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Reto Brun - One of the best experts on this subject based on the ideXlab platform.

  • Alkamides from Anacyclus pyrethrum L. and Their in Vitro Antiprotozoal Activity.
    Molecules, 2017
    Co-Authors: J B Althaus, Reto Brun, Marcel Kaiser, Claudine Malyszek, Thomas J. Schmidt
    Abstract:

    In our ongoing study to evaluate the Antiprotozoal Activity of alkamides from Asteraceae, a dichloromethane extract from the roots of Anacyclus pyrethrum L. showed a moderate in vitro Activity against the NF54 strain of Plasmodium falciparum and against Leishmania donovani (amastigotes, MHOM/ET/67/L82 strain). Seven pure alkamides and a mixture of two further alkamides were isolated by column chromatography followed by preparative high performance liquid chromatography. The alkamides were identified by mass- and NMR-spectroscopic methods as tetradeca-2E,4E-dien-8,10-diynoic acid isobutylamide (anacycline, 1), deca-2E,4E-dienoic acid isobutylamide (pellitorine, 2), deca-2E,4E,9-trienoic acid isobutylamide (3), deca-2E,4E-dienoic acid 2-phenylethylamide (4), undeca-2E,4E-dien-8,10-diynoic acid isopentylamide (5), tetradeca-2E,4E,12Z-trien-8,10-diynoic acid isobutylamide (6), and dodeca-2E,4E-dien acid 4-hydroxy-2-phenylethylamide (7). Two compounds—undeca-2E,4E-dien-8,10-diynoic acid 2-phenylethylamide (8) and deca-2E,4E-dienoic acid 4-hydroxy-2-phenylethylamide (9)—were isolated as an inseparable mixture (1:4). Compounds 3, 4, and 5 were isolated from Anacyclus pyrethrum L. for the first time. While compounds 4 and 5 were previously known from the genus Achillea, compound 3 is a new natural product, to the best of our knowledge. All isolated alkamides were tested in vitro for Antiprotozoal Activity against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Leishmania donovani and for cytotoxicity against L6 rat skeletal myoblasts.

  • Antiprotozoal Activity of dehydroabietic acid derivatives against Leishmania donovani and Trypanosoma cruzi
    MedChemComm, 2016
    Co-Authors: Mikko Vahermo, Marcel Kaiser, Reto Brun, Sara Krogerus, Abdelmajeed Nasereddin, Charles L. Jaffe, Jari Yli-kauhaluoma, Vânia M. Moreira
    Abstract:

    Derivatives of dehydroabietic acid bearing different amino acids scaffolds have potent Antiprotozoal Activity against Leishmania donovani and Trypanosoma cruzi, with good to high selectivity, and can therefore be regarded as good models for further development into new drugs to fight leishmaniasis and Chagas disease. Several of the tested compounds were able to kill parasites residing inside cells, with IC50 values ranging from 2.3 to 9 μM (L. donovani) and 1.4 to 5.8 μM (T. cruzi), reflecting their ability to fight these infections at the relevant stage responsible for disease. One of the compounds, bearing a 3-pyridyl-D-alanine side chain, was 1.5-fold more potent against T. cruzi amastigotes residing in L6 cells than the reference compound benznidazole.

  • Antiprotozoal Activity of bicycles featuring a dimethylamino group at their bridgehead.
    Bioorganic & Medicinal Chemistry, 2016
    Co-Authors: Johanna Faist, Marcel Kaiser, Reto Brun, Werner Seebacher, Robert Saf, Robert Weis
    Abstract:

    Several dimethylamino-derivatives of the new compound-class 3-azabicyclo[3.2.2]nonanes were prepared. For better comparison of Activity also a few analogues of bicyclo[2.2.2]octanes and 2-azabicyclo[3.2.2]nonanes were synthesized. Their activities were examined in vitro against the multiresistant K1 strain of Plasmodium falciparum and against Trypanosoma brucei rhodesiense (STIB 900). A couple of the newly synthesized compounds showed promising Antiprotozoal Activity and selectivity. The results of the biological tests of the novel compounds were compared with the activities of already synthesized compounds and of drugs in use. Structure-Activity relationships were discussed.

