Síntese total da lisicamina e sua interação em modelos de membrana celular
Data
2022-04-04
Autores
Machado, André Campos 
Orientadores
Caseli, Luciano
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A lisicamina é um alcaloide encontrado principalmente em plantas do gênero Annona, e que possui atividade biológica para algumas linhagens celulares de câncer. A fim de explicar parte do seu mecanismo molecular de ação e também sua seletividade, o intuito deste trabalho foi sintetizá-la e testá-la em modelos de membrana celular de células saudáveis e de tumores. A síntese da lisicamina partiu da 2-(3,4-dimetoxifenil)etilamina e por meio de de oito etapas sintéticas o alcaloide foi obtido com 0,8% de rendimento global. A lisicamina e seus intermediários sintéticos foram purificados e caracterizados pelos seus valores de faixas de fusão e de fatores de retenção, bem como por meio de análises de RMN de 1H e de GC-MS. Utilizaram-se filmes de Langmuir de fosfolipídios para estudar a interação da lisicamina nem modelos de células saudáveis (DPPC, POPC, DOPC e MLF1 (35% DOPC, 30% DOPE, 20% esfingomielina e 15% colesterol)) e de células de câncer (DPPS, POPS, DOPS e MLF2 (35% DOPS, 30% DOPE, 20% esfingomielina e 15% colesterol). A lisicamina apresentou efeitos relevantes em todos os modelos, tal como avaliado por isotermas pressão superficial-área (π-A), estabilidade tensiométrica de monocamadas pré-comprimidas, microscopia no ângulo de Brewster (BAM) e espectroscopia de reflexão-absorção no infravermelho com modulação da polarização (PM-IRRAS). As isotermas π-A indicam um efeito de expansão da monocamada fosfolipídica com a incorporação da lisicamina, potencializada quando o número de insaturações presentes no fosfolipídio aumenta (tal como nos modelos das células saudáveis) e atenuada para os modelos de células tumorais. Observou-se que a lisicamina desempenha papel de estabilizar as monocamadas que possuem insaturações e de desestabilizar as que não possuem. As imagens de BAM ilustram o efeito macroscópio que a lisicamina tem no filme, apresentando diminuir a quantidade relativa de agregados nos modelos de terminação colina e não possuindo padrão nos modelos preparados com fosfolipídios com terminação polar com o grupo químico serina. Os resultados de PM-IRRAS indicam as principais interações que o alcaloide produz ao ser incorporado na monocamada, havendo efeitos antagônicos com relação a ordem configuracional quando comparado os modelos de membrana de células saudáveis com os de tumores.
Lysicamine is an alkaloid found mainly in plants of the Annona genus, which has biological activity for some cancer cell lines. In order to explain part of its molecular mechanism of action and also its selectivity, the aim of this work was to synthesize and test it in cell membrane models of healthy cells and tumors. The synthesis of lysicamine started with 2-(3,4-dimethoxyphenyl)ethylamine and through eight synthetic steps the alkaloid was obtained with 0,8% overall yield. Lysicamine and its synthetic intermediates were purified and characterized by their melting ranges and retention factors, as well as by means of 1H NMR and GC-MS analyses. Langmuir films of phospholipids were used to study the interaction of lysicamine in healthy cell models (DPPC, POPC, DOPC and MLF1 (35% DOPC, 30% DOPE, 20% sphingomyelin and 15% cholesterol)) and cancer cells. (DPPS, POPS, DOPS and MLF2 (35% DOPS, 30% DOPE, 20% sphingomyelin and 15% cholesterol). Lysicamine showed relevant effects in all models, as evaluated by surface pressure-area isotherms (π-A) , tensiometric stability of pre-compressed monolayers, Brewster angle microscopy (BAM) and polarization-modulated infrared absorption-reflection spectroscopy (PM-IRRAS).The π-A isotherms indicate an expansion effect of the phospholipid monolayer with the incorporation of lysicamine, potentiated when the number of unsaturations present in the phospholipid increases (as in healthy cell models) and attenuated for tumor cell models. It was observed that lysicamine plays a role in stabilizing the monolayers that p have unsaturations and to destabilize those that do not. The BAM images illustrate the macroscopic effect that lysicamine has on the film, showing a decrease in the relative amount of aggregates in the choline-terminated models and having no pattern in the models prepared with polar-terminated phospholipids with the chemical group serine. The PM-IRRAS results indicate the main interactions that the alkaloid produces when incorporated into the monolayer, with antagonistic effects regarding configurational order when comparing the membrane models of healthy cells with those of tumors.
Lysicamine is an alkaloid found mainly in plants of the Annona genus, which has biological activity for some cancer cell lines. In order to explain part of its molecular mechanism of action and also its selectivity, the aim of this work was to synthesize and test it in cell membrane models of healthy cells and tumors. The synthesis of lysicamine started with 2-(3,4-dimethoxyphenyl)ethylamine and through eight synthetic steps the alkaloid was obtained with 0,8% overall yield. Lysicamine and its synthetic intermediates were purified and characterized by their melting ranges and retention factors, as well as by means of 1H NMR and GC-MS analyses. Langmuir films of phospholipids were used to study the interaction of lysicamine in healthy cell models (DPPC, POPC, DOPC and MLF1 (35% DOPC, 30% DOPE, 20% sphingomyelin and 15% cholesterol)) and cancer cells. (DPPS, POPS, DOPS and MLF2 (35% DOPS, 30% DOPE, 20% sphingomyelin and 15% cholesterol). Lysicamine showed relevant effects in all models, as evaluated by surface pressure-area isotherms (π-A) , tensiometric stability of pre-compressed monolayers, Brewster angle microscopy (BAM) and polarization-modulated infrared absorption-reflection spectroscopy (PM-IRRAS).The π-A isotherms indicate an expansion effect of the phospholipid monolayer with the incorporation of lysicamine, potentiated when the number of unsaturations present in the phospholipid increases (as in healthy cell models) and attenuated for tumor cell models. It was observed that lysicamine plays a role in stabilizing the monolayers that p have unsaturations and to destabilize those that do not. The BAM images illustrate the macroscopic effect that lysicamine has on the film, showing a decrease in the relative amount of aggregates in the choline-terminated models and having no pattern in the models prepared with polar-terminated phospholipids with the chemical group serine. The PM-IRRAS results indicate the main interactions that the alkaloid produces when incorporated into the monolayer, with antagonistic effects regarding configurational order when comparing the membrane models of healthy cells with those of tumors.