Objectives: 

Polyphenols, molecules with antioxidant properties, are ubiquitous in fruits, vegetables, and various plant-derived food and beverages that have been claimed to be beneficial for human health. Cork extracts containing polyphenols, such as ellagitannins, not only have shown a high antioxidant and antiradical activity, but also inhibitory effect on growth of several types of tumour cells. Herein, we evaluated the effect of different phenolic fractions of cork on apoptosis in the human leukaemia cell line HL-60.

Materials: 

The phenolic extractives of cork from Quercus suber L. were obtained following distinct organic solvent/water fractionation procedures. To evaluate the cell viability under treatment of phenolic fraction, DNA was propidium iodide (PI) stained to discriminate died cells from alive unstained cells. Caspase-3 activity was determined from cleavage of specific substrate and measured by spectrofluorimetry. Cell cycle phase distribution was analysed loading cells with PI by cytometry. Apoptotic and/or necrotic cell death were discriminated by flow cytometry using annexin-V FITC/PI.

Results: 

The effect of cork extractives on viability of HL-60 cells was doses- and time-dependent reaching the maximal toxicity after 72 hours of stimulation at 30 mg/ml total phenols present in the extractives. Cork extractives evoked caspase-3 activation. In line with this, cell cycle phases S and G2/M were arrested increasing the amount of cells in phase G0/G1, showing also cells containing hypodiploid DNA. Consistent results have been obtained when cells charged with annexin-V/PI, the polyphenolic extractives evoked apoptotic cell death in HL-60 cells.

Conclusions: 

The treatment with different cork extractives containing phenolic compounds induced a inhibition of cell growth inducing cell death by apoptosis in the human leukaemia cell line HL-60.

Supported by Fondos FEDER. Gobierno de Extremadura Subproyecto: PCJ100503. Proyecto: PCJ1005.