  • Antiprotozoal Activity of achillea ptarmica asteraceae and its main alkamide constituents
    Molecules, 2014
    Co-Authors: J B Althaus, Reto Brun, Marcel Kaiser, Thomas J. Schmidt
    Abstract:

    In the course of our ongoing screening of plants of the family Asteraceae for Antiprotozoal Activity, a CH2Cl2-extract from the flowering aerial parts of Achillea ptarmica L. (sneezewort yarrow) was found to be active in vitro against Trypanosoma brucei rhodesiense (IC50 = 0.67 µg/mL) and Plasmodium falciparum (IC50 = 6.6 μg/mL). Bioassay guided fractionation led to the isolation and identification of five alkamides from the most active fractions. Pellitorine and 8,9-Z-dehyropellitorine are the main components of the extract. Beside these olefinic acid amides, four alkamides with diene-diyne structures were isolated. All alkamides were tested for Antiprotozoal Activity in vitro. Pellitorine was the most active compound so far within this study against P. falciparum (IC50 = 3.3 µg/mL), while 8,9-Z-dehydropellitorine was most active against T. b. rhodesiense (IC50 = 2.0 µg/mL). The Activity of pure pellitorine against Plasmodium is higher than that of the crude extract and thus explains the Activity of the latter. None of the isolated alkamides, however, was as active against T. b. rhodesiense as the crude extract whose antitrypanosomal Activity must therfore be due to a synergistic effect of the isolated compounds or to more active yet to be identified constituents.

  • Antiprotozoal Activity of buxus sempervirens and Activity guided isolation of o tigloylcyclovirobuxeine b as the main constituent active against plasmodium falciparum
    Molecules, 2014
    Co-Authors: J B Althaus, Marcel Kaiser, Reto Brun, Gerold Jerz, Peter Winterhalter, Thomas J. Schmidt
    Abstract:

    Buxus sempervirens L. (European Box, Buxaceae) has been used in ethnomedicine to treat malaria. In the course of our screening of plant extracts for Antiprotozoal Activity, a CH2Cl2 extract from leaves of B. sempervirens showed selective in vitro Activity against Plasmodium falciparum (IC50 = 2.79 vs. 20.2 µg/mL for cytotoxicity against L6 rat cells). Separation of the extract by acid/base extraction into a basic and a neutral non-polar fraction led to a much more active and even more selective fraction with alkaloids while the fraction of non-polar neutral constituents was markedly less active than the crude extract. Thus, the Activity of the crude extract could clearly be attributed to alkaloid constituents. Identification of the main triterpene-alkaloids and characterization of the complex pattern of this alkaloid fraction was performed by UHPLC/+ESI-QTOF-MS analyses. ESI-MS/MS target-guided larger scale preparative separation of the alkaloid fraction was performed by 'spiral coil-countercurrent chromatography'. From the most active subfraction, the cycloartane alkaloid O-tigloylcyclovirobuxeine-B was isolated and evaluated for antiplasmodial Activity which yielded an IC50 of 0.455 µg/mL (cytotoxicity against L6 rat cells: IC50 = 9.38 µg/mL). O-tigloylcyclovirobuxeine-B is thus most significantly responsible for the high potency of the crude extract.

Thomas J. Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Salvia Species as Sources of Natural Products with Antiprotozoal Activity
    International Journal of Molecular Sciences, 2018
    Co-Authors: Núria Llurba-montesino, Thomas J. Schmidt
    Abstract:

    Natural products from plants have been used since ancestral times to treat a wide variety of diseases worldwide. Plants of the genus Salvia (Sage) have been reported to be used for the prevention and treatment of various diseases and ailments. In particular, some Salvia species have been used in traditional medicine to treat diseases caused by protozoan parasites of the genera Trypanosoma, Leishmania and Plasmodium and scientific studies have demonstrated the Activity of various isolated constituents from these plants against these pathogens. The current review attempts to give a critical overview of published information about the Antiprotozoal Activity of species of the genus Salvia and their chemical constituents. It is meant to give a unified overview of these results in order to avoid repetitions caused, e.g., by limited access to some primary reports, and to stimulate further research to possibly facilitate the development of new molecular leads against protozoal neglected tropical diseases (NTDs) based on Salvia constituents.

