RESUMO
INTRODUCTION: The first total synthesis of ω-phenyl Δ6 fatty acids (FA) and their cytotoxicity (A549) and leishmanicidal (L. infantum) activities are described. The novel 16-phenyl-6-hexadecynoic acid (1) and the known 16-phenylhexadecanoic acid (2) were synthesized in 7-8 steps with overall yields of 46 % and 41 %, respectively. The syntheses of the unprecedented 10-phenyl-6-decynoic acid (3), 10-cyclohexyl-6-decynoic acid (4) and 10-(4-methoxyphenyl)-6-decynoic acid (5) was also performed in 3 steps with 73-76 % overall yields. The use of lithium acetylide coupling enabled the 4-step synthesis of 10-phenyl-6Z-decenoic acid (6) with a 100 % cis-stereochemistry. The cytotoxicity of these novel FA was determined against A549 cells and L. infantum promastigotes and amastigotes. Among the ω-phenylated FA, the best cytotoxicity towards A549 was displayed by 1, with an IC50 of 18 ± 1 µM. On the other hand, among the C10 acids, the ω-cyclohexyl acid 4 presented the best cytotoxicity (IC50 = 40 ± 2 µM) towards A549. RESULTS: Based on caspase-3/7 studies neither of the FA induced apoptosis in A549, thus implying other mechanisms of cell death. CONCLUSION: The antileishmanial studies were performed with the top Leishmania donovani topoisomerase IB (LdTopIB) inhibitors, namely 1 and 2 (EC50 between 14 and 36 µM, respectively), acids that did not stabilize the cleavage complexes between LdTopIB and DNA. Acids 1 and 2 displayed cytotoxicity towards L. infantum amastigotes (IC50 = 3-6 µM) and L. infantum promastigotes (IC50 = 60- 70 µM), but low toxicity towards murine splenocytes. Our results identified 1 as the optimum ω- phenylated acid of the series.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Ácidos Graxos Ômega-6/síntese química , Ácidos Graxos Ômega-6/farmacologia , Leishmania infantum/efeitos dos fármacos , Inibidores da Topoisomerase I/farmacologia , Antineoplásicos/química , Antiprotozoários/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA Topoisomerases Tipo I/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Ácidos Graxos Ômega-6/química , Humanos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Inibidores da Topoisomerase I/síntese química , Inibidores da Topoisomerase I/químicaRESUMO
Porcelia macrocarpa (Warm.) R. E. Fries (Annonaceae) is an endemic plant in Brazil where its tasty pulp has been eaten fresh. The hexane extract from its flowers was subjected to chromatographic procedures to afford four acetylene derivatives identified as octadec-9-ynoic (stearolic acid - 1), (11E)-octadec-11-en-9-ynoic (santalbic acid - 2), 8-hydroxyoctadec-9,11-diynoic (3) and 8-hydroxyoctadec-17-en-9,11-diynoic (isanolic acid - 4) acids by NMR and HRESIMS. Among tested compounds against trypomastigote forms of T. cruzi, octadec-9-ynoic acid (1) displayed higher potential with IC50â¯=â¯27.6⯵M and a selectivity index (SI) higher than 7. Compounds 2 and 3 showed IC50 of approximately 60⯵M while compound 4 was inactive. The lethal action of the compound 1 was investigated using spectrofluorometric techniques to detect ROS content, plasma membrane permeability and plasma membrane potential by flow cytometry. Compound 1 showed no alteration in the production of ROS of treated trypomastigotes and no alteration of the plasma membrane permeability was observed as detected by the fluorescent probe SYTOX-green after 120â¯min of incubation. However, by using the potential-sensitive fluorescent probe DiSBAC2(3), compound 1 caused depolarization of the plasma membrane potential when compared to untreated parasites. Our results demonstrated the anti-T. cruzi effects of compounds 1-3 isolated from flowers of P. macrocarpa and indicated that the lethal effect of compound 1 in T. cruzi could be associated to the plasma membrane disturbance of the parasite.