Estudo de plantas medicinais do cerrado em busca de substâncias bioativas e o potencial anti-leishmania de Momordica charantia LINN

Abstract

Natural products are still the main source of innovation of therapeutic agents and allies to the traditional knowledge become key tools in the search of pharmacologically active compounds. For these reasons the objective of this study was to evaluate the biological activities of plant species used by the population of the region of Cerrado in the state of Mato Grosso do Sul in the search for bioactive substances and assess the potential antileishmanial of specie Momordica charantia. We collected 14 species in the Region of Bonito (MS), of which we obtained 23 ethanol extracts gross. These extracts were subjected to bioassay of antibacterial activity (Staphylococcus aureus and Pseudomonas aeruginosa) and antifungal (Candida albicans, C. krusei and C. neoformans) by the method of microdilution, antileishmanial in promastigotes of Leishmania amazonensis strain, cytotoxicity on Artemia salina and antiradicalar on the ability of DPPH scavenging. Of the 14 species tested, 12, that is, 85.7% of the species was moderate to high activity in at least one of the activities evaluated. Of these, the kind Momordica charantia showed an activity that is very significant as the antileishmanial activity and therefore was selected for study bioguided. This extract was subjected to chromatographic techniques of separation, including column chromatography on silica gel, Sephadex LH-20, preparative and high performance liquid chromatography in reverse phase. The structural determinations were made on the basis of spectroscopic data of 'H NMR, 13C and and bidimensional techniques NOESY, COZY, HMQC, HSQC, and comparative DEPT 135° analysis with the data in the literature. The bioassay-guided chemical study of the extract of Momordica charantia it lead to the isolation of six substances, being that four correspond the two pairs of stereoisomers and had been characterized as 25-methoxy-3ẞ, 7ẞ- dihydroxycucurbita-5,23 (E) - dien-19-al; 3β. 7β, 25-trihydroxycucurbita-5,23 (E) - dien-19-al, isomers (19R, 23E) and (19S, 23E) - 5β, 19-Epoxy-19,25-dimethoxycucurbita-6,23-dien-3ẞ-ol and isomers (19R, 23E) e (19S, 23E) 5β, 19-Epoxy-19-methoxycucurbita-6,23-dien-3ẞ, 25-diol; presenting a IC50 in the band of 4,6 the 5,2 µg/mL. These data indicate not to exist a specific substance for action antipromastigota, but yes the promising classroom of antileishmania called substance action generically of cucurbitacins.