  • Alkamides from Anacyclus pyrethrum L. and Their in Vitro Antiprotozoal Activity.
    Molecules, 2017
    Co-Authors: J B Althaus, Reto Brun, Marcel Kaiser, Claudine Malyszek, Thomas J. Schmidt
    Abstract:

    In our ongoing study to evaluate the Antiprotozoal Activity of alkamides from Asteraceae, a dichloromethane extract from the roots of Anacyclus pyrethrum L. showed a moderate in vitro Activity against the NF54 strain of Plasmodium falciparum and against Leishmania donovani (amastigotes, MHOM/ET/67/L82 strain). Seven pure alkamides and a mixture of two further alkamides were isolated by column chromatography followed by preparative high performance liquid chromatography. The alkamides were identified by mass- and NMR-spectroscopic methods as tetradeca-2E,4E-dien-8,10-diynoic acid isobutylamide (anacycline, 1), deca-2E,4E-dienoic acid isobutylamide (pellitorine, 2), deca-2E,4E,9-trienoic acid isobutylamide (3), deca-2E,4E-dienoic acid 2-phenylethylamide (4), undeca-2E,4E-dien-8,10-diynoic acid isopentylamide (5), tetradeca-2E,4E,12Z-trien-8,10-diynoic acid isobutylamide (6), and dodeca-2E,4E-dien acid 4-hydroxy-2-phenylethylamide (7). Two compounds—undeca-2E,4E-dien-8,10-diynoic acid 2-phenylethylamide (8) and deca-2E,4E-dienoic acid 4-hydroxy-2-phenylethylamide (9)—were isolated as an inseparable mixture (1:4). Compounds 3, 4, and 5 were isolated from Anacyclus pyrethrum L. for the first time. While compounds 4 and 5 were previously known from the genus Achillea, compound 3 is a new natural product, to the best of our knowledge. All isolated alkamides were tested in vitro for Antiprotozoal Activity against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Leishmania donovani and for cytotoxicity against L6 rat skeletal myoblasts.

  • Antiprotozoal Activity of achillea ptarmica asteraceae and its main alkamide constituents
    Molecules, 2014
    Co-Authors: J B Althaus, Reto Brun, Marcel Kaiser, Thomas J. Schmidt
    Abstract:

    In the course of our ongoing screening of plants of the family Asteraceae for Antiprotozoal Activity, a CH2Cl2-extract from the flowering aerial parts of Achillea ptarmica L. (sneezewort yarrow) was found to be active in vitro against Trypanosoma brucei rhodesiense (IC50 = 0.67 µg/mL) and Plasmodium falciparum (IC50 = 6.6 μg/mL). Bioassay guided fractionation led to the isolation and identification of five alkamides from the most active fractions. Pellitorine and 8,9-Z-dehyropellitorine are the main components of the extract. Beside these olefinic acid amides, four alkamides with diene-diyne structures were isolated. All alkamides were tested for Antiprotozoal Activity in vitro. Pellitorine was the most active compound so far within this study against P. falciparum (IC50 = 3.3 µg/mL), while 8,9-Z-dehydropellitorine was most active against T. b. rhodesiense (IC50 = 2.0 µg/mL). The Activity of pure pellitorine against Plasmodium is higher than that of the crude extract and thus explains the Activity of the latter. None of the isolated alkamides, however, was as active against T. b. rhodesiense as the crude extract whose antitrypanosomal Activity must therfore be due to a synergistic effect of the isolated compounds or to more active yet to be identified constituents.

