Silvia E. Asís

Diarylsemicarbazones: synthesis, antineoplastic activity and topoisomerase I inhibition assay

A series of diarylsemicarbazones was synthesized and tested against human neoplastic cell lines. The more active members have a l-naphthyl ring at the carbamidic nitrogen, and chloro, dimethylamino or nitro group substituents at the benzylidene moiety. None of these showed affinity to DNA. One of the more active compounds was tested as a topoisomerase I inhibitor and showed a potent effect. SAR studies demonstrated linear correlation between lypophilicity and activity on the most sensitive lines and a definite conformational shape for antineoplastic action.

Synthesis, trypanocidal activity and molecular modeling studies of 2-alkylaminomethylquinoline derivatives

Research and development of new drugs effective in the treatment of Trypanosoma cruzi infections are a real need for the 16 million people infected in the Americas. In a previous work, a quinoline derivative substituted by a 2-piperidylmethyl moiety showed to be active against Chagas disease and was considered a lead compound for further optimization. A series of ten analogous derivatives were tested against epimastigotes as a first approach. In view of their promising results, six of them were evaluated against the blood and intracellular replicative forms of the parasite in humans. Among them, compound 12 which possesses a 6-acetamidohexylamino substituent showed remarkable improvement in activity against epimastigotes, trypomastigotes and amastigotes compared with the structure lead, as well as a good selectivity index for the two parasite stages present in humans. In addition, treatment of infected mice with compound 12 induced a significant reduction in parasitemia compared with non-treated mice. Molecular modeling studies were performed by computational methods in order to elucidate the factors determining these experimental bioactivities.

EVALUATION OF ANTIPARASITIC, ANTITUBERCULOSIS AND ANTIANGIOGENIC ACTIVITIES OF 3-AMINOQUINOLIN-2-ONE DERIVATIVES

Parasitic infections such as leishmaniasis, trypanosomiasis and malaria have significant impacts in third world countries and are the major reasons of mortality. In order to search a new class of antiprotozoal agent, a series of ten quinolin-2-one derivatives was tested in vitro against the parasites causative of malaria, leishmaniasis, sleeping sickness and Chagas´ disease. In general, these compounds exhibited moderate activity against Plasmodium falciparum and showed no activity against Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Facing to establish a possible mechanism of antimalarial activity their binding to hemin was assayed. Furthermore, the need of developing new therapeutic strategies for the effective control of tuberculosis prompted us to assay twelve of these compounds against Mycobacterium tuberculosis but they did not demonstrate inhibitory activity. In addition, three terms resulted also structurally related to linomide, a recognized drug against angiogenesis, an interesting target for designing new antineoplastic agents. So these compounds were selected at the National Cancer Institute for angiogenesis testing and they exhibited similar activity to those recently reported for linomide and its analogues

Synthesis and evaluation of 2-(1H-indol-3-yl)-4-phenylquinolines as inhibitors of cholesterol esterase.

A series of 2-(substituted) phenyl and 2-indolyl quinoline derivatives (10a-l) was synthesized by an efficient microwave-assisted, trifluoroacetic acid-catalyzed, solvent-free method. Evaluation of the inhibitory activity led to the identification of two quinoline inhibitors of cholesterol esterase. 2-(1H-Indol-3-yl)-6-nitro-4-phenylquinoline (10l; IC50=1.98μM) was characterized as a mixed-type inhibitor with a pronounced competitive binding mode.

Microwave-assisted Synthesis of 2-Styrylquinoline-4-carboxylic Acids as Antitubercular Agents

BACKGROUND Many 2-substituted quinolines and especially 2-arylvinyl derivatives isolated from plants or prepared by synthesis have been designed from ethnopharmacological studies. OBJECTIVE In order to explore new aspects of the structure-antituberculosis activity relationship, a series of styrylquinoline derivatives was prepared. METHOD A series of styrylquinoline derivatives was prepared from quinaldic acid and a variety of arylbenzaldehydes under eco-friendly conditions via Knoevenagel reaction and trifluoroacetic acid (TFA) as catalyst. RESULTS The products were obtained in short reaction times and good yields and were evaluated for growth inhibitory activity towards Mycobacterium tuberculosis H37Rv (Mtb) through the National Institute of Allergy and Infectious Diseases (NIAID, USA). CONCLUSION Three compounds had activity under aerobic conditions.