Efeito do tucumã (Astrocaryum aculeatum, Meyer) na citoproteção causada pelo estresse oxidativo e na modulação de células de leucemia promielocítica aguda

Abstract

Carotenoids are natural pigments soluble inversely associated with risk of a variety of diseases. In the Amazon region there is a wide variety of native fruits which are rich in carotenoids, which functional properties need to be clarified. This is the case of the fiber palm fruits (Astrocaryum aculeatum Mart.), regionally consumed. Therefore, we investigated the protective effects of ethanol extract isolated from the peel and the pulp of fruits tucumã against cytotoxicity and DNA damage induced by H2O2 in human lymphocytes and antiproliferative activity against the same cell lineage Acute Promyelocytic Leukemia (APL), NB4- APL, with and without concurrent exposure to all-trans retinoic acid (ATRA), drug used for the treatment of APL, thus constituting the subjects of the first and second article of this thesis. Firstly, the main chemical compounds present in the extracts were determined by chromatographic and spectrophotometric methods. The bark extract showed higher concentration of total polyphenols, flavonoids, alkaloids, tannins, β-carotene and quercetin than extract pulp of tucumã . Cultures of human lymphocytes with and without H2O2 and NB4 cells, APL was obtained after 72h and cell viability assay Picogreen® DNA, as well as the activity of caspase 1, 3 and 8 related to events of apoptosis was assessed by immunoassay tests. In cultures of human lymphocytes with and without H2O2 treated with the extracts of the skin and pulp of the present tucumã showed that both cytologic and genoprotetor effect especially in intermediate doses (300 to 900 ug / ml) when compared to lower and higher concentrations. The extracts were able to largely decrease the activity of caspases 1, 3 and 8 which were higher in cells exposed to H2O2. These results suggest a positive effect of tucumã in cells exposed to toxic compounds. When submitted to culture the LPA-NB4 cells to the treatment with the ethanolic extract of the pulp and the peel of tucumã 72 hours after the cell proliferation in concentrations greater than 600 mg / ml was effective at inhibiting cell proliferation. When NB4 cells were treated with ATRA showed a strong inhibitory effect as expected (14.5 ± 2.7% of control). Despite extracts also present tucumã antiproliferative effect on NB4 cells, this effect was more moderate than ATRA. The levels of caspases tested were shown to be higher in extracts of ATRA and tucumã indicating that it can trigger apoptosis in NB4 cells. These results suggest that fruits rich in retinoids may have cytotoxic effects against APL cells.