  • Antiprotozoal Activity of buxus sempervirens and Activity guided isolation of o tigloylcyclovirobuxeine b as the main constituent active against plasmodium falciparum
    Molecules, 2014
    Co-Authors: J B Althaus, Marcel Kaiser, Reto Brun, Gerold Jerz, Peter Winterhalter, Thomas J. Schmidt
    Abstract:

    Buxus sempervirens L. (European Box, Buxaceae) has been used in ethnomedicine to treat malaria. In the course of our screening of plant extracts for Antiprotozoal Activity, a CH2Cl2 extract from leaves of B. sempervirens showed selective in vitro Activity against Plasmodium falciparum (IC50 = 2.79 vs. 20.2 µg/mL for cytotoxicity against L6 rat cells). Separation of the extract by acid/base extraction into a basic and a neutral non-polar fraction led to a much more active and even more selective fraction with alkaloids while the fraction of non-polar neutral constituents was markedly less active than the crude extract. Thus, the Activity of the crude extract could clearly be attributed to alkaloid constituents. Identification of the main triterpene-alkaloids and characterization of the complex pattern of this alkaloid fraction was performed by UHPLC/+ESI-QTOF-MS analyses. ESI-MS/MS target-guided larger scale preparative separation of the alkaloid fraction was performed by 'spiral coil-countercurrent chromatography'. From the most active subfraction, the cycloartane alkaloid O-tigloylcyclovirobuxeine-B was isolated and evaluated for antiplasmodial Activity which yielded an IC50 of 0.455 µg/mL (cytotoxicity against L6 rat cells: IC50 = 9.38 µg/mL). O-tigloylcyclovirobuxeine-B is thus most significantly responsible for the high potency of the crude extract.

  • natural product derived Antiprotozoal agents synthesis biological evaluation and structure Activity relationships of novel chromene and chromane derivatives
    Journal of Medicinal Chemistry, 2013
    Co-Authors: Dipak Harel, Thomas J. Schmidt, Reto Brun, Dirk Schepmann, Helge Prinz, Bernhard Wunsch
    Abstract:

    Various natural products with the chromane and chromene scaffold exhibit high Antiprotozoal Activity. The natural product encecalin (7) served as key intermediate for the synthesis of different ethers 9, amides 11, and amines 12. The chromane analogues 14 and the phenols 15 were obtained by reductive amination of ketones 13 and 6, respectively. Angelate 3, ethers 9, and amides 11 did not show considerable Antiprotozoal Activity. However, the chromene and chromane derived amines 12, 14, and 15 revealed promising Antiprotozoal Activity and represent novel lead compounds. Whereas benzylamine 12a and α-methylbenzylamine 12g were active against P. falciparum with IC50 values in the range of chloroquine, the analogous phenols 15a and 15b were unexpectedly 10- to 25-fold more potent than chloroquine with selectivity indexes of 6760 and 1818, respectively. The phenylbutylamine 14d based on the chromane scaffold has promising Activity against T. brucei rhodesiense and L. donovani.

Marcel Kaiser - One of the best experts on this subject based on the ideXlab platform.

  • Phototemtide A, a Cyclic Lipopeptide Heterologously Expressed from Photorhabdus temperata Meg1, Shows Selective Antiprotozoal Activity.
    ChemBioChem, 2020
    Co-Authors: Lei Zhao, Marcel Kaiser, Helge B. Bode
    Abstract:

    A new cyclic lipopeptide, phototemtide A (1), was isolated from Escherichia coli expressing the biosynthetic gene cluster pttABC from Photorhabdus temperata Meg1. The structure of 1 was elucidated by HR-ESI-MS and NMR experiments. The absolute configurations of amino acids and 3-hydroxyoctanoic acid in 1 were determined by using the advanced Marfey's method and comparison after total synthesis of 1, respectively. Additionally, three new minor derivatives, phototemtides B-D (2-4), were identified by detailed HPLC-MS analysis. Phototemtide A (1) showed weak Antiprotozoal Activity against Plasmodium falciparum, with an IC50 value of 9.8 μm. The biosynthesis of phototemtides A-D (1-4) was also proposed.

