Efeitos Biológicos de um Novo Oxifitoesterol Derivado da Ozonização do β-Sitosterol

Abstract

β-Sitosterol is one of the main phytosterols found in vegetable oils, which is widely consumed due to its ability to reduce the risk of atherosclerosis by inhibiting intestinal cholesterol absorption. However, the structural similarity to cholesterol, makes them susceptible to oxidation by reactive oxygen species, such as ozone, giving rise to oxyphytosterols. The mechanisms of action and biological effects of oxyphytosterols are still poorly investigated due to the complexity of synthesis, purification, and characterization of pure compounds. This study sought to investigate the biological effects and mechanisms of action of β-OX, the main oxyphytosterol derived from the β-Sitosterol ozonation, in human liver tumor HepG2 cells. HepG2 cells were seeded in coverslips with a final density of 4.8x104 cells/cm2 in DMEM Low Glucose medium and incubated for 72 h. The cells were exposed to β-Sito (0.5 μM) or β-OX (40 μM) for 48 h and morphological analysis was performed by immunoassay and confocal microscopy. Cells treated with 0.5 μM β-Sito did not show any alteration in the distribution of microtubules (MT) network, mitosis and nuclear morphology when compared to control. In contrast, treatment with β-OX 40 μM showed alterations in the MT network with more intense fluorescent staining on the periphery of the cytoplasm, with more round-shaped cells and presence of MT clusters compared to control. There was also a reduction in mitoses and altered nuclei with a retracted and irregular appearance. These results suggest that β-OX may be interfering with the formation of the mitotic spindle, causing the interruption of the cell cycle progression to mitosis. Alteration in nuclear morphology may also be associated with the destabilization of microtubules. Therefore, the results of this work are significant to elucidate the main mechanisms of action of β-OX, providing essential information for the understanding of possible adverse effects or its application as a potential therapeutic agent.