of inhibition was limited only by the availability of the thiol reducing agent. In homogeneous phase, inhibition of styrene autoxidation absolute rate constants kinh for quenching of peroxyl radical were as large as 1 x 107 M-1 s -1, thus outperforming the best phenolic antioxidants including α-tocopherol. Tellurium-containing 3-pyridinols could be quantitatively regenerated in homogeneous phase by N-tert-butoxycarbonyl cysteine methyl ester, a lipid-soluble analogue of N-acetylcysteine. In the presence of an excess of the thiol, a catalytic mode of action was observed, similar to the one in the two-phase system. Overall, compounds bearing the alkyltelluro moiety ortho to the OH group were much more effective antioxidants than the corresponding para isomers. The origin of the high reactivity of these compounds was explored using pulse-radiolysis thermodynamic measurements, and a mechanism for their unusual antioxidant activity was proposed. The tellurium-containing 3-pyridinols were also found to catalyze reduction of hydrogen peroxide in the presence of thiol reducing agents, thereby acting as multifunctional (preventive and chain-breaking) catalytic antioxidants.
- Kumar, Sangit,Johansson, Henrik,Kanda, Takahiro,Engman, Lars,Mueller, Thomas,Bergenudd, Helena,Jonsson, Mats,Pedulli, Gian Franco,Amorati, Riccardo,Valgimigli, Luca
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supporting information; experimental part
p. 716 - 725
(2010/06/13)
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- COMPOUNDS COMPRISING A 3-PYRIDINOL OR 5-PYRIMIDINOL RING HAVING AN ORGANOSELENO OR ORGANOTELLURO SUBSTITUENT FOR USE AS ANTIOXIDANTS
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Compounds comprising a 3-pyridinol or 5-pyrimidinol ring carrying an organoseleno- or organotelluro- substituent on the pyridine or pyrimidine ring, exhibit useful antioxidant properties. The compounds may for example be in accordance with the following formula (I) as defined herein. Catalytic chain-breaking and hydroperoxide decomposing antioxidant properties are also disclosed. Furthermore the compounds may be used in combination with a reducing agent. The compounds are useful for the stabilization of man-made and natural materials, or for the prevention or treatment of disorders caused by or involving free radical-mediated or oxidative tissue damage.
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Page/Page column 44
(2009/12/27)
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- NOVEL AMINOPYRIDINE DERIVATIVES AS mGIuR5 ANTAGONISTS
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The invention relates to novel aminopyridine derivatives of formula (I) wherein R1 is methyl an R4 and amino group NR6R7 and R5 forms an arylalkynyl- or heteroarylalkynyl-group. The compounds are useful in the p
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- Condensed Heteroaromatic Ring Systems. IV. Synthesis of Naphthyridine Derivatives by Cyclization of Aminopyridineacrylic Esters
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The reaction of aminohalopyridines with ethyl acrylate in the presence of palladium(II)acetate and triarylphosphine gave ethyl aminopyridineacrylates.The cyclization of the resulting acrylates under basic conditions gave naphthyridinones having a carbostyril-type moiety.Keywords- intramolecular cyclization; palladium catalyst; ethyl acrylate; naphthyridinone; pyridineacrylic ester
- Sakamoto, Takao,Kondo, Yoshinori,Yamanaka, Hiroshi
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p. 4764 - 4768
(2007/10/02)
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