  • Design, Synthesis, and Testing of Antiprotozoal Activity of Primin and Analogues
    Journal of Medicinal and Chemical Sciences, 2019
    Co-Authors: Hamid R. Nasiri, Marcel Kaiser, Betül Ceylan, Katharina F. Hohmann, Harald Schwalbe
    Abstract:

    A set of conformationally restricted analogues of the natural product primin were synthesized as potential Antiprotozoal agents. The synthesis utilizes quinone C-H functionalization methods to enable an efficient and easy access to primin analogues. The Antiprotozoal activities of this series were evaluated in a panel of parasites and compared with the natural product primin. For all synthesized primin analogues a potent in vitro Activity was found against the pathogen Trypanosoma brucei rhodesiense (IC50 < 0.05 µg/mL). The observed Antiprotozoal Activity is not related to production of reactive oxygen species (ROS). Initial results of the in vivo experiments with a T. b. rhodesiense rodent animal model of the human disease were also reported. Intraperitoneal injection administration of compound 7 resulted in complete clearance of T. b. rhodesiense in tested rodent animals 24 hours after the last treatment. Our results show that the primin scaffold represents a new scaffold for further development of potent inhibitors of Trypanosoma brucei rhodesiense.

  • Synthesis of Jacaranone-Derived Nitrogenous Cyclohexadienones and Their Antiproliferative and Antiprotozoal Activities.
    Molecules, 2018
    Co-Authors: Armin Presser, Marcel Kaiser, Robert Saf, Gunda Lainer, Nadine Kretschmer, Wolfgang Schuehly, Marc Manuel Kalt
    Abstract:

    The cytotoxic and Antiprotozoal activities of the phytoquinoide, jacaranone, and related compounds have been an ongoing topic in recent drug discovery. Starting from the natural product-derived cyclohexadienone scaffold, a series of nitrogen-containing derivatives were synthesized and subsequently evaluated for their antiproliferative and Antiprotozoal Activity. Anticancer potency was analyzed using different types of cancer cell lines: MDA-MB-231 breast cancer, CCRF-CEM leukemia, HCT-116 colon cancer, U251 glioblastoma, and, in addition, non-tumorigenic MRC-5 lung fibroblasts. Antiproliferative activities at micromolar concentrations could be shown. Antiprotozoal Activity was assessed against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. For all compounds, selectivity indices (SI) were calculated based on assessed cytotoxicity towards L6 cells. In addition, the structure-Activity-relationships and physicochemical parameters of these compounds are discussed.

  • Alkamides from Anacyclus pyrethrum L. and Their in Vitro Antiprotozoal Activity.
    Molecules, 2017
    Co-Authors: J B Althaus, Reto Brun, Marcel Kaiser, Claudine Malyszek, Thomas J. Schmidt
    Abstract:

    In our ongoing study to evaluate the Antiprotozoal Activity of alkamides from Asteraceae, a dichloromethane extract from the roots of Anacyclus pyrethrum L. showed a moderate in vitro Activity against the NF54 strain of Plasmodium falciparum and against Leishmania donovani (amastigotes, MHOM/ET/67/L82 strain). Seven pure alkamides and a mixture of two further alkamides were isolated by column chromatography followed by preparative high performance liquid chromatography. The alkamides were identified by mass- and NMR-spectroscopic methods as tetradeca-2E,4E-dien-8,10-diynoic acid isobutylamide (anacycline, 1), deca-2E,4E-dienoic acid isobutylamide (pellitorine, 2), deca-2E,4E,9-trienoic acid isobutylamide (3), deca-2E,4E-dienoic acid 2-phenylethylamide (4), undeca-2E,4E-dien-8,10-diynoic acid isopentylamide (5), tetradeca-2E,4E,12Z-trien-8,10-diynoic acid isobutylamide (6), and dodeca-2E,4E-dien acid 4-hydroxy-2-phenylethylamide (7). Two compounds—undeca-2E,4E-dien-8,10-diynoic acid 2-phenylethylamide (8) and deca-2E,4E-dienoic acid 4-hydroxy-2-phenylethylamide (9)—were isolated as an inseparable mixture (1:4). Compounds 3, 4, and 5 were isolated from Anacyclus pyrethrum L. for the first time. While compounds 4 and 5 were previously known from the genus Achillea, compound 3 is a new natural product, to the best of our knowledge. All isolated alkamides were tested in vitro for Antiprotozoal Activity against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Leishmania donovani and for cytotoxicity against L6 rat skeletal myoblasts.

