Atividade citotóxica de Piper nigrum e Struthanthus marginatus. Estudo preliminar da correlação entre a citotoxicidade e hidrofobicidade da piperina e derivados sintéticos

Abstract

Chemical and biological studies of two plants were realized. The species Piper nigrum, commonly knowed as black pepper, is of great economic, ecological and pharmaceutic importance. Piperine, amide majority and prototype for the synthesis of analogous derivatives was obtained from the ethanolic extract of dried black pepper seeds. Cytotoxic proprieties of the extract, piperine, its analogous and derivatives were quantitavely evaluated against Ehrlich ascites carcinoma (EAC). The inhibitory value for cell viability of the EAC was approximately 49% for extract concentration of 25μg/ml. Piperine was less cytotoxic than its analogous and derivatives and its IC50 value was 108.23μM. Possible mechanisms for celular death induced by piperine, analogous and derivatives were analysed through expression of phosphatidylserine and of the lactate dehydrogenase. The cytotoxic activity of the above mentioned compounds were correlated with their hydrophobic parameters: molar refractivity (RMw) and theoretical partition coefficient (ClogP) values. The other plant analysed was Struthanthus marginatus, tropical mistletoe specie, less studied than Visco album, a very known and studied plant in Europe, due to its pharmaceutical properties and antitumoral activity. Chemical screening of hydro-alcoholic extracts of leaves, stem and haustorius of this plant were realized. Different classes of special metabolites such as tannins, flavonoids and alkaloids were detected in different intensities. The cytotoxic evaluation of this mistletoe was realized in fractions of different polarities.