Mikania laevigata: chemical characterization and selective cytotoxic activity of extracts on tumor cell lines.

Cancer is the second major cause of mortality worldwide, losing only to cardiovascular disease. Nowadays, around 50% of antineoplastic drugs were discovered and isolated by indications of plants in folk medicine. In Brazilian flora there are many species of plants which have great therapeutic importance, highlighting the Mikania laevigata (Asteraceae) that has been used for their valuable properties, especially in the respiratory tract. In the present study, the compounds of M. laevigata extracts were characterized by High Resolution Mass Spectrometry (HRMS) and Gas Chromatography with Mass analysis (GC/MS-EI). Therefore, the presence of some compounds with promising biological properties as antitumor activity was detected. Coumarin (1,2-benzopyrone) was previously reported as responsible for some biological activities of this plant species. Here, the extracts were evaluated by their cytotoxic activity against tumor (Hep-2, HeLa) and non tumor (MRC-5) cell lines, presenting significant inhibitory activity of cell growth in all extracts analyzed, chloroform, ethyl acetate, hexane, ethanol, which is related to its chemical composition. From the four different extracts here tested, two of them, hexane and ethanol, presented a clear selectivity against both tumor cells lines investigated. This can be explained by variances and increase of phenolic compounds in the ethanol fraction and an association of molecules with coumarin found in the hexane fraction.