  • Antiprotozoal Activity-Based Profiling of a Dichloromethane Extract from Anthemis nobilis Flowers.
    Journal of Natural Products, 2017
    Co-Authors: Maria De Mieri, Marcel Kaiser, Giannicola Monteleone, Isidor Ismajili, Matthias Hamburger
    Abstract:

    A dichlomethane extract of Anthemis nobilis flower cones showed promising in vitro Antiprotozoal Activity against Trypanosoma brucei rhodesiense and Leishmania donovani, with IC50 values of 1.43 ± 0.50 and 1.40 ± 0.07 μg/mL, respectively. A comprehensive profiling of the most active fractions afforded 19 sesquiterpene lactones, including 15 germacranolides, two seco-sesquiterpenes, one guaianolide sesquiterpene lactone, and one cadinane acid. Of these, 13 compounds were found to be new natural products. The compounds were characterized by extensive spectroscopic data analysis (1D and 2D NMR, HRMS, circular dichroism) and computational methods, and their in vitro Antiprotozoal Activity was evaluated. The furanoheliangolide derivative 15 showed high potency and selectivity in vitro against T. b. rhodesiense bloodstream forms (IC50 0.08 ± 0.01 μM; SI 63). In silico calculations were consistent with the drug-like properties of 15.

Simon L. Croft - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of the Antiprotozoal Activity of Galphimia glauca and the isolation of new nor-secofriedelanes and nor-friedelanes
    Journal of Natural Products, 2002
    Co-Authors: Maria Del Rayo Camacho, J. David Phillipson, Simon L. Croft, Dereck Marley, G. C. Kirby, David C. Warhurst
    Abstract:

    Four new terpenoids, comprising three nor-secofriedelanes (1-3) and one nor-friedelane (4), were isolated from Galphimia glauca, together with the known flavonol quercetin and the sterols stigmasterol and sitosterol 3-O-beta-D-glucoside. The structure elucidation of the new isolates was conducted by 1D and 2D NMR techniques. Compounds 1-4 were given the trivial names galphin A, galphin B, galphin C, and galphimidin, respectively. All isolates were tested for in vitro Antiprotozoal and cytotoxic activities. Quercetin was the only substance isolated that showed any Antiprotozoal Activity, and this was weak; the IC(50) values were 14 microM against Plasmodium falciparum K1, 13.2 microM against Trypanosoma brucei brucei, and 63.8 microM against Leishmania donovani. Quercetin was found to be inactive against KB cells (IC(50) = 295.8 microM).

  • in vitro Antiprotozoal Activity of extract and compounds from the stem bark of combretum molle
    Phytotherapy Research, 2001
    Co-Authors: Kaleab Asres, Franz Bucar, E Knauder, Vanessa Yardley, Howard Kendrick, Simon L. Croft
    Abstract:

    The Antiprotozoal Activity of the Ethiopian medicinal plant Combretum molle (R. Br. ex G. Don.) Engl & Diels (Combretaceae) was evaluated by in vitro testing against Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania donovani. The acetone fraction of the stem bark of this plant prepared by soxhlet extraction was inactive against the intracellular amastigotes of L. donovani and T. cruzi in murine peritoneal macrophages but showed significant Activity against extracellular T. b. rhodesiense blood stream form trypomastigotes and trophozoites of P. falciparum with IC(50) values of 2.19 and 8.17 microg/mL, respectively. Phytochemical examination of the bioactive fraction resulted in the isolation of two tannins and two oleanane-type pentacyclic triterpene glycosides. One of the tannins was identified as the ellagitannin, punicalagin, whilst the structure of the other (CM-A) has not yet been fully elucidated. The saponins that were characterized as arjunglucoside (also called 4-epi-sericoside) and sericoside displayed no Activity against any of the four species of protozoa tested. On the other hand, punicalagin and CM-A had IC(50) values of 1.75 and 1.50 microM, respectively, against T. b. rhodesiense and were relatively less toxic to KB cells (cytotoxic/Antiprotozoal ratios of 70 and 48, respectively). The tannins also showed intermediate Activity against P. falciparum, although their selectivity against these parasites was less favourable than the above. It appears that our findings are the first report of hydrolysable tannins exhibiting antitrypanosomal and antiplasmodial activities.

  • cytotoxicity of 2 2 6 2 terpyridine platinum ii complexes to leishmania donovani trypanosoma cruzi and trypanosoma brucei
    Journal of Medicinal Chemistry, 1999
    Co-Authors: Gordon Lowe, Vanessa Yardley, Anne Sophie Droz, Tirayut Vilaivan, George W. Weaver, Lindsay Tweedale, Jonathan M. Pratt, Peter Rock, Simon L. Croft
    Abstract:

    A range of (2,2‘:6‘,2‘ ‘-terpyridine)platinum(II) complexes are shown to possess Antiprotozoal Activity in vitro against Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei, the causative organisms of tropical diseases leishmaniasis and trypanosomiasis. The best compounds caused 100% and 78% inhibition of growth of the intracellular amastigote forms of L. donovani and T. cruzi, respectively, at a concentration of 1 μM and 100% inhibition of growth of the bloodstream trypomastigote forms of T. brucei at a concentration of 0.03 μM. The results obtained with complexes in which the fourth ligand to platinum(II) is capable of being substituted with a substitution inert hydroxyethanethiolate complex are compared. The ammine complexes show high Antiprotozoal Activity suggesting that the trans influence of the 2,2‘:6‘,2‘ ‘-terpyridine ligand has a profound effect on the ease of displacement of the fourth ligand in (2,2‘:6‘,2‘ ‘-terpyridine)platinum(II) complexes, although nonbonded interaction between ...

  • Cytotoxicity of (2,2':6',2''-terpyridine)platinum(II) complexes to Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei.
    Journal of Medicinal Chemistry, 1999
    Co-Authors: Gordon Lowe, Vanessa Yardley, Anne Sophie Droz, Tirayut Vilaivan, George W. Weaver, Lindsay Tweedale, Jonathan M. Pratt, Peter Rock, Simon L. Croft
    Abstract:

    A range of (2,2‘:6‘,2‘ ‘-terpyridine)platinum(II) complexes are shown to possess Antiprotozoal Activity in vitro against Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei, the causativ...

Fernando Calzada - One of the best experts on this subject based on the ideXlab platform.

  • Antiprotozoal Activity of Secondary Metabolites from Salvia circinata
    Revista Brasileira de Farmacognosia, 2020
    Co-Authors: Fernando Calzada, Elihu Bautista, Elizabeth Barbosa, Luis A. Salazar-olivo, Eva Alvidrez-armendáriz, Lilian Yépez-mulia
    Abstract:

    Salvia circinata Cav., Lamiaceae, is commonly used in Mexican traditional medicine to treat gastrointestinal ailments, including diarrhea. An acetone-soluble extract from the aerial parts of S. circinata was suspended in a 9:1 methanol–water mixture and fractionated by partition with hexane and EtOAc. The hexane, EtOAc, and aqueous fractions were evaluated for their Antiprotozoal activities, where the EtOAc-soluble fraction displayed the best Antiprotozoal Activity. Resolution of this fraction by chromatographic methods afforded the known diterpenoids amarissinins A–C ( 1 – 3 ), teotihuacanin ( 4 ), and amarisolide F ( 5 ), along with two flavones, apigenin ( 6 ) and 5,6-dihydroxy-7,3′,4′-trimethoxy flavone ( 7 ). Compound 7 was the most active one, with IC_50 values of 0.05 μM and 0.13 μM against Entamoeba histolytica and Giardia lamblia , respectively. Interestingly, it was even more active than metronidazole and emetine, used as positive controls. Compounds 1 – 6 showed moderate Antiprotozoal Activity with IC_50 values ranging from 23.9 to 67.8 μM against Entamoeba histolytica , and 39.4 to 127 μM against Giardia lamblia . These results provide evidence-based support for the traditional use of S. circinata , and suggest that the 5,6-dihydroxy-7,3′,4′-trimethoxy flavone ( 7 ) may have an important role in the antidiarrheal Activity of the plant. Graphical abstract

  • Antiprotozoal Activity of 8-acyl and 8-alkyl incomptine A analogs.
    Bioorganic & Medicinal Chemistry Letters, 2014
    Co-Authors: Elihu Bautista, Fernando Calzada, Lilian Yépez-mulia, Fabiola A. López-huerta, Alfredo Ortega
    Abstract:

    The activities of 11 C-8-O-acyl and alkyl analogs of the Antiprotozoal sesquiterpene lactone, incomptine A (1) against Entamoeba histolytica and Giardia lamblia, were determined. Here, the effects of different lengths and amounts of branching of the acyl and alkyl groups on the Antiprotozoal Activity of the synthesized incomptine A-analogs are reported.

  • Incomptines C and D, two heliangolides from Decachaeta incompta and their Antiprotozoal Activity.
    Planta Medica, 2012
    Co-Authors: Elihu Bautista, Fernando Calzada, Lilian Yépez-mulia, Marco Antonio Chávez-soto, Alfredo Ortega
    Abstract:

    Two new heliangolides, incomptines C (3) and D (4), were isolated from the leaves of Decachaeta incompta. The structures were established by spectroscopic methods and confirmed by X-ray crystallography. The Antiprotozoal Activity of incomptines C and D was evaluated. Additionally, the chromatographic profile of the leaves and roots extracts were compared to identify incomptines A-D (1-4) in each extract.

  • Antiprotozoal Activity of flavonoids isolated from Mimosa tenuiflora (Fabaceae-Mimosoideae)
    Journal of the Mexican Chemical Society, 2011
    Co-Authors: Elihu Bautista, Fernando Calzada, Alfredo Ortega, Lilian Yépez-mulia
    Abstract:

    As result of the chemical study of the leaves and flowers of Mimosa tenuiflora (Willd.) Poir. (Fabaceae-Mimosoideae) eigth fla-vonoids were isolated: 6-methoxy-4'-O-methylnaringenin (1), santin (2), 6-methoxynaringenin (3), tenuiflorin A (4), 5, 7, 4'-trihydroxy-3, 6-dimethoxyflavone (5), 6-demethoxy-4'-O-methylcapilarisine (6), 6-methoxykaempferol (7) and tenuiflorin C (8). Antiprotozoal Activity of these compounds as well as the tenuiflorina B (9) and 6-desmethoxy-capilarisine (10), isolated in a previous study was assessed against Entamoeba histolytica and Giardia lamblia trophozoites.

  • Evaluation of the Antiprotozoal Activity of neo-clerodane type diterpenes from Salvia polystachya against Entamoeba histolytica and Giardia lamblia.
    Phytotherapy Research, 2009
    Co-Authors: Fernando Calzada, Elihu Bautista, Lilian Yépez-mulia, Amparo Tapia-contreras, Emma Maldonado, Alfredo Ortega
    Abstract:

    Chia (Salvia polystachya Ort., Lamiaceae) is frequently used in Mexican traditional medicine to treat dysentery. In this study the main neo-clerodane diterpenes (polystachynes A, B and D, as well as linearolactone) were isolated from the aerial parts of chia, and their Antiprotozoal activities toward Entamoebahistolytica and Giardia lamblia trophozoites were evaluated in vitro. Linearolactone was the most potent antiamoebic and antigiardial compound with IC50 values of 22.9 μM for E. histolytica and 28.2 μM for G. lamblia. Polystachynes A, B and D, showed moderate Antiprotozoal Activity against both protozoans with IC50 values ranging from 117.0 to 160.6 μM for E. histolytica and from 107.5 to 134.7 μM for G. lamblia. These data suggest that linearolactone may play an important role in the antidiarrhoeal Activity of S. polystachya. Copyright © 2009 John Wiley & Sons, Ltd.